Simpósio Internacional sobre Esquistossomose

Soluble Schistosoma mansoni Egg Antigens Induce Pathophysiological Changes in Murine Models

Gabriel Couto Thurler Klein — 2024-11-07

During Schistosoma mansoni infection, the parasite's eggs are retained in organs such as the liver, spleen and intestine, causing an inflammatory response through the formation of schistosomal granulomas. In previous studies, our research group used murine models to characterize the main pathophysiological changes associated with schistosomal granulomas, emphasizing that soluble egg antigens (SEA) may be critical in modulating these pathophysiological changes. To investigate this hypothesis, Schistosoma mansoni eggs were isolated from the liver of previously infected mice and used in the SEA extraction and purification protocol. SEA was injected into two groups of mice daily for four consecutive days at doses of 10 and 20 μg, and they were sacrificed 24 h after the last injection. In two other groups, we performed a single injection at a dose of 80 μg, and one group was sacrificed 24 and the other 96 h after the single injection. Livers, kidneys, spleens, and intestines were collected for histological analysis for all groups. Histological analysis of the liver using HE staining showed acute liver lesions, with intense intracytoplasmic vacuolization of the hepatocytes, with macrogoticular steatosis. We also noticed evidence of increased accumulation of blood in the hepatic canaliculi, which could be stasis and some hemorrhagic foci. To analyze the deposits of hepatic glycogen, we used PAS staining. This showed that there was a marked reduction in glycogen deposits in the cytoplasm of the hepatocytes. In the analysis of the histological slides of the kidneys using HE staining, we observed degradation of the renal ducts, renal stasis and hemorrhagic foci, typical features of renal lesions. Using PERLS staining, we observed imbalances in iron deposits in the spleen and liver. We noticed an accumulation of splenic iron, as well as a positive correlation between the dose of SEA injected and the amount of hemosiderin accumulated, suggesting an increase in erythrocyte death. When analyzing the histological sections of the livers, we observed an increase in iron accumulation in the hepatocytes of zones one, two and three. We also observed positive iron deposits by Kupffer cells according to the doses of SEA. No significant morphological changes were observed in the intestine. No macroscopic changes were observed in the material collected from these animals during necropsy. We can conclude that the total SEA of Schistosoma mansoni has various toxic and immunogenic components that induce pathophysiological changes in organs such as the liver and spleen.

Roles of the Schistosoma mansoni tyrosine kinase SmFES in schistosomiasis: Functional characterization and evaluation of compound activity

Gabriella Parreiras Torres — 2024-11-07

The SmFES protein kinase is hypothesized to play a key role in the signal transduction pathways of Schistosoma mansoni, particularly in larval transformation following host penetration. Our previous research identified SmFES as an essential protein for parasite reproduction, hepatic granuloma formation in a murine model, and attraction to host mucus molecules. In this study, first, we explored the function of SmFES in cell recruitment for granuloma formation, immune response, and potential strategies to disrupt the parasite's lifecycle. Thus, we assessed the impact of reduced liver granulomas on the survival of infected mice, observing a 23% increase in mortality compared to the nonspecific control group. Histological analysis of liver tissue revealed an increase in fibrosis and decreased cellular profile in the SmFES-knockdown group relative to controls. Then, to investigate immune factors associated with cell recruitment in the livers of mice infected with SmFES-depleted parasites, we measured TNF-α, IFN-γ, IL-10, IL-6, CCL2, and IL-12p70 levels in liver homogenates. Mice infected with SmFES-knockdown schistosomula exhibited a 72.3% and 46.3% reduction in CCL2 and IL-6 concentrations, respectively. To detect SmFES expression patterns in adult female S. mansoni worms, fluorescence in situ hybridization was employed, showing transcription in the encephaloesophageal and reproductive regions, including the uterus, ootype, and vitellaria. This suggests a role in oviposition and potential neurological functions. Then, since it has been demonstrated that miracidia were unable to sense the snail host and explore control strategies to interrupt the parasite's cycle, we evaluated in silico-predicted SmFES-binding compounds with anti-Schistosoma activity. Compounds were tested on egg cultures, assessing miracidia hatching, attraction, and infectivity in Biomphalaria glabrata. Compound SmFES17 reduced hatching rates by 8-12.9%. Miracidia exposed to SmFES9, SmFES15, SmFES18, and SmFES22 showed decreased attraction to B. glabrata mucus. Moreover, snails were challenged with hatched miracidia from eggs exposed to the five compounds. After 40 days, cercariae release was evaluated, resulting in a reduction of 30.7% for SmFES9-exposed parasites to 58% for SmFES17. These findings suggest that SmFES influences cytokine production in the liver, affecting immune modulation, diminished cellular recruitment, and increased fibrosis, potentially contributing to increased mortality in SmFES-knockdown infections due to insufficient retention of toxic egg proteins. SmFES expression in female reproductive organs indicates a role in oviposition, while its presence in the encephaloesophageal region hints at neurological involvement. Moreover, the identified compounds offer potential for new schistosomiasis control strategies by reducing miracidia hatching and cercariae release, a mathematical models would aid in stating its potential.

Leukocyte characterization of milky spots from Schistosoma mansoni-infected mice – Comparison with spleen and bone marrow, and extramedullary eosinopoiesis.

Bruno Marques Vieira — 2024-11-07

The milky spots are structures found in the omentum of humans and other vertebrates, representing a fraction of the lymphomyeloid tissue associated with the celom. They consist of B lymphocytes, T lymphocytes, and macrophages. Also found in smaller quantities are mesothelial cells, stromal cells, dendritic cells, and rare mast cells. In an experimental model of Schistosoma mansoni infection, there is significant activation of the omentum and milky spots, which start to exhibit numerous eosinophils. Despite being described for many years, the complete profile of cells found in milky spots, as well as their functions, remains largely unexplored. Here we evaluate the leukocyte populations of the milky spots in homeostasis and in a murine model of Schistosoma mansoni infection. The histopathological characterizations, phenotypic profile analysis, and characterization of the eosinopoietic potential of progenitors and precursors, comparing the milky spots with the spleen and bone marrow, showed a significant activation of milky spots in infected mice, with changes in the profile over the analyzed times, showing signs of migration and activation of eosinophils, with local eosinopoiesis and maintenance of the eosinophilic population. The behavior of milky spots differs from other primary and secondary lymphoid organs, acting as a central lymphoid organ in cavity immunity.

Preliminary Evaluation of Anti-Fibrotic Potential of Green Propolis Extract: Inhibition of NLRP3 Inflammasome and Modulation of Hepatic Stellate Cell in Schistosomiasis Mansoni

Lizandra Guidi Magalhães Caldas — 2024-11-07

Schistosomiasis mansoni is one of the main parasitic diseases affecting public health, characterized by the formation of granulomas and hepatic fibrosis due to the response to parasite eggs trapped in the host tissue. Several studies indicate that soluble egg antigens (SEA) of Schistosoma mansoni activate hepatic stellate cells (HSCs), promoting hepatic fibrosis. This process involves the activation of the NLRP3 inflammasome, which results in the synthesis of IL-1β and IL-18, cytokines that regulate the expression of TGF-β1 and promote the transition of quiescent HSCs to a myofibroblastic phenotype, increasing collagen production and extracellular matrix. Considering that praziquantel does not reverse this pathogenesis, this study aims to evaluate the potential of a standardized green propolis extract (Pex) to inhibit the activation of the NLRP3 inflammasome and the progression of hepatic fibrosis in murine models of schistosomiasis, positively modulating molecular factors associated with HSC inactivation, and investigating the parasitological and immunological effects associated with the disease. In vitro, GRX cells (cell line obtained by spontaneous migration of cells from granulomas induced in liver of C3H/Hej mice infected with Schistosoma mansoni) demonstrated a cytotoxic concentration (CC50) gt; 100 µg/mL (6 h and 12 h) and gt; 70 µg/mL (24 h) after treatment with Pex, while LX-2 cells human hepatic stellate cell line) showed a CC50 gt; 100 µg/mL at 24 h and 48 h of incubation. Western blot analyses showed a significant reduction in NLRP3 protein expression in GRX cells that were doubly stimulated for inflammasome activation [1º signal lipopolysaccharides (LPS) and 2º signal SEA] subsequently incubated with Pex. Furthermore, qRT-PCR assays showed that Pex reduced the expression of transcription factors associated with HSC activation (NF-κB, TGF-β1, and COL1α1) in LX-2 cells, while factors associated with HSC inactivation (PPARγ and GATA) were positively regulated after 24 h and 48 h of incubation. In the in vivo model, treatment with 300 mg/kg of Pex from the 35th to the 42nd day post-infection also showed a significant reduction in NLRP3 protein expression in liver. These preliminary results suggest the potential of Pex to inhibit the formation and activation of the NLRP3 inflammasome, as well as negatively modulate the transcription of molecular factors associated with the progression of hepatic fibrosis and positively modulate factors associated with the regression of this disease.

A 17-Year Epidemiological Survey of Schistosomiasis in Tremedal, Bahia: Challenges in Disease Control and Treatment

Larissa de Carvalho Medrado Vasconcelos — 2024-11-07

Schistosomiasis, a poverty-associated parasitic disease, results from exposure to freshwater contaminated with Schistosoma larvae. The adult worms typically settle in the intestinal veins, leading to significant tissue damage. This disease predominantly affects low-income communities, where inadequate sanitation and contaminated water sources perpetuate its endemic presence. Globally, schistosomiasis impacts nearly 240 million people, primarily in tropical and subtropical regions. Regular administration of anthelmintic drugs, such as praziquantel, can significantly mitigate severe morbidity associated with the disease. This observational, descriptive study conducted an epidemiological survey in Tremedal, a city in southwestern Bahia, Brazil, to identify cases of S. mansoni from 2002 to 2019. The study utilized secondary data from the Center for Endemic Disease Control in Tremedal and the Schistosomiasis Control Program Information System (SISPCE). A total of 232 localities were surveyed, with 13,215 Kato-Katz tests analyzed, leading to the identification of S. mansoni eggs in 231 individuals (1.7%). The intensity of infection, measured by the number of eggs per gram of feces, ranged from low (lt; 5 eggs) in 82 cases (35.2%), to medium (5-33 eggs) in 56 cases (24%), and high (≥ 34 eggs) in 95 cases (40.8%). Urban areas accounted for 109 (46.8%) of the positive cases, while rural areas contributed 124 (53.2%). The localities of Furado da Cancela (n = 32), Lagoa Preta (n = 15), and Olho d’Água (n = 14) were the most affected. Approximately 92.6% (n = 214) of infected individuals received etiological treatment. The mean age of these individuals was 29 years (IQR: 21-38 years), with a female-to-male ratio of 0.47:1. Among those residing exclusively in urban areas, the mean age was 31.5 years (IQR: 20.6–36 years), with a female-to-male ratio of 0.87:1. For individuals living in rural areas, the mean age was 28.0 years (IQR: 21.0–39.0 years), with a female-to-male ratio of 0.60:1. Schistosomiasis control in Tremedal faces significant challenges, particularly in urban areas where low sewage disposal coverage contributes to ongoing transmission and the emergence of new cases. Despite active transmission, the municipal schistosomiasis surveillance program is currently inactive, as the responsible professionals have been reassigned to combat other diseases, such as dengue and other arboviruses.

Screening and evaluation of Schistosoma mansoni peptides as targets of serological tests for the schistosomiasis diagnosis

Larissa Meira Resende — 2024-11-07

Despite advances in schistosomiasis control, it remains a serious global public health issue. New diagnostic strategies are crucial for its control and elimination since the current Kato-Katz test has low sensitivity. Serological tests are promising alternative in the diagnosis of active Schistosoma mansoni infection, necessitating the identification of antigens for these tests. Our group identified potential target proteins, including a protein named PPE, through immunoproteome and bioinformatics studies. Therefore, this project aims to screen and evaluate antigenic peptides from these S. mansoni proteins for new serological diagnostic tests for schistosomiasis. The experimental strategy is defined in two axes. The first involves in silico prospecting of PPE peptides, and the second uses microarrays of peptides derived from PPE and other proteins selected through bioinformatics in immunoassays. In silico analysis selected six potentially antigenic PPE peptides(P1-6). These peptides were synthesized, and P6 was used in ELISA assays to evaluate antibody reactivity in serum samples from S. mansoni infected and non-infected individuals, previously characterized by Helmintex and Kato-Katz parasitological tests. After standardization, the assay was conducted as follows: 96-well Maxisorp plates were coated with 100µL of P6 (6µg/mL) in carbonate-bicarbonate buffer pH 9.6, overnight at 4°C, then blocked with 10% FBS in PBS-T for 2h at 4°C and washed. Serum samples diluted 1:80 in PBS-T were added in duplicate and incubated at 37°C for 2h. Following washing, plates were incubated at 37°C for 1h with anti-human IgG-HRP secondary antibody at 1:60.000 dilution in PBS-T and then washed again. TMB susbtrate (100µL) was added for 30 min in the dark at room temperature, and 50µL of 4M sulfuric acid were used to stop the reactions. The colorimetric signal was read in a microplate spectrophotometer at 450nm. Under these conditions, the assay showed a coefficient of variation lower than 5%. However, peptide P6 failed to distinguish infected from non-infected individuals, regardless of their residence in an endemic area. In parallel, the custom-made high-density peptide microarrays were synthesized containing 726 peptides of 15 aminoacids derived from five S. mansoni proteins: 340 peptides from PPE, 179 from Smp33, 130 from Smp13, 56 from Smp18 and 21 from Smp19. ELISA-like immunoassays were performed using pooled serum samples from S. mansoni infected and non-infected individuals, and anti-human IgG and IgG4 fluorescent antibodies. Two larger peptides from regions highly recognized by antibodies were selected for synthesis and further ELISA assays. Additionally, 120 of the 726 peptides showing the greatest reactivity differences between serum pools from infected and non-infected individuals were selected for a new microarray, which will be used to determine their performance in a schistosomiasis diagnostic test.

Schistosomiasis Surveillance Action in Municipalities Considered Endemic in the State of Pará, Amazon, Brazil in the Year 2024

Joyce Favacho Cardoso Nogueira — 2024-11-07

Data from the National Schistosomiasis Survey conducted in Brazil between 2010 and 2015 revealed that the State of Pará, out of 6,198 examined, presented only 02 positive cases and a 0.02% positivity rate, not reflecting the real situation of the disease in the State. In this sense, the objective of this study was to carry out surveillance action in municipalities considered endemic for Schistosomiasis in the state of Pará, to assess the current situation of the disease in this region studied. This work was carried out by the Laboratory of Intestinal Parasitosis, Schistosomiasis and other Helminths of the Evandro Chagas Institute, Regional Reference for Schistosomiasis, with the support of the selected municipalities and the 4th Regional Health Center of Sespa, and took place from May 13 to 28, 2024, in which 418 stool samples were collected from individuals residing in the municipalities of Bragança (223/418) and Quatipuru (195/418), selected because they are considered areas of active transmission of the disease, to perform the parasitological diagnosis of stool using the Kato-Katz method. This test was performed in duplicate, and children from 2 years of age, adolescents, adults and the elderly were included. The positivity rate for Schistosomiasis was 9.1% (38/418) and 9.3% (39/418) for other helminths. Among the positive patients in the municipalities studied, 31.6% (12/38) had a medium to high parasite load, with a low parasite load predominating at 68.4% (26/38). Taking into account the total number of positive cases found with Schistosoma mansoni and other helminths in the two areas studied, the coinfection rate was 17.3% (13/75), with Schistosoma mansoni and Hookworm spp. being the most common coinfection, with a rate of 10.7% (8/75). However, the results indicate a significant positivity rate for Schistosomiasis in the studied areas of Pará, which is not the rate recommended by the Ministry of Health. In addition, the presence of coinfections and the variation in the parasite load reinforce the need for continuous and integrated interventions to control the transmission of the disease. Active surveillance, combined with health education, more accurate diagnosis and appropriate treatment, is crucial to reduce the prevalence of schistosomiasis and improve public health in endemic areas of Pará. The neglected disease status is reinforced by limited research and by the fact that it is recorded in areas of greater social vulnerability. With a view to elimination, there is a clear challenge to the sustainability of actions in view of the possibility of the disease reoccurring. It is essential to assess and monitor data in information systems to ensure the completeness and consistency of hospitalization and death records. These perspectives are of significant relevance considering the 2030 target of eliminating schistosomiasis as a public health problem proposed by the World Health Organization to achieve the Sustainable Development Goals.

Histone code of love : chromatin structure and sexual maturation of Schistosoma mansoni

Christoph Grunau — 2024-11-07

We analyzed histone modifications, chromatin accessibility, transcription, and genome features to decode the histone code in mature and immature ovaries and testes of the human parasite Schistosoma mansoni. Our findings reveal: (i) two classes of protein-coding genes in schistosome gonads—H3K4me3-positive genes with canonical histone features and H3K4me3-negative genes, suggesting possible schistosome-specific histone marks; (ii) distinct "chromatin colors" associated with gene function, particularly in H3K4me3-positive genes; (iii) significant chromatin structure changes during gonadal maturation, varying by sex; and (iv) the potential of targeting histone demethylation as a drug strategy, as shown by the effect of an inhibitor of histone modifying enzymes on schistosome pairing. These insights advance our understanding of histone codes and chromatin dynamics in S. mansoni reproductive development.

Revisiting the schistosomiasis foci in the Touros region, Rio Grande do Norte, Brazil: A retrospective analysis.

Lucia Abrantes Aguiar — 2024-11-07

INTRODUCTION. In 1976, the Special Schistosomiasis Control Program (PECE/MS) chose the municipality of Touros, RN, to conduct an epidemiological survey in a perennial lagoon whose waters drain into the sea through the Jiqui River in a system of streams, ditches, and marshes. The local population used the lagoon, where Biomphalaria glabrata (BG) was recorded, for bathing, leisure, and fishing. In that survey, 4,620 BG specimens were collected, with Schistosoma mansoni (SM) natural infection ranging from 1.2% to 3.3%. The positivity of SM in the population examined (88.3%), a single Kato-Katz (KK) stool sample, was 56.4%. Collective treatment covered 93.4% of the population; after 14 months the prevalence was 20.6%.OBJECTIVES. (1) To revisit the snail sites of Touros, Pureza, and Rio do Fogo, endemic municipalities; (2) to analyse the parasitological and malacological data from PCE/SES-RN for 2016-2023.METHODS. In May 2024, a malacological survey was carried out in the breeding sites regularly monitored by the PCE in the region. The specific identification of the collected snails and the natural infection by SM was performed at the Schistosomiasis Reference Laboratory and Service of the IAM using crushing and SmITS-qPCR techniques (10% of the collected sample). Secondary data from the malacological and stool surveys of the local PCE were analysed and spatialized in thematic maps.RESULTS. In the period 2016-2023, the PCE/SSRN recorded the following percentages of population examined (pex) and positivity (pos) for SM: Touros, 70.1% (pex) and 4.2% (pos); Rio do Fogo, 3.8% (pex) s and 18% (pos); and Pureza, 18.7% (pex) and 3% (pos). During the same period, 42 BG specimens were collected in Touros and 1,071 in Pureza, with one (2.3%) and 22 (2.1%) infected snails detected, respectively. The survey carried out in 2024 confirmed B. glabrata as the local intermediate host species and collected 87, 1,123, and 237 specimens in Touros, Pureza, and Rio do Fogo, respectively. The crushing and SmITS-qPCR techniques did not reveal naturally infected specimens. CONCLUSION: Natural infection of BG specimens in the localities tended to be low (1-3%), even when human infection was high. This finding, combined with the difficulty of the crushing technique in detecting larval stages of SM in recent infections and the low percentage (10%) of snails subjected to the SmITS-qPCR technique, may have contributed to the non-detection of natural infection in the snails collected in 2024. Despite this, recent data show that SM infection persists, affecting 3% to 5.8% of the population. Rio do Fogo surprises with 18% of human cases registered from only 3.8% of the population. The lack of sanitation and residents' constant use of the lagoon, combined with past and recent epidemiological data, show the need for permanent monitoring of the epidemiological situation in the locations evaluated.

CHANGES IN THE DISTRIBUTION PROFILE OF INTESTINAL BACTERIA IN SCHISTOSOMOTIC C57BL/6 MICE FED A HIGH-FAT DIET: AN ANALYSIS BY FLUORESCENCE IN SITU HYBRIDIZATION (FISH)

Carlos Eduardo da Silva Filomeno — 2024-11-07

There is increasing evidence that the concomitance between schistosomiasis mansoni and obesity aggravates liver, splenic and intestinal tissue by modifying the architecture and physiology of these organs. Studies have supported the role of the mammalian gut microbiota in hepato-intestinal schistosomiasis and open the way to understanding the complex relationships between helminths, gut microbiota, host immunity and the pathophysiology of infection in the acute and chronic phases. Therefore, using a model of diet-induced obesity (DIO), we sought to understand this association. C57BL/6 male mice fed either a high-fat diet (60% fat) or a standard diet (10% fat) for 13 weeks was infected with 100 Schistosoma mansoni cercariae (BH strain). Mice were allocated into four groups: USC (uninfected fed standard diet), UHFC (uninfected fed high-fat diet), ISC (infected fed standard diet) and IHFC (infected fed high-fat diet). The development of obesity was assessed by blood lipid profile, including TC (total cholesterol), TG (triglyceride levels), LDLC (low-density lipoprotein cholesterol), HDLC (high-density lipoprotein cholesterol) and VLDL-C (very low-density lipoprotein cholesterol) and glucose concentrations, OGTT (oral glucose tolerance test), body mass and adiposity index. Mice were euthanized by CO2 exposure 9 weeks after infection. Histological sections of the jejunum were stained with hematoxylin and eosin (Hamp;E). For fluorescence in situ hybridization (FISH), sections of the mice's jejunum were collected and fixed in 10% bu ered formalin for 48 hours. The material was incubated in 10 % and 30% sucrose at 4°C for 24 hours for inclusion in OCT (Optimum Cutting Temperature) gels and subjected to rapid freezing in liquid nitrogen. FISH was performed on each slide using the conditions and bu ers using 30% formamide in the hybridization bu er and probes for eubacteria (Thermo Fisher Scientific). IHFC showed a reduction in lipid profile, an increase in HDL-c, and better oral glucose tolerance, as well as a reduction in body mass. The results obtained from fluorescence in situ hybridization suggest the occurrence of bacterial translocation in the infected groups, especially in the group subjected to the high-fat diet. FISH revealed a higher concentration of bacteria around the S. mansoni egg and in the apex of the mucosal layer in ISC mice, while in the IHFC group we found a distribution of bacteria in the mucosal layers, especially in the crypts of Lieberkühn, the submucosa and the muscle, suggesting a possible translocation of bacteria in IHFC mice. This process is known to occur due to increased permeability of the intestinal mucosa, stimulated by the diet, increased bacterial growth, a weakened immune system and lesions caused by the S. mansoni egg during its passage into the intestinal lumen. Taken together, our data suggest that concomitant obesity and acute schistosomiasis have a significant impact on the architecture of the jejunum in C57BL/6 mice

Development and Application of qPCR as an Alternative for the Diagnosis and control of Schistosomiasis in Areas of Low Endemicity for the Disease

Eduardo Henrique Matos Pires — 2024-11-07

Introduction: The diagnosis of schistosomiasis is one of the major problems regarding its control and further elimination as a public health problem. The parasitological methods are limited in sensitivity, which is directly dependent on the parasite load of the host. This problem becomes evident in low-endemic areas, represented by low positivity rate and low parasite load. Facing this problem, the aim of this study is to develop and evaluate a new Real-Time PCR system for the diagnosis of schistosomiasis in areas of low endemicity for the disease. Methodology: A new qPCR system was designed to target the Sm1-7 gene. The assay limit of detection was defined in a standard curve experiment with different concentrations in a 10-fold dilution of Schistosoma mansoni DNA ranging from 1 ng/μl to 1 fg/μl. Also, the Sm1-7-qPCR specificity was evaluated in a MegaBLAST search and experimentally, using 1 ng of genomic DNA from the parasites Wuchereria bancrofti, Mycobacterium tuberculosis, Strongyloides stercoralis, Leishmania infantum, L. braziliensis and Escherichia coli. A cross-sectional study was conducted in Catamarã, a neighborhood in Jaboatão dos Guararapes (PE) to evaluate the Sm1-7-qPCR performance. All individuals who signed an Informed Consent form, approved by the Aggeu Magalhães Ethics Committee, and handed the stool samples were included in the study. After, the patients were diagnosed using the Kato-Katz (KK) method, in which two slides were examined per sample, and Hoffman (HH), in which all the sediment was analyzed. In parallel, the stool samples had their DNA extracted, then submitted to the optimized Sm1-7-qPCR, together with an Internal Positive Control of the reaction (IPC). The results were used to estimate the sensitivity, specificity, Cohen’s kappa and predictive values of the qPCR. Results: The system showed high sensitivity, amplifying up to 1 fg /μl of S. mansoni genomic DNA with an average Ct of 30.737, which was the cut-off point for determining positive and negative samples. There was no amplification of the other parasites’ DNA, nor was there any probable alignment with any other sequence by the MegaBlast search. A total of 351 stool samples were collected during the coproscopic investigation, of which 38 were positive for S. mansoni in KK, while 23 were positive in HH and 162 were positive for Sm1-7-qPCR. A composite reference method (CRM), including the results of the parasitological methods, resulted in 44 positive samples in total. Compared with the CRM, the sensitivity of Sm1-7-qPCR was 85.11%, the specificity was 59.61%, the positive predictive value was 24.39%, the negative predictive value was 96.32% and the Kappa was 0.218. Conclusion: The new Sm1-7-qPCR has high sensitivity and moderate specificity and may be used as a screening test for schistosomiasis in low-endemic areas. In addition, the selection of sensitive reference methods is essential for the evaluation of new diagnostic methodologies under development.

Description of the clinical profile of individuals with schistosomiasis in an urban transmission area in the Metropolitan Region of Recife - PE

Maria Eduarda da Silva Pereira — 2024-11-07

Introduction: Schistosomiasis mansoni is a parasitic disease caused by the parasite Schistosoma mansoni, whose pathogenesis results in the development of liver fibrosis, which can be classified according to the severity level and is responsible for the morbidity and mortality associated with the disease. In Brazil, Pernambuco has the highest number of deaths associated with the disease. The aim of this study was to describe the disease clinical profile in an endemic area for Schistosomiasis. Methodology: A cross-sectional study was carried out with a coproscopic survey in micro-areas 3 and 7 covered by USF Barra de Jangada I in Novo Horizonte in the municipality of Jaboatão dos Guararapes (PE). Residents were invited to take part in the survey by providing a stool sample which was analyzed using the Kato-Katz (KK) and Hoffman techniques. Positive individuals were summoned for an upper abdominal ultrasound to characterize the disease according to the Niamey protocol. The project was approved by the Research Ethics Committee under protocol number 5.905.584. Results: 413 residents were registered, and stool samples were obtained from 263 individuals, 52.5% male and 47.5% female with an average age of 34.8 years (1-86 years). By analyzing two KK slides, 57 individuals were identified as positive for S. mansoni with an average parasite load of 282 EPG (12-3,168 EPG) and 3 individuals by Hoffman. There was no statistically significant difference between the distribution of parasite loads and age groups. Of the 60 infected individuals, 65% were male and 35% female (p = 0.027) with a mean age of 36.9 years (6-81 years). There was a statistically significant difference between the mean age in the classification of moderate and high parasite load (p = 0.009). Among the positives, 14 individuals had pattern A or B, 50% male and 50% female with an average parasite load of 161.53 OPG (24-552 OPG) and 27 individuals had periportal fibrosis with pattern C, D, E or F, 74.07% male and 25.92% female, with an average parasite load of 339.38 OPG (12-3,168 OPG). The group without fibrosis had a mean age of 21 years (5-54 years) and the group with fibrosis had a mean age of 38.76 years (7-77 years) (p = 0.003), however, there was no statistically significant difference when comparing the parasite loads between the two groups. The other 11 individuals had hepatic steatosis or chronic liver disease with an average age of 45.45 years and an average parasite load of 440 OPG (12-1,800 OPG) and 8 did not attend. Conclusion: The locality has moderate prevalence and parasite load, even in a previously classified low endemic municipality, and has individuals with moderate to severe clinical involvement, highlighting the need for control program actions.

Funtional characterization of the recombinant elastase from Schistosoma mansoni and its role in immunomodulation

Carolina Orrico Melo Ferreira de Jesus — 2024-11-07

Shistosoma mansoni parasite has a complex life cycle and the host infection occurs by the active penetration of cercariae through the skin. This penetration process starts a several immune mechanisms which are different between individual who has been infected for the first time and individual who had previous contact with the parasite antigens. Among the S. mansoni antigens, the protein involved in the penetration process: serine protease elastase (SmCE) has been identified as the most abundant and most important protease in the process. Despite that, the trigger to the initial response against infection remains unknown. So the present study aims to produce and characterize the Schistosoma mansoni recombinant elastase enzyme and evaluate its importance in the development of the immune response to the parasite in healthy individuals and previously infected ones. The heterologous production of rSmCE was conduct in different Escherichia coli strains: pLys, BL21 and Rosetta. The plasmid containing SmCE coding sequence was transformed into each strain and the protein production was induced using IPTG. Bacterial lysates were analyzed by SDS-PAGE. Following the protein production protocol we used the soluble supernatant to purify the rSmCE through affinity chromatography. The samples were evaluated by Western blot. Also performed an enzymatic assay with the chromatogenic substrate for 24h in some different pHs and protein concentrations. With these results we did another incubation, change the substrate concentration to determinate the Vmax and Km of the enzyme. Human peripheral blood mononuclear cells were incubated for 48 hours with the SmCE and a viability test was made, the supernatant was used to determinate the optimal and sub-optimal concentration of the protein for cytokines assays as well. All bacterial strains tested were able to produce the protein after a 24- hours induction; however, Rosetta presented a better yield. The purification of the protein extract resulted in a purified SmCE. The enzyme was also identified by Western blot. The best protease activity was found in the concentration of 650μg/mL at pH 9, and its Vmax and Km was 0,02568 mM/min and 0, 04089mM respectivily. The test of viability shows about 52% of viable cells in the presence of 100 μg/mL of SmCE and the optimal concentration was 6.2μg/mL for IL-10 and INF-ϒ and 12,5 μg/mL for IL-5. This experiment concluded so far that in higher concentration the SmCE protein is cytotoxic to cells, thus the protein seams to modulate the immune responses creating satisfactory levels of IL-10 and cytokines from the Th1 responses. (FAPESB, CNPq 403336/2021-0).

Co-expression gene modules analysis in response to attenuated cercaria vaccine reveals a critical role for NK cells in protection against S. mansoni

Almiro Pires da Silva Neto — 2024-11-07

Background: Schistosomiasis affects nearly 240 million people, with 779 million at risk. Developing a vaccine would greatly enhance current control measures and elimination efforts. However, despite decades of research, an effective vaccine for schistosomiasis remains elusive. The Radiation-attenuated (RA) cercarial vaccine remains the best model for eliciting high levels of protection. We have recently explored this model in mice to identify potentially protective pathways by examining gene expression patterns in peripheral blood mononuclear cells (PBMC) using Gene Set Enrichment Analysis (GSEA). Aims: In this study, we reanalyzed transcriptomic data from PBMCs obtained from vaccinated (n = 12) and infected (n = 12) C57BL/6 mice at three time points (Days 7 and 17 after infection or vaccination, and Day 7 post-challenge), as well as from unmanipulated animals (n = 12). Additionally, we generated new data from PBMCs collected 35 days post-infection. Methods: Deconvolution analysis was performed to estimate immune cell composition by CIBERSORTx. Gene co-expression networks and Over Representation Analysis (ORA) were performed using the CEMiTool package. Protein-protein interaction networks were constructed using STRING and the hub proteins for each module were identified using Cytoscape. Results: Co-expression network analysis identified a module (M2) associated with the infection process, grouping genes related to a Th2 immune response, and a second module (M6) associated with the vaccination process, displaying pathways related to a Th1 response, CD8+ T cells and NK cells. Within each module, five hub proteins were identified based on protein-protein interaction networks. The M2 infection module revealed Chil3, Il4, Cx3cr1, Emr1 and Ccl2 as hubs, while module M6, associated with vaccination, disclosed Prf1, Klrc1, IFN-γ, Ncr1 and Tbx21 as hub proteins. Conclusion: Our data highlight the potential involvement of NK cells in bolstering the response to the RA vaccine via IFN-γ production regulated by the T-bet transcription factor (Tbx21). These findings may provide a basis for predicting favorable outcomes in the development of a vaccine against schistosomiasis.

Malacological surveillance of the Schistosomiasis Control Program in the city of Salvador-Bahia between 2021 and 2023.

NINA PEREIRA DE MEDEIROS — 2024-11-07

Introduction: Since 2008, the Zoonosis Control Center of the Municipal Health Department (CCZ-SMS) has monitored water collections (CHs) in Salvador within the schistosomiasis control program. The objective of this study was to identify CHs with Biomphalaria spp. eliminating cercariae of the Schistosoma mansoni worm. Material and Methods: Malacological surveys were carried out at CH stations registered by CCZ-SMS to collect Biomphalaria ssp. in the period from 2021 to 2023. Due to basic sanitation works, urbanization, environmental modifications, or public security of the location, some CHs were excluded over time and others were registered after investigating a death registered in SINAN or resulting from an active search for snails. Field visits and snail collections occurred every six months, except in CHs with a history of cercariae elimination, which was monthly. The collection method used was that of Oliver and Schneiderman (1956), which employed the use of shells and storage pots with dechlorinated water to transport the snails to the laboratory. The collection time at each station was 10 minutes. The snails were diagnosed based on the 5-day classic cercariae elimination test (CCS). The water from the containers was transferred to Petri dishes and stained with lugol to visualize the cercariae under a stereoscopic microscope. Results: In 2021, 77 CHs were monitored, 37 (48%) with snails, accounting for a total of 7,187 snails collected. Of these, 16% (6/37) had snails eliminating cercariae (positive). In 2022, 84 CHs were monitored, 37 (44%) with snails, resulting in 6,919 snails collected, and 21.6% (8/37) of these were positive. In 2023, 88 CHs were monitored, 59 (67%) with snails, 6,429 snails were collected, and of these 8.5% (5/59) were positive. Three CHs were positive throughout the period, the others showed transient positivity. Furthermore, we observed a reduction in the number of snails collected over the years. Conclusion: By monitoring CHs, it was possible to identify schistosomiasis transmission foci in a large urban center. An integrated set of measures to combat schistosomiasis may be necessary.

EVALUATION OF THE POTENTIAL OF CHALCONES AGAINST SCHISTOSOMA MANSONI

João Marcos Santos Neves — 2024-11-07

Schistosomiasis is a neglected disease that affects populations in tropical and subtropical regions. The disease is caused by trematodes of the genus Schistosoma, with Schistosoma mansoni being the only species present in Brazil. Currently, praziquantel (PZQ) is the only drug available for the treatment of this parasitic disease. After decades of mass administration, the number of treatment failures has been increasing, raising concerns about the emergence of tolerant or resistant strains, and highlighting the need for new therapeutic alternatives. Chalcones are plant-derived metabolites have demonstrated broad antiparasitic activity, suggesting that compounds of this class could be promising candidates for drug development. In this study, we evaluated the schistosomicidal potential of six chalcones in vitro at different concentrations: 5 μg/mL, 2.5 μg/mL, 1.25 μg/mL, and 0.675 μg/mL over 72 hours. We then, selected the two chalcones with notable in vitro activity for in vivo testing at a concentration of 100 mg/kg in mice infected with 70 cercariae. In the in vitro assays, male and female S. mansoni were evaluated on a scale of 0 to 3, where scores of 1 to 3 indicated varying levels of viability: At score 3, the worms were viable, showing no tegumental damage or contractions; at score 1, the worms were non-viable, with significant tegumental damage and intense contractions; A score of 0, indicated that the worms were dead, showing no movement. At the concentration of 5 μg/mL, chalcones 3, 4, and 6 killed 100% of males and females within 24 hours. By 48 hours, males and females exposed to chalcone 2 and females exposed to chalcone 5 showed 100% mortality. Males exposed to chalcone 5 and males and females exposed to chalcone 1 showed over 50% mortality and significantly reduced viability (lt;1) by the end of the experiment. At the lower concentrations (2.5 μg/mL, 1.25 μg/mL, and 0.625 μg/mL), none of the compounds killed 100% of the whitin 72 hours. However, all groups showed a statistically significant reduction in viability compared to the untreated control and yielded results comparable to PZQ. Chalcone 3 stood out for maintaining activity at all concentrations tested, while compound 5 was particularly effective at lower concentrations, suggesting better solubilization. Consequently, these two chalcones were selected for in vivo assays. In the in vivo schistosomicidal assays, chalcone 3 significantly reduced the number of females recovered during perfusion compared to the control group. Additionally, both chalcone 3 and chalcone 5 effectively reduced the number of eggs per gram of feces, as well as the number of immature, mature, and total eggs found in the oogram. These results indicate that the tested compounds hold potential for the treatment of schistosomiasis.

Effects of green silver nanoparticles in the digestive gland of Biomphalaria glabrata: insights into the toxicity of a new molluscicide

Luiz Felipe da Silva Ferreira — 2024-11-07

Green nanoparticles (G-NPs), particularly green silver nanoparticles (G-AgNPs), have numerous biomedical applications, such as their use in controlling vectors, pests, and intermediate hosts. Among their applications in nanomedicine and parasitology, G-AgNPs exhibit molluscicidal activity against gastropods that act as intermediate hosts for medically and veterinary important parasites, causing diseases like schistosomiasis. Schistosomiasis is a neglected parasitic disease caused by the digenean trematode of Schistosoma genus, with the snail Biomphalaria glabrata (Say, 1818) as an intermediate host. In mollusks, the digestive gland is the main organ for the bioaccumulation and metabolism of inorganic NPs; however, knowledge about the effects of G-AgNPs on the digestive gland of freshwater gastropods is still scarce. Therefore, this study aimed to evaluate whether a 7-day exposure to two concentrations of G-AgNPs synthesized with aqueous leaf extract of Croton urucurana induces histopathological changes and inflammatory response in the digestive gland of the neotropical snail B. glabrata. After exposing the snails, the digestive gland was dissected, and included in glycol methacrylate resin, the slides were stained with 1% toluidine blue pH 8.5, and the histopathological biomarkers were analyzed qualitatively, quantitatively, and semi-quantitatively (histopathological alteration index). The results indicated that G-NPs induced several histopathological alterations such as nuclear changes, vacuolization, atrophy, tubular regression, and necrosis in the epithelium of the digestive gland tubules and the formation of granulocytomas. Snails exposed to G-AgNPs and the extract showed a higher histopathological index in comparison with the control group. G-AgNPs also induced inflammatory response in the digestive gland, mainly increased hemocyte infiltration and aggregation. This study contributes to understanding the biodynamics and toxicity of G-NPs in medically important gastropods, and for the development of new materials with molluscicidal potential.

SANITATION AND WATER EXPOSURE AS RISK FACTORS FOR SCHISTOSOMA MANSONI PARASITIC LOAD IN A RURAL COMMUNITY IN BAHIA

Maria Gabriella Brito dos Santos — 2024-11-07

Introduction: The lack of sanitation and consumption of unsafe water pose a health risk and contribute to the persistence of diseases such as schistosomiasis, which proliferate due to contact with contaminated water during essential activities for community development. Our objective is to assess how varying levels of river water exposure and inadequate sanitation conditions influence Schistosoma mansoni parasitic load in affected populations. Methodology: Individuals from a cross-sectional study conducted in 2018 who had Kato-Katz results and completed questionnaires on water exposure were evaluated. Data from previous studies in the same area were used complementarily to analyze trends in the prevalence of Schistosoma mansoni, parasitic load, and practices related to sanitation and water exposure. The objective of this study is to assess how varying levels of river water exposure and inadequate sanitation conditions influence Schistosoma mansoni parasitic load in affected populations. Results: Between 2004 and 2018, the association between basic sanitation, river water exposure, and S. mansoni parasitic load was investigated. In 2018, 340 individuals were included in the study, with a median age of 23 (IQR 13- 43), the majority being female (57.1%). However, parasitic load was significantly higher among men (p= 0.0209). Of these, 189 (55.6%) had S. mansoni eggs in their stools, with a median parasitic load of 36 (IQR 12-108) epg. River water exposure was predominant, with 93.5% of participants reporting contact with local water bodies, similar to 84.34% in 2010 and 70.76% in 2004. Among 2018 participants, the highest infection rate was observed among those who bathed in the river (96.2%), with 69.9% of infected individuals engaging in this activity more than three times per week, followed by activities such as fishing and leisure. However, the frequency of these activities did not influence the intensity of S. mansoni infection, corroborating data from other periods. Basic sanitation data over the period indicated limited improvement in water treatment and waste disposal conditions. In 2018, only 13.82% reported treating their drinking water, a decrease from 39.54% in 2010. Burning waste continued to be the predominant method of waste disposal (66.66% in 2014, 61.30% in 2010). Analysis of parasitic load over time revealed that although there was a high prevalence of infection among those exposed to water, the intensity of infection remained low, which may be related to the frequency and type of exposure, as well as to other factors, such as repeated treatment and improvement in socioeconomic conditions. Conclusion: The persistence of schistosomiasis in a community is complex, as continuous exposure to contaminated water bodies occurs during daily and subsistence tasks. To eradicate schistosomiasis in these areas, actions such as those proposed in the WASH strategy are of fundamental importance and extreme necessity.

Epidemiology of hospitalizations and deaths from schistosomiasis in the state of Bahia between 2018 and 2023

THIAGO SANTOS DE MELO — 2024-11-07

Introduction: Schistosomiasis is a parasitic disease caused by Schistosoma mansoni. The infection is acquired when a person comes into contact with fresh water contaminated by parasite-infected snails. In this sense, acute and chronic clinical manifestations can be observed, the most prevalent being: dizziness, fever, asthenia, bloody diarrhea, splenomegaly, etc. In Brazil, data estimates that more than 1 million people live in areas at risk of contracting the disease. This makes it important to analyze hospitalizations and deaths from the disease in the state of Bahia. Objectives: To describe the epidemiological profile of hospitalizations and deaths from schistosomiasis in Bahia between 2018 and 2023. Methods: This is a mixed ecological study covering the territory of Bahia from 2018 to 2023, based on secondary data extracted from the SUS Hospital Information System (SIH/SUS) and the Mortality Information System (SIM) available from the Department of Informatics of the Unified Health System (DATASUS), tabulated in Excel®.2019. The outcomes considered were: number of hospitalizations and deaths; the variables analyzed included: gender, age group, race and micro-region. Results: Between 2018 and 2023, 348 deaths from schistosomiasis occurred in the state of Bahia. In addition, 91 hospitalizations for the disease were identified during this period, with 2022 recording the highest number of hospitalizations, with 26 cases, while 2023 had the lowest incidence, with only 4 hospitalizations. It can also be seen that men were more affected than women, and the most affected age group was between 50 and 59. In terms of mortality, the most affected age group was 70 to 79, followed by 60 to 69. The highest number of deaths was recorded in 2018, with 67 deaths. Mortality remained stable in the following years, but even with the variations in absolute numbers, deaths continued to occur mainly in elderly patients. Geographical analysis of the data showed that the municipalities: Salvador, Feira de Santana and Vitória da Conquista concentrated the majority of mortality cases. Conclusion: From the analysis of the data, it is possible to note a higher number of hospitalizations for schistosomiasis in 2022, and a higher number of mortalities in 2018, as well as showing a predominance in the 70-79 age group. In addition, there is a predominance of mortality cases in the municipalities of Salvador, Feira de Santana and Vitória da Conquista. Given these data, we can infer that schistosomiasis represents a major challenge for public health, and it is necessary to continue monitoring the evolution of the disease, implementing preventive measures and carrying out more effective control, as well as reinforcing public health measures in order to reduce these rates and achieve better results.

Temporal trend in mortality from schistosomiasis mansoni in the state of Alagoas: an analysis of the last 10 years

Maria Wilma da Silva Lima — 2024-11-07

Introduction: Schistosomiasis mansoni is a neglected tropical disease caused by the Schistosoma mansoni trematode. Brazil is considered one of the most endemic countries for morbidity, and among the most affected areas is the state of Alagoas (AL), located in Northeast Brazil. Objective: To analyze the temporal trends of the mortality rate due to schistosomiasis mansoni in Alagoas, between 2013 and 2022. Methodology: This is an ecological study of a time series, based on data from the Mortality Information System (SIM). We considered all deaths due to schistosomiasis between 2013 and 2022 that occurred in the state of Alagoas. We considered the variables sex, age group, and ethnicity. The segmented linear regression model (Joinpoint) was used to calculate the annual percent change (APC) and the average annual percent change (AAPC), along with their respective 95% confidence intervals (CI). We used a maximum of 9,999 Monte Carlo permutations for the analysis. Mortality rates were classified as decreasing, stable, or increasing, considered significant when plt;0.05. Results: During the analysis period, there were 522 deaths due to schistosomiasis mansoni. The overall mortality rate due to schistosomiasis mansoni remained stable, considering the entire analysis period (AAPC -4.3; 95% CI: -9.1 to 0.8, p = 0.1). Regarding sex, females showed a decreasing trend (AAPC = -6.1; 95% CI: -11.6 to -0.2; p = 0.001) throughout the entire analyzed period. With respect to age group, between 2013 and 2022, mortality rates significantly increased among the 0 to 9 years age group and the 10 to 19 years age group (AAPC = 3.5; 95% CI: 2.2 to 4.8 and APC = 8.8; 95% CI: 7.0 to 10.7, p = 0.001, respectively). Between the time segment of 2016 to 2022, the 40 to 69 age group showed a decrease in mortality rates with APC = -13.0 (95% CI: -20.7 to -4.5). Furthermore, among the groups aged ≥70 years, the rates also decreased (AAPC = -6.9; 95% CI: -13.0 to -0.5) considering the entire analysis period. Regarding ethnicity, only indigenous people showed a decreasing trend (AAPC = -11.3; 95% CI: -15.6 to -6.8). Conclusion: The trend analysis revealed an overall stability in mortality rates due to the disease in the state. An increase in mortality among children and a reduction among the elderly were also observed. This may indicate an improvement in the diagnosis and early treatment of schistosomiasis mansoni for specific age groups, as well as suggest infections with high parasite burdens, which may result in more severe cases of the disease among young people. Thus, understanding variations in mortality rates by gender, age, and ethnicity allows for directing efforts and resources to the most affected areas and populations.

Evaluation of ELISA tests for the diagnosis of schistosomiasis using a Schistosoma mansoni chimeric recombinant protein

Mariana de Andrade Fernandes — 2024-11-07

Introduction: The Kato-Katz method has low sensitivity for detecting S. mansoni infected individuals with low parasite burden. To overcome this, the Enzyme-Linked Immunosorbent Assay (ELISA) arises as an alternative. But the applicability of the ELISA is limited by its low specificity. We hypothesize that the use of a chimeric recombinant protein, containing epitopes from different parasite antigens, in an ELISA would result in a more accurate test. Objective: The aim of this study was to obtain a chimeric recombinant protein and to standardize and evaluate an ELISA test using this antigen. Methods: The recombinant protein was constructed by combining 5 epitopes of S. mansoni proteome. The gene that encodes the protein was inserted into a vector and the expression was carried out in a prokaryotic system. After induction with IPTG, the bacteria were lysed by sonication in a denaturing lysis buffer and purified using nickel affinity chromatography. ELISA standardization was performed by testing different microplates, antigen concentrations and blocking solutions. In the microplate’s evaluation 1; 2; 4; 6; 10 and 12µg/mL of antigen was tested in a Maxisorp and Corning EIA/RIA plates using an anti-his-HRP antibody (1:2000) as the detector antibody. The blocking solutions tested were 10% FBS and 3% BSA in a Phosphate Saline Buffer with tween 20. Serum from uninfected and infected individuals from an endemic region, tested by parasitological and molecular methods, was used to evaluate test’s performance. The standardized test was carried out using two different batches of recombinant protein. The absorbance was measured in a microplate reader at 450nm. Arbitrary unit was calculated by dividing the absorbance of the sample by the absorbance of a calibrator. Data were analyzed using the ROC curve test. It was determined a cutoff point that prioritize the highest values for the test accuracy. Result: The recombinant protein (25kDa) was obtained with satisfactory purity and yield (4.9mg/L). ELISA standardization demonstrated that 11g/mL of recombinant protein is sufficient to saturate the well of the Maxisorp plate while the Corning EIA/RIA plate required more antigens to do that. The solution containing 3% BSA was more effective in blocking nonspecific bonds. So, the ELISAs assays were performed in a Maxisorp plate, coated with 12µg/mL of chimeric protein, blocked with 3% BSA. Serum samples and anti-IgG conjugated to HRP were used at a 1:50 and 1:60.000 dilution respectively. TMB was used as substrate. A common cutoff point of 0.18191 was used for both batches of test. For batch 1 the sensitivity was 76% and the specificity was 38% with an Area Under the curve (AUC) of 0.63. For batch 2, the sensitivity was 83% and specificity 30% with an AUC of 0.65. Conclusion: Despite demonstrating a high sensitivity value, the chimera-Elisa test showed low specificity for diagnosing the infection in endemic areas, limiting its use to an initial screening stage.

Schistosomiasis in an Endemic Area: Epidemiological Profile and Disease Control Measures

Natália Oliveira Spinelli — 2024-11-07

Introduction: In Brazil, schistosomiasis is considered a public health problem, mainly affecting rural areas and urban outskirts with inadequate sanitation. In the municipality of Jaboatão dos Guararapes, there are still rural areas, and only part of the territory has adequate sanitation. Due to these factors and the continued occurrence of the disease, the municipality needs to define intersectoral strategies for disease control, such as controlling the proliferation of snails, improving sanitation, and raising awareness through health education for at-risk populations.Objective: To analyze the epidemiological profile of schistosomiasis and describe the control measures used in the municipality of Jaboatão dos Guararapes.Methods: This study consisted of cross-sectional epidemiological research with a descriptive approach. The study was developed using secondary data obtained through SISPCE, encompassing reported cases of schistosomiasis in the municipality of Jaboatão dos Guararapes - PE, from January 2022 to June 2024. The data were evaluated based on the total number of tests performed, the number of positive cases, and the distribution of cases by age group and sex.Results and Discussion: According to SISPCE, 9,713 parasitological stool tests were conducted in the municipality of Jaboatão dos Guararapes, with 6,008 (61.8%) performed on females, 1,923 (19.8%) on individuals aged 51 to 60, followed by 1,517 (15.6%) on individuals aged 61 to 70. Of these, 217 individuals tested positive for the disease.Regarding control measures, the Epidemiological Surveillance routinely provides antiparasitic drugs, such as praziquantel. This medication is essential for treating infected individuals and helps reduce the parasitic load in the community. Additionally, there is a program encouraging healthcare professionals to carry out educational initiatives to inform the population about the risks of the disease, modes of transmission, and preventive measures. The program also promotes community participation in control and prevention actions, such as eliminating snail breeding sites. Another important strategy is the decentralization of parasitological stool tests, which are now conducted by health units, providing the population with more timely access to testing and treatment for the disease. However, despite all the actions taken by the municipal health department, success in combating schistosomiasis depends on an integrated approach involving collaboration among various government sectors and active participation from affected communities.Conclusion: Investment in research, public policies, and control programs is essential to eliminate schistosomiasis as a health problem in Brazil, thus promoting a better quality of life for the population.

Genetic Divergence and Species Delimitation in Biomphalaria Snails Using COI and ITS1 Markers: A Multi-Algorithm Approach

Amanda Domingues de Araújo — 2024-11-07

The genus Biomphalaria contains medically significant snail species that serve as intermediate hosts for Schistosoma mansoni and exhibits complex patterns of genetic divergence and speciation. Morphological identification methods struggle to distinguish cryptic species, making molecular techniques essential for accurate species-level classification. Reliable species identification is essential for understanding schistosomiasis epidemiology, improving disease surveillance and biodiversity conservation efforts. We aim to assess genetic divergence among Biomphalaria populations using COI and ITS1 markers and delimit operational taxonomic units (OTUs) to identify potential cryptic species and genetic lineages. We constructed a database by collecting sequences from NCBI, and snails from the Fiocruz-MG Medical Malacology Collection and the UNM Museum of Southwestern Biology. DNA was extracted, COI and ITS1 genes were partially sequenced, aligned using MAFFT, and phylogenetic relationships were reconstructed using maximum likelihood and Bayesian inference. Identification and delimitation of species were performed using DNA barcoding methodology, applying the BOLD Identification Criteria and Best Close Match approaches, and five species delimitation algorithms: GMYC, bPTP, ABGD, ASAP, and haplotype networks (TCS). Divergence metrics were calculated for each species using DnaSPv.6. Integrating morphological identification, PCR/RFLP analyses and phylogenetic reconstructions, 29 of the 415 COI sequences required taxonomic revisions. Phylogenetic reconstructions resolved well-supported clades for most species, except for the cryptic species pairs B. choanomphala/B. sudanica, B. straminea/B. kuhniana, B. cousini/B. amazonica, and B. peregrina/B. oligoza, which BOLD and BCM analyses also failed to distinguish. In the genetic divergence analyses, both markers corroborated the patterns of genetic proximity observed within the cryptic species complexes. In pairwise comparisons between species, B. schrammi had the highest average nucleotide divergence, suggesting significant evolutionary isolation. Species delineation into OTUs revealed multiple groups within each nominal species, suggestive of high intraspecific diversity and complexity not fully recognized by traditional morphological taxonomy. The presence of mixed groups containing sequences from closely related species suggests the possibility of hybridization or ongoing gene flow between these species. Although the bPTP algorithm identified 43.8% of the groups with medium to high statistical support (gt;0.7), the mixed-species groups tended to have lower support values. TCS analyses revealed haplotype exclusivity for most species, but also indicated potential hybridization. Our multi-algorithm approach reveals the complex patterns of genetic diversity and potential presence of cryptic species in the genus underscoring the need for integrative taxonomic revisions that combine multiple approaches.

Anti-Schistosoma mansoni antibodies detection in Indigenous communities living in low endemicity areas

Maria Cristina Carvalho do Espírito Santo — 2024-11-07

In Brazil, schistosomiasis is caused by Schistosoma mansoni and is present in 19 Federative Units. Around 1.5 million people live in areas at risk of contracting the disease. Transmission is focal in São Paulo and Paraná, not reaching large areas. The presence of transmitting mollusks, poor sanitation, and low human development index contribute to the spread of the disease. In Brazil, the main objectives of the schistosomiasis control program are to reduce human infection in endemic areas and to contain expansion to new geographic areas. This research aimed to evaluate the prevalence of anti-S. mansoni antibodies in sera from six indigenous communities in Paraná State (n = 546) and one in São Paulo State (n = 349). The communities in Paraná, located in the Atlantic Forest, depend on natural resources such as fishing and agriculture and have poor hygiene conditions. In contrast, the community in São Paulo, located in the Cerrado biome, is less traditional, with adequate basic sanitation, an economy centered on agriculture, and many works outside the community. Our research used S. mansoni adult worms to prepare a total extract (TE) and a trichloroacetic acid-soluble fraction (TCA). We then used TE to detect IgG and TCA to detect IgM. By testing a reference panel of 30 positive and 37 negative samples, we achieved a sensitivity (IC 95%) of 90.0% (74.4 - 96.5) and a specificity of 97.3% (86.2 - 99.9) for IgM. IgG showed a sensitivity of 92.6% (76.3 - 98.7) and a specificity of 97.4% (86.5 - 99.9). In samples from Paraná indigenous communities, IgM-ELISA showed a positivity of 0.7% (0.2% - 1.8%), and in IgG-ELISA, a positivity of 0.5% (0.1% - 1.6%) was obtained. Regarding Indigenous from São Paulo, IgM-ELISA gave 1.4% (0.4% - 3.3%) positivity and 0.8% (0.2% - 2.5%) was obtained by IgG-ELISA. When we compared the positivity of the two groups, we found no significant differences between IgM (Chi-square with Yates correction test, p=0.7361) and IgG (Chi-square with Yates correction test, p=0.5531). We highlighted that all positive samples by IgG-ELISA were also positive by IgM-ELISA. These seroprevalence results demonstrated the risk of S. mansoni infections among indigenous populations and the maintenance of the transmission of this parasitic disease.

Epidemiological profile of schistosomiasis in Brazil: an analysis based on public data from the last five years

THIAGO SANTOS DE MELO — 2024-11-07

Introduction: Schistosomiasis is a parasitic disease, acquired mainly through contact with fresh water where there are snails infected with Schistosoma mansoni. According to the Ministry of Health, an estimated 1.5 million people live in endemic areas. It is therefore important to analyze the epidemiological profile in order to understand its distribution and evolution and to contribute to the country's public health strategies. Objectives: To analyze the epidemiological profile of schistosomiasis in Brazil over the last five years based on public data from the Unified Health System (SUS). Methods: This is an ecological and retrospective study based on the Notifiable Diseases Information System of the SUS Information Technology Department (SINAN/DATASUS) on the epidemiological profile of schistosomiasis in Brazil between January 2018 and December 2023. The variables used were: Year, Region, Clinical Form, Evolution, Sex, Color/race and Age Group. Approval from the Research Ethics Committee is not required, as this is public data, with no identification of participants. Results: Between 2018 and 2023, 17,794 confirmed cases of schistosomiasis were recorded in Brazil. The year with the lowest number of cases was 2020, 1,873 (10.5%), and the year with the highest number was 2018, 4, 219 (23.7%). In terms of region, the Southeast had the most positive cases, with 12,322 (69.2%), followed by the Northeast, 4,664 (26.2%), the North, 287 (1.6%), the Midwest, 275 (1.5%) and the South, 241 cases (1.3%). In terms of clinical form, the most relevant was intestinal, 8,960 (50.3%), followed by hepatosplenic, 959 (5.3%), hepatointestinal, 828 (4.6%), acute, 726 (4.0%), and 1,020 (5.7%). Regarding the progression of the disease, 9,687 (54.4%) were cured, 329 (1.8%) were not cured, 434 (2.4%) died from schistosomiasis and 7,150 (40.1%) had the “progression” field ignored. The most positive sex was male, with 10,783 (60.5%), and the least was female, with 7,009 (39.3%). With regard to color/race, the most registered was brown, 10,029 (56.3%), followed by white, 4,901 (27.5%), black, 1, 528 (8.5%), yellow, 181 (1.0%) and indigenous, 66 (0.3%). The age group with the highest number of notifications was 20 to 59 years, with 6,458 (36.2%) cases between 40 and 59 years and 5,558 (31.2%) between 20 and 39 years. Conclusion: Therefore, based on the above data, schistosomiasis is a relevant disease in Brazil, especially in the Southeast and Northeast regions, with the hepatosplenic form as the main clinical manifestation, cure as the main evolution of the disease and, in the epidemiological profile, male individuals, aged between 20 and 59 years and of brown color. It is therefore hoped that this study will make a significant contribution to more in-depth studies on the schistosomiasis scenario in Brazil and will be a step forward in the fight to reduce the incidence of the disease, increase access to healthcare and improve the prognosis for those affected.

Effect of essential oil from the plant Aloysia triphylla on the snail Biomphalaria glabrata

Leticia Pereira Bezerra — 2024-11-07

Introduction: Schistosomiasis mansoni is one of the neglected tropical diseases (NTDs) of great relevance to public health in Brazil and other countries where it is endemic. To combat and reduce the disease in endemic countries, the World Health Organization (WHO) recommends, among other measures, the treatment of human cases and the control of the intermediate hosts of the parasite. Objective: To evaluate the molluscicidal action of the essential oil (EO) of Aloysia triphylla on Biomphalaria glabrata. Methods: Experimental in vivo study, based on behavioral aspects (survival and mortality) of B. glabrata. All experiments were carried out using chlorine-free water and with adult animals (B. glabrata - from the São Lourenço da Mata lineage – Pernambuco, Brazil), measuring 10 to 15 mm in diameter. Initially, we performed an EO screening to verify whether it presented molluscicidal potential. For this purpose, we followed the guidelines established by the WHO for testing candidate molluscicide products. This screening was performed at a concentration of 100 µg/mL, with a volume of 250 mL of water and 5 animals per beaker, randomly arranged into different groups: test group (T = EO + water + 0.001% dimethyl sulfoxide (DMSO)), co-solvent control (CSC = water + 0.001% DMSO), and negative control (C- = water only). After exposure (24h), the animals in the treated and control waters were rinsed, transferred to containers containing water, and fed lettuce; after a 24h recovery period, mortality was recorded for up to 96h post-exposure. Subsequently, we performed Bioassay I, using well plates with volumes of 2 mL per well, using a concentration of 100 µg/mL. This bioassay was performed according to the previous conditions, with 5 animals per group (T, CSC, C-) and positive control (C+ = 1 µg/mL of Niclosamide). This bioassay was performed in technical triplicate. Results: Regarding screening, the EO of A. triphylla showed good results. After 24h of exposure to the EO, we obtained 20% mortality, reaching 100% mortality 48h after exposure. For bioassay I, we observed a disparity between the replicates of group T, receiving in the first replicate, a mortality of 40% after 24h, and reaching 100% mortality 48h after exposure. However, in the second and third replicates, mortality was obtained at 0% and 20%, respectively. Conclusion: Our results indicate that A. triphylla EO is a promising candidate for molluscicide, and can be used to control B. glabrata populations and aid in actions to control schistosomiasis mansoni in Brazil since this is the main species that transmits the parasite Schistosoma mansoni in the country. However, it is necessary to optimize the use of EO in the bioassay involving well plates to better elucidate the effect of the oil on exposed animals, as well as to evaluate the ecotoxicity profile of this EO.

Functional roles of the Schistosoma mansoni tyrosine kinases SmABL1 and SmABL2 in a murine model of infection

Bianca Luiza Moreira Lopes — 2024-11-07

Protein kinases (PKs) regulate complex cellular processes such as metabolism, cell cycle progression, apoptosis, cytoskeleton modifications, and differentiation. Previous studies showed that some PKs in S. mansoni may represent potential targets for anti-Schistosomadrug development, with PK inhibitors, such as Imatinib, affecting the reproductive biology as well as gut integrity of the adult parasite. Specifically, it has been reported that two Abl-kinases (SmABL1/SmABL2) in S. mansoni are targets for Imatinib. To better understand the roles of SmABLs, expression profiling through in situ-hybridization analyses showed that both proteins are expressed around the ootype, ovaries, and vitellaria in female worms, in the testes of males, and weakly in some parenchyma cells and the gastrodermis. In this study, we present an in silico analysis of Smabl1 and Smabl2expression levels at different S. mansoni life stages, using RNA-seq data available on the tool https://lifecycle.schisto.xyz/. This analysis revealed that both genes are more highly expressed in the adult worm stage. To evaluate the function of SmABL1 and SmABL2during S. mansoni infection in the mammalian host, we first synthesized specific dsRNA and exposed, by soaking, newly transformed schistosomula to 200 nM Smabl1-dsRNA or electroporated them with Smabl2-dsRNA. The schistosomula were then maintained in culture, and transcript levels were assessed. The highest inhibition was observed after two and three days for Smabl1 and Smabl2, respectively. Knockdown levels were measured by RT-qPCR, showing a reduction in transcript levels of 98% for Smabl1 and 80% for Smabl2. Next, mice were infected with 350 knocked-down schistosomula and kept for 45 days after which they were perfused for worm recovery. Liver and intestine of each mouse were removed, weighed, and digested to determine the number of eggs. To assess egg maturation, slides were prepared with segments of the ileum. The level of egg maturation in the ileum of animals infected with Smabl1-knocked-down schistosomula showed a 2.5x increase in the percentage of immature and dead eggs, whereas 1.64x decrease in mature eggs was found when compared to the ileum of negative control group. However, there were no significant differences in adult worm recovery, female fecundity, or the total number of eggs in the liver and intestine in the Smabl1-knocked-down group. Conversely, in the Smabl2-knocked-down group, no differences were observed in adult worm recovery, female fecundity, total number of eggs, or egg maturation. In summary, our preliminary results indicate that Smabl1 is associated with egg maturation and may be involved in female reproduction during murine infection.

Diagnosis and risk factors associated with Schistosoma mansoni infection in a population living in an endemic area of Northeastern Brazil

Rosalia Elen Santos Ramos — 2024-11-07

Brazil is one of the countries that the World Health Organization (WHO) has set as a goal to eliminate schistosomiasis as a public health problem by 2030. However, the current scenario is that of a country with 19 of the 26 states of the federation being affected by the disease. This study aimed to evaluate the positivity, parasite load, risk factors associated with Schistosoma mansoni infection in the population, and potential foci of parasite transmission in a municipality in Northeastern Brazil. We carried out a cross-sectional study between January and October 2023, in Feira Grande, Alagoas, to determine the positivity and parasite load of Schistosoma mansoni infections using four slides of the Kato-Katz method, in addition to applying a questionnaire to identify risk factors. We also collected intermediate host mollusks and examined their trematode infection. Spatial analysis was used to identify risk areas, and univariate and multivariate logistic regression assessed the association between disease and risk factors. The overall positivity was 5.5% (n=20), with 90% (n=18) presenting a low parasite load. In the univariate analysis, the predictors of infection by S. mansoni were the age group of 25 to 64 years, marital status married or widowed, occupation as farmer, and the use of water sources such as dams, lakes, reservoirs, wells, or wells. After adjusting for confounding factors, only the occupation of farmer remained associated with a higher risk of infection. Of the 22 water collections identified, 12 were classified as breeding sites and one was considered a focus of transmission from a specimen of Biomphalaria glabrata. We identified four risk areas, two of which had breeding sites for Biomphalaria straminea and one with breeding sites for B. glabrata. Despite the low positivity rate, we found all the necessary conditions for the maintenance of the parasite cycle, associated with both the behavior of the population and the presence of breeding sites and transmission foci. Our results indicate that understanding the particularities of endemic areas is crucial for developing prevention and control strategies adapted to each location.

Tissue reaction of Biomphalaria glabrata (Gastropoda: Planorbidae), sporocyst development and cercarial shedding in populations with different levels of compatibility to Schistosoma mansoni (Trematoda: Digenea)

Cristhiane Oliveira da Fonseca — 2024-11-07

Biomphalaria glabrata is the main intermediate host of Schistosoma mansoni in the Americas, and the availability of experimental models with different levels of compatibility is an important tool for parasite-host interaction studies. Most of the populations are highly compatible with different strains of the parasite and it is challenging to find a low compatibility population. The objective of this study was to evaluate the tissue reaction, sporocysts development and cercarial shedding in a population of B. glabrata that presents low compatibility to S. mansoni LE strain and compare it to other populations. Individual crossings were carried out between pigmented (low susceptibility – LS) and albino snails (susceptible – S), and their progenys (Crossings - CR) were compared to the ones of the groups LS and S. In the CR group, egg masses were collected only from albino S snails. Tissue reaction: F1 snails were fixed at 1, 5, 10, 24, 36 hours and 35 days after individual exposure to 50 miracidia and histological sections were carried out. Sporocysts development: Snails were individually exposed to 8, 20 and 50 miracidia and fixed after 8 to 17 days (N=300/group) and dissected. A highly susceptible population (HS) was included in this analysis. Cercarial shedding: Snails were individually exposed to 8 miracidia (N=45/group), and cercarial shedding was quantified. Tissue reaction: CR and LS groups presented several foci of hemocyte infiltrates in the tissues and hemocyte reactions around most parasites in the first hour. The S group presented a different pattern, since most of the parasites were morphologically intact after 36 hours. In the CR group, degenerated parasites were observed after 36 hours. After 35 days, in the group S, parasites were found in the entire area of the digestive gland, while in groups LS and CR, they were found only in a portion of the organ. Sporocysts development: The HS group presented more sporocysts than S and LS groups. The LS group presented areas of cicatricial tissue and fragmented parasites. The CR group is under analysis. Cercarial shedding: The infection rates were: LS=3%, CR=47%, S=91%. The number of cercaria released was: S(198.202) gt; CR(94,212) gt; LS(1,353) and plt;0.001. The degree of compatibility of these groups was: LS=0, CR=II, S=III. The results indicate that hemocyte reaction was an important component, that negatively influenced the development of sporocysts. The results also show that crossings induced a reduction in compatibility, since reactions occurred mainly in snails with low compatibility to the parasite and in those resulting from crossings with susceptible snails. Considering these findings, the population with low compatibility to S. mansoni LE strain is a potential experimental model in studies of the parasite-host relationship. More studies of this population will enrich knowledge about these interactions and may contribute to the control of schistosomiasis in the future.

Evaluation of the molluscicidal and anti-cercarial activity of the methanolic extract of Pouteria caimito species on Biomphalaria glabrata infected by Schistosoma mansoni

Isis Fernandes Magalhães Santos — 2024-11-07

Schistosomiasis mansoni, a neglected parasitic disease affecting millions of people worldwide, primarily involves the Biomphalaria glabrata snail as its intermediate host. Biological control of this species and the cercariae released into the water is crucial to interrupting the transmission of the disease. In this context, knowledge of secondary metabolites obtained from medicinal plants with biocidal effects emerges as a promising and environmentally friendly alternative for schistosomiasis control. This study aimed to evaluate the molluscicidal and anti-cercarial activity of the methanolic extract of the species Pouteria caimito on Biomphalaria glabrata infected by Schistosoma mansoni. As a methodology, the P. caimito species, popularly known as Abiu, was initially collected. The crude methanolic extract was obtained, and a phytochemical screening was carried out through chemical reactions resulting in color development and/or precipitation, characteristic for identifying metabolites such as flavonoids, tannins, saponins, steroids/triterpenoids, alkaloids, leucoanthocyanidins, and anthraquinones. The cytotoxic activity (Lethal Dose - LD) of the plant was then evaluated with the microcrustacean Artemia salina at concentrations of 0.625 mg/mL, 1.25 mg/mL, 2.5 mg/mL, and 5 mg/mL. For evaluating the molluscicidal and anti-cercarial activity on B. glabrata infected and non-infected by Schistosoma mansoni, concentrations of 0.625 mg/mL, 1.25 mg/mL, and 2.5 mg/mL of the P. caimito extract were used. The results of the cytotoxicity assay showed an LD above 90% at the concentration of 2.5 mg/mL of the extract. In the molluscicidal activity, regardless of the concentration, mortality of the snail was observed between 20% and 33%. Regarding the anti-cercarial activity, the concentration of 2.5 mg/mL prevented the release of cercariae by the infected snail. Although the preliminary results suggest that P. caimito may be a promising source for the biological control of schistosomiasis through the destruction of cercariae and low snail mortality, other concentrations should be tested to avoid compromising the biome in which B. glabrata is inserted.

Parasitological profile of Schistosoma mansoni from the wild rodent Nectomys squamipes in Swiss Webster mice after infection and treatment with Praziquantel

Thayná Couto de Barros — 2024-11-07

Introduction: The mass administration of a single dose of Praziquantel (PZQ) has been recommended by theWorld Health Organization for reducing or eliminating schistosomiasis transmission. The Fio-Schisto program ofFundação Oswaldo Cruz, in Brazil, recommends that the local conditions of each focus, such as socioeconomicand epidemiological characteristics, the role of wild reservoirs, public health policies and the history ofchemotherapy intervention, must be considered. Therefore, studying experimentally the parasitologicalparameters after the use of PZQ is essential as an indicator of PZQ resistance or elimination of parasite infection.Objective: To investigate the effects of PZQ treatment on the parasitological parameters of S. mansoni, such asthe number of worms recovered, the number of eggs eliminated in feces and the viability of eggs in intestinaltissue. Methods: Experimental infections were conducted in 18 outbred mice individually infected with 120cercariae via transcutaneous route through the tail. The mice were divided into three groups of six animals each:1) the infected control group (IC); 2) the infected group and treated with 3× 150 mg/kg PZQ (IT150) (50% LD);and 3) the infected group and treated with 3× 300 mg/kg PZQ (IT300) (90% LD). The treatment occurred at 50,51, and 52 days post-exposure, and the mice were necropsied 15 days later. The elimination of parasite eggs infeces was determined by the number of eggs per gram of feces (EPG) using the Kato-Katz and the Hoffmanmethods at 42, 45 and 48 days before treatment and at 60 and 63 days after treatment. The oogram method wasused to quantify the number of S. mansoni eggs retained in the intestinal wall tissue. The worms were washed insaline solution (0.85% NaCl), counted to determine the parasite load after treatment and stored individually in70% ethanol at -20°C. Results: The pre-patent period varied from 45 to 48 days after infection, depending on thediagnostic technique used. Both the Kato-Katz and the Hoffman methods resulted in a progressive increase in thenumber of eggs released in the IC group until 60 days post-infection. In the treated groups, there was a decreasein the number of eggs after treatment with both doses until no eggs were observed at the end of the experiment. Asignificant increase in eggs without miracidia was observed in the second through fourth intestinal segmentstrapped in the intestinal wall. An 85.5% reduction in parasite load (p = 0.04) was observed after 300 mg/kg PZQtreatment, with greater efficacy in male worms. Conclusion: This study demonstrated that in experimentalinfection of mice with a wild-type strain of S. mansoni, the treatment with PZQ led to a reduction in the parasiteburden and number of eggs in feces and an increase in the number of eggs without miracidia trapped in theintestinal wall, contributing to the approach proposed by the Fio-Schisto program regarding the role of wildrodents as reservoirs.

Biological activity of Abelmoschus esculentus extracts on mollusks and embryos of Biomphalaria glabrata (SAY, 1818) and Schistosoma mansoni Cercariae.

Keyla Nunes Farias Gomes — 2024-11-07

Schistosomiasis is a neglected tropical disease caused by parasites of the genus Schistosoma. It is the second most prevalent infectious parasitic disease and has a major impact on socioeconomic factors, overall morbidity, and public health. According to the World Health Organization (WHO), this disease has been reported in 78 countries, 52 of which are endemic. The presence of snails as intermediate hosts for schistosomes, along with socioeconomic factors like inadequate sanitation, is linked to the occurrence of the disease. Therefore, controlling snail populations is an essential preventive measure. In Brazil, S. mansoni is the only species reported to cause infections so far, with three species of snails acting as intermediate hosts: Biomphalaria tenagophila, Biomphalaria straminea, and Biomphalaria glabrata. Among these, Biomphalaria glabrata has a wider geographic distribution and a higher susceptibility to infection by the parasite compared to the other species. According to the WHO, the only molluskicide recommended for controlling intermediate hosts is niclosamide®. However, this product has high toxicity to the environment and has been used to treat mollusk infections. Therefore, it is necessary to discover and develop new compounds originating from natural products with molluskicidal activity. The species used in this work was Abelmoschus esculentus. The objective of the present study was to evaluate the molluskicidal effect of crude extracts of A. esculentus seeds on embryos and mollusks of B. glabrata and cercariae of S. mansoni. The seeds were collected in Araruama, Rio de Janeiro. The crude extract was extracted using a Soxhlet extractor. The following solvents were used: ethyl acetate, acetone, dichloromethane, ethanol and hexane. The molluskicidal, ovicidal and cercaricidal activity assays were performed in 24-well plates. They were evaluated for of 24 and 48 hours, except for the Cercaricide assay, which was evaluated for a period of 4 hours (kinetics). In the tests, water and dimethyl sulfoxide (1% DMSO) were used as the negative controls and niclosamide was used as the positive control. In the molluskicide test, the crude extract in acetone had a mortality rate of 75 ppm (33.33%) and a mortality rate of 100 ppm (100%). In the ovicidal assay, the crude extracts in hexane and ethanol showed 92.56% and 100% mortality, respectively, at a lethal concentration of 90. In the Cercaricide test, among the extracts used, the crude extract in dichloromethane showed a mortality of 100% at the lethal concentration 90. According to the results obtained, the crude extracts influenced the mollusks, embryos and cercariae of S. mansoni; however, more studies are needed.

BUILDING KNOWLEDGE ON SCHISTOSOMIASIS MANSONI: EDUCATIONAL INTERVENTIONS AND EPIDEMIOLOGICAL INSIGHTS IN MURITIBA, BAHIA

Victor Rosa Monte Belo — 2024-11-07

Schistosomiasis mansoni (SM) is a parasitic disease caused by Schistosoma mansoni, transmitted via freshwater contaminated by snails of the genus Biomphalaria. The Recôncavo region of Bahia, including Muritiba, has historically faced significant public health challenges related to SM due to the presence of rivers and water bodies that facilitate transmission. Between 2011 and 2021, Muritiba recorded 2 confirmed cases of SM, with no reported treatments. However, neighboring municipalities such as São Félix and Maragogipe reported much higher case burdens, with 1,288 and 2,102 cases, respectively, indicating substantial local transmission risks. To address this, we designed two complementary educational interventions aimed at raising awareness and understanding of SM in Muritiba and surrounding areas. The first initiative, implemented by the Human Parasitology Study Group (GEPaH), involved an interactive parasitological stand at the Multidisciplinary Pathology Seminar (SEMULPATO) in Muritiba. Through various educational tools—including biscuit models of the parasite life cycle, microscopy slides, and health fair-style engagement—the stand catered to diverse audiences ranging from schoolchildren to community elders. By adapting scientific content to different knowledge levels, the initiative fostered a deepened understanding of SM transmission, prevention, and diagnosis within the local population. The second intervention, conducted at the Health Sciences Center of the Federal University of Recôncavo of Bahia, utilized playful learning methods, such as a life-sized board game and interactive banners displaying SM epidemiology and life stages. This "Dialogues and Biointeractive Interactions" (DBI) event engaged university students, healthcare professionals, and community members, promoting SM awareness through engaging, game-based learning. Participants answered questions about the parasite’s life cycle, prevention strategies, and the role of the Biomphalaria snail, enhancing their knowledge in an enjoyable, competitive setting. Both initiatives highlight the effectiveness of combining scientific education with interactive, community-focused outreach. The integration of playful pedagogical tools and microscopic visualization provided a creative platform for disseminating knowledge about SM. These efforts not only increased awareness but also empowered participants to become health advocates within their communities. The prevalence of SM in the region underscores the need for continued education and community engagement to control the spread of the disease. Our interventions, complemented by epidemiological data, emphasize the vital role of health education in regions facing parasitic disease challenges and foster university-community collaborations for sustainable health solutions.

Profile of Hospitalizations for Schistosomiasis in the Five Main Capitals of the Northeast: Comparative Epidemiological Study of the Last 10 Years

Marcos Vinícius Lobo Milhor — 2024-11-07

Introduction: Schistosoma mansoni, which causes schistosomiasis mansoni, is classified by the World Health Organization (WHO) as a neglected tropical parasitic disease of waterborne transmission, with clinical manifestations classified into phases: acute, chronic and severe. According to the WHO, 251 million people are affected worldwide, with a high incidence in Latin America, Africa and the Eastern Mediterranean. In Brazil, it is estimated that 1.5 million people live in areas at imminent risk of contracting the disease, with the states with the highest prevalence being in the Southeast and Northeast regions. The Northeast due to the high prevalence in endemic areas and the severity of cases, which can evolve into more serious forms, such as hepatosplenic and medullary neuroschistosomiasis, both of which can lead to serious complications and/or death, thus, the disease is a relevant concern for public health in Brazil.Objective: To analyze the epidemiological profile of patients with schistosomiasis in the Northeast over the last ten years and to draw a comparative context between the five main capitals, Salvador (SSA), Fortaleza (FOR), Recife (REC), São Luís (SLS) and Maceió (MAC).Method: This is an epidemiological, ecological, retrospective and descriptive study, with data from SIH/DATASUS, from 2015 to May 2024. The analysis of the epidemiological profile between the capitals was performed using the statistical software Statistical Package for Social Science for Windows (SPSS), considering the number of hospitalizations, sex, ethnicity/self-declared color and number of deaths. Results: Of the 1,574 hospitalizations in Brazil, 765 (48.6%) occurred in the Northeast, and 66 (8.63%) of these were in the five main capitals. Of the total among the capitals, REC had 46.97% of the cases, followed by SSA (33.33%); SLS (10.61%); FOR (7.58%) and MAC (1.51%). Men predominated in hospitalizations (56.06%), except in REC, where women were the majority (54.84%). Regarding ethnicity, most hospitalizations were of mixed race (51.51%), followed by white (3.03%) and black/yellow (1.52% each), but 42.42% of the records did not indicate ethnicity. The most affected age groups were 40-44 years and 55-59 years (12.12% each). There were 3 deaths in the period, with fatality rates of 9.09 in SSA (2) and 14.29 in SLC (1) for every 100 hospitalizations. Conclusion: The capitals, despite concentrating the majority of the population of the Northeast, presented a small portion of hospitalizations. Most cases are possibly distributed in smaller cities with higher poverty rates, highlighting the relationship between schistosomiasis and the lack of basic sanitation. Men aged between 40 and 59 years old accounted for the majority of hospitalizations. Greater efficiency of control and sanitation strategies was observed in large urban centers, mainly SSA and REC, which, despite being the most populous, did not lead, proportionally, in the number of cases.

Active Surveillance: Investigation of Schistosomiasis cases and vectors in a historical endemic municipality of Alagoas, Brazil.

Thuelly Juvencio da Rocha — 2024-11-07

In Brazil, schistosomiasis is exclusively caused by Schistosoma mansoni and presents high endemicity where mollusk species, the intermediate hosts, are distributed, and where basic sanitation is considered inadequate. Alagoas is one of the Brazilian states with historical endemicity, recording 70 endemic municipalities out of 102. The aim of this study was to assess the frequency of schistosomiasis in a rural population in the municipality of Viçosa-AL and to check for the presence of the parasite in the environment through malacological investigation. The study area is located along the banks of the Paraíba River. A total of 169 stool samples were collected and analyzed by Kato-Katz (KK) and Helmintex (HTX) methods. These techniques are considered the gold standard and highly sensitive, respectively, for the diagnosis of schistosomiasis. The collection of mollusks occurred along the riverbanks, near the residences of the studied population. A total of 120 snails were collected, of which 24 died during transport to the laboratory, leaving 96 animals for experimentation. The analysis of the snails consisted of 6 weeks of photo exposure followed by crushing for malacological diagnosis. The taxonomic identification of the specimens was performed according to the dissection method and evaluation of the morphological parameters indicated by the Ministry of Health. The results showed that the use of two direct coprological techniques allowed for more efficient screening of positive human cases: 18.7% of the samples were positive by KK and 72.29% were positive by HTX. The overall prevalence of schistosomiasis reached 66.28% (112/169) in the studied population, a high rate even for an endemic region. The evaluation of parasitic load using two KK slides in the analyzed samples showed that most positive cases had low parasitic load (87.1% or 27/31), while 12.9% (4/31) presented moderate parasitic load, and no cases of high parasitic load were identified. Therefore, the studied region maintains the epidemiological pattern seen in most other endemic areas for this parasitosis, where interventions by the PCE (Schistosomiasis Control Program) occur repeatedly but without total elimination of the infection. No snail was identified releasing cercariae of S. mansoni, nor were any sporocysts found in the crushed animals. The specimens were identified as belonging to the Biomphalaria straminea complex, which groups the species B. straminea, B. kuhniana, and B. intermedia, due to their great morphological similarity. Resources from integrative taxonomy, such as the use of molecular methodologies, are needed for species confirmation. Based on the results obtained, it was possible to identify the infected population but not the identification of positive Biomphalaria sp. Therefore, new malacological and environmental analyses are needed in a spatiotemporal dynamic to locate the potential transmission focus of the disease in the studied area.

TEMPORAL ANALYSIS OF SCHISTOSOMIASIS POSITIVITY IN A RURAL BRAZILIAN COMMUNITY UNDERGOING REPEATED PRAZIQUANTEL INTERVENTIONS

Brenda Rodrigues Brito Cunha Silva — 2024-11-07

Introduction: Northeastern of Brazil is one of the most affected areas by schistosomiasis, even with interventions promoted by the Ministry of Health. Numerous treatments have been carried out since the creation of the Schistosomiasis Control Program, however, we have observed that the prevalence of the disease in some areas remains high, despite the reduction in the parasite load. Methodology: The positivity rate and parasite load of Schistosoma mansoni were evaluated using the Kato-Katz test in individuals from the rural area of Conde, Brazil, from independent cross-sectional studies (CS) carried out between 2001 and 2018, as well as the response of these individuals to treatment with praziquantel. Results: Data on the positivity rate and parasite load of 2,628 individuals included in six CS carried out in 2001, 2004, 2008, 2010, 2014 and 2018 were evaluated. Regarding the parasite load, most individuals remained below 99 epg. In this regard, the lowest parasite load observed among the CS was in 2010 (36– IQR 12–90) epg and the highest was in 2014, (108– IQR 24–516) epg. In 2010, significant differences in parasite load were observed between all age groups when compared to the group ≥ 60 years (p lt; 0.0001). The parasite load was higher in the ≥ 60 years groups (96 – IQR 72-219 epg) compared to the 0 to 9 years (30 – IQR 12-99 epg), 10 to 19 years (36 – IQR 16-78 epg), and 20 to 59 years groups (36 – IQR 24-48 epg). In 2001, differences were observed between the groups 0 to 9 years (48 – IQR 24 – 156, p= 0,0071) and 10 to 19 years groups (120 – IQR 48-264, p = 0,0080), compared to the ≥ 60 years group (24 – IQR 24-60). In 2010 and 2018, the median parasite load was consistently higher in the elderly group (60–90 years), reaching 96 (IQR 72–219) epg in 2010, and 96 (IQR 48–804) epg in 2018, despite a general decreasing trend over time. Evaluating these independent studies, with their respective treatments, we can observe a reduction in positivity rate of 70,0% in 2021 to 55,6% in 2018 and in parasite load p lt; 0.0001 (42.9%) for S. mansoni, indicating that praziquantel can temporarily reduce the prevalence of Schistosoma mansoni, as observed in 2018, where we saw a 96.9% reduction in prevalence 30 days after treatment, and an increase of 13.4% 1 year after treatment. Between 2010 and 2014 there was only one treatment (2010), which resulted in a 66.1% increase in prevalence and 300% in parasite load (p = 0.0002) in 2018. Conclusion: It is concluded that, although treatment with praziquantel has high cure rates, and subsequent reduction in parasite load, it is not sufficient to eliminate transmission in the medium-long term, due to the characteristics and habits of the affected populations.

Spatial Distribution of Schistosomiasis in an Endemic Municipality in Pernambuco.

Natália Oliveira Spinelli — 2024-11-07

Introduction: Jaboatão dos Guararapes is located in the metropolitan region of Recife and has the second-largest population in the state of Pernambuco, with about 630,000 inhabitants. It covers an area of 258.724 km², comprising both urban and rural zones. Due to its spatial characteristics and demographic density, understanding the geographical aspects of public health events adds more quality to the analysis of information. In this sense, spatial distribution involves a set of techniques used for the manipulation of spatial information aimed at conducting studies, planning, and decision-making in various areas, including public health.Objective: To use spatial distribution as a tool for planning and management in public health.Method: For georeferenced visualization, the QGis program was used with data available in the SISPCE from patients residing in the municipality who tested positive for schistosomiasis.Result: From 2022 to 2024, it was observed that the disease was present in all seven health regions. The highest number of parasitological exams was conducted in Region V (Prazeres and Cajueiro Seco), followed by Region VI (Candeias, Piedade, and Barra de Jangada). Region VI had the highest number of positive cases, particularly in the Barra de Jangada neighborhood, where the Nautical Lagoon is located.Discussion: Georeferencing assists managers and health teams by exposing epidemiological data that contribute to the planning of health actions. Additionally, the combination of geoprocessing with monitoring tools provides a more specific understanding of spatial patterns and trends, facilitating the implementation of more effective and sustainable policies and actions. Regarding epidemiological surveillance, the use of geospatial data helps identify high-risk areas and patterns of spread, allowing spatial analysis of disease outbreaks and facilitating the identification of infection sources and transmission routes. In terms of health management, maps can be used to develop predictive models that estimate the risk of disease outbreaks based on environmental and climatic factors, allowing the simulation of different intervention scenarios, as well as evaluating the effectiveness of disease control and prevention measures. As a limitation of this type of study, the quality and reliability of the data, the lack of structured municipal geographic information systems, the absence of digital cartographic bases, and official address records, especially in underserved areas such as informal settlements, stand out.Conclusion: Geoprocessing is essential to face current and future challenges in public health, as it allows for a more efficient approach to managing health problems, contributing to the prevention of diseases and outbreaks, better allocation of resources, and rapid responses to emergencies.

Health Education x schistosomiasis: prevention and control of the disease as a tool to strengthen Health Surveillance in the north of Minas Gerais

Diane Aparecida Oliveira de Menezes — 2024-11-07

Introduction: Educational approaches are valuable actions for the control of endemic diseases, and should also be used in neglected diseases, which can be considered non-free and underreported, such as schistosomiasis in some parts of the country. Objectives: To understand the epidemiological profile of cases in the Pirapora Health Region – Minas Gerais; Check the response capacity of municipal teams to the existence of the problem; Assess, from the point of view of municipal teams, the need for health education approaches. Methodology/Development: To carry out the study, the territory was delimited, belonging to the northern macro-region of the state of Minas Gerais, covering seven municipalities: Buritizeiro, Ibiaí, Lassance, Pirapora, Ponto Chique, Santa Fé de Minas and Várzea da Palma. It has 51 Family Health Teams, estimated care coverage is 88%, with 7 Health Surveillance teams. The data was extracted from the Notifiable Diseases Information System (SINAN), in the historical series from 2014 to 2023. Applied The Google Forms form was used, with qualitative assessment on the topic “Education and Health Promotion in Schistosomiasis” for municipal teams. Results: Cases were reported in 100% of the municipalities, with 29 notifications in the confirmed series. Of the total number of cases reported, the highest concentration occurred in the municipality of Pirapora with 11 notifications (38%), followed by the municipality of Ibiaí with 06 cases (11%). Regarding the question whether the schistosomiasis program is implemented in the municipal service, 83.30% highlighted yes; 50% reported that they report cases, with 83.30% stating that their teams are capable of reporting suspected cases; 100% of municipalities have an established notification flow to direct action. In general, 83.30% declared that they have average knowledge and capacity to respond to the problem and need partial support from the state, while 16.70% have low knowledge and need full support from the state to carry out program actions. Regarding education and health promotion actions, 100% of municipalities carry out such actions. Regarding the promotion of training, 100% of the municipalities highlighted that they need such an activity, which is routinely promoted by the State Department of Health of Minas Gerais. Conclusions: Although the study health region is not located in an unaffected area in the north of Minas Gerais, cases were reported in the municipalities. As it is not part of the scope of epidemic diseases in the study territory, the occurrence of specific cases may favor underreporting. There is a need to strengthen education and health promotion actions.

Evaluation of the reactivity of 17 peptides and a multipeptide against Schistosoma mansoni infection

ANA CRISTINA LOIOLA RUAS — 2024-11-07

The trematode of the species Schistosoma mansoni is the etiological agent of schistosomiasis mansoni, one of the neglected tropical diseases that is of greatest concern to public health due to the prevalence of its severe forms and the large number of deaths that occur worldwide. Currently, the standard diagnosis recommended by the WHO is the Kato-Katz parasitological method, which performs well in regions with high infection intensity. However, low sensitivity in regions with low intensity makes diagnosis difficult and masks the real number of infected individuals, interfering with their treatment and proper control of the infection. The objective of this work was to validate, through the Enzyme-Linked Immunosorbent Assay (ELISA), 17 peptide targets derived from the S. mansoni proteome, previously identified and selected by bioinformatics and immunoblotting, in their individual forms and in multipeptide form, in addition to evaluating recognition at different infection intensities. For this purpose, 33 sera from infected individuals from the endemic area of Januária/MG (23 of low intensity; 8 of moderate intensity and 2 of high intensity) and 7 sera from uninfected individuals from a non-endemic area were used. Of the 17 peptides, 6 presented satisfactory reactivity frequency, being above 30% in their individual forms. With the multipeptide, a reactivity frequency of 54.5% was observed. When different infection intensities were evaluated, the multipeptide showed greater recognition of low-infection individuals (65.2%), when compared with the recognition of the 6 individual forms. Through these results, we can conclude that the use of peptides in the recognition of S. mansoni infection in its different forms represents a promising tool to aid in tracking and improving the diagnosis of the infection, especially in areas of low-intensity infections.

Expression and purification of a recombinant chimeric antigen for diagnosis of schistosomiasis mansoni

Natália Adriely Ribeiro da Silva Costa — 2024-11-07

Introduction: Schistosomiasis is a neglected disease caused by the helminth Schistosoma mansoni. The Kato-Katz parasitological diagnostic method, which is recommended by the WHO and the Brazilian Ministry of Health, has low sensitivity for detecting infected individuals with a low parasite load. Thus, the ELISA detection method may be indicated for alternative or complementary diagnosis in patients with suspected S. mansoni infection. However, the known antigens used in ELISA have low sensitivity and cross-react with other diseases. An alternative is the use of recombinant chimeric antigens, which consist of a combination of immunodominant antigenic epitopes from S. mansoni proteins, which allows for an increase in the sensitivity and specificity of the test. Objective: This work aimed to optimize the expression and purification of a recombinant chimeric antigen in order to evaluate it and use it in an ELISA immunological test for diagnosing patients with schistosomiasis mansoni. Methods: To optimize the expression of the chimeric antigen, induction was evaluated at temperatures of 30°C for 3h, 37°C for 2h and 18°C for 16h in the BL21 strain and 18°C for 24h in the Arctic strain. Next, a solubility test was carried out with the antigen, in which the cells were resuspended with solution without and with different concentrations of urea (2M, 4M, 6M and 8M). After assessing solubility, a new induction was carried out and the antigen was purified by affinity column chromatography using AKTA start equipment. Once quantified on a gel, the chimeric antigen was used in an ELISA immunoassay at a concentration of 100 ng and a dilution of 1:50 of the sera of five schistosomiasis-positive patients with different parasite loads and five negative patients. Along with the chimeric antigen, the soluble egg (SEA) and adult worm (SWAP) antigens were used as positive controls for S. mansoni infection. The serum samples used were obtained from the Biorepository of the Schistosomiasis Reference Laboratory of the Aggeu Magalhães Institute, approved by the Human Research Ethics Committee under opinion numbers 5.905.584 and 7.020.057. Results: Induction showed good results at all temperatures in both strains, but the best was at 30°C for 3 hours in the BL21 strain, which presented a higher concentration of the protein after the induction period. Regarding the solubility test, the concentrations that yielded the most protein levels in the supernatant were 4, 6 and 8 M. The ELISA test showed a cutoff of 0.120 for the chimeric antigen, with no false positives or false negatives, but there was no differentiation between the parasite loads. Conclusion: The chimeric antigen has the potential to be used in the ELISA diagnostic test, as it can be detected in serum samples from patients with the disease. However, it is still necessary to test with a larger number of samples to evaluate its sensitivity and specificity.

Spatial and spatiotemporal analysis of schistosomiasis mansoni positivity in Alagoas: a 10-year retrospective

Francisco Lucas Silva de Lima — 2024-11-07

Introduction: Schistosomiasis mansoni is an important waterborne disease in Brazil, closely associated with socioeconomic, structural, cultural, and political factors. Objective: To analyze the spatial and spatiotemporal distribution of positivity rates for schistosomiasis mansoni in Alagoas between 2012 and 2021. Methods: This is an ecological study with a spatiotemporal approach. Data were obtained through the Schistosomiasis Control Program Information System (SISPCE). To this end, we considered positivity rates for the disease by the municipality in Alagoas. We verified the existence of autocorrelation using the Global Moran Index (GMI) and identified municipalities presenting similar patterns through the Local Moran Index (LMI). Risk clusters were identified using Kulldorff's spatiotemporal scanning analysis. Results: Throughout the studied period, 73,325 positive cases of Schistosoma mansoni infection were recorded in the state. The positivity rate for the disease is distributed heterogeneously across the endemic Health Regions (HR) of the state, with the majority of positivity rates lt;5.0 (low endemicity). Our analysis also identified 20 municipalities in the state with average endemicity (rates between 5.1 and 15.0). Only 1 municipality (Branquinha) had a positivity rate higher than 15.0 (high endemicity). Furthermore, we identified positive spatial autocorrelation (IMG = 0.52308; p = 0.001). A total of 16 municipalities presented a Q1 (high/high) pattern, high risk for the disease, located in the 1st, 2nd, 3rd, 4th, and 6th HR. Another 30 municipalities located in the 7th, 8th, 9th, and 10th HR presented standard Q2 (low/low), low-risk areas, it is noteworthy that the 9th and 10th HR are not endemic for the disease. The spatiotemporal scanning analysis revealed 2 high-risk clusters, with the primary cluster being present in all endemic HR in the state, with a relative risk of 11.06 (p lt;0.001) and likelihood ratio of 46895.10. Conclusion: These data demonstrated that the areas at risk for schistosomiasis are mainly concentrated in municipalities in the 3rd, 4th, and 6th HR of the state. Furthermore, most municipalities have low endemicity, which may indicate that the state has taken promising steps in controlling the disease. However, the profile of serious infections within these municipalities needs to be better elucidated, to demonstrate that the state has reduced the number of serious infections to less than 1%, as the WHO aims to eliminate schistosomiasis as a public health problem.

Evaluation of the Th1/Th2/Th17 cytokine profile association with liver fibrosis in individuals infected with Schistosoma mansoni

Maria Eduarda da Silva Pereira — 2024-11-07

Introduction: In Brazil, schistosomiasis is a parasitic disease caused by the blood parasite Schistosoma mansoni. Its clinical manifestations are due to hepatosplenic involvement resulting from the development of periportal fibrosis in response to the presence of the parasite egg in the tissue, which is responsible for the morbidity and mortality associated with the disease. However, the associated immunological mechanisms have been insufficiently explored regarding the search for biomarkers of clinical progression. The aim of this study was to associate the cytokine profile produced in vitro by peripheral blood mononuclear cells (PBMC) from infected individuals with different degrees of fibrosis. Methodology: soluble egg antigen (SEA) was produced from frozen eggs kindly provided by the Biomedical Research Institute's Schistosomiasis Resource Center (NIH-NIAID HHSN272201700014I). Briefly, the eggs were broken down using the cell and tissue disruptor L-BEADER 6 (Loccus, São Paulo, Brazil), followed by ultracentrifugation. Protein concentration was determined using the BCA kit (Thermo Scientific, Rockford, USA). Peripheral blood was collected and 3x106 PBMCs were isolated from 10 infected individuals with ultrasonography (USG) patterns A or B (considered as group without fibrosis), 7 individuals with fibrosis pattern C, 6 individuals with fibrosis pattern D and 4 individuals with fibrosis pattern E. PBMC’s were then stimulated with 10 ug/mL of SEA for 48 hours. Culture supernatant was collected and subjected to cytokine quantification using the BD™ Cytometric Bead Array (CBA) Human Th1/Th2/Th17 kit. Statistical analyses were carried out using GraphPad Prism 8.0.2 software. This project was approved by the Research Ethics Committee (protocol number 5.905.584). Results: A statistically significant reduction in IL-10 was observed in the group with fibrosis pattern E when compared to the group without fibrosis (p = 0.04). In the group of infected individuals without fibrosis, a significant positive correlation was observed between IL-6 and IFN- cytokines (r = 0.74, p = 0.017) and also between IL-6 and IL-10 (r = 0.87, p = 0.02). In the group with fibrosis pattern C, a significant positive correlation between IL-6 and IL-10 (r = 0.96, p = 0.003) also occurred. As the severity of fibrosis in the groups increased, an elevation of the IFN-y levels (R2 = 0.899, p = 0.206) and a reduction in IL-10 and IL-6 levels (R2 = 0.992 and 0.947, respectively) were noted. Conclusion: The results suggest that IL-10, IL-6 and IFN-γ cytokine levels may be associated with fibrosis patterns in the liver as revealed by USG. Ongoing experiments with a larger sample size of individuals may ascertain whether these cytokines can be utilized as blood markers for fibrosis in human schistosomiasis.

Differential expression of miRNAs in susceptible and resistant strains of Biomphalaria spp. to Schistosoma mansoni and establishment of Biomphalaria glabrata embryonic cells (Bge) cell cryopreservation.

João Gabriel Rodrigues Vieira — 2024-11-07

Schistosomiasis is prevalent in impoverished populations. In Brazil, the disease is caused by Schistosoma mansoni and three species of the genus Biomphalaria are the intermediate hosts: Biomphalaria glabrata, Biomphalaria tenagophila, Biompalaria straminea. The susceptibility of these molluscs to S. mansoni is influenced by environmental, physiological, genetic, and behavioral factors. Differential expression of microRNAs also may play a role in parasites development, and influence hosts susceptibility. MicroRNAs expression may be studied in vivo or in vitro. However, studies with cells are less complex and cost and labor-effective; and the use of cell cultures is a viable approach for developing techniques and practices that can be initially established and later transferred to whole organisms. Thus, we are working with both approaches. First we focused on quantifying and comparing the expression of two microRNAs (miR-750 and miR-1984) in Biomphalaria spp. strains exposed or not exposed to S. mansoni. To further explore molecular aspects, this study also aims to establish an effective protocol for cryopreservation of B. glabrata embryonic cells (Bge) and evaluate miRNAs expression in this model. Snails: Hemolymph and head/foot region RNA extraction from infected and non-infected molluscs was followed by Reverse Transcription-quantitative PCR (RT-qPCR) assessments, revealing the microRNAs expression profiles. Both miRNAs were expressed in all evaluated molluscs. In other invertebrates, miR-750 is related to development and immune system regulation. Expressions in the susceptible B. straminea population do not significantly change between the two miRNAs. In B. glabrata and B. tenagophila species the negative regulation of miR-750 and miR-1984 in strains resistant to S. mansoni infection suggests a possible relationship with the host's immune response, conferring resistance to the parasite. BgE: Selected and nonspecific miRNA inhibitors (anti-miR) were designed and used in the in vitro transfection of Bge cells. The cells were co-cultured for 24 h with S. mansoni sporocysts transformed in vitro. Cell morphology will be evaluated, and the cell adhesion index will be calculated. A decrease in miR-750 and miR-1984 expression was observed in Bge cells after exposure to S. mansoni sporocysts. Also, no high mortality rate was observed in Bge cells exposed to anti-miRs. In parallel, for developing an effective cryopreservation protocol, Bge cells were frozen and thawed using different media and procedures. We standardized a protocol with the addition of 5% DMSO during freezing, followed by a specific thawing process using a water bath, centrifugation, and subsequent cell maintenance for one week, ensuring better viability of Bge cells. Elucidating the function of miRNAs, in Bge model and molluscs, is an important point in understanding the susceptibility and resistance to infection of the intermediate host.

Application of PCR for the identification of Biomphalaria species and Schistosoma mansoni infection in mollusks from a region with high schistosomiasis prevalence in Sergipe.

ELICIA GIOVANNA COSTA DOS SANTOS — 2024-11-07

Schistosomiasis is a parasitic disease caused by the trematode Schistosoma mansoni, with mollusks of the genus Biomphalaria serving as its intermediate hosts and humans as the definitive hosts. In Brazil, approximately 1.5 million individuals are currently affected, predominantly in the North and Northeast regions, with Sergipe exhibiting the highest prevalence nationwide. Despite this, the Schistosomiasis Control Program (PCE) remains inactive in several municipalities within Sergipe, including São Cristóvão, which experiences a notably high prevalence of the disease. Objectives: The primary goals of this study were to identify schistosomiasis-transmitting mollusks in São Cristóvão, Sergipe, utilizing PCRRFLP (PCR-Restriction Fragment Length Polymorphisms) for species identification, and to detect S. mansoni infection in these mollusks using conventional PCR techniques. Methodology: Mollusks were collected from four regional locations and transported to the Laboratory of Tropical Entomology and Parasitology at the Federal University of Sergipe (LEPaT/UFS). DNA was extracted from the mollusks using the Wizard Genomic DNA Purification Kit (Promega), adhering to the manufacturer's protocols. Following DNA extraction, PCR-RFLP was performed to determine the molecular profiles and identify the mollusk species, while conventional PCR was used to detect S. mansoni infection. Results: A total of 454 mollusks were collected, and DNA was extracted from 63 specimens. The analysis revealed a significant prevalence of S. mansoni infection at 28.6% (18/63). All mollusks were identified as Biomphalaria glabrata, the predominant species in Sergipe. Conclusions: Mollusks infected with S. mansoni were identified at two collection sites within the municipality, indicating that the populations in these areas are at risk of infection. As schistosomiasis is classified as a Neglected Tropical Disease (NTD) primarily impacting impoverished communities, the enhancing of molecular analysis techniques, such as PCR, is essential for the effective operation of the PCE. This improvement will facilitate more efficient and costeffective environmental surveillance, thereby contributing to the implementation of effective control measures.

Immune profile of chimeric elastase containing T-cell epitopes (SmCET) from Schistosoma mansoni

Paulo Emílio de Oliveira Cruz — 2024-11-07

The hygiene hypothesis supports the increased prevalence of allergies in developing countries. Such diseases, characterized as the most common chronic immune disorders, lack definitive cures, making the development and availability of treatments essential. Among the major causes of allergies, dust mites, such as Blomia tropicalis, stand out as significant sources of aeroallergens in the Brazilian population. In this context, allergen-specific immunotherapy has gained relevance as a viable alternative to pharmacotherapy due to its ability to modulate the immune response and potentially alter the natural course of allergic diseases. Since helminth infections activate immune mechanisms similar to allergic responses—promoting Th1 response polarization and modulating Th2 responses through immune evasion strategies—recombinant molecules from S. mansoni present a promising treatment option. Molecules from the cercarial stage, such as cercarial elastase (SmCE), can regulate inflammatory mediators and influence both Th1 and Th2 responses, depending on the phase of infection. This study aimed to evaluate the immunoregulatory and immunomodulatory profile of a chimeric protein, SmCET, designed with T-cell epitopes from SmCE, using in vitro stimulation of PBMCs from allergic and nonallergic individuals sensitized to B. tropicalis. PBMCs offer a comprehensive representation of immune responses, covering various immune cell types, such as T and B cells, involved in allergic reactions and regulatory mechanisms. The chimeric protein was designed based on T-cell epitope predictions from different isoforms of SmCE, with peptide ligands incorporated into the construct. The three-dimensional structure of the protein was predicted using modeling tools. For protein expression, the cDNA sequence encoding the chimeric protein was synthesized into plasmids and transformed into E. coli strains (Star and Rosetta). The recombinant protein was purified, dialyzed, and quantified. Mite extract was also prepared. Venous blood samples were collected from both allergic and non-allergic individuals sensitized to B. tropicalis. To assess IgE reactivity to mite proteins, an indirect ELISA was performed. PBMCs were isolated and stimulated with the chimeric protein SmCET for 48 and 72 hours. Following incubation, cell viability was assessed, and the culture supernatant was analyzed for cytokine production, including IL- 1β, IL-4, IL-5, IFN-γ, IL-10, IL-13, and TNF-α. Results showed that SmCET significantly stimulated IL- 1β production and inhibited IL-13 levels in both allergic and non-allergic individuals, while other cytokine levels remained at basal levels. No changes were observed in cell viability tests, indicating that the protein did not affect cell culture growth. These findings suggest that the chimeric protein SmCET could provide a favorable proposal for specific immunotherapy, potentially replacing or complementing traditional corticosteroid-based treatments in the future.

ASSOCIATION OF PLAYFUL AND SCIENTIFIC APPROACHES AS A STRATEGY FOR EDUCATION AND HEALTH PROMOTION IN SCHISTOSOMIASIS MANSONI AWARENESS

Emilly Mercês Vasco — 2024-11-07

Schistosomiasis mansoni is a parasitic infection caused by Schistosoma mansoni. Its high prevalence in Brazil justifies the need for health education initiatives aimed at prevention, recognizing the importance of empowering individuals and promoting health in a holistic manner. Playful elements are essential, as they facilitate learning in an innovative, stimulating, and engaging way. The creation of three-dimensional models representing the parasite's life cycle using biscuit clay serves as an effective tool, allowing participants to handle the pieces while explaining the life cycle, transmission, prevention, and diagnosis of the disease. This approach enhances understanding and makes learning more engaging. The use of this educational technology improves knowledge retention, transforming participants into agents of health education. The objective of this study is to highlight the relevance of playful methods in building and disseminating knowledge about schistosomiasis mansoni and its prevention, demonstrating how these approaches make it easier to understand the parasite's life cycle, captivating participants in a more interactive way. Several resources were utilized in setting up an exhibition stand as the action site, incorporating it into health and knowledge fairs to make the educational experience more interactive. The resources included an informational banner displaying epidemiological data, biscuit models representing the S. mansoni life cycle, a microscope for viewing slides containing eggs, cercariae, adult worms, and liver tissue with schistosomal granulomas, as well as Biomphalaria snails and a gamified quiz to assess participants' knowledge. The activities at the stand engaged spectators in various ways. The banner provided a technical approach with epidemiological data, while the biscuit models allowed for hands-on learning during explanations of the life cycle, prevention, and pathophysiology of schistosomiasis, making the learning process more engaging. Specific details, such as the lateral spine of S. mansoni eggs and its importance in identifying the parasite in stool samples, were emphasized. The visualization of different life stages under the microscope reinforced the understanding of the disease's pathophysiology. The event concluded with a gamified quiz to test participants' knowledge, adding a fun and stimulating aspect to the learning experience. The use of playful tools as pedagogical instruments proved effective in health education about schistosomiasis mansoni, facilitating the visualization and understanding of the parasite's life cycle in an interactive and accessible manner. The three-dimensional model complemented other pedagogical methods, such as banners, slides, and a board game. This study demonstrates that innovative techniques can enhance the understanding of complex concepts and can be replicated for other diseases and educational contexts, broadening the impact of health education.

Immunopathological Changes in Spinal Neuroschistosomiasis

Hanna dos Anjos Gomes — 2024-11-07

Introduction: Spinal schistosomiasis is a severe form of Schistosoma mansoni infection that affects the central nervous system (CNS). However, underreporting and similarity to other myelopathies may lead to underestimation of the true incidence. Epidemiological data report that approximately 20–30% of patients infected with S. mansoni have CNS involvement, and that 5–6% of nontraumatic myelopathies are of schistosomal etiology. The medullary form, more frequent than the cerebral form, is favored by the parasite's spike, which prevents brain infection, but predisposes to spinal cord injury due to progressive necrotizing granulomatous myelitis with the participation of cytokines and deposition of immune complexes, characterizing the immunopathological picture of the disease. Objective: The aim of this study is to understand the influence of the immune response on the immunopathological changes in spinal cord neuroschistosomiasis. Methods: This study is a descriptive/integrative literature review based on articles published in the following databases: PubMed, Scielo, Google Scholar and LILACS, published between 2014 and 2024. The descriptors: Schistosoma mansoni, neuroschistosomiasis, myeloradiculopathy, transverse myelitis, immunopathogenesis, were confirmed through the descriptors in science and health (DeCS). Articles that were outside the period and did not address the topic were excluded. Of the 34 articles found, 12 were used, according to the inclusion criteria. Results: The pathogenesis of spinal neuroschistosomiasis is associated with the eggs deposition in the spinal nervous tissue. The most common neurological manifestation is myelopathy, which includes myeloradiculopathy and transverse myelitis. The main route of arrival of the eggs is through retrograde flow through Batson's venous plexus, which connects the portal veins to the spinal column. The initial inflammatory process results in the formation of necrotic-exudative granulomas, consisting of epithelioid cells, eosinophils and fibroblasts; these structures are responsible for compression and tissue damage. The persistence of eggs amplifies the immune response mediated by lymphocytes, macrophages and fibroblasts, which varies in intensity according to the egg load and the host's immune response. In the initial phase, a Th1 profile response predominates, which later evolves to Th2. Egg deposition and the consequent mass effect may occur in the conus medullaris and in the nerve roots of the cauda equina, resulting in spinal cord compression and neurological symptoms such as back pain, muscle weakness, paresthesia and sphincter dysfunction. Immunopathological alterations are confirmed by histopathology, the gold standard for diagnosis. Conclusion: We conclude that the immune response triggered by spinal neuroschistosomiasis results in significant myelopathy with severe neurological damage. Thus, delay in diagnosis and treatment results in irreversible impacts of the disease.

Description of the Reach of Schistosomiasis Treatment in Brazil, Between 2012 and 2021

Thais França do Couto — 2024-11-07

OBJECTIVETo analyze the reach of schistosomiasis treatment in endemic regions of Brazil between 2012 and 2021.METHODOLOGY/DEVELOPMENTData on the number of patients diagnosed with schistosomiasis who required treatment and those who were treated were compared to determine the extent of treatment for patients with the disease in Brazil's endemic regions, specifically the Northeast and Southeast regions. For this purpose, data was collected from the TabNet platform using the following filters on the DATASUS website: tab "Epidemiologies and Morbidity," data "Schistosomiasis Control Program (PCE)," location "Brazil by Region, State, and Municipality," row in "Region," column in "Year," content in "To treat" and "Treated," for the years 2012 to 2021. Data from the most recent 10 years were considered for analysis to provide the most updated values. Tables were generated for better visualization of the data.RESULTS In the 10 years analyzed for schistosomiasis cases in the Northeast region, there were 502,528 patients diagnosed, with only 211,992 considered treated. In total, in this region, there were 290,536 patients (57.81%) diagnosed but not treated from 2012 to 2021, as described in Table 01. In the Southeast region, from 2012 to 2021, 98,712 patients were diagnosed, with only 52,385 treated, leaving 46,327 (46.93%) diagnosed with schistosomiasis but not treated, as described in Table 02.Table 01Source: Self-authoredTable 02Source: Self-authoredOver the analyzed years, there was a decrease in the proportion of untreated cases in the Northeast region by 58.59% and in the Southeast region by 32.23%. However, in 2021, the percentage of untreated patients was still above 30% in both regions. Regarding the absolute number of diagnosed patients, there was a decrease of 93.68% and 96.39% in the Northeast and Southeast regions, respectively, over the 10 years.CONCLUSIONSGiven the difficulty in dispensing certain medications through the public health system and considering that treatment for schistosomiasis is exclusively provided by the SUS (Unified Health System), it is crucial that treatment be made available to all infected individuals, especially in the Brazilian regions considered endemic. According to the analyzed data, over 10 years, the total number of diagnosed but untreated patients was close to 50% in regions deemed endemic for the disease in Brazil.There was a decrease in the absolute number of schistosomiasis cases; however, the number of patients without treatment only dropped by 15 percentage points, remaining around 35% of the patients. Therefore, it is necessary to improve treatment techniques and subsequent follow-up to increase the chances of eradicating the disease in Brazil.

Spatial distribution and temporal trends of hospitalization and mortality rates due to schistosomiasis in the states of Alagoas, Pernambuco, and Sergipe, between 2013 and 2022

Milene Pinto Oliveira — 2024-11-07

Introduction: Schistosomiasis mansoni is a parasitic disease caused by the digenetic trematode Schistosoma mansoni. Its transmission is directly associated with poor socio-environmental conditions, such as lack of basic sanitation and exposure to contaminated water. Objective: To analyze the spatial distribution and temporal trends of hospitalization and mortality rates due to schistosomiasis mansoni in Alagoas (AL), Pernambuco (PE), and Sergipe (SE) between 2013 and 2022. Methodology: This is an ecological time series study using secondary data obtained from the Hospital Information System (SIH) and the Mortality Information System (SIM), referring to hospitalizations and mortality due to schistosomiasis in the states of AL, PE, and SE, between 2013 and 2022. For trend analysis, we used segmented linear regression to obtain the annual percentage change (APC) rates, calculated for each time segment, and the average annual percentage change (AAPC) rates, calculated for the full period when more than one inflection point was significant. We considered the 95% Confidence Interval (95%CI) and significance of 5% (p lt; 0.05). Crude rates were calculated for each municipality with hospitalizations and mortality from the disease, in addition, spatial distribution maps were generated to identify areas with the highest concentration of hospitalizations and deaths from the disease. Results: Between 2013 and 2022, 471 hospitalizations and 2,239 deaths from schistosomiasis were recorded in the states analyzed. When the data were examined by state, PE stood out with the highest number of hospitalizations, totaling 362 (76.86%), and deaths, which reached 1,497 (66.86%) in the state. When analyzing the temporal trend of hospitalization rates, the three states studied showed stable trends throughout the period (AL: APC = 0.7; 95% CI; -13.6 to 17.4; p-value = 0.917; PE: APC = -2.4; 95% CI; -8.5 to 4.2; p-value = 0.425; and SE: APC = 7.8; 95% CI; -1.3 to 17.6; p -value = 0.086). When analyzing the mortality rate, between 2018 and 2022, PE showed a statistically significant decline (APC = -15.2; 95% CI; -21 to -7.9; p-value = 0.003), while AL and SE remained stable. Regarding the spatial distribution of hospitalizations, the highest rates were distributed in the three states, while the highest mortality rates were found in AL and SE. Conclusion: Our study demonstrated stability in the rates of hospitalizations due to schistosomiasis in the three states analyzed. However, although the state of PE had the highest number of hospitalizations and deaths due to the disease, mortality rates due to schistosomiasis in the state have decreased in recent years. The spatial analysis also revealed high rates of hospitalizations and mortality due to the disease, reinforcing the importance of maintaining control actions for the disease, especially in areas endemic to the disease.

Immunopathological Aspects of Concomitant Immunity in Swiss Webster Mice Infected by Schistosoma mansoni.

ESTER MARIA MOTA — 2024-11-07

Concomitant Immunity is a poorly studied phenomenon despite Schistosomiasis being a well-established parasite-host interaction. It is known that resistance to reinfection in S. mansoni hosts results from a protective immune process conferred by this relationship. However, there are still gaps in the complete understanding of this phenomenon, such as which are the main molecules that prevent the full development of a second infection, and how the age of the host, amount of cercarial inoculum, genetics of the host, and the helminth strain influence resistance. This work aims to address the effect of reinfection with inoculum of 200 cercariae subcutaneously in Swiss Webster mice, with an interval of 45 days between infections and their controls. The choice of these parameters about the cercaria inoculum and the non-syngeneic animal model was due to the more faithful reproduction of the human population, as the works described in the literature use more syngeneic murine models. The results described here are preliminary liver and small intestine analyses of histologically processed tissues stained with HE, Giemsa, Masson's Trichromatic, Picrosirius, and Gomori's Reticulin. Reinfected mice, analyzed at 60 dpi, showed many granulomas in the liver, with smaller diameters, compared to the first-infected control groups from the first (60 dpi) and second infection (45 dpi). Many granulomas were distributed along the periphery of the lobules. The reinfected group had many productive granulomas, some containing lymphocytes in the periphery. This area was smaller and exhibited mild hematopoiesis. Intrahepatic branches of the portal vein containing adult worms were dilated with hemorrhage and subendothelial fibrosis, sometimes accompanied by vegetative lesions, which compressed the bile duct due to the mass effect. Eosinophilic content was observed in some hypertrophic hepatic duct epithelial cells. In the intestine, no significant differences were observed among the groups. However, some animals in the reinfection control group (infected once animals at 45 dpi) presented serositis. The cumulative effect of eggs in the liver, resulting from two infections, generating embolization and granulomas on the periphery of the lobules is indicative that portal hypertension can hurry up in cases of reinfection, depending on the inoculum, with worsening of venous lesions, with highlighting phlebitis and endophlebitis.

EVALUATION AND OPTIMIZATION OF POINT-OF-CARE IMMUNOCHROMATOGRAPHIC TEST (POC-CCA) READINGS PERFORMED IN AN AREA OF HIGH ENDEMICITY IN NORTHEASTERN BRAZIL FOR SCHISTOSOMIASIS, USING IMAGE ANALYSIS

Francisca Janaína Damasceno Morais — 2024-11-07

Schistosomiasis, caused by the Schistosoma mansoni parasite, is a Neglected Tropical Disease with a significant impact in underdeveloped countries. The Kato-Katz (KK) method, recommended by the World Health Organization, is widely used, but it has low sensitivity in regions with low endemicity. The POCCCA, an immunochromatographic test that detects parasitic antigens in urine, has emerged as a sensitive and rapid alternative. However, this test is prone to variations in interpretation between readers, especially when the test response is weak (trace), which can affect the determination of prevalence. This study aimed to quantify the coloration of POC-CCA test results to reduce the subjectivity involved in visual interpretation. For this purpose, a dataset of 158 images from POC-CCA tests was used, collected from a highly endemic area for schistosomiasis. The ImageJ® software, a public Java-based image analysis tool, was employed to quantify the pixel intensity of the test results' color. This pixel quantification strategy demonstrated good accuracy, effectively distinguishing between positive and negative results, with an area under the ROC curve of 0.859. The optimal cutoff point was 0.042 pixels, corresponding to a Youden's J index maximum of 0.656. At this threshold, sensitivity reached 0.779, and specificity was 0.877. When compared to the Kato-Katz results and other POC-CCA reading strategies, pixel quantification showed similar prevalence rates of positives and negatives to the Kato-Katz method and qualitative visual reading. However, the prevalence of positive cases was lower than that observed with the G Score reading strategy (G1 to G10). A weak, yet statistically significant, positive correlation (r² = 0.4812, p lt; 0.0001) was identified between the OPG results of the Kato-Katz test and pixel quantification of the POC-CCA test. There was good agreement between the pixel quantification reading strategy and the Kato-Katz test (Kappa value = 0.6572, p lt; 0.0001), as well as with stratified G Score readings (Kappa value = 0.5498, p lt; 0.0001) and qualitative visual interpretation (Kappa value = 0.5383, p lt; 0.0001). Although the image processing technique performed satisfactorily, there is room for improvements in usability and efficiency, including parameter optimization and refining signal cutoff metrics. The study concludes that the visual interpretation of the POC-CCA test is inherently subjective; however, pixel quantification provides an objective analysis, eliminating subjectivity and enabling a more precise determination of test results.

Action of quercetin in the acute phase of mansonic schistosomiasis

Beatriz Machado Silva — 2024-11-07

Schistosomiasis is a neglected and endemic disease in Brazil. The only drug used for treatment is praziquantel, and the lack of other therapeutic options has raised concerns in the scientific community due to the potential emergence of worm resistance, as this drug only acts against the adult worm. Quercetin is a natural polyphenolic flavonoid with low toxicity, possessing antioxidant, anti-inflammatory, and immunomodulatory activities, as well as in vitro antiparasitic action. The objective of this study was to evaluate the schistosomicidal potential of quercetin during the acute phase of mansonic schistosomiasis in a murine model. This was an in vivo experimental study conducted with 39 male albino Swiss Webster mice, experimentally infected with Schistosoma mansoni. Quercetin was administered via gavage at the following doses: 800 mg/kg, 1600 mg/kg, and 2400 mg/kg, with treatments performed according to the infection days: 5th and 15th days post-infection or 10th to 14th days post-infection. The animals were euthanized through deep anesthesia after 60 days of infection, and blood perfusion was performed to recover and count the worms. The recovered worms were subjected to scanning electron microscopy for tegument analysis. The results were expressed as mean and standard deviation. The group treated with quercetin 800 mg/kg (5th and 15th days) had an average of 23 recovered worms; the group treated with quercetin 800 mg/kg (10th to 15th days) also had an average of 23 recovered worms; the group treated with 1600 mg/kg (5th and 15th days) had an average of 27 recovered worms; the group treated with quercetin 1600 mg/kg (10th to 14th days) had an average of 23 recovered worms; and the group treated with quercetin 2400 mg/kg (10th to 14th days) had an average of 33 recovered worms. Although quercetin did not reduce the number of recovered worms in any of the doses and treatment intervals used, scanning electron microscopy revealed some damage to the tegument of the parasites. The results obtained in this study suggest that quercetin, at the doses used, is not capable of destroying S. mansoni in its young stage. In this sense, further in vivo studies are needed to elucidate the action of quercetin at different evolutionary stages of S. mansoni.

THE USE OF GEOPROCESSING APPLIED TO CASES OF SCHISTOSOMIASIS IN A COMMUNITY IN CAPELA, ALAGOAS

Patricia Martins Parreiras — 2024-11-07

Schistosomiasis, designated as one of the Neglected Tropical Diseases (NTDs) by the World Health Organization (WHO), is under the scope of elimination by 2030, according to the Sustainable Development Goals (SDGs). In Brazil, schistosomiasis mansoni represents a major public health challenge, especially among vulnerable groups subject to poor environmental and sanitary conditions. The country faces notable challenges in the field of sanitation, with a considerable portion of the population lacking basic sewage and drinking water services. Within this broad context, which ranges from waste management to hygiene practices, the use of technologies such as geoprocessing, notably through Geographic Information Systems (GIS), emerges as a fundamental tool for organizing and analyzing spatial data related to public health. This study aims to use geoprocessing techniques, as a pilot study, to assess which techniques would be the most appropriate for the analyses that will contribute to a more complete and agile understanding of schistosomiasis cases spatially. The site chosen for this initial study was a community in Capela, Alagoas. Initially, a mapping of disease conditions was carried out, involving the random selection of participants. Those who agreed to take part provided their consent by means of an Informed Consent Form. The coordinates of the participants' homes were collected using a Garmin GPS, and comprehensive questionnaires were administered on socioeconomic and demographic aspects, sanitation conditions and water habits. Containers were also distributed for collecting feces, which was then collected by the team in charge. The fecal samples were analyzed using the Kato-Katz method to diagnose schistosomiasis mansoni and other helminthiases. After the diagnosis, all the information was georeferenced using QGIS software, allowing a spatial analysis of the patterns of occurrence of the disease. The results were presented using thematic maps, making it easier to visualize the community's spatial scenario. The Kernel Density Estimation (KDE) technique was used to estimate the intensity of the event throughout the area, revealing more pronounced incidence patterns at three specific points. This pilot study allowed us to outline a future project to be carried out on a larger spatial scale in the state of Alagoas, in order to integrate the analyses for specific recommendations and guidelines for communities, with the aim of mitigating the impacts of the disease and contributing to the promotion of public health. Insights into the relationship between environmental factors and the occurrence of schistosomiasis will support the development of recommendations for local public policies and the implementation of sanitation solutions suited to different environmental and epidemiological contexts.

PREVALENCE OF SCHISTOSOMIASIS MANSONI AND RISK FACTORS IN ENDEMIC COMMUNITIES IN NORTHEASTERN BRAZIL

Rosangela Lima de Freitas Galvão — 2024-11-07

Introduction: Schistosomiasis mansoni is a parasitic disease commonly found in impoverished and rural populations. In endemic regions, multiple factors can influence the occurrence and severity of the disease. Objective: This study aimed to assess the prevalence and identify risk factors contributing to the transmission of schistosomiasis mansoni in endemic regions of Sergipe State, located in Northeast Brazil. Methodology: A cross-sectional study was conducted between August 2022 and April 2023 in the villages of Patioba and Colônia Miranda, within the municipalities of Japaratuba and São Cristóvão, respectively. All participants completed a sociodemographic questionnaire. Disease prevalence was determined by detecting S. mansoni eggs using the Kato-Katz method. Results: A total of 721 residents took part in the study (n=351 from Patioba, n=370 from Colônia Miranda). Schistosomiasis prevalence was higher in Patioba (33.61%) compared to Colônia Miranda (25.67%). In Patioba, infection was more prevalent among males (52.54%). There was a significant correlation between infection rates and low education levels (55.08%, p = 0.034). Negative test results were linked to the use of indoor bathrooms (p = 0.005, OR = 5.5365, 95% CI = 1.4393-21.2969) and being female (p = 0.008). In Colônia Miranda, infection rates were higher among females (52.63%). In households with fewer than five residents, negative S. mansoni results were more common (68.72%, p = 0.041, OR = 0.4537, 95% CI = 0.1924- 1.0698). In Patioba, 74.57% of those who tested positive for S. mansoni had contact with natural water sources, mainly for bathing and personal hygiene (58.47%), washing clothes (44.91%), and fetching water (27.96%). Fishing was the only activity significantly associated with infection (22.03%, p = 0.002, OR = 2.461, 95% CI = 1.34-4.51). In Colônia Miranda, 77.89% of those infected accessed natural water sources, with bathing and personal hygiene (38.94%) being the most common activities linked to schistosomiasis (p = 0.027, OR = 1.733, 95% CI = 1.06-2.83). Individuals who used natural water sources were 2.756 times more likely to be infected (OR = 2.7567, 95% CI = 1.5737-4.8290). Conclusion: The study highlights that the two villages are high-prevalence areas for schistosomiasis, with infection risk varying between them. The results offer valuable insights into the status of schistosomiasis in the study areas, supporting efforts to control the disease in Sergipe. The implementation of integrated disease control measures and prevention strategies is vital to reduce prevalence. Additionally, collaborative health education programs are essential for increasing public awareness.

Molluscicidal activity of copper oxide nanoparticles against embryos and newly hatched Biomphalaria glabrata (Say, 1818): A comparative approach

Luiz Phelipe Souza Silva — 2024-11-07

Nanobiotechnology has been identified as a promising tool for the control of gastropods of medical importance, such as Biomphalaria glabrata. In Brazil, this snail serves as the primary intermediate host for the parasite Schistosoma mansoni, which is responsible for the disease schistosomiasis. Copper oxide nanoparticles (CuONPs) have demonstrated toxicity against pests, vectors, and certain intermediate hosts. However, their toxicity to B. glabrata remains unconfirmed, particularly with regard to the early stages of development. This study aimed to assess the toxicity of CuONPs functionalized with mercaptosuccinic acid (MSA) in B. glabrata embryos and newly hatched snails. The nanoparticles were synthesized by chemical precipitation, with copper acetate being used as the metal precursor for the synthesis and the addition of MSA for colloidal stability and surface charge, knowing that this molecule already has known mucosal adhesion activity. Toxicity was analyzed through the embryotoxicity test on Biomphalaria spp. using 9 clutches of eggs per concentration (± 180 embryos at blastula stage) in 12-well microplates in triplicate for 168h (5mL per well) at concentrations from 0.08 to 2.11 mg L-1. The parameters analyzed were mortality, hatching, delayed embryonic development, morphological changes, and cardiotoxicity. The acute toxicity test on newly hatched snails was carried out using 10 animals per concentration in triplicate (± 240 animals), with concentrations ranging from 0.01 to 0.08 mg L-1 for 96 hours. The parameters analyzed were mortality, cardiotoxicity, and behavioral changes (reclusion, distance traveled, average speed, and time at rest). The results showed that exposure to MSA-CuONPs caused mortality in both embryos and newly hatched snails. In embryos, MSA-CuONPs inhibited hatching and embryonic development, and induced cardiotoxicity through a decrease in heart rate. The morphological changes analyzed were mainly hydropic embryos and a reduction in shell size. In the case of newly hatched snails, MSA-CuONPs also showed cardiotoxicity, a decrease in average speed and distance traveled and an increase in resting time, as well as an effect on seclusion time and exposure of the cephalopedial mass of the shell. Therefore, MSA-CuONPs are promising for the control of schistosomiasis, interrupting the biological cycle of B. glabrata.

HEALTH EDUCATION AND PROMOTION WITH A FOCUS ON THE PRODUCTION OF A BOOKLET ON SCHISTOSOMIASIS: CASE REPORT

Marcelo dos Santos Souza — 2024-11-07

Schistosomiasis is a parasitic disease caused by Schistosoma mansoni, with a high prevalence in rural areas and regions with poor sanitation in Brazil, including the city of Itabuna, in the state of Bahia. Schistosomiasis control depends on integrated interventions, which include treatment of infected individuals, improvements in basic sanitation, and health education strategies. In this context, the development of educational materials is essential to inform the population about disease prevention measures. This report describes the creation of an educational booklet with the objective of promoting knowledge about schistosomiasis. A public health team, composed of physicians, nurses, community health agents, and educators, identified a high prevalence of schistosomiasis in riverside communities in the city of Itabuna. Given this scenario, the development of a booklet with accessible language was proposed, aiming to improve the understanding of the local population. The booklet was developed in partnership with the Municipal Health Department, based on guidelines from the Ministry of Health and recommendations from the World Health Organization (WHO) for controlling parasitic diseases. The content was prepared in a simple and objective manner, covering: what schistosomiasis is, its transmission cycle, preventive measures and treatment. In addition to the text content, the booklet was illustrated with colored images to facilitate understanding, especially among functionally illiterate people or people with low levels of education. The material was distributed in schools, health units and during home visits made by community agents. Educational lectures and workshops were also held in schools and community centers, where the material was used to engage the population. In addition, practical activities were promoted, such as demonstrations on the importance of using treated water and recognizing snail breeding sites. After the booklet was distributed and educational activities were carried out, there was a greater awareness among the community about the risks and ways to prevent schistosomiasis. Community agents reported an increase in adherence to preventive practices, such as the use of treated water and seeking treatment at health facilities. Epidemiological monitoring indicated a significant reduction in the incidence of new cases in the region, suggesting that the health education strategy had a positive impact on disease control. The creation and distribution of an educational booklet on schistosomiasis prevention in Itabuna proved to be an effective health promotion tool. The combination of accessible educational material and practical activities contributed to changing community behavior, reinforcing the importance of health education in controlling endemic diseases. This approach can be replicated in other regions affected by schistosomiasis, promoting greater awareness and engagement of the population in combating the disease.

Environmental drivers of Biomphalaria straminea population dynamics in rivers of the Brazilian semiarid

Edenísio Zacarias Galvão Costa — 2024-11-07

Some species of molluscs are of significant sanitary importance due to their role in the life cycle of trematodes that cause parasitic diseases in humans and animals, such as schistosomiasis, which is transmitted by the genus Biomphalaria. In Brazil, particularly in the North and Northeast regions, there are gaps in information regarding these species' ecology, distribution, and morphology. This lack of understanding of these vectors' biological and ecological aspects hinders surveillance and disease control efforts. To address these knowledge gaps, this study assessed the environmental determinants influencing the populations of Biomphalaria straminea in the Parnaíba River Basin, one of the main rivers in the Brazilian semi-arid region. Specimens were collected during the dry season 2022 (September and October) at three points (source, midstream, and mouth) along each of the main rivers in the basin. Samples were obtained from two types of substrates: sediment and macrophytes. The population structure was analysed based on the distribution of individuals by size classes, age, and substrate type. We modelled species abundance about environmental variables using generalised linear models (GLM), with adjustments made using a Negative Binomial error distribution. All analyses were conducted using RStudio software, utilising the car, MASS, and stats packages. A total of 85 individuals were collected. The Pirangi River had the highest number of specimens (n=45), followed by the Itaueira River (n=39) and the Longá River (n=1). No individuals were recorded in the other rivers. Our model explained approximately 57% of the variation in species abundance, with higher presence in areas with elevated pH and temperature, while deeper environments had a negative influence. A total of 56 individuals were measured, of which 35 were associated with sediment and 21 with macrophytes. Although the animals found in macrophytes were slightly larger (x̅=4.36 ± 0.81 mm) than those collected from sediment (x̅=4.10 ± 1.61 mm), this difference was not significant. The number of young individuals was 17 times greater than that of adults in the sampled rivers. Our study demonstrated that the abundance of Biomphalaria straminea in the Parnaíba River Basin is strongly influenced by environmental variables, and its occurrence in different substrates highlights its adaptive capacity. The predominance of young individuals suggests that the habitats studied also function as recruitment areas, which is critical for population control strategies. These findings provide valuable insights for developing public policies aimed at surveillance and controlling schistosomiasis in the semi-arid region, contributing to improved local public health

Immune profile of Chimeric elastase containing T- and B-cell epitopes (SmCETB) from Schistosoma mansoni

João Vitor Borges Rios — 2024-11-07

The hygiene hypothesis suggests that reduced exposure to infectious agents during early childhood impairs immune development, favoring a Th2-dominant profile and increasing allergy risks, particularly in high-income countries. Helminth infections, like allergies, induce Th2 responses with CD4+ T cells producing IL-4 and IL-5. However, helminths also promote IL-10 production and activate regulatory T cells (Tregs), helping to control inflammation. These parasite-induced mechanisms offer promising alternatives for treating allergies beyond corticosteroids, which are palliative and often cause side effects. Among the proteins secreted by Schistosoma mansoni, elastase (SmCE) plays a key role in immune evasion during cercarial invasion, inducing both Th1 and Treg responses, which may help rebalance Th2-dominant allergic responses. Dust mites, such as Blomia tropicalis, are significant aeroallergens in Brazil, highlighting the importance of allergen-specific immunotherapy, which can modulate immune responses and alter the progression of allergic diseases.This study aimed to evaluate the immunoregulatory potential of a chimeric elastase protein containing T- and B-cell epitopes (SmCETB) by promoting Th1 responses. SmCETB was expressed in Escherichia coli strains (Star and Rosetta) via IPTG induction, with samples collected at 4 and 24 hours. Protein extracts were solubilized in Tris-HCl buffer (pH 9.5) with and without 6M urea and purified by affinity chromatography on nickel columns (ÄKTA system). Protein identity and purity were confirmed by Western Blot using a 6-His tag, and endotoxins were removed with a commercial kit. Human Peripheral Blood Mononuclear Cells (PBMCs) were isolated from healthy and allergic donors using Ficoll-Hypaque separation. PBMCs were stimulated with SmCETB at 7.5 μg/mL for 48 and 72 hours, with unstimulated cells as controls. Polymyxin A was used to neutralize any residual endotoxins. After incubation, cell viability was assessed, and cytokines (IL-1β, IL-4, IL-5, IFN-γ, IL-10, IL-13, and TNF-α) were measured in the culture supernatant. SmCETB stimulation increased TNF-α production without altering baseline IL-10 levels, suggesting a Th1 response without suppressing Treg activity. These findings highlight the potential of SmCETB as an immunotherapeutic agent capable of promoting Th1-type responses while maintaining regulatory T cell levels. Further studies are needed to confirm these preliminary results and ensure the safety and efficacy of the protein preparation.

CORRELATION BETWEEN EGG COUNT IN FECES AND SCHISTOSOMIASIS PROGRESSION

Thais França do Couto — 2024-11-07

Objectives:To analyze the relationship between the number of schistosome eggs in the feces of infected individuals and the clinical progression of the disease. Methodology/Development:The analysis involved cross-referencing the number of people diagnosed with schistosomiasis based on the quantitative number of eggs found in their feces with the progression of the disease. Data was sourced from the DATASUS website, using the TabNet platform with the following filters: “Diseases of Notification - 2007 onwards (SINAN)”; “Schistosomiasis”; “Brazil by region, UF, and municipality”; rows categorized by “evolution”; columns categorized by “quantitative analysis”; and the period from 2014 to 2023. The most recent 10 years were selected to ensure the analysis was up-to-date. Results:For cases diagnosed with zero eggs, out of a total of 20,607 cases, 8,008 had the disease progression field left blank or ignored; 11,265 reported a cure; 387 reported no cure; 618 resulted in death due to schistosomiasis; and 329 resulted in death from other causes. For cases diagnosed with one or more eggs in the feces, out of 19,533 cases, 6,273 had the progression field left blank or ignored; 12,835 reported a cure; 235 reported no cure; 136 resulted in death due to schistosomiasis; and 54 resulted in death from other causes. Conclusion:The data reveals that 35.57% of the 40,140 cases had incomplete or ignored information. This suggests either the use of alternative diagnostic tests beyond fecal parasitology or shortcomings in the healthcare system's data recording. The cure rates were similar regardless of the presence of eggs, as were the non-cure rates, indicating a weak correlation between egg count and disease severity. However, the mortality rate from schistosomiasis in cases with no eggs was 4.5 times higher than in cases with eggs, suggesting greater disease severity in those with negative fecal parasitological exams between 2014 and 2023. Additionally, the mortality rate from other causes was about six times higher in the absence of eggs compared to their presence, further supporting the increased severity in individuals with negative fecal parasitology results. Therefore, expanding diagnostic tests for patients with no eggs found in their feces is crucial for improving health outcomes.

Toxicity of green silver nanoparticles from Croton urucurana on Biomphalaria glabrata hemocytes: genotoxic, mutagenic, and immunogenic effects

Paula Sampaio Araújo — 2024-11-07

Green silver nanoparticles (G-Ag NPs) have emerged as a promising and safe approach in the development of molluscicides, particularly for controlling snails that act as intermediate hosts of medically important parasites, such as Biomphalaria glabrata, the main intermediate host of Schistosoma mansoni. In this context, the current study investigated the effects of G-Ag NPs synthesized using the aqueous extract of Croton urucurana leaves on the hemocytes of B. glabrata after in vivo exposure. Adults of B. glabrata were exposed to G-Ag NPs (0.05 and 0.14 mg L⁻¹), and to an aqueous extract of C. urucurana leaves (5.4 mg L⁻¹), for 7 days. Genotoxicity (comet assay), mutagenicity (micronucleus test and nuclear anomalies), and immunotoxicity (phagocytic activity by flow cytometry) were analyzed in the B. glabrata hemocytes’. The results indicated that G-Ag NPs induced DNA damage, with an increase in the percentage of DNA tail and in the Olive Tail Moment compared to the negative control group and those exposed to the aqueous extract of C. urucurana. Additionally, G-Ag NPs induced mutagenic effects in hemocytes, with notable nuclear alterations such as notched and blebbed nuclei. However, the phagocytic activity and cell viability of hemocytes were not affected by exposure to G-Ag NPs or aqueous extract of C. urucurana leaves. The results showed that G-Ag NPs induced significant genotoxic and mutagenic effects in the hemocytes of Biomphalaria glabrata, demonstrating their potential as effective molluscicides. These effects highlight the relevance of green nanoparticles as a promising and more sustainable alternative in the control of snail hosts of parasites, especially in combating schistosomiasis. The study provides an important basis for the development of new technologies that can contribute to reducing the transmission of parasitic diseases.

Diversity and distribution of limnic mollusks and evaluation of interventions for schistosomiasis in an endemic municipality in Brazil: reflecting on 50 years of Biomphalaria control

NATHÁLIA MOREIRA TEODORO DE OLIVEIRA — 2024-11-07

Baldim, in the Central Region of Minas Gerais, is considered an endemic area with a long history of Schistosoma mansoni infections. Despite different control strategies, such as chemotherapy campaigns with Niclosamide and biological control with Pomacea haustrum between 1969 and 1973, the complete elimination of the disease has not been achieved. The present study analyzed the diversity and spatial distribution of limnic mollusks 50 years after the introduction of Pomacea sp. in the municipality of Baldim, in addition to the evaluation of the effectiveness of biological control for the species of the genus Biomphalaria. The malacological survey was carried out from June/2022 to August/2023 at 28 freshwater, sampling points, distributed in urban and rural areas of the municipality. In the laboratory, captured snails were individualized in tissue-culture plates with dechlorinated water and analyzed under a stereomicroscope after artificial photostimulation for 2 hours to evaluate the release of larval forms of cercariae. The cercariae obtained were mounted on semipermanent slides, stained in Lugol's solution, and fixed in 10% formalin for morphological analysis and identification. The mollusks were identified by morphology and 10% of mollusks of the genera Biomphalaria and Pomacea were identified by Molecular Biology. The mapping of the malacological distribution in the municipality was performed using the GeoDa and QGIS 3.28.2 programs. A total of 2.085 mollusks were collected at 10 locations, and with the identification of 12 different species: Biomphalaria spp. (50.69%; n=1.057); Stenophysa marmorata (25.41%; n=530); Melanoides tuberculata (13.52%; n=161); Pseudosuccinea columella (7.72%; n=98); Gundlachia ticaga (4.50%; n=94); Corbicula largillierti (3.50%; n=73); P. maculata (1.72%; n=36); Drepanotrema anatinum (1.05%; n=22); Idiopyrgus souleyetianus (0.43%; n=9); Physella acuta (0.38; n=8); Drepanotrema cimex (0.14; n=3); Omalonyx matheroni (0.09%; n=2). At the locations, the presence of Biomphalaria species was confirmed, including B. glabrata, B. tenagophila, B. straminea, B. occidentalis, and B. kuhniana. The presence of cercariae of the types Echinostoma, Monostoma, Xiphidiocercaria, Estringiocercaria, Parapleurolophocerca, and Gymnocephala was detected. Although no S. mansoni infection was identified, the distribution of Biomphalaria species was restricted to urban areas and was in agreement with the distribution of confirmed positive human cases, identified by the SPC (Schistosomiasis Control Program) in the period 2008-2017. In addition, it was observed that P. maculata populations remain restricted to the areas of its introduction, without significant impact on the intermediate hosts of schistosomiasis. In this context, it is essential to investigate alternative strategies for schistosomiasis control, while also advancing the understanding of the interactions between mollusk species and their associated trematodes.

Epidemiological Study of Schistosomiasis in Salvador: Data from a Reference Laboratory (2012-2023)

Juliana Mendonça dos Santos Nano — 2024-11-07

Schistosomiasis is a neglected tropical disease affecting approximately 240 million people globally. Brazil has the largest endemic region in the Americas, with over 101,293 cases reported between 2003 and 2012. In Brazil, transmission occurs via Schistosoma mansoni, with snails of the genus Biomphalaria serving as intermediate hosts. This study aims to estimate the prevalence of schistosomiasis among individuals attending the Clinical and Toxicological Analysis Laboratory of the Faculty of Pharmacy (LACTFAR/UFBA) in Salvador, Bahia, between 2012 to 2023. Parasitological data from examinations conducted at LACTFAR/UFBA were retrospectively analyzed, and statistical analyses were performed using SPSS version 29.0.10. A total of 691 individuals were found to have at least one S. mansoni egg in their fecal samples. The highest incidence was observed in 2015, with 110 cases, followed by 98 cases in 2012. The lowest incidence occurred in 2020 and 2021, representing only 1% of total cases, with five and nine cases, respectively. Among the infected individuals, 635 were monoinfected, while 56 presented confections with other helminths, including Strongyloides stercoralis (9 cases), hookworms (23 cases), Ascaris lumbricoides (16 cases), and Trichuris trichiura (17 cases). The mean age of S. mansoni-positive individuals was 40 years (IQR: 28-50 years), with a female-to-male ratio of 1.1:1. The mean age for males was 44 years (IQR: 32.3-52 years), while for females, it was 36 years (IQR: 25-47), showing a significant difference between the genders. Given the considerable economic and health impacts of schistosomiasis, targeted public health interventions are urgently needed to address this neglected population.

MOLECULAR SCREENING OF SCHISTOSOMA MANSONI INFECTION IN ENDEMIC AREA OF THE STATE OF PARÁ, AMAZON, BRAZIL

Pedro Miguel Santos Ferreira — 2024-11-07

Currently, schistosomiasis remains endemic in several regions of Brazil and is considered a serious local public health problem. In the city of Belém, capital of the state of Pará, there are areas of active transmission in approximately 04 neighborhoods of the municipality, among them the neighborhood of Terra-Firme, with the presence of the vector snail. The Kato-Katz technique, considered the reference standard for the diagnosis of schistosomiasis, is an extremely limited method considering areas of low parasite load. It is necessary to develop new diagnostic tools to better support strategies and actions to control this disease. In this sense, the objective of this study was to track at the molecular level the presence of Schistosoma mansoni infection in residents of an endemic area located in Belém, capital of the state of Pará, and to evaluate the applicability of this tool for the surveillance and control of schistosomiasis. This longitudinal study was carried out in the city of Belém, in the Terra-Firme neighborhood, where 200 stool samples were collected from patients to determine the occurrence of S. mansoni infection using the qPCR and Kato-Katz (KK) methods, examining up to 12 slides (KK 12L). 60 and 120 days after the first diagnosis, the same infection detection methodology was applied only to individuals who tested positive for qPCR and negative for KK, to evaluate the presence of parasite eggs in the stool. It was found that the age of the participants ranged from 2 to 88 years, with an average of 36 years, with little difference between the genders that participated in the study, with 52.5% being female (105/200) and 47.5% being male (95/200). The positivity rate for S. mansoni by the KK method ranged from 5% (10/200) to 10% (20/200), depending on the number of slides used, while the molecular method (qPCR) showed a much higher positivity rate, 42.5% (85/200), P less than 0,05. The age group most affected was 10 to 20 years, with a rate of 10.5% for qPCR and 3.5% for KK 12L. The male gender presented the highest number of positives, 24.5% (qPCR) and 6.5% by KK 12L. The intensity of infection in this area was low, with an average parasite load of 20 eggs per gram of feces. The qPCR evaluation revealed an average Ct of 32,66. After monitoring the 65 patients who tested positive only for qPCR, 10 tested positive for the KK method 60 and 120 days after the first diagnosis, with a rate of 15.4% and an average parasite load of 6 to 9 opg. The results revealed a high rate of schistosomiasis in the TerraFirme neighborhood, in the municipality of Belém, capital of the state of Pará, and may contribute to strengthening surveillance and control activities for this disease in the municipality, since real-time PCR has been shown to be a tool capable of improving the identification of S. mansoni carriers, contributing to increasing the effectiveness of the program to control and eliminate this disease in endemic areas of the Brazilian Amazon.

DESCRIPTION OF THE CLINICAL ASPECTS OF SCHISTOSOMIASIS CASES IN SANTO ANTÔNIO DE JESUS, BETWEEN 2017 AND 2023

Thais França do Couto — 2024-11-07

Objective: To describe the clinical data of schistosomiasis cases in Santo Antônio de Jesus (SAJ) from 2017 to 2023. Methodology: This is an observational, cross-sectional, and descriptive study. The data were obtained from schistosomiasis notification forms available at the Municipal Health Department of SAJ, Bahia, from 2017 to 2023. The evaluated data included the diagnostic method, clinical form and clinical presentation (symptoms and signs). They were organized in an Excel spreadsheet according to a pre-structured model. Given the secondary nature of the data, it was not necessary to submit them to the Research Ethics Committee. Statistical analysis was performed by calculating the frequency and percentages of nominal qualitative variables. Results: A total of 112 cases of schistosomiasis were reported. Regarding the diagnostic method, 40 (37.7%), 38 (34%), and 12 (11%) cases were confirmed/suspected by stool parasitological examination, serology, and abdominal ultrasound, respectively. The stool parasitological examination was negative in 18 (16%) cases, and in 15 (83%) of these cases, serology was positive. In terms of clinical form, 9 (8%) had the hepatosplenic form, 4 (4.5%) had only the hepatic form, 3 (2.7%) had only the splenic form, 5 (4.4%) had the intestinal form, 3 (2.7%) had the hepato-intestinal form, 3 (2.7%) had the neurological form, and 1 (0.9%) had the hepato-renal form. In terms of clinical presentation, 9 (8%) reported abdominal pain, diarrhea, nausea, and vomiting; 6 (5.34%) reported portal and splenic impairment, skin rashes, neurological symptoms, esophageal problems, and myalgias. Conclusion: In the last 6 years, 112 cases of schistosomiasis were reported in SAJ. Although serology does not distinguish between current or past infection, it was also considered for diagnostic evaluation, being positive in a proportion similar to that of stool parasitology (about 40% of cases) and in more than 80% of cases with negative stool parasitology. These data highlight the need for new methods with greater sensitivity and precision, as well as indicating that the diagnostic criteria for the disease should be revised. Hepatosplenic, hepatic, splenic, and neurological forms were the most common, signaling possible severity in clinical presentation in SAJ. It is suggested that, since the cases originate from an endemic area, repeated exposures in contaminated environments likely occurred, leading to a higher parasitic load. The description of clinical presentation occurred in few cases, which may be related to underreporting. This study provided updated clinical data on schistosomiasis in SAJ, a key city in the Recôncavo region of Bahia and part of the Northeast macroregion, considered an endemic zone for the disease in Brazil. With an extensive hydrographic basin, the study of schistosomiasis in SAJ can aid in understanding the biological, socio-epidemiological, and behavioral factors involved in the transmission of the disease.

Screening and hit validation of MMV’s Pandemic Response and Global Health Priority boxes against Schistosoma mansoni Thioredoxin Glutathione Reductase (SmTGR)

Lauro Ribeiro de Souza Neto — 2024-11-07

Schistosomiasis is a neglected tropical disease caused by parasites of the Schistosoma genus. In Brazil, this disease is caused by S. mansoni and affects approximately 1.5 million people annually, resulting in around 12,000 deaths. Transmission occurs through direct contact with contaminated water during recreational and occupational activities, with poor sanitation being a significant factor in the prevalence of the infection. The survival of S. mansoni depends on its ability to neutralize reactive oxygen species (ROS) produced by its metabolism and by the immune system of its host. In this context, the S. mansoni Thioredoxin Glutathione Reductase (SmTGR) enzyme plays a crucial role in neutralizing ROS, making it a validated target for the development of drugs against schistosomiasis. This work aimed to screen 640 compounds from two sets provided by Medicines for Malaria Venture (MMV). The first set tested is the Pandemic Response Box (PRB), launched in 2019, containing 400 compounds aimed at infectious diseases. The second, launched in 2022, is the Global Health Priority Box (GHPB), with 240 compounds, including molecules active against infectious agents of neglected diseases. In the screening assay, the reductive activity of SmTGR on 5,5'-dithio-bis-[2-nitrobenzoic] acid (DTNB) was measured by spectrophotometry (412 nm, 5 minutes), recording the appearance of the product, thionitrobenzoic acid (TNB), in the presence of 10 µM of the compounds. So far, the results of inhibition assays on SmTGR using 120 of the 640 compounds from the PRB and GHPB sets allowed us to identify nine hits (GHPB: compounds 34 and 36; PRB: compounds 16, 23, 27, 42, 47, 49, and 53), capable of promoting more than 40% inhibition of enzymatic activity. Compounds 47 and 27 from the GHPB achieved 65.5% and 62.1% inhibition, respectively. All hit compounds will be selected for orthogonal validation by Thermal Shift Assay (TSA). Validated inhibitors will have their IC50 determined and will be subjected to phenotypic assays on distinct parasite life cycle stages. The most promising compounds will have their mechanism of inhibition studied by kinetic assays and biophysical techniques.

MURINE SCHISTOSOMIASIS IN MUTANT STRAINS WITHOUT MAST CELLS

Clara Lucas Bernardino Felix — 2024-11-07

Introduction: Schistosomiasis presents clinical manifestations in the human host associated with the granulomatous inflammatory reaction to the parasite eggs as a result of the cellular components of the immune system. However, the role of mast cells in the immunopathogenesis of schistosomiasis is poorly understood, evidencing a knowledge gap that can be mitigated with the use of murine models. Objective: To characterize the immunopathology of schistosomiasis in a murine model deficient in mast cells. Methods: The project was submitted and approved at CEUA/FIOCRUZ, under the Protocol n°30/17-5. Mice were divided into two study groups, the Control group with animals containing mast cells and the Deficient group with animals without circulating or tissue mast cells. Feces samples were collected from the animals in the Control and Deficient groups at 50 and 70 days post-infection (dpi) to perform the parasitological examination according to the spontaneous sedimentation method HPJ. On the day of euthanasia, the animals, along with their livers and spleens, were weighed, and samples from these organs were collected for histopathological analysis using Hamp;E staining. Statistical differences were assesed using the chi-squared test with p-values lt; 0.05. Results: The parasitological results showed higher detection of parasite eggs in the feces of the animals in the Control group. When analyzing the weight and histopathology of the liver and spleen, higher proportions of weight and structural changes and inflammatory response were observed in the Deficient group as a result of the granulomatous inflammatory response. Conclusion: The results demonstrate a difference in the immune response of animals that contain mast cells, highlighting the influence on the development time of the parasite's life cycle from the elimination of eggs in feces and on the granulomatous inflammatory response related to mast cell deficiency. Thus indicating a potential role of mast cells during the pathogenesis of schistosomiasis. Complementary studies are important to investigate this influence of mast cells on the host's immune response to schistosomiasis.

Zinc-Binding Properties of Schistosoma mansoni MEG 3 Isoforms

LORRAN YVES MACHADO DE SOUSA — 2024-11-07

Schistosomiasis is a neglected tropical disease responsible for a significant number of deaths, particularly in low and middle income countries. The primary causative agent of schistosomiasis in the Americas, Schistosoma mansoni, demonstrates a remarkable ability to persist within its definitive host, often surviving for decades without being cleared by the human immune system. The precise mechanisms behind this immune evasion remain poorly understood. A group of proteins, referred to as MEGs (micro-exon genes), has attracted considerable attention due to their unique structural features, which may contribute to the parasite's survival strategies. This study aims to investigate specific MEG-encoded proteins, with a focus on the isoforms of MEG 3, which are abundant in egg secretions and have been associated with liver fibrosis. Through recombinant expression in E. coli BL21 (DE3) strain, we have successfully expressed the MEG 3.1, 3.2, and 3.3 isoforms, although all isoforms were found to be insoluble and required purification under denaturing conditions. The presence of 16 conserved cysteine residues in these proteins complicates the refolding process, which was accomplished through dialysis. However, the high cysteine content suggests a potential role in metal binding, such as zinc, similar to metallothioneins. We assessed the zinc binding capacity through isothermal titration calorimetry (ITC) and found that MEG 3.1 is able to bind Zn2+ and Cu2+, although with lower affinity for the latter. The presence of both Zn² and Cu² also promoted the oligomerization of MEG 3.1, 3.2, and 3.3. Since MEG 3 isoforms are secreted by both lung-stage schistosomula and eggs, they come into direct contact with the host immune system. The involvement of the MEG 3 protein family in zinc homeostasis and immune regulation suggests their potential as novel therapeutic targets for schistosomiasis, offering new avenues for disease intervention strategies.

Screening of snake venoms for the identification of possible novel therapeutical targets and toxins with schistosomicidal potential

Tereza Cristina Taveira Barbosa — 2024-11-07

Schistosomiasis is a neglected tropical disease caused by flatworms of the genus Schistosoma. Treatment of the disease relies only on a partially effective drug, praziquantel. Therefore, new therapeutic alternatives are needed. Snake venoms have lethal activity against different organisms, ranging from bacteria to higher vertebrates. Several venoms have been shown to be active against protozoa, however, data on the activity of venoms against helminths are scarce. In the search for new antischistosomal compounds, we tested here the in vitro effects of crude venoms from eight Bothrops snake species, from Crotalus d. terrifucus and venom fractions against two developmental stages of Schistosoma mansoni, post-infectious larvae (schistosomula) and adults. We obtained adult S. mansoni worms by perfusion of infected hamsters. We monitored mortality, motility, pairing rates and oviposition of adult worms over 72 h of incubation with the venoms. Furthermore, we assessed the viability of adult and schistosomula worms by ATP quantification. We used scanning electron microscopy (SEM) to examine morphological changes after incubation with venom and EdU assays to measure the effect of venom against parasite stem cells proliferation. We subjected B. jararacussu venom to size-exclusion chromatography and analyzed the effects of protein fractions on parasite viability. We found that adult worms incubated with each venom at concentrations of 100 and 50 μg/mL showed a reduction in parasite viability, motility, pairing, and egg laying. Schistosomula incubated with each venom at concentrations of 3.12, 6.25, 12.5, 25, and 50 μg/mL showed a significant dose and time-dependent decrease in viability. Adult and schistosomula showed the most significant changes after exposure to B. jararacussu venom, which was therefore chosen for further assays. B. jararacussu venom at concentrations of 25 and 50 μg/mL resulted in tegumental damage of adult worms, as shown by SEM. EdU assays revealed a reduction in worm stem cells when incubated with B. jararacussu venom at 50 and 100 μg/mL. Seven fractions of B. jararacussu venom were investigated for antischistosomal activity. After incubation of schistosomula and adult worms with each fraction at 25 or 50 μg/mL, we observed that fraction 4 significantly reduced the viability of these parasites. In conclusion, the anthelmintic activity of snake venoms and their components against S. mansoni is promising, justifying further investigations.

Therapeutic potential of granulocyte colony-stimulating factor (G-CSF) associated with praziquantel in the immunomodulation of hepatic fibrosis in mice with schistosomiasis mansoni

Cicero Jadson da Costa — 2024-11-07

Introduction: Schistosomiasis mansoni is considered a public health problem, as it is responsible for the morbidity and mortality of millions of people every year. One of the issues caused by the disease is hepatic fibrosis, triggered by chronic lesions during S. mansoni infection. Recent studies suggest that stem cell therapy may be associated with the improvement of fibrous tissue. Thus, we propose that stimulation using granulocyte colony-stimulating factor (G-CSF) in combination with praziquantel may improve fibrous tissue in an animal model.Methods: To evaluate the impact of G-CSF combined with praziquantel (PZQ) in BALB/c mice (CEUA IAM-145/19) with chronic S. mansoni infection, hepatic fibrous tissue quantification was assessed using picrosirius red staining, and inflammatory cytokine levels were measured through CBA assay and sandwich ELISA.Results: Quantification of fibrous tissue (p=0.0060) demonstrated that in untreated animals, the percentage was 6.61%, in animals treated with PZQ, it was 8.03%, and in those treated with both PZQ and G-CSF, it was 9.84%. Pro-inflammatory cytokines (IL-2, TNF-α, IFN-γ, and IL-6), anti-inflammatory cytokines (IL-10 and IL-4), and the regulatory cytokine (TGF-β1) showed no statistically significant differences in the concentrations tested in the assay.Conclusion: The preliminary results of using G-CSF in combination with praziquantel did not demonstrate the ability to alter the lesion profile caused by chronic S. mansoni infection. We are currently analyzing the gene expression of α-SMA, albumin, collagen, and galectin-3 to assess fibrogenesis markers and liver function, in order to corroborate the results of the morphometric analysis.

Discovery of new antischistosomal thioxantones as potential parasite efflux pumps inhibitors.

Jordano Reis — 2024-11-07

Schistosomiasis affects approximately 250 million people globally and threatens over 700 million individuals, according to the World Health Organization. In Brazil, Schistosoma mansoni is the primary infecting species. The current treatment and prevention strategy relies solely on Praziquantel (PZQ), which although safe and effective against all Schistosoma species is less active on immature forms of the parasites. Moreover, its extensive use in endemic regions raises concerns about the emergence of drug-resistant strains. Efflux pumps, particularly ABC transporters, play a key role in resistance mechanisms. Recent studies have identified a connection between P-Glycoprotein (Pgp/ABCB1) and PZQ resistance in S. mansoni, highlighting the urgent need for alternative therapies to combat schistosomiasis. One promising avenue involves the use of thioxanthone, an S-heterocycle containing a dibenzo-g-thiopirone substructure. Thioxanthone derivatives have been explored for their role in developing Pgp inhibitors, particularly as antineoplastic agents. Historical drugs like Lucanthone and Hycanthone, previously used to treat schistosomiasis, are also thioxanthones, underscoring the potential of this substructure in the search for new therapeutic compounds. This study aimed to evaluate the antischistosomal activity of seven thioxanthone-derived compounds, along with their toxic effects on human cells. Adult S. mansoni parasites were assessed for motility using bright field microscopy and the ImageXpress Micro Confocal High-Content Imaging System. Adult worms were collected from Swiss mice infected with S. mansoni cercariae 42 days prior, via perfusion. The compounds were then tested on the worms, with a series of 100 time-lapse images of each well captured every 24 hours for a total of 72 hours. A convolutional neural network model processed these images and their binary masks, and motility metrics were calculated using the CellProfiler software. Cytotoxicity assays were performed on WSS-1 and HepG2 human cells using the resazurin reduction method. Results showed that compounds 1 and 2 inhibited the motility of adult S. mansoni worms to a degree comparable to PZQ at 50 µM. Interestingly, only compounds containing aliphatic tertiary amines as substituents exhibited activity against adult worms, suggesting this substructure may hold therapeutic potential. While compound 1 (50 µM) reduced the viability of WSS-1 cells by approximately 70%, compound 2 demonstrated safety across both human cell lines, even at higher concentrations (up to 300 µM). These findings indicate that the thioxanthone core structure is valuable in the ongoing search for effective antischistosomal compounds. Although these results are promising, further investigation is required to fully understand the mechanism of action. Docking, molecular dynamics simulations, and other in silico approaches will be conducted to elucidate the binding mode of these compounds to S. mansoni Pgp.

Mesoporous Silica Carrier-Based Composites for Taste Masking of Praziquantel

Janine Boniatti — 2024-11-07

Praziquantel (PZQ) is the standard treatment for schistosomiasis, a neglected tropical disease that affects over 123 million children worldwide. However, PZQ's bitter taste and low aqueous solubility hinder the development of conventional dosage forms. Therefore, alternatives are crucial for enhancing the physicochemical and biopharmaceutical properties of PZQ. Recently, mesoporous silica has emerged as a feasible material for taste masking and to enhance aqueous apparent solubility of drugs. This study aimed to develop and characterize PZQ-loaded mesoporous silica (MCM-41 type) as a prototype taste masking composite. MCM-41 was synthesized via the sol-gel method with hydrothermal treatment using a surfactant as a pore template, followed by calcination for template removal. PZQ was incorporated into MCM-41 by the incipient wetness impregnation method (MCM-41@PZQ). The MCM-41 and MCM-41@PZQ were characterized by nitrogen adsorption-desorption method, X-ray diffraction (XRD), and differential scanning calorimetry (DSC), while drug release was assessed by the dialysis bag method under sink conditions and apparent aqueous solubility analysis. A high drug load of PZQ (38.25% w/w) was achieved. Morphological analysis showed a reduced surface area and pore volume of MCM-41@PZQ (535 m²/g and 0.37 cm³/g) compared to pristine MCM-41 (808 m²/g and 0.83 cm³/g), which is explained by the incorporation of the PZQ in the inner mesopores of MCM-41. PZQ incorporated into MCM-41 exhibited no crystallinity in XRD analysis and no melting point in DSC, which indicate drug amorphization within MCM-41 composites. MCM-41@PZQ showed a slower drug release behavior than pristine PZQ, with 50% and 66% of PZQ released after 10 h, respectively. Furthermore, the incorporation of PZQ into MCM-41 mesopores enhanced apparent aqueous solubility of PZQ due amorphization by 1.3x compared to pristine drug. The results indicate that MCM-41 is a feasible material as a PZQ composite by the drug amorphisation and controlled release. Further studies will be carried out to evaluate the taste masking properties of MCM-41@PZQ.

Evaluation of molecular diagnostic tests for intestinal schistosomiasis in a rural area in the state of Bahia, Brazil

Juliana Oliveira da Mata — 2024-11-07

Among neglected tropical diseases, schistosomiasis stands out for presenting an important degree of morbidity, affecting thousands of people throughout Brazil. Currently, disease control is mainly based on parasitological diagnosis by Kato-Katz (KK) and treatment of infected individuals. However, despite being extremely specific, KK does not present the same performance in relation to its sensitivity when applied in samples of individuals from low endemic areas. This fact is relevant since nowadays the majority of the endemic areas in Brazil present low endemicity for disease. Therefore, an effective diagnosis, with wide application in the detection of active infections and in the precise monitoring of cure after treatment, represents an essential instrument for knowing the real prevalence of schistosomiasis and to guide controlling actions. In this sense, this work proposed to evaluate diagnostic tests based on real-time PCR (qPCR) and Loop-Mediated Isothermal Amplification (LAMP) in order to improve disease diagnoses, due to its ease of execution, stability of reagents and performance in clinical evaluation. All tests were conducted blindly. Stool samples collected from residents of Conde, BA, a high endemicity area in the state of Bahia, were examined by KK and Helmintex technique (HTX). After sample examination, a positivity rate of 34.3% (IC95%: 27.7-42) and 45.3% (IC95%: 37.4-54.4) was observed with KK and HTX techniques, respectively. Participants who were positive for S mansoni eggs by KK or HTX were treated and collected new stool samples 30, 180 and 360 days after treatment. Total DNA was extracted from 500 mg of feces using the commercial QIAamp Power Fecal Pro Kit (Qiagen, Germany), following the manufacturer’s recommendations. Extracted DNA was analyzed and quantified in the Nanodrop and amplified by qPCR and LAMP techniques. The qPCR’s results were interpreted considering a cut-off point of Ct 42, and demonstrated a positivity of 24.07% (IC95%: 18.9-29.7) at T0, before treatment. No samples were positive at T30. At T180 and T360 the positivity rates were of 2.56 and 12.12%, respectively. Regarding LAMP results, a positivity of 55.64% (IC95%: 49.4-61.6) was observed before treatment, while at T30, T180 and T360 the positivity rates were 46.65; 44.73; and 9.09%, respectively. Compared to KK, qPCR showed lower positivity, while LAMP showed higher positivity, before treatment. After treatment, LAMP continued to show high positivity, while qPCR presented drastically reduced positivity. After opening the database of study participants, it will be possible to carry out further analyzes to determine which diagnostic technique performed best in the endemic area studied.

Assessment of the effect of sanitary conditions on the occurrence of schistosomiasis: A pilot study

Natalia de Melo Nasser Fava — 2024-11-07

From 2000 to 2020, schistosomiasis in Brazil showed an average annual positivity rate of 4.3%. Disease transmission is influenced not only by the presence of the intermediate host but also by water supply, environmental changes, hygiene practices, and local sanitary conditions. The disease disproportionately affects poorer populations who are more vulnerable due to limited access to water, sanitation, and hygiene (WASH) services. The study aimed to determine the prevalence of schistosomiasis using a more sensitive diagnostic method and to assess the association between various types of access to WASH services and the occurrence of schistosomiasis in a rural community in Alagoas, Brazil. Between March 4 and 8, 2024, 50 residents of the Usina João de Deus community were randomly selected for the study, including individuals aged seven and older, excluding pregnant and lactating women. After signing informed consent, participants completed a socio-epidemiological questionnaire and provided fecal samples. Each sample was used to prepare 18 Kato-Katz slides. After the microscopic analysis 20% of the slides were sent to Fiocruz Minas for quality control. Data on WASH conditions were correlated with the results of the fecal samples through estimations of Odds Ratio (OD) and Relative Risk (RR). Among the 50 participants (26 women and 24 men), aged between 10 and 79 years, 17(34%) were positive for Schistosoma mansoni, being 11 women and 6 men, with an average age of 54 years, all of them exhibiting low levels of parasitemia (≤ 99 eggs per gram of feces). The official community prevalence, according to the 2023 Schistosomiasis Control Program (SCP), was 2%, based on a single Kato-Katz slide per fecal sample. Analysis of environmental variables associated with the disease revealed that 76.5% (13/17) of infected participants reported frequenting water bodies, primarily for recreational activities. Furthermore, 94% (16/17) and 35,3% (6/17) of the positive cases reported a lack of piped water at home for consumption and other activities, respectively. Additionally, 41% (7/17) did not have a bathroom at home and 41% (7/17) practiced open defecation. These last four factors emerged as significant risks for the disease, with Odds ratio ranging from 1.6 to 5.07 and relative risk from 1.48 to 2.52. The results suggest that the prevalence reported by the SCP is underestimated due to the use of a single Kato-Katz slide per fecal sample, which, combined with low parasitemia, makes egg detection challenging and may cause false results. The findings also highlight the importance of environmental and infrastructural factors in schistosomiasis transmission, indicating that individuals without adequate WASH services are more prone to infection. Therefore, improving WASH infrastructure and employing accurate diagnostic methods are crucial for reducing schistosomiasis prevalence.

Exploratory analysis of an urban transmission area for schistosomiasis in the Metropolitan Region of Recife, Pernambuco

Maria Eduarda da Silva Pereira — 2024-11-07

Introduction: Schistosomiasis mansoni is a water-borne infectious parasitic disease that persists due to the poor socio-sanitary conditions of the current population. In Brazil, the state of Pernambuco has a high number of cases, chronicity and ranks first in the number of deaths related to the disease. Schistosomiasis, once seen as a rural problem, is now a concern in cities, where the lack of urban planning exacerbates the situation. Therefore, the central aim of this study was to analyze the occurrence of urban transmission through epidemiological description in a city in the Metropolitan Region of Recife. Methodology: The representative study area consisted of the locality of Barra de Jangada, Jaboatão dos Guararapes, Pernambuco, in which the urban conglomerates of Catamarã and Novo Horizonte were geographically demarcated for the coproscopic census survey. The survey involved filling out epidemiological bulletins to collect data from participants and all residents of the areas analyzed were invited to participate by providing a stool sample that was analyzed using two slides of the Kato-Katz technique. The information collected was registered using Excel spreadsheets (2016) and statistical analysis was carried out using Prisma 8.0.2 software. The project was approved by the Human Research Ethics Committee under protocol numbers 5.905.584 and 5.652.210. Results: 1,159 people were registered, 47.8% of whom were male and 52.1% female, with an average age of 33 years (0-92). A total of 478 were obtained from the Catamarã area and 262 from Novo Horizonte, totaling 740 samples, where the sex varied between 47.6% male and 52.4% female with an average age of 36.7 years (6-80 years). Of these, 100 individuals were identified as positive for Schistosoma mansoni, with four individuals co-infected with Ascaris lumbricoides and one individual with Trichuris trichiura and Ancylostomide. Among the individuals positive for S. mansoni, 61% were male (p lt; 0.0038), the average age was 37 years (6-80), and the average parasite load was 210 eggs per gram of feces (EPG) (12-3,168 EPG), however, 64% of the positives had a low parasite load (1-99 EPG) (p lt; 0.001). The highest number of positives occurred in the 30-39 age group (19%) and the lowest in the 0-9 age group (6%). There was no statistically significant difference between parasite load classification and mean age or age groups and parasite loads (p gt; 0.05). Among those who tested negative for S. mansoni, three were infected with A. lumbricoides, three with T. trichiura and one with Ancylostomide. Conclusion: Areas of urban transmission with moderate endemicity were identified in a municipality previously classified as having low endemicity, where cases may be underreported due to the low sensitivity of the KK and the low number of tests carried out routinely in the municipality. Male individuals were more likely to be positive for S. mansoni.

Development of a spectrophotometric model for early diagnosis of Schistosoma mansoni Infection in Biomphalaria glabrata

Vanessa Valladares — 2024-11-07

Schistosomiasis mansoni is a waterborne parasitic infection caused by the trematode Schistosoma mansoni and transmitted by planorbid snail of the Biomphalaria spp. In Brazil, this disease continues to represent a significant public health issue, making it essential to have prior and effective diagnosis of transmission areas from an epidemiological perspective. Understanding the dynamics of the host-parasite interaction is crucial for maintaining the parasite's life cycle and developing more effective control strategies. In this context, the aim of this work is to develop a spectrophotometric model for parasitological diagnosis of Biomphalaria glabrata infected with S. mansoni throughout the infection process. A total of 150 live specimens of B. glabrata from the Belo Horizonte (MG, Brazil) and Sumidouro (RJ, Brazil) strains, maintained in the laboratory. The specimens were individually infected with 7 to 10 miracidia of S. mansoni BH strain and divided into two groups: BgBH - sympatric S. mansoni infection; BgSu - allopatric S. mansoni infection. The spectra were obtained weekly, from infection until the 8th week. To obtain the spectra, the mollusks were dried on absorbent paper, and individual spectra were obtained using the ABB Boomen FT-NIR equipment with a resolution of 16 cm⁻¹. The chemometric analyses were carried out using unscrambler software, where the raw spectra were pre-processed and an exploratory data analysis, principal component analysis (PCA), was used. The spectrophotometric model, elaborated from the weekly analysis of infected mollusks, demonstrated differences between the spectra obtained in the 2nd and 3rd week of infection, based on PC-1 (88%) for BgBH and PC-1 (79%) for BgSu. Therefore, these results corroborate the occurrence of metabolic changes in mollusks infected by S. mansoni even before the cercariae shedding, the 2nd and 3rd weeks being the period of differentiation of the cercariae in the digestive gland and their release into the hemolymph. Thus, near-infrared spectroscopy (NIRs) stands out as an innovative, fast, and non-destructive tool, with potential applicability for the diagnosis of schistosomiasis in the prepatent period of infection, allowing for the detection of S. mansoni infection even before the mollusks start the cercariae shedding period (patent period). NIRS is therefore a promising technique for optimising diagnostic measures and controlling schistosomiasis transmission in Brazil.

Environmental DNA (eDNA) approach for detecting schistosomiasis transmission foci in a moderate endemic area in Brazil

Sandra Grossi Gava — 2024-11-07

Schistosoma sp. detection is challenging, mainly in moderate and low-endemic areas where the monitoring is hampered by difficulties in snail collection, particularly in the dry season. Also, snail sampling, shipment, and parasitological detection require trained personnel. Thus, there is a need to improve tools for surveillance of transmission foci, as targeted in the WHO/NTD road map. In response to these challenges, we used the environmental DNA (eDNA) approach to monitor schistosomiasis transmission areas in Brazil, where only Schistosoma mansoni is present. This approach involves analyzing water samples from potential endemic locations to detect traces of parasite DNA, facilitating the assessment of active transmission foci. The eDNA assay was standardized for local conditions by evaluating the specificity of qPCR primers and probe targeting the mitochondrial gene cytochrome c oxidase (coi) of S. mansoni for detecting the parasite DNA. Following, water from snail breeding tanks containing Biomphalaria glabrata infected or not with S. mansoni was used for eDNA extraction. Specific eDNA detection was done by three previously described molecular techniques for S. mansoni detection: Low-Stringency PCR (LS-PCR), Loop-mediated isothermal amplification (LAMP), and quantitative PCR (qPCR). After standardization, the approaches were used to investigate samples from five water body collections in a schistosomiasis moderate endemic area from a rural District in Northeastern Minas Gerais, Brazil, where an epidemiological study is in progress (personal communication). A malacological survey was also carried out. The qPCR primers and probe specifically amplified Schistosoma sp. DNA but no other trematodes occurring in Brazil. Additionally, all three molecular assays amplified S. mansoni DNA only from eDNA samples collected from tanks with infected snails. Using the traditional light exposure, we identified snails shedding cercariae at collection point 3 during the malacological survey. However, the eDNA approach allowed us to identify potential transmission foci in collection points 3 and 4 using eDNA field sampling associated with LAMP and qPCR assays. The LS-PCR assay could not detect parasite DNA in any collection point. In summary, our study illustrates the potential of eDNA detection approach in a moderate endemic area in Brazil, as an effective strategy for monitoring schistosomiasis endemic areas and identifying active S. mansoni transmission foci. This approach may be used in the detection of S. mansoni in non-human animal hosts, an under studied area, particularly in Brazil. Yet, LAMP technique demonstrated promising results as a more feasible molecular technique, to be used as the detection method in the field.

CASE REPORT: PULMONARY COMPLICATION IN A FARMER WITH SCHISTOSOMIASIS MANSONIS IN THE CITY OF ITABUNA, BAHIA

Marcelo dos santos Souza — 2024-11-07

Schistosomiasis mansoni is a parasitic disease caused by Schistosoma mansoni, which predominantly affects the hepatosplenic system. Although the hepatic form is the most common, pulmonary complications are rare and less recognized, but can have serious clinical consequences. This report describes a rare case of schistosomiasis mansoni with significant pulmonary involvement, highlighting the importance of early diagnosis and appropriate management of these complications. A 48-year-old male farmer living in a rural area in Itabuna, Bahia, an endemic region for schistosomiasis, presented to the health service complaining of progressive dyspnea for two months, associated with dry cough and sporadic chest pain. He denied hemoptysis, but reported unintentional weight loss and intermittent low-grade fever. The patient had been diagnosed with the disease 10 years ago, but never completed treatment. The physical and clinical examination revealed signs of chronic liver disease, such as collateral circulation and hepatosplenomegaly, in addition to bibasilar rales on pulmonary auscultation. Laboratory and imaging tests revealed significant eosinophilia (12%), slightly elevated liver enzymes, bilateral infiltrates (chest X-ray), and nodular lesions with peripheral distribution (chest computed tomography (CT), suggesting possible granulomatous involvement. Serology for other lung infections was negative. Given the clinical history and other findings, a CT-guided lung biopsy was performed, which revealed epithelioid granulomas without central necrosis, with viable and calcified eggs of S. mansoni. The test for eggs in the blood was positive, confirming the diagnosis of pulmonary complications due to schistosomiasis. The patient was treated with a single dose of praziquantel, followed by corticosteroid therapy to manage the lung inflammation. There was significant improvement in respiratory symptoms after six weeks, with partial resolution of lung lesions observed on repeat CT. Pulmonary involvement in schistosomiasis is rare and may be underdiagnosed, since respiratory symptoms can be confused with other diseases, such as tuberculosis. The presence of pulmonary granulomas and S. mansoni eggs outside the gastrointestinal tract highlights the ability of the parasite to cause disseminated disease, complicating the clinical picture and making management more challenging. This report highlights the importance of considering schistosomiasis in the differential diagnosis, in addition to emphasizing the importance of continued surveillance for extrahepatic complications, particularly in endemic areas. The inclusion of advanced diagnostic methods, such as CT-guided lung biopsy, may be crucial for identifying rare manifestations. Correct patient counseling on the importance of complete treatment and regular monitoring are essential to prevent serious complications and improve clinical outcomes.

LIVER INJURY IN MICE INFECTED BY SCHISTOSOMA MANSONI AND TREATED WITH PHARMACOLOGICAL AGENTS

Lorena Conceição de Queiroz — 2024-11-07

The chronic phase of schistosomiasis is marked by the formation of granulomas to contain Schistosoma mansoni eggs, a process aggravated by frequent reinfections that cause unregulated proteolysis and compromise the extracellular matrix. Because praziquantel does not directly affect granulomatous reactions, is not effective at all stages of the parasite cycle, and does not prevent reinfection, there is an urgent need for more effective treatment alternatives. Swiss mice were infected with 75 cercariae subcutaneously and after 45 days, treated for 8 and 15 days with praziquantel, farmx and the combination of treatments. Histological sections of liver were obtained and stained with picrosirius red and masson's trichrome. The analysis of extracellular matrix remodeling was performed using ImageJ ® software, Fiji version (Versatile tool). Analyses were performed in GraphPad Prism v. 8.2.1, with normality testing to assess data distribution. p-values lt; 0.05 were considered significant. In the Masson's trichrome analysis, a significant difference was observed in which there was a greater area of the extracellular matrix in the groups treated with praziquantel (p = 0.0079) and association (p = 0.0017) in relation to the positive control group in 8 days of treatments. Regarding the intensity of the marking, there was a significant difference with greater marking in the groups treated with farmx (p=0.0447) and positive control (p=0.9999) in relation to praziquantel in the group treated for 15 days. Picrosirius analysis revealed a statistical difference between type 3 collagen in the 8-day positive control compared to the 15-day positive control (p = 0.0449), presenting a median of 3,846,135 μm (1,496,978 – 9,171, 444) and 3,269,607 μm (1,782,035 – 4,131,127) respectively. The group treated with praziquantel showed a significantly higher deposition of type 3 collagen after 15 days 2,774,350 μm (2,067 – 5,106; p= 0.0062). Regarding the PS analysis for type 1 collagen, only the group treated with the combination of drugs showed a statistically significant difference (p = 0.0047), in which there was greater deposition of type 1 collagen in the group treated for 15 days 1,745 μm (626,857 - 2,415) in relation to the group treated for 8 days 154,259 μm (93,692 - 462,705): Our results suggest that, although the treatment with praziquantel has some efficacy in killing the worm, the increase in the area and the low intensity of the extracellular matrix suggest that the treatment is not acting directly on the lesion, which reinforces that Praziquantel is not enough to combat granulomatous lesions, even when associated with a drug that can help kill the parasite. And the increase in collagen in the group treated for 15 days may be due to the longer healing time between the two times.

IMMUNOREGULATORY POTENTIAL OF CHIMERIC PROTEINS FROM SCHISTOSOMA MANSONI IN MURINE MODEL FOR ALLERGY

Carolina Orrico Melo Ferreira de Jesus — 2024-11-07

Allergies are among the most prevalent chronic diseases worldwide, with an increasing incidence in developing countries, particularly in urban areas of Latin America. Numerous studies have investigated the effectiveness of immunotherapies utilizing recombinant molecules capable of modulating allergic responses. Among the promising candidates, certain molecules derived from helminths, particularly Schistosoma mansoni, have shown potential. Infection with S. mansoni activates mechanisms similar to those involved in allergic responses, including IgE production and eosinophil recruitment, while also promoting Th1 polarization and IL-10 production, which may lead to reduced symptoms of atopy and allergic diseases. This study aims to evaluate the immunomodulatory potential of two chimeric proteins derived from S. mansoni cercarial elastase, SmCET and SmCETB, in a murine model of allergy induced by the mite Blomia tropicalis. AJ mice were divided into four groups: Negative Control (non-allergic), Positive Control (allergic without treatment), Q1 (allergic treated with SmCET), and Q2 (allergic treated with SmCETB). Allergy was induced through two intraperitoneal injections of B. tropicalis extract, followed by seven intranasal challenges with B. tropicalis lysate (BtE) over one week. Subsequently, mice were treated with PBS, dexamethasone, or one of the chimeric proteins for seven days (CEUA nº 8373280920). Post-treatment, serum levels of specific IgE, IgA, and IgG2a antibodies were analyzed, along with bronchoalveolar lavage (BAL) content. Additionally, mice splenocytes were cultured for 48 and 72 hours with BtE and either SmCET or SmCETB. Culture supernatants were assessed for cytokine production via ELISA. Splenocyte proliferation was measured using the MTT assay, and cells were labeled with CD4 and CD25 for flow cytometry analysis. Results indicated no significant differences in total BAL cell counts between treated and untreated groups; however, differential cell counts showed an increase in specific cell types in the chimeric protein-treated groups. The antibody profiles in serum and cytokine levels in the lung and BAL fluid suggest immune modulation. Notably, cytometry analysis revealed elevated lymphocyte levels in the untreated allergic group after 48 hours of exposure to SmCETB, along with altered CD4+ cell concentrations in treated groups. These findings suggest that the chimeric proteins SmCET and SmCETB could be viable alternatives for allergen-specific immunotherapy. Further studies are needed to better understand the immunoregulatory profiles of SmCET and SmCETB.

Intermediate and definitive hosts of wild Schistosoma mansoni: ecological niche modeling of hosts in low endemicity areas

Elisiane Rodrigues dos Santos — 2024-11-07

IntroductionThe relationship between the environment and animal life began to be seen as an important tool to help control zoonoses. Climate variations lead to changes in the environment, which can influence the spatial distribution of species and, consequently, the spread of diseases to humans. Considered the main non-human definitive host species of Schistosoma mansoni in Brazil, the wild rodent Nectomys squamipes plays an important role as a reservoir in maintaining the schistosomiasis cycle in the absence of humans. This study demonstrates the results of ecological niche modeling of intermediate and definitive wild hosts of S. mansoni in the Regional Health Superintendence of Barbacena (Minas Gerais State), which has registered 31 municipalities, 80% of which are classified as endemic for parasitosis. Methods Environmental variables associated with the distribution of each species were used based on information from the scientific collections of Global Biodiversity Information Facility (GBIF) and Species Link to project the ecological niche model in the geographic space. Abiotic variables such as the mean annual temperature, isothermality, and precipitation seasonality were obtained from World Clim.The R-Studio software (version 4.3.1, R Core Team), a script-based statistical programming environment, was used for ecological niche modeling, in which occurrence data and abiotic variables were loaded. The modeling algorithms used were BIOCLIM and MAXENT (R-Studio packages), they project, in pixels, the area suitable for the establishment of the species, according to the selected bioclimatic variables. Results Ecological niche modeling of the wild host, N. squamipes, revealed the occurrence of the species in geographic overlap with the Biomphalaria species. Conclusions Knowing the influence of bioclimatic variables and identifying favorable conditions for the establishment, occurrence, and distribution of species are important information for developing strategic actions for the surveillance and control of this endemic species. The presence of the definitive wild host needs to be considered by control programs of schistosomiasis.

"LabPar de Portas Abertas": THE CONTRIBUTIONS OF LUDICITY TO RAISE AWARENESS OF BASIC EDUCATION STUDENTS FOR THE PREVENTION OF SCHISTOSOMIASIS IN ALAGOAS, BRAZIL

Müller Ribeiro Andrade — 2024-11-07

In Brazil, schistosomiasis is an endemic disease with significant impact on public health. It involves an ecological interaction, directly associated with poor sanitation, and is caused by the trematode Schistosoma mansoni. The magnitude of its prevalence is linked to socioeconomic, environmental, and cultural factors. The interaction between humans, a contaminated environment, and intermediate hosts enables the maintenance of the parasite in vulnerable populations. In light of these challenges, health education initiatives potentially offer an effective approach to controlling schistosomiasis. When combined with engaging methods, such as playful activities, prevention strategies can become even more effective, promoting preventive practices. Therefore, the purpose of this work is to report theatrical activities titled "Bia's Chronicles" and demonstrations of life forms through microscopy, aiming to raise awareness among primary school students about schistosomiasis by focusing on the ecology of intermediate hosts. The "LabPar de Portas Abertas" Extension Project, from the Parasitology Laboratory at the Federal University of Alagoas, carried out activities promoting One Health education and parasitology with a focus on schistosomiasis for middle and high school students from May to August 2023. A total of 325 students from four private schools and three public schools in Maceió, Alagoas, participated. Most participants were girls (72%) and aged between 12 and 17 years (95%). "Bia's Chronicles" narrates the story of a snail from the Biomphalaria genus, who, after witnessing a human defecating near the river where it lives, learns about parasites whose eggs may be in the feces and infect other snails around it. Terrified, the protagonist Bia urges readers to consider whether exterminating snails from her genus is a preventive measure and reflects on improper fecal disposal, especially near water sources, as it contributes to the spread of schistosomiasis. In addition to presenting the chronicle, we conducted microscopy demonstrations to illustrate different life forms. Students were able to view slides with specific samples, offering them the opportunity to distinguish a snail from the Biomphalaria genus from other species and understand its life cycle. Based on these activities, using theatrical performance and microscopy made it possible to present essential concepts for understanding schistosomiasis, as well as debunk the idea that transmission is solely due to the presence of the snail. Therefore, health education is crucial for the prevention of schistosomiasis, as it empowers students and communities to adopt practices that reduce the risks of the disease, while also increasing knowledge retention and interest in the subject.

Epidemiological characterization and temporal trends of Schistosomiasis mansoni in the Northeast region of Brazil: analysis of a decade

Luís Gabriel dos Santos Gomes — 2024-11-07

Introduction: Among the six species of Schistosoma known to cause disease in humans, Schistosoma mansoni is the only one present in Brazil, responsible for infections in 19 out of the country's 26 states. Objective: To analyze the epidemiological characteristics, prevalence, and temporal trends of schistosomiasis mansoni in the Northeast region from 2012 to 2023. Methods: Data for this study were obtained from the Notifiable Diseases Information System (SINAN). We considered the nine states in the Northeast region that had reported cases during the study period. Epidemiological characteristics such as gender and age group were analyzed using descriptive analysis and Relative Risk (RR). Furthermore, a temporal trend analysis was conducted using a log-linear regression model with the Joinpoint program. All statistical analyses were performed with a 95% Confidence Interval (CI), and results were considered significant when p≤0.05. Results: During the study period, 12,420 cases of schistosomiasis were reported in the Northeast region of Brazil. The three states with the highest number of cases were Bahia, with 5,683 cases (46.43%); Pernambuco, with 2,657 cases (27.71%); and Paraíba, with 994 cases (8.12%). Regarding gender, males accounted for the highest number of reported cases (N = 6,847; 55.13%), with a higher Relative Risk (RR) of 1.289 (95% CI: 1.244 to 1.335) for disease occurrence. The most affected age group was 40 to 69 years, with 5,379 cases (43.31%). However, the age group with the highest risk was individuals over 70 years (RR = 5.901; 95% CI: 5.358 to 6.499). In terms of temporal trends, both Pernambuco, from 2012 to 2023 (AAPC = -7.5; 95% CI = -11.5 to -3.4; p = 0.001), and Bahia, from 2014 to 2023 (APC = -19.9; 95% CI = -28.2 to -10.7; p = 0.006), showed decreasing trends. Conversely, the state of Piauí exhibited an increasing temporal trend (APC = 31.0; 95% CI = 5.3 to 63.0; p = 0.001) between 2016 and 2023. Conclusion: Our data demonstrate that Pernambuco is one of the most affected states by schistosomiasis in the Northeast, although temporal trends show a decrease in prevalence rates over the years. In terms of epidemiological characteristics, men and individuals aged 40 to 69 are at a higher risk of contracting the disease. These findings highlight the profile of individuals most affected by schistosomiasis, which may reflect occupational or labor activities of people living in endemic areas for the disease.

Filling the gaps: overcoming the Prestonian shortfall in Biomphalaria straminea (Gastropoda: Planorbidae) populations in Neotropical dry forest reservoirs

Lucas Henrique Sousa da Silva — 2024-11-07

The semi-arid region of Brazil has historically been characterised by water scarcity, which for centuries has influenced the dynamics of the environment and the way of life of human populations. In this region, water reservoirs serve as important sources of supply during long periods of drought; however, they frequently receive untreated sewage discharges. This practice fosters the maintenance of disease vector populations, such as schistosomiasis mansoni. The lack of information about the abundance and dynamics of these vectors over space and time, known as Prestonian shortfall, adds an extra layer of concern to the situation of the semi-arid reservoirs. This limited understanding hampers our ability to predict events and manage and effectively conserve freshwater mollusc populations. To bridge this gap, we investigated the effect of seasonality in the semi-arid region on the dynamics of Biomphalaria straminea populations, the primary vector of the Schistosoma mansoni in Caatinga reservoirs. We conducted monthly collections between June 2017 and May 2020 in three reservoirs in the municipality of São Julião, Piauí, located in urban and rural zones. Based on the literature, specimens were identified, measured, and categorised into young and adult individuals, and precipitation data were obtained from public government databases (INMET). We used GLMs and circular statistics to verify the existence of seasonal patterns in the abundance of molluscs. We recorded 5,555 specimens of B. straminea, with an average size of 5.11 mm. In terms of age composition, young individuals predominated (79%) compared to adults (p lt; 0.001; W = 9). We found that precipitation has a negative effect on the abundance of B. straminea (intercept = 5.52; coefficient = -1.08; R² = 0.41; p lt; 0.001), with the dry season (n = 3,411; 61%) presenting a higher number of individuals than the rainy season (n = 2,144; 39%). The dry season coincided with the highest abundance peak recorded in the reservoirs (rho = 0.6) and with a greater number of young individuals (n = 2,741) compared to adults (n = 629) compared to the rainy season (young = 1,667; adults = 518). We did not observe uniformity in the distribution of B. straminea abundances throughout the study period, indicating the presence of seasonal variations in the abundance of this species (Rayleigh test = 0.6099; p lt; 0.001). The abundance of the Biomphalaria straminea species during the dry season highlights the need for more effective surveillance and control strategies, considering the increased risk of helminthiases, especially schistosomiasis. This elevated risk is associated with environmental conditions favourable to vector proliferation at this time of year and with the increased density of animals and the greater demand for water resources in the reservoirs.

Morphological and molecular characterization of Biomphalaria snails in Belém, Pará, Eastern Amazon area in Brazil

Salathyel Farias Pereira — 2024-11-07

Introduction: The Biomphalaria genus includes snails that are considered hosts of Schistosoma mansoni, the etiological agent of schistosomiasis in Brazil. Three are considered main hosts of this trematode: Biomphalaria glabrata, Biomphalaria tenagophila and Biomphalaria straminea, all previously reported in Pará state. Objective: This study aimed to morphologically and molecularly characterize Biomphalaria snail species collected in Belém municipality, Pará state, and investigate the presence of Schistosoma mansoni cercariae infecting these specimens. Methods: Malacological surveys were conducted between 2020-2023, on eight Administrative Districts (ADs) of Belém. Collected snails were preserved and transported to the Malacology Department (LABMAL) of Evandro Chagas Institute (IEC) for examination. The specimens were measured and individually exposed for S. mansoni cercarial shedding. Subsequently, specimens were randomly selected from each collection site for fixation and morphological analysis. Morphological identifications were based on a comparison of shell characteristics, excretory organ morphology and features of the female and male reproductive systems. Molecular characterization using Polymerase Chain Reaction Restriction Fragment Length Polymorphism (PCR-RFLP) was performed on dissected snail foot tissue. Results: A total of 7.648 snails were collected, and 6.959 were identified as Biomphalaria genus. Four species were morphologically identified: 4.097 as B. glabrata, 2.728 as B. straminea, 129 as B. tenagophila, and 5 as B. occidentalis. The molecular characterization by PCR-RFLP confirmed the morphological findings. S. mansoni infection was observed in 78 B. glabrata specimens, with an infectivity rate of 1,9% (78/4.097). The Biomphalaria snails were found in 13 neighborhoods alongside the ADs. Biomphlaria glabrata and B. tenagophila were found in the ADs of Guamá and Sacramenta; B. straminea was found in the ADs of Benguí, Guamá, Icoaraci, Mosqueiro, Outeiro and Sacramenta; B. occidentalis was found in AD of Guamá. Conclusion: These findings enhance our understanding of Biomphalaria snails’ distribution and diversity in Pará state. This knowledge is valuable for health and environmental surveillance efforts, aiding in targeted control actions for schistosomiasis and their intermediate hosts in Belém.

Deaths from Schistosomiasis in Jaboatão dos Guararapes-PE: Epidemiological and Sociodemographic Profile

Natália Oliveira Spinelli — 2024-11-07

Introduction: Schistosomiasis is a prevalent disease in all states of Brazil; however, the highest annual mortality rates are concentrated in the Northeast region, with the states of Pernambuco, Alagoas, Bahia, and Sergipe showing the highest percentages of deaths. Pernambuco has 103 endemic municipalities for this condition, along with others where the disease is expanding, mainly in urban and coastal areas. Being located in one of these endemic regions, the municipality of Jaboatão dos Guararapes has been developing various strategies for controlling this disease. Objective: To describe the epidemiological and sociodemographic profile of schistosomiasis death cases among residents of the municipality of Jaboatão dos Guararapes – PE. Methods: This is an epidemiological, descriptive study using secondary data on deaths with schistosomiasis as the underlying cause, recorded in the Mortality Information System, between 2013 and 2023. The data were analyzed using Tabwin and electronic spreadsheets. Results: The municipality has seven health regions located in rural and urban areas. A total of 237 deaths were recorded during the study period. Regarding age, 31.39% of cases occurred in individuals aged 60 to 69, followed by ages 70 to 79 (26.28%). In terms of race, individuals who self-identified as brown were the most affected (58.3%), followed by white individuals (32.8%). Concerning gender, men were more affected (51.8%) compared to women (48.2%). Regarding marital status, 45.2% of the total cases were married. In terms of educational level, 34.3% of the infected population had completed one to three years of schooling. Discussion: To strengthen the schistosomiasis control program, the municipality promotes the following actions: Training primary healthcare professionals to identify suspected and confirmed cases early, ensuring appropriate diagnosis and treatment; Ensuring that patients have easy access to healthcare services, including adequate medical treatment and continuous follow-up; Planning health education actions aimed at the community, focusing on awareness about prevention methods. Additionally, other actions can contribute to reducing the incidence of schistosomiasis and improving the quality of life of the residents, such as investment in basic sanitation infrastructure to reduce water contamination and interrupt the schistosomiasis transmission cycle, and training professionals to properly complete death certificates. Conclusion: The study highlighted the persistence of schistosomiasis-related deaths due to sociodemographic conditions. Despite the strategies employed, the elimination of the disease seems a distant reality, highlighting the need to strengthen actions related to the disease control program.

Individual and collective approaches for educational interventions integrated into primary care and the school environment aimed at preventing schistosomiasis mansoni: an experience report

Adriano Jose dos Santos — 2024-11-07

Schistosomiasis mansoni is a prevalent parasitic infection in Brazil, with its occurrence linked to inadequate sanitation. In this context, risk behaviors resulting from the population's limited knowledge about the disease may lead to increased reinfections and the development of severe forms. This study aims to assess the level of knowledge regarding schistosomiasis among a population residing in an endemic area of Alagoas-Brazil, and subsequently propose educational actions to raise awareness among the community. This is a qualitative-quantitative action research study with an interventionist character, conducted in the municipality of Feira Grande, AL, from March to September 2021. The study population consisted of 412 adult individuals residing in micro-areas served by two Basic Health Units (BHU). To collect data on the participants' knowledge, a structured questionnaire was administered through active search in the BHU. Following this, health education activities were conducted in the UBS and in three public schools in the municipality. This study was approved by the Research Ethics Committee involving Human Beings at the Federal University of Sergipe under opinion nº 4442234. The results demonstrate that the study population exhibits a low level of knowledge regarding the diagnosis, treatment, and prevention of schistosomiasis. The educational actions were structured into two types of approaches: the first was an individual approach, involving counseling with each participant after the interview to clarify doubts and address possible misinformation. The second approach was collective, consisting of lectures for elementary and high school students, covering the origin of the disease, the etiological agent, transmission, symptoms, diagnosis, treatment, control measures, and prevention of schistosomiasis, utilizing slide presentations as educational resources. After the lectures, a reinforcement activity titled “Fact or Fake” was conducted, which involved presenting various statements related to the topics discussed during the oral presentation, including both true and false statements. Students used to signal placards to indicate a positive signal when they considered a statement to be true (Fact) or a negative signal when they deemed it false (Fake). The experience gained from this study enhanced the authors' understanding of initiatives that can effectively contribute to the control of schistosomiasis. Among these, we emphasize the potential implementation of a health education nucleus within health units, which would operate in an integrated manner with health surveillance and the school health program, recognizing the important role schools play in disseminating accurate information about schistosomiasis.

Repurposing human cathepsin D inhibitors for fighting schistosomiasis

Bárbara Figueira Gomes — 2024-11-07

Schistosomiasis is a disease caused by trematodes of the genus Schistosoma. Endemic in several countries, more than 264 million people required preventive chemotherapy in 20221. The disease is treated almost exclusively with praziquantel (PZQ), the drug of choice for more than 40 years2. Given this limited treatment , a few molecular targets have already been identified and validated for the development of new drugs to treat schistosomiasis3. One validated targets is S. mansoni’s cathepsin D (SmCD1)4, an aspartyl protease that stands out for its role in the digestion of hemoglobin. Obtained from ingested host erythrocytes, hemoglobin is the parasite's main source of aminoacids, therefore, interfering with its digestion has a fundamental impact in the nutrition and normal development of S. mansoni. In our group, the production of recombinant SmCD1 (rSmCD1) and the identification of hit compounds have been carried out in the last years5,6. In this work, we present new SmCD1 inhibitors, identified using a drug repositioning strategy, an alternative to traditional drug development with reduced time spent in the approval of a molecule. In partnership with Merck’s GHI we had access to a series of 78 acylguanidines, previously investigated as human cathepsin D (hCD) inhibitors. All compounds are being screened in ex vivo experiments, with adult S. mansoni. Compounds’ effect on parasite are evaluated by automated high-content microscopy (HCS)7, and the images obtained are analyzed using the Cellprofiler software version 4.2.18, to segment the parasite as an object and extract features related to motility and morphology. In parallel, enzymatic assay are also being carried out, to evaluate the potency of the compounds as rSmCD1 inhibitors. In this assay, a FRET peptide (Abz-AIAFFSRQ-EDDnp) is used as a substrate, and the fluorescence produced by the product is used to analyze rSmCD1 activity. In both screenings, compounds are evaluated at 10 µM. To date, 68 compounds were tested in the ex-vivo assay and 21 of them have reduced S. mansoni motility by up to 78%. These compounds were also active against rSmCD1, decreasing its activity by up to 99%. Taken together, these results may indicate a decrease in parasite motility caused by inhibition of rSmCD1 activity. One of these compounds, M8214, is more selective for rSmCD1 (IC50 = 0.09 µM) than for hCD (IC50 = 1.1 µM). Using Deep-PK platform9, M8214 was predicted to have high gastrointestinal absorption, and interesting pharmacokinetic properties. Both characteristics are desirable in a candidate drug molecule. Currently, ex vivo screening, cytotoxicity of the active compounds and molecular modeling studies with rSmCD1 are ongoing. 1ISBN: 978-92-4-009153-5. 2DOI: 10.1016/j.pt.2019.11.002. 3DOI: 10.3389/fimmu.2021.642383. 4DOI: 10.1016/j.molbiopara.2007.10.009. 5DOI: 10.1016/j.pep.2019.105532. 6DOI: 10.1590/0074-02760230031.7DOI: 10.1021/acs.jmedchem.5b02038.8DOI: 10.2144/000112257. 9DOI: 10.1093/nar/gkae254.

Unraveling the expression and function of Lysine Specific Demethylases (SmLSDs) in different life stages of Schistosoma mansoni

Ester Silva Souza dos Santos — 2024-11-07

The complex life cycle of Schistosoma mansoni requires many changes and intense regulation of gene expression, including epigenetic mechanisms. These are also responsible for the rise in phenotypic variation influencing disease establishment. Among them are histone modifications, made by histone-modifying enzymes (HMEs) that alter histone tails. Lysine Specific Demethylases of S. mansoni (SmLSDs) are a group of these HMEs (SmLSD1, 2, and 3) responsible for removing methylation from lysine four on the tail of histone H3. Given the limited effectiveness of praziquantel in immature worms, the disease recurrence, and reported parasite drug resistance, new therapeutic targets are needed. This study aims to elucidate epigenetic control in S. mansoni by identifying SmLSDs regulatory profile, exploring the implications of Smlsds knockdown mediated by RNA interference, and evaluating their expression in different parasite stages and cell types. Schistosomula and adult worms were exposed to specific double-stranded RNA (dsRNAs) for seven and ten days, respectively. Different conditions were evaluated: in schistosomula, addition of dsRNA (1) on day of transformation, (2) on day of transformation and 48 h later, (3) associated with PEI carrier. In adult worms, the dsRNA was associated with PEI (1) after plating and (2) after plating and 48 h later. For both stages, the first condition showed greater knockdown efficacy. In schistosomula, Smlsd1 (86%) and Smlsd3 (92%) knockdown were more significant on day four, while Smlsd2 showed maximum reduction (81%) on day two. In adult worms, the most expressive reduction in Smlsd1 (63%), Smlsd2 (43%), and Smlsd3 (64%) transcripts was observed on day four. Furthermore, reduction in egg-laying was observed in couples exposed to SmLSD2 dsRNA. The motility of adult worms exposed to dsRNAs was assessed using WormAssay. There was difference in motility in females (day 6) and in males (days 3 and 10) for SmLSD1 group, and a reduction in motility in males (day 8) in SmLSD1 and SmLSD3 groups. RT-qPCR was performed to evaluate the expression of SmLSDs in parasite's life stages. Smlsd1 presented higher expression in tree-days-old schistosomula, Smlsd2 in cercariae, and Smlsd3 in females. Furthermore, we also performed searches in public databases containing RNA sequencing and single-cell RNAseq (scRNAseq) data to investigate Smlsds expression in different stages and cell types. In general, Smlsds expression converges between studies showing lower expression in mixed-sex infections and the last days of infection. Also, we observed a low expression of the Smlsds in miracidia, Smlsd1 and 3 in cercariae, and a high expression of all in sporocysts and juveniles. Additionally, from scRNAseq data, no enrichment of Smlsds expression in any cell cluster was observed. Thus, the analyses revealed variations in Smlsds expression in different parasite stages, highlighting their relevance in gene regulation during the parasite's life cycle.

Stability of the helminth community in Nectomys squamipes 22 years apart in a low endemic area for schistosomiasis in Brazil

KARINA VARELLA ARPON — 2024-11-07

The municipality of Sumidouro in the state of Rio de Janeiro, Brazil, is recognized as an area of low endemicity for mansonic schistosomiasis. In addition to humans, the wild rodent Nectomys squamipes acts as a reservoir for Schistosoma mansoni. A study conducted between 1997 and 1999 in Sumidouro investigated the helminth community in populations of N. squamipes. In the present study, we compared the helminth fauna and helminth community structure of N. squamipes with a recent survey after a 22-year time interval, considering that the prevalence of S. mansoni infection in humans remained stable despite regular treatment and that the area maintained the same environmental characteristics. Seventy-three N. squamipes specimens collected between 1997 and 1999 and 21 specimens collected in 2021 were analysed in this study. Seven helminth species were found in each collection period. The nematode Syphacia evaginata was recorded for the first time in N. squamipes in 2021. Syphacia venteli was the most abundant species in both periods and the most prevalent in 2021. During the period 1997–1999, the most prevalent species was Hassalstrongylus epsilon. A higher prevalence and abundance in male hosts were observed only for S. mansoni in 1997–1999 period. Significant differences in helminth species abundance were observed only in Physaloptera bispiculata. The species H. epsilon, S. venteli and S. mansoni were dominant in the helminth community in both periods. Litomosoides chagasfilhoi, Echinostoma paraensei and P. bispiculata became dominant, codominant and subordinate, respectively, over time. Therefore, the helminth community of N. squamipes remained stable, with similar values of species richness, prevalence and abundance and low beta-diversity over time. The occurrence of S. mansoni in the water-rats remained stable over 22 years in Sumidouro. These results highlight the ecological importance of these rodents as reservoirs of the parasite, regardless of Sumidouro being an area of low endemicity and the treatment with praziquantel. In this context, infection in wild rodent reservoirs needs to be considered by schistosomiasis control programs.

Can worm feeding be blocked using polyclonal antibodies against Esophageal Gland epitopes from Schistosoma mansoni?

Mariana Ivo Khouri — 2024-11-07

Background: Schistosomiasis is endemic in 78 countries and has the highest morbidity among helminth infections. A vaccine against this disease would therefore be a valuable addition to the toolbox of control measures and elimination strategies. Most vaccines investigated to date have been based on single antigens, none of which have reached the final stage of development. We propose that using multiple immunogenic epitopes associated with protective responses would be a more promising strategy for developing an effective vaccine. Our group previously mapped epitopes associated with protection in the murine model immunized with attenuated cercariae. Based on this study, 86 epitopes, each 10 - 22 aa long, were selected for their protective potential and localization in host-parasite interface tissues (esophageal gland, tegument, and gastrodermis). Objective: The primary goal of this study is to assess whether high titers of polyclonal antibodies against a recombinant protein containing 20 previously mapped epitopes from the esophageal gland are effective in blocking the development of schistosomula in vitro. Methods: A synthetic gene was designed containing 20 epitopes from Esophageal Gland proteins (19 MEGs and VAL7). The recombinant protein (rESO) was expressed in E. coli (BL21 strain) and purified using nickel affinity chromatography. For polyclonal antibody production, BALB/c mice were immunized six times with 10 ug of rESO formulated in Alum adjuvant. Sera were collected to evaluate the IgG1 antibody titter by ELISA. For hybridoma production, splenocytes from immunized mice were collected and fused with myeloma cells (P3X63Ag8.653) at a ratio of 5 x 107 myeloma cells per spleen. Following the hybridoma fusion, the polyclonal antibodies were collected, and a dot blot assay was performed to verify reactivity against individual epitopes. Additionally, immunohistochemistry was conducted to assess reactivity against the native proteins in whole-mount worms. Results: The rESO protein was purified with a yield of 67 mg/L of culture. The IgG1 titer in the serum of the immunized animals reached a high titer (1/13M). The hybridoma fusion yielded 39 clones, of which 36 were reactive against rESO. Dot blot analysis of antibodies against individual epitopes showed that the hybridoma culture supernatant recognizes 70% of the epitopes present in the protein. The most reactive epitopes were those from the MEG-8.2 and MEG-4.2 proteins. The polyclonal antibodies produced were able to recognize the native proteins of the worm, primarily in the esophageal plates of the anterior esophageal gland. Conclusion and Perspectives: It was possible to obtain 36 reactive clones against rESO that recognizes 70% of the epitopes. The polyclonal antibodies could recognize the native proteins of the worm. The next step is to functionally evaluate the capacity of these antibodies to impair or block the development of 3-day-old to 21-day-old-schistosomula in vitro cultures.

Comparative molluscicidal activity of two silver nanoparticles against Biomphalaria glabrata (Say, 1818)

Gabrielly Rodrigues Leao — 2024-11-07

The neotropical snail Biomphalaria glabrata is considered the main intermediate host of the trematode Schistosoma mansoni in Brazil, the etiological agent of schistosomiasis, a neglected tropical disease. To reduce the prevalence of the disease, the World Health Organization recommends the development of technologies to control intermediate hosts. Silver nanoparticles (AgNPs) have been indicated as a technological alternative for the control of medically important gastropods. However, knowledge about the toxicity of mercaptosuccinic acid (MSA)-functionalized AgNPs (MSA-AgNPs) to B. glabrata is still scarce. Therefore, this study aimed to evaluate the toxicity of two MSA-AgNPs, both with the same synthesis route, having the same substances, but differing with heating in the last step for 60 minutes, giving rise to AgNPs functionalized with heated MSA (∆-MSA-AgNPs) and the other without heating (MSA-AgNPs). Embryotoxicity tests on Biomphalaria spp. was conducted using 9 egg clutches per concentration in 12-well microplates for 168h. Embryos were exposed individually to both AgNPs at concentrations from 0.39 to 24.96 mg L-1. The parameters analyzed were mortality, hatching, delay in embryonic development, morphological changes, and cardiotoxicity. The acute toxicity test on newly hatched animals was carried out using 15 animals per concentration, with concentrations ranging from 6.24 to 49.92 mg L-1 for 96 hours, with the mortality and cardiotoxicity parameters analyzed. The results demonstrated that both MSA-AgNPs caused mortality, hatching inhibition, delayed embryonic development, and morphological changes such as shell malformation and hydropic snails. For newly hatched snails, both NPs did not induce cardiotoxicity and changes in the mortality rate when compared to the negative control. Therefore, MSA-AgNPs are more promising in controlling intermediate host embryos in comparison with ∆-MSA-AgNPs. Overall, the molluscicidal activity of AgNPs to B. glabrata is dependent on the synthesis method and developmental stages of snails.

Characterization of optimal spreading of fecal sediments produced by Helmintex method to optimize automated image analysis detection of S.mansoni eggs

Hannah Segóvia Pereira — 2024-11-07

Egg microscopy is the most commonly employed tool for diagnosing schistosomiasis. A significant advancement in diagnosing schistosomiasis in low-endemic areas was the developing of the Helmintex method (HTX), which isolates S. mansoni eggs based on their interaction with paramagnetic particles in a magnetic field. However, the HTX method involves multiple steps, culminating in a final sediment that must be analyzed by reading an average of 21 slides. In advancing the improvement of the Helmintex method, this study aimed to evaluate the importance of sample spreading on glass slides for microscopy analysis of the sediment after HTX. Different dilutions were tested using an aliquot from the final stage of HTX, Tween20 at various concentrations, and different volumes of 0.9% NaCl solution to investigate the spreading of the sample on the slide. The sample was spread over an area of approximately 8.5 cm² on a clean glass slide. Pre-selected slides, categorized as having good or poor spreading based on fluorescence microscopy observations, were evaluated for the uniformity of sample distribution using image analysis. Eight random images were captured and analyzed in terms of the area and diameter (measured in micrometers) occupied by granules on the slide for all fragments, using the ImageJ software. It was observed that slides with good spreading covered larger areas than those classified as having poor spreading. An experimental apparatus was created to measure the lux that passes under the glass slide, after analyzing the data from the photometer, we observe that sheets classified as "good" have an average light intensity of 427.5 LUX, while those classified as "bad" have an average of 790.03 LUX. The luximeter measures the amount of light passing through a square meter. This result is analogous to granulometry: good-quality sheets, with their uniform structure, allow less light to pass through, whereas bad-quality sheets, with their irregularities and aggregate disorder, permit more light to pass through.Under the microscope, poorly spread slides exhibited the formation of clusters, resulting in several small areas. Consequently, the spreading of the final HTX sediment was standardized by applying a 30 µL aliquot of the final HTX sediment to the glass slide, followed by the addition of 90 µL of 5% Tween20 solution and 20 µL of 0.9% NaCl solution. It is crucial to note that the quality of the sample spread on the slide can affect the identification of S. mansoni eggs. If the sample is poorly spread and contains aggregates of debris, the eggs may not be visible. Standardizing the sample spreading on the slide is essential for accurate and efficient identification, especially considering the ongoing development of automated image analysis systems. Proper distribution prevents the aggregation of fecal material and plant residues, facilitating specific readings and ensuring precise results.

LIPID METABOLISM: INSIGHTS INTO THE PARASITE-INTERMEDIATE HOST INTERACTION IN SCHISTOSOMIASIS

Suellen Silva Cabral — 2024-11-07

Schistosomiasis is a neglected tropical disease that affects over 200 million people worldwide, caused by the trematode parasite Schistosoma mansoni, which develops part of its life cycle in the intermediate host, the snail Biomphalaria glabrata. During its life cycle, the parasite acquires and utilizes molecules from its hosts, such as lipids, due to its inability to synthesize them. Therefore, the main objective of this study was to characterize the transport and metabolism of lipids in the intermediate host during the development of S. mansoni cercariae.The incorporation and transport profile of fatty acids via hemolymph was analyzed through the injection of radioactive fatty acid, ³H-palmitic acid, into the hemolymph of control and infected animals, followed by tissue collection. Communication was observed between the transport of fatty acids in the hemolymph, the digestive gland, and the albumen gland, with a reduction in this transport noted in animals on the 28th day of infection. The capacity for incorporation and synthesis of lipids by newly released cercariae from the snail or during their development was studied through incubation in the presence of radioactive palmitic acid or injection of the acid into the hemolymph of infected animals. Lipid extraction, separation via high-performance thin-layer chromatography (HPTLC), and counting of the radiation associated with lipid species were subsequently performed. As a result, cercariae exhibit a high capacity for lipid synthesis, both in the environment and during their development. The profile of neutral lipids in the digestive gland of snails was evaluated through lipid extraction and separation by thin-layer chromatography (TLC), revealing an increase in the content of fatty acids, triacylglycerol, and phospholipids on the 28th day of infection. The main lipid metabolism enzymes were studied on the 28th and 35th days of infection in the digestive glands of B. glabrata using western blotting. Here, we describe for the first time the presence and phosphorylation of the central metabolic enzyme AMPK, as well as an increase in the levels of key enzymes in the lipid synthesis pathway, ACC and FAS, at critical points of infection.Digestive glands from snails infected with S. mansoni were analyzed using real-time PCR and western blotting with serum from rabbits immunized against Sm 14, a fatty acid-binding protein from S. mansoni. For the first time, the gene and protein expression of Sm 14, the target of the schistosomiasis vaccine, is demonstrated during the intramolluscan phase of S. mansoni. These findings are crucial, as there are currently no data in the literature showing how the dynamics of lipid transport and metabolism function in the intermediate host of schistosomiasis. This study provides insights into the parasite-host interaction, offering valuable information on molecular targets for developing control strategies for the world's most prevalent helminthic disease.

Malacological survey and occurrence of trematode larvae in Santana do Ipanema, Sertão de Alagoas, Brazil.

Ednelma Dias Santos — 2024-11-07

Introduction: In Brazil, studies for identifying trematode larvae began with discovering Cercaria blanchardi, the infective form of Schistosoma mansoni. Following this discovery, various types of cercariae were reported by Brazilian scientist Adolpho Lutz and subsequently by other researchers. Objective: To assess the occurrence and diversity of trematode larvae in mollusks collected in Santana do Ipanema, Alagoas, Brazil. Methods: Limnic mollusks were collected in the urban area of the mentioned municipality at 13 collection points: Monte Vera (P1), exit to Poço (P2), Beach street (right and left side - P3 and P4), São Cristóvão (P5), IFAL (P6), Uneal stream (P7), Bode stream (P8), Frog stream (P9), Camoxinga stream (three distinct points - P10, P11, and P12), Ipanema River (P13). The collection was performed using gloves, forceps, malacological shells, and universal collectors, with a sampling effort of 20 minutes per point. Subsequently, the animals were taken to the Parasitology and Malacology Laboratory of the State University of Alagoas (Campus II), where they were sorted and separated by species. The live animals were analyzed for positivity for trematode larvae. For this analysis, the mollusks were subjected to photo-stimulation for a period of two hours and then examined under a stereomicroscope using 2x and 4x magnifications. This procedure was repeated weekly for four weeks to evaluate the elimination of trematode larvae. Results: In total, 586 live animals were collected, from the species Biomphalaria straminea (540 animals), Melanoides tuberculatus (43 animals), Pomacea lineata (2 animals), and Drepanotrema depressissimum (1 animal). Of the 13 points, only locations P7 and P8 had animals positive for trematode larvae. Among the collected species, positivity for cercariae of the Armata group was observed in 1 out of 540 animals of the species B. straminea, representing 0.18% positivity (P7). In location, P8, 5 out of 43 specimens of the species M. tuberculatus tested positive for two different types of cercariae. One of these animals tested positive for Centrocestus formosanus (pleurolofocerca), representing 2.32% positivity, while the other animals (9.30% positivity) tested positive for a type of cercaria not yet identified by us. Conclusion: This study showed that even with few animals in an environment, there is a possibility of positivity for larvae that affect human health, as in the case of the cercaria Pleurolofocerca, which is part of the larval phase of the parasite C. formosanus, whose infection occurs through the ingestion of raw or undercooked fish. This finding highlights the importance of reporting the types of larvae that may exist in spaces frequented by the population for fishing and leisure activities.

AI-assisted instance segmentation of Schistosoma mansoni schistosomula in high content microscopy images

Walter César Góes Valente — 2024-11-07

Traditionally, the schistosomicidal effect of compounds is evaluated through optical microscopy, monitoring parasite’s motility and morphology visually—a process that is slow, subjective, and semi-quantitative. To overcome these limitations, automated assays, such high content microscopy (HCA) have been employed to capture and analyze the images of larval and adult forms of schistosomes. Recently, our group began developing a novel HCA-based assay to screen compounds on Schistosoma mansoni schistosomula. In this study, we show our initial efforts to segment the parasites in the HCA images using an artificial intelligence (AI) model. First, schistosomula were distributed in 96-well microplates and incubated with or without 10 µM praziquantel (PZQ) for up to 72h. Then, timelapse (5 images, 6s interval) brightfield images from four adjacent sites within each well were captured by a ImageXpress Micro Confocal HCA microscope (Molecular Devices) coupled with a 4x objective. Image annotation was carried out with Anylabeling software (Neural Research Lab) using an AI-powered semi-automated data label tool (Segment Anything Model from Meta AI). The JSON files generated in this process, along with their associated images, were employed to fine-tune a mask region-based convolutional neural network (mask R-CNN) model (X101-FPN) available in the detectron2 (Meta AI) package for Python. This step was conducted using a nested cross-validation (CV) technique, with 3-fold and 2-fold splits for the outer and inner CV loops, respectively. In both CV, model performance was evaluated with the mean average precision (mAP) metric considering a 50-95% IoU (intersection over union) threshold interval (mAP50-95). Hyperparameter (number of epochs and learning rate) tunning was carried out with the inner CV training/validation datasets by the optuna package for Python. After 15 optimization trials, the best hyperparameter values were used to train three models, one per outer CV, giving a mean mAP50-95 score of 80.6 ± 1.4 (mean ± standard deviation) for the test datasets. Additionally, the metrics mAP50 and mAP75 were also determined as 96.4 ± 0.4 and 96.3 ± 0.5, respectively. A visual analysis comparing the predicted segmentation masks and those generated by semi-automated annotation corroborated the high mAP scores, as parasites with normal and PZQ-induced phenotypes were consistently identified in the images, even when in contact with each other. In contrast, experimental artifacts, such as the remaining tails of the cercaria, debris and air bubbles were mostly ignored. These results suggest that this segmentation model can be implemented as the first step in the image analysis pipeline, allowing for the subsequent extraction of morphological and motility features from each schistosomula. Our next steps include continuing model optimization with additional hyperparameters, as well as conducting new experiments with parasites exposed to other schistosomicidal compounds.

Droplet digital PCR assay (ddPCR) for the diagnosis of intestinal schistosomiasis caused by Schistosoma mansoni

Matheus Alves de Almeida — 2024-11-07

Intestinal schistosomiasis is a disease caused by the Schistosoma mansoni parasite in Brazil. The laboratory diagnosis recommended by the WHO for active search of cases of the disease is based on the Kato-Katz parasitological technique. However, this technique present low sensitivity when applied in stool samples from individuals with low parasite burden, what compromises the estimative of the real prevalence of the disease. Droplet digital PCR (ddPCR) allows direct quantification of the target sequence contained in the sample and, it presents better sensitivity and specificity compared to other diagnostic techniquesThe ddPCR assay appears as an option for diagnose S. mansoni infection, giving its sensitivity and specificity, in view of the low concentration of parasite DNA and the heterogeneity of the stool samples. The aim of this study was to standardize a ddPCR assay for the diagnosis of the intestinal schistosomiasis caused by S. mansoni. Total DNA was extracted from three S. mansoni eggpositive and three egg-negative stool samples, using the commercial QIAamp® Power Fecal Pro® Kit (Qiagen GmbH), as recommended by the manufacturer. The ddPCR assay was performed using sense primer 5′-CCG ACC AAC CGT TCT ATG A-3′, antisense primer 5′-CAC GCT CTC GCA AAT AAT CTA AA-3′ and probe 5′-6[FAM]/TCG TTG TAT CTC CGA AACCAC TGG ACG/[3BHQ1] which amplify a 90 bp fragment of the Sm1-7 repetitive region of the S. mansoni genome (GenBank: M61098). To determine the best laboratory conditions for the assay reactions were performed for a final volume of 22 L, at different primers annealing temperatures, different primers and probes concentrations and different concentrations of the total DNA, using supermix for probes (no dUTP) as hydrolysis probe detection reagent (Bio-Rad Laboratories). The droplets were generated in the Auto Droplet Generation, the amplification reaction was performed using the C1000 Touch Thermal Cycler and the fluorescence reading was performed in the QX200 Droplet Reader all from Bio-Rad Laboratories. The results analysis was performed using the QuantaSoft Analysis Pro software, version 1.0.596 (Bio-Rad Laboratories). The best laboratory conditions were defined as an annealing temperature of 56,5° C, primer concentration of 700 nM, probe concentration of 150 nM and total DNA concentration of 40 ng. Analytical sensitivity performed using DNA extracted from adult worms indicated a limit of detection (LOD) of 0.1 pg of DNA. The ddPCR results are preliminary and will undergo validation using DNA extracted from stool samples of 249 individuals from the municipality of Conde in Bahia, Brazil, an area of moderate endemicity for the disease. The ddPCR can constitute a alternative test for intestinal schistossomiasis diagnosis. However, larger studies are still needed to confirm ddPCR superior performance compared to conventional diagnostic techniques.

Synthesis and evaluation of catecholic chalcones as potential agents against Schistosoma mansoni

Kevin Henrique Souza Lima — 2024-11-07

Schistosomiasis, a neglected tropical parasitosis, is caused by trematode helminths of the genus Schistosoma. In Brazil, the most affected country by schistosomiasis on the continent, the only species present is Schistosoma mansoni. Praziquantel (PZQ) is the drug of choice, and the only one available, for the treatment of parasitosis. However, long-term and repeated use of PZQ can induce drug resistance or reduce its susceptibility. In this context, the imminence of PZQ-resistant strains represent a serious public health problem. Thus, there is a need to find new compounds that can be developed into antiparasitic drugs. In this scenario, natural products are presented as a valuable alternative for the investigation of new compounds that have activity against S. mansoni. Chalcones, specialized plant metabolites, are characterized by two phenyl units (A and B rings) linked by a α,β-unsaturated ketone bridge. They are privileged structures by medicinal chemistry because they have concise and versatile syntheses, and a wide spectrum of bioactivities. Within this spectrum, hydroxylated chalcones showed antiparasitic activities against species of Leishmania, Trypanosoma and Plasmodium, as well as schistosomicidal activity. In this work, through aldolic condensation in an acid medium, we synthesized and characterized a series of 18 catecholic chalcones with modifications on A ring. We evaluated the in vitro activity of these compounds at 5 μg/mL, in a period of 72 h. The mortality and viability of the worms were evaluated, the latter parameter was analyzed on a scale of 0 to 3, where 3 do not present changes compared to the control and 0 are dead. Catecholic chalcones 6 and 7 caused 100% mortality of male worms in 72 h, and 100% of female mortality in 48 h and 24 h, respectively. Worms exposed to chalcone 6 displayed a reduced viability (lt;2) in 24 h. Catecholic chalcone 5 demonstrated 100% mortality of males and females in 48 h, and reduced viability of male worms in 6 h of exposure, while in females the reduced viability was observed after 24 h. These results evidenced the potential of catecholic chalcones against S. mansoni and consequently may contribute to the development of new therapeutic agents against schistosomiasis.

Statewide Distribution of Schistosomiasis Hospitalization Incidence from 2014 to 2023.

Petrus Pinheiro Laurentino — 2024-11-07

Objective: To investigate the incidence of schistosomiasis among hospitalized patients by state. Methods: Morbidity and mortality data were collected from the SIH/SUS system; population data were obtained from SIDRA, and analyses were conducted using SPSS. Data on deaths and hospitalizations due to schistosomiasis from 2014 to 2023 were collected, as well as population data from the 2022 Census. Incidence and mortality rates were calculated based on 100,000 inhabitants. Results: During the selected period, 378 municipalities reported schistosomiasis cases, with representation from 26 of the country's federative units (only the state of Roraima recorded no hospitalizations during the period). Hospitalization incidence by state ranged from 0.36 to 174.78, with an average incidence of 22.69 new hospitalizations per 100,000 inhabitants. Six states had incidences above the Brazilian average: Pernambuco, Sergipe, Bahia, Minas Gerais, Rio de Janeiro, and São Paulo, with incidences of 39.74, 31.67, 134.36, 174.78, 37.37, 58.32, respectively. The states with the highest incidences were Minas Gerais (174.78) and Bahia (134.36). Of the 853 municipalities in Minas Gerais, 78 reported hospitalizations for schistosomiasis. The state had a mortality rate of 3.41 and a schistosomiasis lethality rate of 1.45%. Of the 417 municipalities in Bahia, 59 reported hospitalizations for schistosomiasis. The state had a mortality rate of 9.19 and a schistosomiasis lethality rate of 6.34%. Conclusions: The clustered distribution of schistosomiasis hospitalization incidence suggests the presence of environmental, regional, social, and/or economic factors that make the inhabitants of Bahia and Minas Gerais more susceptible to hospitalization for schistosomiasis. Regarding outcomes, the risk of death is four times higher in Bahia compared to Minas Gerais, suggesting the existence of factors influencing this outcome. Further studies are needed to assess these findings and investigate potential associated factors. There is a significant need for health education initiatives aimed at helping the populations of these states to prevent contamination and to identify early symptoms and signs of the disease, in order to reduce the number of deaths.

Time series and spatial Distribution of Schistosomiasis Mansoni in Four Historically Endemic States in Brazil

Welleson Sousa da Silva — 2024-11-07

Introduction: Schistosomiasis is present in most Brazilian states, especially in the Northeast and Southeast regions. In the Northeast, the states of Alagoas (AL), Bahia (BA), Pernambuco (PE), and Sergipe (SE) stand out as endemic areas for the disease. Objective: To analyze the temporal trends and spatial distribution of Schistosoma mansoni positivity in four states of Northeast Brazil between 2012 and 2021. Methods: This ecological study analyzed the states of AL, BA, PE, and SE using data from the Schistosomiasis Control Program Information System (SISPCE). Temporal trend analysis used a regression model adjusted through the Joinpoint program. Annual percent change (APC) and average annual percent change (AAPC) were calculated. Additionally, maps illustrating the spatial distribution of raw positivity rates were constructed. Results: During the study period, 193,569 positive cases of schistosomiasis were recorded in AL, BA, PE, and SE, with AL having the highest number of positives (N = 73,325 (37.8%)). In the trend analysis, PE showed a decreasing trend in positivity rates between 2012 and 2016 with APC = -20.5 (95% CI: -29.0 to -1.0; p = 0.003). Over the entire period from 2012 to 2021, positivity for the disease in PE also showed a significant reduction, with AAPC = -10.9 (95% CI -16.8 to -4.6; p lt;0.005). Although AL had the highest number of cases, its positivity rates decreased throughout the study period, with an AAPC of -9.6 (95% CI -11.4 to -7.7; p = 0.004). In contrast, the states of SE and BA showed stable trends throughout the period, with AAPC of -6.2 (95% CI: -12.0 to 0.1; p = 0.053) and -1.0 (95% CI: -11.3 to 10.6; p = 0.840), respectively. Conclusion: This study demonstrates that despite AL having the highest percentage of positive cases among the states with the highest infection rates of Schistosoma mansoni in Northeast Brazil, the state showed decreasing trends. However, it is still necessary to maintain control measures, especially in endemic areas of the disease. Additionally, the lack of data updates in SISPCE was a limiting factor for this work, as it prevented the measurement of positive cases in the states studied after 2021.

MALACOLOGICAL AND PARASITOLOGICAL SURVEY IN THE WEST ZONE OF THE CITY OF RIO DE JANEIRO, BRAZIL, CONSIDERED OF LOW ENDEMICITY FOR SCHISTOSOMIASIS MANSONI

Elizangela Feitosa da Silva — 2024-11-07

Schistosomiasis is the most important disease transmitted by mollusks in terms of Public Health. In Brazil the transmission occurs in 19 states, covering an endemic area along the Brazilian coast from Maranhão state to Espírito Santo and part of Minas Gerais. Schistosomiasis focus are also reported in the states of Pará, Piauí, Goiás, Federal District, São Paulo, Rio de Janeiro, Paraná, Santa Catarina and Rio Grande do Sul. The city of Rio de Janeiro is historically considered of low endemicity for schistosomiasis mansoni, although the presence of the three species of Biomphalaria intermediate hosts, associated to poor environmental, basic sanitation conditions and many immigrants from areas where schistosomiasis is endemic have been reported in several localities. The aim of this study is to present the partial results of a doctoral thesis on malacological and parasitological surveys carried out in one of the areas of Rio de Janeiro most highly impacted by the effects of accelerated urbanization and the reception of a large number of immigrants, mainly from the Northeast region of the country, the West Zone. The snails were collected at 32 georeferenced sampling stations (May, June, August and September 2024) in 10 neighborhoods. All specimens were examined for larval forms of Schistosoma mansoni and other trematodes that could offer human health risk. A total of 4,407 mollusks were obtained belonging to seven families: Ampullariidae, Assimineidae, Lymnaeidae, Physidae, Planorbidae, Succineidae and Thiaridae. Considering the snails of health interest we found intermediate hosts of S. mansoni, Biomphalaria straminea and Biomphalaria tenagophila, Galba sp. and Pseudosuccinea columella, natural hosts of Fasciola hepatica, ethiological agent of fasciolosis in Brazil. Other nine species were also identified: Drepanotrema anatinum, Drepanotrema cimex, Drepanotrema lucidum, Melanoides tuberculata, Omalonyx sp., Stenophysa marmorata, Physella acuta, Pomacea sordida, and Pomacea sp. The parasitological examination revealed four cercarian types in three snail species: the Armatae cercarie type in B. tenagophila and D. cimex, Distoma Brevifurcate Pharingeada cercarie type in B. tenagophila, Ubiquita cercarie type in D. cimex and Pleurolophocerca cercariae type in M. tuberculata. Even though none of the specimens of B. straminea, B. tenagophila, Galba sp. and P. columella were parasitized by S. mansoni or F. hepatica, respectively, we emphasize that some localities are potential source of urban transmission of S. mansoni and F. hepatica, given the presence of the snails transmitters and the presence of migrants from endemic areas for schistosomiasis associated to poor conditions of basic sanitation that favour the water contamination.

IDENTIFICATION OF RISK FACTORS ASSOCIATED WITH THE PREVALENCE OF SCHISTOSOMIASIS IN A HIGHLY ENDEMIC COMMUNITY IN NORTHEAST BRAZIL

Katrine Pereira — 2024-11-07

Schistosomiasis has a complex epidemiological profile, with transmission influenced by multiple factors, including sanitary, environmental, political, economic, social, cultural, biological, lifestyle, and social organization elements. It remains a significant public health concern in Northeast Brazil, particularly in the State of Sergipe, where prevalence is high in several areas. This study aimed to describe the epidemiological aspects of schistosomiasis mansoni, along with household characteristics and water contact patterns in the human population. Secondary data from parasitological and epidemiological surveys conducted in Colônia Miranda, São Cristóvão, Sergipe, were analyzed. The study took place in 2023, focusing on a community of 622 residents, with 583 completing a socio-environmental questionnaire. Among these, 370 individuals provided stool samples for the Kato-Katz (KK) method, used to diagnose the disease. Sociodemographic data were compiled in an Excel spreadsheet for analysis alongside the results from the KK parasitological method. For schistosomiasis diagnosis, two stool samples were collected over two consecutive days, and two slides were prepared for each sample. The findings indicate that Colônia Miranda is a highly endemic area, with a prevalence of 25.7 cases per 100 inhabitants. The distribution of parasite loads was as follows: 85.3% had a low parasite load (81/95), 12.6% had a moderate load (12/95), and 2.1% had a high load (2/95). The prevalence was 47.36% among men and 52.64% among women. A significant portion of the population (44.21%) had not completed primary education, 23.16% had a family income between one and three minimum wages, and around 45.26% reported receiving federal government assistance. Regarding sanitary conditions, only 33 participants (34.74%) had sanitation connected to a sewage network, while 59 participants (62.11%) used other methods for waste disposal, such as directly discarding waste into the street, using sealed septic tanks, or disposing of waste in a canal. A total of 23 individuals reported previous diagnoses of schistosomiasis and treatment at some point in their lives. The inadequate water supply and sewage treatment, the low socioeconomic status of the families studied, and the widespread presence of S. mansoni intermediate hosts in the village streets strongly indicate that this population is at high risk of contracting the disease. These risk factors pose significant challenges, leading to severe health impacts for the most vulnerable segments of the population. More effective interventions from government agencies and the Schistosomiasis Control Program are urgently needed to address these challenges.

Playful methods in the prevention of schistosomiasis in schoolchildren in Bahia

Camila Pereira — 2024-11-07

Intestinal parasites are still neglected in a large part of Brazil. In Bahia, schistosomiasis mansoni is still a public health problem. In children, this parasitosis has an impact on nutrition, intellectual and somatic development. Playful activities can help the teaching-learning process and are pleasurable, interesting and challenging. This work began in the municipality of Jequié-BA and after the year 2015 in Vitória da Conquista-BA, with the aim of teaching the prevention of intestinal parasitosis with emphasis on schistosomiasis in public schools. These schools were chosen for this study because they are in an area that combines a series of risk factors, determinants of many parasitic diseases, with a low-income clientele. The target audience were students aged between 6 and 11 years, enrolled in the 1st and 2nd grade classes. To achieve the goal, a questionnaire was used and, based on its analysis dynamics and education workshops were started that allowed the effective and participatory interaction of the students. For the presentations of the specific’s topics, a series of pedagogical activities were used, such as: reading of children's books on the themes of schistosomiasis, taeniasis, pediculosis and others, theatrical presentations on schistosomiasis, educational film, songs, games, and other playful resources so that the preventions measures were assimilated by the schoolchildren. Meetings were held with the children's parents at the public schools to offer coprological examination. The stool samples analysis was performed in the laboratory of the “Universidade Estadual do Sudoeste da Bahia” - UESB, by the methods of spontaneous sedimentation and centrifugal flotation in 35% zinc sulfate. Playful evaluative activities were applied, and most of schoolchildren showed interest and learning about the prophylaxis of the worked parasites. The expected results, which can be summarized in the expectation that students will learn simple ways of prevention, with the intention of improving their health status, were achieved through low-cost and effective methods, but sensitive to the next generation. This work is taking knowledge, clarification and awareness about the intestinal parasites, providing the realization of stool exams and referral of the parasitized schoolchildren for the specific treatment.

Granulometric approach to characterize fecal sediment spreading onto microscope slides for detection of Schistosoma mansoni eggs by Helmintex method

Gabriela de Carli — 2024-11-07

In the current context, where there is a low presence of parasites due to repeated schistosomiasis treatments, it becomes important to study methods with higher sensitivity for detecting eggs in feces. This research is part of efforts to improve Helmintex (HTX), a highly sensitive method mainly proposed as “reference method”. HTX involves several sieving steps and a unique feature—magnetic properties of S. mansoni eggs and their isolation in a magnetic field. Granulometry is a well-established procedure for analyzing soil sediments in geology and has also been used in studies of digestive physiology in animals. We used granulometry to analyze the spatial distribution of debris obtained from the feces of different individuals, who underwent different sequences of filtering procedures. Human feces were processed using sieves with openings of 500, 150, and 45 micrometers. For slide preparation, 10 µL of the debris obtained from each sieve, 70 µL of 0.9% saline solution, and 20 µL of 5% Tween 20 were used. Fresh preparations were examined under a photomicroscope. Ten random images were captured and analyzed using ImageJ software to count the number of granules and measure the size of all fragments in pixels. The fragments were categorized based on their size into six groups: A) 0-200 px, B) 201-400 px, C) 401-600 px, D) 601-800 px, E) 801-1000 px, and F) gt;1000 px for further analysis. We observed that the highest number of granules was found in category A across all sieves, followed by a consecutive decrease in the number of granules in the subsequent categories, except for category F, where an increase in granules was observed compared to category E. This may suggest a hypothesis of particle aggregation after sieving. An ANOVA test (p ≤ 0.05) was performed to compare the categories, demonstrating a significant difference between the mean values of the categories, which indicates variation in the distribution of particles retained by the sieves. The confirmed extreme complexity of fecal sediments poses a challenge for standardization, but preliminary results suggest that there may be windows in the distribution analysis that can provide better characterization of the sieving procedures as part of coproparasitological examinations. We anticipate that this improvement will positively impact not only egg detection methods but also DNA or antigen detection methods in feces. Diagnosis is one of the pillars for the successful control of schistosomiasis and other intestinal parasitic infections.

EPIDEMIOLOGICAL PROFILE OF SCHISTOSOMIASIS IN BRAZIL BETWEEN 2014 AND 2023

DANUSE APARECIDA MARQUES SILVA — 2024-11-07

Introduction: Schistosomiasis mansoni (SM), caused by Schistosoma mansoni, is a parasitic and neglected disease in Brazil. Its epidemiological understanding is essential for developing more targeted and effective public health policies, as it remains a challenge in the country. Objectives: To describe the epidemiological profile of SM in Brazil between 2014 and 2023, aiming to identify trends, changes in risk factors, and patient characteristics. Methods: This is an ecological time-series study. Data from 2014 to 2023 were obtained from the Notifiable Diseases Information System (SINAN)/DATASUS in July and August 2024. The study population consisted of individuals diagnosed and reported with SM in Brazil. Results: During the studied period, 40,140 notifications were recorded. The year 2014, which registered the highest number of cases, represented 16.1% of the total, and in 2023, 7.6% of cases were observed. There was a gradual reduction in cases throughout the monitoring period. No changes were seen in the profile regarding sex and age group, with males (60.1%) and individuals aged 20 to 59 years (75.5%) predominating. Summing up the black and brown skin categories, there was a significant increase in the proportion of cases, from 60.2% in 2014 to 70.3% in 2023. In terms of education level, elementary school accounted for 56.1% of the total SM cases throughout the period, which may be associated with a lack of health education and greater environmental vulnerability. The Southeast Region was the most affected, with 71.5% of the records, followed by the Northeast, with 24.6% of the cases. The predominant clinical form was the intestinal one (35.7%); however, the "Ignored/Blank" category had a significant value in 2022 (38.1%), reflecting possible difficulties in classification. In 2014, 65.2% of cases resulted in a cure, contrasting with 2023, when a decrease in the indicator was observed, with 46.2% of cases resulting in a cure. Nevertheless, the overall cure rate was 60.1%. Additionally, the high proportion of missing data for this variable (35.6% of the total) may distort the presented data, suggesting failures in data collection or patient follow-up. Conclusion: The epidemiological profile remained relatively stable, with a predominance of men aged 20 to 59 years of black race. The Southeast concentrated the majority of records, and the intestinal clinical form was the most common. Regarding the cure rate, there was a decline over the period, and the "Ignored/Blank" category remained high, highlighting reporting failures. Thus, the analysis of epidemiological characteristics and continuous surveillance are essential for developing prevention and control strategies and guiding public health actions.

Auramine stainning and adherence of Schistosoma mansoni eggs onto microscope slides for detection step of Helmintex method

Carlos Graeff Teixeira — 2024-11-07

Diagnostic tools are essential for controlling schistosomiasis. Helmintex (HTX) method isolate eggs based on their magnetic behavior when attached to paramagnetic beads sediments are submitted to a magnetic field. It is 100% sensitive for egg burdens higher than 1.3 eggs per gram of feces (EPG). But it still is a very labor-intensive set of concentration and cleaning procedures, including the final stage of detecting eggs at the microscope. Batch staining with auramine and observation at a fluorescence microscope greatly facilitates the screening of dried sediments. The objective was to test the persistence of auramine stain over time and the adherence of eggs to the microscope slides. Each of 3 slides were prepared as follows: 12 eggs were introduced into 30 µL of HTX sediment and stained with auramine. The HTX sediment was then diluted with 90 µL 0.9% NaCl, 5% Tween 20 solution, evenly spread on each glass slide, and left to dry at room temperature. Slides were totally screened at a fluorescence microscope (Nikon, Japan) at times zero, 2, 4, 7, 30, 60, 90 days. All eggs had charriot coordinates registered for follow up. After 90 days, 68.7% of the eggs were found and all of them kept the auramine fluorescence. These results indicate that auramine staining and dry spreading of HTX sediments are suitable for the detection of eggs at the microscope, even after long term storage of slides, what guarantees the appropriate examination and identification of S.mansoni eggs. Reducing work load and complexity of HTX is important to consolidate it as a very sensitive reference method, for accuracy studies of molecular methods.

Spatial and spatiotemporal analysis of positivity and prevalence rates for Schistosomiasis mansoni in the state of Alagoas: an ecological study between the years 2012 and 2021

Mikaelly Maria Vieira de Carvalho — 2024-11-07

Introduction: Schistosomiasis is a Neglected Tropical Disease (NTD) associated with social, economic, cultural, and political aspects. It is caused by the trematode Schistosoma mansoni, with the intermediate host being snails of the genus Biomphalaria, and humans as the definitive host. Objective: To evaluate the spatial distribution of schistosomiasis mansoni in the state of Alagoas, Brazil, from 2012 to 2021 using data from the Schistosomiasis Control Program Information System (SISPCE) and the Notifiable Diseases Information System (SINAN). Methods: This ecological study utilized data obtained from SISPCE and SINAN between 2012 and 2021. Positivity rates for the disease were considered for SISPCE data, while prevalence rates were considered for SINAN data. Empirical Bayesian kriging was used for spatial smoothing, and Global Moran's I and Local Moran's I (LISA) statistics were calculated to detect spatial autocorrelation and clusters. Space-time retrospective analysis using the scan statistic was performed to identify high-risk clusters. Maps were constructed using QGIS 3.10.14, and results were considered significant at plt;0.05. Results: The municipalities of Santana do Mundaú, São José da Laje, Capela, Atalaia, and Campestre exhibited moderate (5-15) raw positivity rates. After smoothing, the highest positivity rate (gt;15.0) was found in Branquinha. Regarding raw prevalence, the highest rate (60.0-93.0/100,000 inhabitants) was observed only in Campo Grande, with Olho D’Água Grande showing the highest smoothed prevalence (gt;40.0/100,000 inhabitants). Spatial autocorrelation was identified, with Global Moran's I for positivity and prevalence of 0.526071 (p = 0.001) and 0.184817 (p = 0.024), respectively. Space-time analysis for SISPCE identified two clusters, with the primary cluster comprised of 56 municipalities, exhibiting an annual positivity rate of 4238.6/100,000 inhabitants and a relative risk (RR) of 12.6 (plt;0.001). For SINAN, four clusters were identified, with the first cluster consisting of two municipalities showing an annual prevalence of 128.5/100,000 inhabitants and RR of 77.59 (plt;0.001). Conclusion: Our data reveal notable differences in disease positivity and prevalence between areas in the state, with municipalities showing high rates in SISPCE diverging from those with high rates in SINAN. These findings suggest potential shortcomings in disease control program coverage, leading to sporadic notifications in SINAN and compromising effective case management. It is crucial to enhance surveillance and program coverage to ensure more effective detection and appropriate case management.

Sociodemographic profile of deaths from schistosomiasis, Brazil, 2017 to 2022

Mariela Sousa dos Santos — 2024-11-07

Introduction: Schistosomiasis is a parasitic disease caused by the trematode helminth Schistosoma mansoni. It is an endemic disease in areas where there are water collections with transmitting molluscs and is associated with ecological, biological, socioeconomic and cultural factors of a society that, interconnected, influence the development cycle and control of the disease (Melo, 2019). Objective: To describe the sociodemographic profile of deaths from schistosomiasis, in Brazil, from 2017 to 2022. Method: Descriptive study using microdata from records of deaths due to schistosomiasis, for the entire Brazilian territory, from 2017 to 2022. All Death Certificate (DO) records that contained information on the underlying cause of death were included. The data were obtained from the Mortality Information System (SIM), from the DOs, made available by the Information Technology Department of the Unified Health System, accessible at: (https://datasus.saude.gov.br/). To select the outcome, all records in field 40 of the DO were considered, filled with codes B65, referring to schistosomiasis, according to Chapter I – Some Infectious and Parasitic Diseases, according to ICD-10. Population data were obtained through the Demographic Census, available in the IBGE Automatic Recovery System (SIDRA), table 3584, (https://sidra.ibge.gov.br/Table/3584). To characterize the profile of deaths from schistosomiasis, information on sex (male/female), age group (≤29 years, 30 to 39 years, 40 to 49 years, 50 to 59 years, 60 to 69 years and ≥70 years) was analyzed), race/color (white, brown, black, yellow and indigenous), education in years of study (≤3 years, 4 to 7 years, 8 to 11 years and ≥12 years), macro-regions of Brazil (north, northeast, midwest, southeast and south). The database was built in the R 4.4.1 software and analyzed using descriptive statistics with absolute numbers and relative frequencies. Project not submitted to the Research Ethics Committee because it is public domain data. Results: In the period from 2017 to 2022, in Brazil, 8,912,922 deaths were registered in the SIM. Of these, 2,843 had schistosomiasis as the underlying cause of death. Men represented (51.2%) of the sample, (44.0%) were ≥70 years old, mixed race/color (57.3%) and had ≤ 3 years of education (27.2%). Regarding geographic distribution, the Northeast and Southeast macro-regions recorded, respectively, 64.8% and 32.5% of deaths. Final considerations: Between 2017 and 2022, 2,843 deaths from schistosomiasis were recorded in the Brazilian population. Of this total, 64.8% occurred in the Northeast macro-region. The profile corresponds to brown people, with low education and an age group of ≥70 years. The health vulnerability of the population has an important relationship with the sociodemographic profile. Thus, there is a need for a better understanding of the determinants that may be related to deaths.

The dynamics of schistosomiasis mansoni in a rural community in Minas Gerais, Brazil

Patrícia Caetano Helmold — 2024-11-07

In Brazil, Minas Gerais is an endemic state for schistosomiasis mansoni. The municipality of Januária, northern Minas Gerais, contains several rural communities with precarious socio-economic and environmental conditions that favor parasite transmission. This study aimed to conduct an epidemiological survey of schistosomiasis mansoni in Pindaibal, municipality of Januária. For the parasitological diagnosis, fecal samples were collected from individuals aged between 6 and 70, and processed using the Kato-Katz (KK) method (6 slides per person). A structured questionnaire evaluated the population's socioeconomic and health information. The risk of S. mansoni infection associated with the variables was measured by the Odds Ratio (OR). The malacological survey was developed in April/2024. In the laboratory, the snails were placed individually on plates containing dechlorinated water and observed under a stereomicroscope following 2 hours of artificial photostimulation to evaluate the release of larval forms. Both residences and water collections were georeferenced using a portable GPS (GARMIN 64s) for the spatial analysis, the Kernel Density Estimator (KDE) was used based on the number of positive cases in each residence and using a radius of 300 meters. 209 individuals were included in the study, with an overall positivity rate for schistosomiasis of 18.66% (39/209). 53.84% (21/39) of the egg-positive individuals were male, and 35.89% (14/39) aged between 11 and 20 years. Based on the KK egg counts, the parasite load found in 87.2% (34/39) of the individuals was considered low; 7.7% (3/39) had a moderate, and 5.1% (2/39) of the individuals harbored a heavy parasite load, according to the WHO (World Health Organization) classification. Concerning water supply, 93.3% (56/60) of the houses had a water tank and 66.7% (40/60) used the stream as their water source. The soil and brook near the housings are the only destinations for sewage when there is no bathroom. The KDE results highlighted a hotspot in Pindaibal II, with an average of 6.53 positive cases. A total of 58 mollusks were collected in 7 locations, among which 3 specimens were: Biomphalaria sp. (32,8%; n=19); Stenophysa marmorata (58,6%; n=34); Pomacea sp. (8,6%; n=5). There was no release of cercariae for S. mansoni from intermediate hosts. In the same places where the snails were collected, water samples were taken for analysis of the water resource, using the Colilert method. The samples indicated the presence of total coliforms in all locations. The results of this study confirmed the epidemiological profile of the disease observed in many other regions and communities in Brazil, with mostly low prevalences and low, individual parasite loads. Therefore, Pindaibal has a significant prevalence rate for schistosomiasis mansoni, and integrated actions are needed to combat and prevent transmission, such as health education and sanitation in risk areas.

AN OVERVIEW OF SCHISTOSOMIASIS MANSONI: FOR STUDENTS OF TECHNICAL COURSES IN HEALTH OF A FEDERAL PUBLIC SCHOOL, RIO DE JANEIRO, BRAZIL

Cleide Cristina Apolinário Borges — 2024-11-07

The main objective of this study is to arouse students' interest in schistosomiasis, enabling them to diagnose the disease, with emphasis on the morphological identification of Schistosoma mansoni. In addition, the study seeks to promote a critical and reflective training, preparing students to act consciously in combating this neglected disease, focusing on social commitment and public health. The methodology adopted in the study is based on an experience report with students of the courses of Clinical Analysis (4th year) and Biotechnology (3rd year) of the Joaquim Venâncio Polytechnic School of Health during the academic year of 2023. The activities were divided into five stages: 1) theoretical lectures and dialogues, in which concepts about schistosomiasis were presented interactively; 2) practical laboratory classes, where students learned parasitological diagnostic techniques, as Kato-Katz and Spontaneous Sedimentation by Hoffman, Pons and Janer ; 3) Morphological identification of Schistosoma mansoni eggs using optical microscopes; 4) Preparation of reports of practical activities; 5) Workshops and debates, with reading and discussion of scientific articles on schistosomiasis. The results of these activities demonstrated that the students were able to acquire and apply the technical knowledge necessary for the diagnosis of schistosomiasis, properly handling the samples and identifying the eggs of the parasite. The laboratory practices, especially with the use of Kato-Katz and spontaneous sedimentation techniques, consolidated the practical learning of the students. In addition, the reports showed that students developed a critical capacity for analysis, reflecting on the applicability of techniques in public health contexts. The workshops stimulated teamwork, communication and critical thinking, strengthening understanding of the implications of schistosomiasis and the importance of public health policies such as strengthening the Unified Health System (SUS). The study concludes that the teaching experience of parasitology, focused on schistosomiasis mansoni, was highly productive. The combination of theory, practice and critical debate provided students with a solid technical background and a reflection on their role in society. They not only acquired important laboratory skills for the diagnosis of the disease, but were also encouraged to develop interpersonal skills and a critical look at collective health issues. The approach adopted, which includes the articulation between technical knowledge and social awareness, proved to be an effective pedagogical tool to prepare future health professionals committed to strengthening SUS and coping with neglected diseases. Thus, the study highlights the importance of integrating technical education with a critical view on public health policies, contributing to the construction of a more efficient and equitable health system.

EPIDEMIOLOGY OF SCHISTOSOMIASIS MANSONI IN THE STATE OF BAHIA FROM 2019 TO 2023

Renata Mayara Barbosa Almeida — 2024-11-07

Objectives: To map the distribution of schistosomiasis mansoni (SM) in the municipalities of Bahia from 2019 to 2023, identifying clusters of municipalities with the highest incidence. Methods: QGIS was used for thematic map creation, and Geoda for bivariate and univariate spatial analyses. Socioeconomic variables (HDI, Social Vulnerability Index, Gini Index) and housing variables (sewage network connection and piped water supply) were utilized. Excel® software was applied for data organization, tabulation, and graph generation. Information from SINAN notifications was used to detail the characteristics of the population affected by the disease, as well as to integrate IBGE territorial meshes. Results: The Global and Local Moran Indexes were calculated to verify spatial autocorrelation between neighboring municipalities, with emphasis on local univariate and bivariate analyses of the incidence during the period. Clusters were observed in many microregions, particularly in municipalities adjacent to Aracatu, which had the highest incidence coefficient during the period (361.13 per 100,000 inhabitants) and the most significant incidence rate in 2023, reaching 1,729.33 per 100,000 inhabitants. A higher concentration of clusters and outliers was identified in the microregions of Brumado, Vitória da Conquista, and Porto Seguro. In the state capital, Salvador, a Low-Low cluster was found in the univariate incidence analysis, specifically in municipalities of the Juazeiro, Bom Jesus da Lapa, and Boquira microregions. Conclusions: Critical vulnerability areas for schistosomiasis were identified in the municipalities of the Brumado and Porto Seguro microregions, where the most affected municipalities, Aracatu and Jucuruçu, are located. Furthermore, the importance of geoprocessing tools in guiding public health measures to border municipalities was reinforced. Study advancements and/or applications This study advances epidemiological knowledge on the incidence of schistosomiasis, given that the Schistosomiasis Control Program (PCE) focuses only on highly endemic municipalities in the state. This study helps clarify and reformulate public health policies for SM in a broader scope across the presented municipalities. For example, Jucuruçu had a 100% positivity rate in the last two years studied, except for 2021 when the PCE was not conducted.

Historical series of malacological surveillance in the state of Alagoas, Brazil (1997-2020).

Bruna Mesquita de Moraes — 2024-11-07

The state of Alagoas is one of the endemic regions for mansonic schistosomiasis (MS), with reports of moderate to high prevalence rates. It is vulnerability to environmental and health impacts, in addition to hosting a wide distribution of planorbid mollusks of the genus Biomphalaria spp., which are intermediate hosts in the Schistosoma mansoni life cycle. One of the responsibilities of the Schistosomiasis Control Program (PCE) is to conduct malacological research, to identify risk areas and transmission foci of the disease. This study’s objective was to analyze the data from malacological surveys conducted by the Alagoas Health Secretariat throughout the entire period of PCE operation in the state, to assess the periodicity of malacological surveys over the years. The data comes from the Schistosomiasis Control Program System (SISPCE) of the Alagoas Health Secretariat. The analysis consisted of checking silent municipalities (>12 years without data), evaluating patterns of downgrades in collections and number of snails collected, species identification, and positivity. Between 1997-2020, 109,715 collection stations distributed across the 70 municipalities in Alagoas endemic to MS were surveyed and 86,688 snails were collected. The years between 1997-2000 had the highest searches for collection stations (72.16%) and the largest number of animals collected (60.29%), with emphasis on 1999 with 21.98% of stations visited and 21.70% of snails captured. From the 2000s onwards there was a sharp decrease in research and animal capture actions, significantly from 2004 onwards. The years 2019-2020 showed the lowest registers. From the total number of mollusks collected 40,80% were identified, of which 35,59% were identified as B. glabrata; 5,16% B. straminea and 0,05% B. tenagophila. By the distribution of the B. tenagophila species and its morphological similarity with B. glabrata, the occurrence might be mistaken. Among the animals collected, 1.08% were detected positive for S. mansoni, with 96.69% identified as B. glabrata and 3.31% as B. straminea. Concerning the adherence and consistency of municipalities that carried out malacological surveillance activities, 4 towns presented no data throughout the period evaluated (24 years), 41 did not present data for a period ≥ 20 years, and 20 cities did not report due to more than 12 years. Only 5 municipalities (Arapiraca, Junqueiro, Maceió, Penedo, Teotônio Vilela) weren't considered silent, as they reported data in at least 12 years of the analyzed period. The low adherence and decrease in mollusk tracking actions carried out until 2020, in Alagoas, especially in the most recent period, demonstrates the weakening of MS prophylaxis approaches while harming the effectiveness of other control measures. Government encouragement and compliance with EPC actions by the state and municipalities are necessary to improve the determination of transmission foci and the current scenario of Schistosomiasis in Alagoas.

SCHISTOSOMIASIS MANSONI AS A PUBLIC HEALTH PROBLEM IN THE SUS AND ITS IMPACT ON THE POPULATION OF THE COP 30 CAPITAL

Sheila Paula Prestes — 2024-11-29

The capital of Pará is preparing to host the 30th UN conference on climate change (COP 30), to be held in Belém (PA), in November 2025. One year before the event, the capital's population still faces serious health problems public health such as Schistosomiasis mansoni. Surveillance and control of the disease in Belém is carried out through the municipal schistosomiasis control program (PMCE) which carries out parasitological examinations of feces through the active search for patients as recommended by the Ministry of Health and monitors the prevalence of the disease through the insertion of results based on the KATO-KATZ method. This study aims to determine which population groups are most affected by the infection and the territorialization of the disease in the last decade. Methods: This is a descriptive study of the epidemiological situation of schistosomiasis, which used secondary data from Schistosomiasis surveillance and control program (SISPCE) version 10.00 extracted from the field (pce_r13b) the parasitic load and prevalence of infection by sex and age group, as well as well as in the field, (pce_r11b) referring to coproscopy and treatment activities by location. These were made available through the Belém Municipal Health Department (SESMA) for the period from 2014 to 2023. He data were processed using the Epi-info software, version 3.01/2013. With the aim of analyzing the variables sex and age in relation to parasite infection, the Person chi-square test was used with a confidence level of 95% where it was relative risk is also calculated. SESMA authorized the release of data for this research through official document 18/24. Results: Over a 10-year period, a total of 41.495 tests were performed using the Kato Katz technique, of which 784 (1.89%) were positive for schistosomiasis infection. Of those infected, 596 (76.02%) were male and 188 (23.97%) were female. The analysis of the association between sex and infection revealed that male individuals had a relative risk 3.67 times greater than female individuals of contracting the disease, while for the age group of 10 to 45 years the risk is 2.86 when compared to the age group of 0 to 9 years. Schistosomiasis mansoni is present in 7 of the 8 administrative districts of Belém. Conclusions: Through the data obtained in this study, we can infer that schistosomiasis is present in almost the entire territory of Belém, especially in populated and peripheral neighborhoods where the population depends predominantly on Brazil’ s Unified Health System (SUS) services. In Belém, the prevalence of the disease is closely linked to insufficient engineering and public health works that were not able to interrupt the cycle of transmission of the disease.

Novel praziquantel analogs with TRPMPZQ modulatory activity and antiparasitic effects on immature and adult worms of Schistosoma mansoni

Rafael Ferreira Dantas — 2024-11-07

Praziquantel (PZQ) is the standard treatment for schistosomiasis, but resistance may develop with its widespread use. The discovery of a transient receptor potential ion channel of the melastatin subfamily activated by PZQ (TRPMPZQ) has opened new opportunities for target-based drug discovery. In this study, we evaluated the schistosomicidal potential of a novel series of 1H-1,2,3-triazole derivatives of PZQ and their synthetic intermediates on immature and adult forms of Schistosoma mansoni and tested their ability to activate schistosome TRPMPZQ (Sm_TRPMPZQ). High content microscopy was used to determine the effect of the compounds on schistosomula and adult worms. Compounds’ cytotoxicity was assessed in human kidney epithelial (WSS-1) cells by a viability assay. A Fluorescent Imaging Plate Reader (FLIPR) assay was conducted to test whether the compounds activate TRPMPZQ channels expressed transiently or stably in human embryonic kidney (HEK293) cells. The same method was carried out with a schistosome TRPM channel activated by meclonazepam (TRPMMCLZ) and TRPMPZQ from Fasciola hepatica (Fh_TRPMPZQ) to evaluate selectivity. Initial screening at 50 µM on schistosomula identified four compounds that altered the motility and morphology of the worms after 72 h of incubation: F23, F36, F38_12, and F41_17. F27 only affected parasites motility. F27, F36, and F38_12 significantly decreased the motility of adult worms after 24-72 h of incubation at 10/30 µM. None of them showed significant toxicity at 10 µM in WSS-1 cells after 48 h incubation. In the FLIPR assay, F27, F35_2, F36, and F38_12 activated Sm_TRPMPZQ channel at 0.3-100 µM, with F38_12 being the most potent, exhibiting a 50% effective concentration (EC50) of 0.81 and 0.52 µM for transient and stable expression of TRPMPZQ, respectively. All tested compounds showed only negligible effect on Sm_TRPMMCLZ and Fh_TRPMPZQ, suggesting they have a similar activity profile to PZQ. Apart from F27, the other compounds that modulated Sm_TRPMPZQ activity are intermediates in the synthesis of the triazoles, with small substituent groups (-N3, -NH2 or -NO2), at position 10 of the isoquinoline pyrazine nucleous. Inspection of a theoretical model of PZQ bound to Sm_TRPMPZQ suggests this result can be explained by the small volume available around position 10 of the isoquinoline pyrazine nucleus delineated by residues Tyr 1517, Arg1514, Asp1455 and Leu1454 from helices 1504-1512 and 1451-1467. F27 has a 4-propyl-1H-1,2,3-triazole group which, unlike other PZQ derivatives tested in this work with larger groups attached to the triazole ring, can still fit inside the subpocket within the PZQ binding site of the Sm_TRPMPZQ receptor. Interestingly, F41_17 was active on schistosomula and male worms after 72h of incubation, but showed no effect on Sm_TRPMPZQ, suggesting a different mechanism of action than PZQ. Other experiments are in progress, including the screening of the compounds on juvenile worms.

SEX DIFFERENCES IN PATHOGENIC NEUTROPHIL RESPONSES DURING SCHISTOSOMIASIS

Camila de Oliveira Silva e Souza — 2024-11-07

Schistosomiasis is a chronic helminth disease that can progress to severe fibrosis and eventually death in some individuals but not others. This heterogeneity of immune responses and susceptibility to infection is associated with genetic factors. Our results show that male C57BL/6 are more resistant to S. mansoni infection than BALB/c mice. Susceptibility in BALB/c was positively correlated with a pathogenic type 2 immune response driven by neutrophils. In the liver, we observed neutrophilic granulomas with a substantial neutrophil elastase trap (NET) release in BALB/c mice. Additionally, infected BALB/c neutrophils increase reactive oxygen species (ROS) release compared to C57BL/6 neutrophils upon PMA activation. Moreover, ROS inhibition in infected-BALB/c mice reduced ALT levels to baseline levels. In humans, AST levels are positively correlated with neutrophils in patients with severe schistosomiasis. Together, these results suggesting neutrophils drive liver injury during schistosomiasis. However, other intrinsic host factors may also contribute to the severity and pathogenic neutrophil responses during schistosomiasis. Males are more vulnerable to infections and death than females, and sex hormones have been associated with increased neutrophils counts and degranulation. Based on this, we evaluated mortality by genotype and sex. C57BL/6 mice are the most resistant across both sex and genotype, while female BALB/c mice were more resistant than males BALB/c, suggesting that both genotype and sex impact disease severity. Next, we measured ROS release in neutrophils from male and female BALB/c. Upon PMA stimulation, male neutrophils release more ROS than female neutrophils, suggesting that male hormones may affect neutrophil function. To validate the role of male hormones in the neutrophil, we performed castration in male BALB/c mice. Castrated BALB/c mice displayed neutropenia and lymphocytosis in the blood. In the bone marrow (BM), castration did not affect GMP progenitor or pre-neutrophils, but male hormones played a role in the neutrophil maturation. Compared to male BALB/c, immature Ly6G+CXCR2- and mature Ly6G+CXCR2+ neutrophils were reduced in the BM from castrated BALB/c male. Together, these results suggest that male hormones contribute to pathogenic neutrophil responses during schistosomiasis.

Schistosoma mansoni population genetics in Brazil revealed sharing of wild-host and human strains and geographical structure

KARINA VARELLA ARPON — 2024-11-07

In Brazil, the parasite associated with human intestinal schistosomiasis is Schistosoma mansoni, which has also been found infecting wild rodent species. The municipality of Sumidouro is a low endemic area for S. mansoni, and populations of the water-rat Nectomys squamipes act as reservoirs of the parasite. Schistosoma mansoni populations infecting humans and water-rats in Sumidouro present chronobiological variation in cercariae emergence (chronotype) and phenotypic characteristics between host species. Some studies have postulated that chronotype adjustment of S. mansoni populations to human (diurnal chronotype) and water-rat (nocturnal chronotype) hosts could result in prezygotic isolation. To test this hypothesis, we used the mitochondrial cytochrome c oxidase subunit 1 (MT-CO1) and microsatellite loci as genetic markers. We analysed the population structure of S. mansoni from the definitive host species and the spatial distance of the isolates between two endemic localities (PAM and ENC-SOL) in the municipality of Sumidouro, Brazil. We obtained 555 bp MT-CO1 sequences from 243 S. mansoni specimens, and seven microsatellite loci were genotyped for 158 S. mansoni specimens, including eggs and adult helminths from water-rat and eggs from human feces. Four haplotypes of the MT-CO1 gene were found, with haplotypes 1 and 2 shared by two studied localities and haplotypes 3 and 4 exclusive to the ENC-SOL locality. Haplotypes 1, 2 and 3 were shared between human and N. squamipes hosts. The population structure analysis revealed geographical structure and no structure associated with definitive host species, indicating that the populations of S. mansoni of different chronotypes are not isolated, with significant gene flow between them. In conclusion, our results confirm that wild rodents can contribute to the maintenance of the S. mansoni life cycle in Sumidouro and can be used as indicators of local transmission areas.

Functional evaluation of miRNAs in schistosomiasis transmitting snails and their role in resistance/susceptibility to Schistosoma spp. (Trematoda: Digenea)

Isabela Thamara Xavier Dutra — 2024-11-07

Schistosomiasis is a parasitic disease caused by parasites of the genus Schistosoma spp., which have different snails as intermediate hosts, such as those of the genus Biomphalaria and Bulinus. Small RNA sequencing on Biomphalaria glabrata, revealed for the first time, 89 mature microRNAs (miRNAs) predicted as important in regulating the expression of genes involved in immunological, epigenetic, and metabolic processes. Therefore, the present objective of this study was to evaluate the influence of miRNAs in the snail response towards parasite. Snails of different species or lineages with variable susceptibilities to infection were used for this approach. Thus, six miRNAs, identified in Biomphalaria spp. were selected based on their potential role in the regulation of innate immune genes in other organisms. The expression levels of those miRNAs are being evaluated by qPCR in hemolymph and head/foot of Biomphalaria spp. and Bulinus spp., selected for their susceptibility and resistance to parasite. These snails were exposed or not to miracidia of the parasite Schistosoma spp.. Also, the expression of these miRNAs was evaluated in nine different tissues (hemolymph, plasma, head/foot, hepatopancreas, stomach/intestine, ovotestis, albumen gland, kidney, and mantle) of B. glabrata snails with different compatibilities selected from one original population. Subsequently, Biomphalaria spp. snails will be injected with selected and non-specific miRNA inhibitors designed as anti-miR. After confirming the inhibition of miRNAs, the snails have been exposed to S. mansoni miracidia. After four weeks, shell sizes, morphological changes, infection rate, and cercariae release have been evaluated. To date, an increase of miR-8, miR-124, miR-184, and miR-1985 expression was observed in resistant Biomphalaria spp. snails after exposure to S. mansoni miracidia when compared to susceptible snails. Also, an increase in miR-184 expression was observed in Bulinus wrighti after exposure to Schistosoma haematobium miracidia. We had no evidence of miR-124 expression in Bulinus spp. and it appeared as only expressed in the head/foot of Biomphalaria sp.. This study aims to characterize miRNAs and genes potentially involved in mechanisms of resistance to infection by Schistosoma spp..

Development of a vaccine candidate against Schistosoma mansoni: production, immunogenicity assessment and vaccine protection assay in rhesus macaques

Vilaça Guimarães de Oliveira — 2024-11-07

Schistosomiasis is a disease caused by blood flukes from the Schistosoma genus that affects more than 200 million people worldwide. The treatment indicated today is the use of praziquantel, which cannot prevent reinfection. One way to prevent the disease would be a prophylactic vaccine. Over the last decades, several vaccine candidates have been tested, but no vaccine against schistosomiasis is available today. Our group aims at developing a new vaccine candidate by unraveling the mechanisms behind the self-cure of rhesus macaques from a Schistosoma mansoni infection. Previously, we identified S. mansoni peptide epitopes recognized by rhesus macaques' antibodies using phage-display and peptide microarray assays. In the present work our objective is to evaluate the possible immunogenicity and protection generated in rhesus macaques against a S. mansoni infection using as an immunogen a chimeric protein comprised of thirteen previously identified peptide epitopes. The chimeric protein was produced together with a Rhizavidin motif as an adjuvant in its C-terminal portion. Twelve female rhesus macaques were immunized with three doses of the chimeric protein-rhizavidin, each dose spaced four weeks apart. Biotinylated Outer Membrane Vesicles from Neisseria lactamica and alum were used as adjuvants. At week 12 post-first-immunization (pfi), all macaques were challenged with 700 S. mansoni cercariae and the course of the infection was followed until week 36 pfi. We collected blood and feces samples at week 0 (before), and at weeks 2, 4, 6, 8, 10, 12, 13, 16, 18, 20, 22, 24 and 28 pfi to evaluate (i) the rhesus macaques’immune response, (ii) parasite development by Circulating Anodic Antigen (CAA) measurements, and (iii) eggs per gram of feces (EPG) using the Percoll gradient technique. The same samples will be collected at week 36 pfi, when the macaques will be euthanized and perfused. As a control group for comparison, we will use the data already collected from twelve female rhesus macaques non-immunized and infected from our previous work, which were submitted to the same experimental procedures that are being performed in this project. The results show that the average EPG decreased by half at the peak of infection establishment (week 10 postinfection) compared with the peak EPG of non-immunized macaques. We analyzed the antibody profile against the chimeric protein by ELISA and we were able to detect a considerable immunogenic capacity of the construct after each of the three doses. In conclusion, there is preliminary evidence that a mild protection against S. mansoni infection was induced in the rhesus macaques immunized with the vaccine candidate. Parasite CAA will be quantified at all time points to be used as the metric to determine possible protection induced by the immunization. Peptide microarray assays will be performed to identify and map within the chimeric protein the main targets of the antibodies responses elicited after immunization.

Praziquantel effect on the genetic diversity of wild rodent-derived Schistosoma mansoni in experimentally infected mice

Thayná Couto de Barros — 2024-11-07

Introduction: Praziquantel (PZQ) is currently the only drug recommended by the World Health Organization (WHO) for treating schistosomiasis, raising concerns about potential resistance. Frequent use of PZQ may reduce the genetic diversity of Schistosoma mansoni, affecting its adaptability and survival. Objective: To evaluate the effects of PZQ treatment and population bottlenecks on the genetic variability of S. mansoni through experimental infections with a naturally derived strain from the rodent Nectomys squamipes. Methods: Experimental infections were conducted in 18 outbred mice individually infected with 120 cercariae via a transcutaneous route through the tail. The mice were divided into three groups of six animals each: 1) the infected control group (IC); 2) the infected group and treated with 3× 150 mg/kg PZQ (IT150), (50% LD); and 3) the infected group and treated with 3× 300 mg/kg PZQ (IT300) (90% LD). The treatment occurred at 50, 51, and 52 days post-exposure, and the mice were necropsied 15 days later. The worms were subsequently washed in saline solution (0.85% NaCl), counted, and stored individually in 70% ethanol at -20°C. We first used the MT-CO1 marker for an initial exploratory analysis according to previous reports that used MT-CO1 in genetic studies of S. mansoni. Microsatellite markers have also been used due to their higher genetic variability, making them more informative for population genetic diversity studies. Results: MT-CO1 analysis revealed two haplotypes differing by one polymorphic site, with one haplotype representing 84.2% of the population. FST demonstrated low genetic differentiation between groups, and AMOVA indicated a greater percentage of variation within the groups than between groups. All seven microsatellite loci studied presented polymorphisms, with 3 to 7 alleles per locus. Praziquantel treatment caused a population bottleneck, reduced genetic variability in both dosage groups: IT150 (RST = 0.14043, p = 0.000) and IT300 (RST= 0.13610, p = 0.005), and eliminated alleles with low initial frequencies. Conclusion: Our analysis of microsatellite markers revealed genetic differentiation and the loss of rare alleles, supporting the hypothesis of a genetic bottleneck caused by PZQ treatment. This study highlights the potential of PZQ treatment to reduce genetic diversity in S. mansoni, underscoring the importance of continuous monitoring of its populations due to the possibility of the emergence of a resistant strain.

Comprehending the molecular bases of differential cercarial emission in Schistosoma mansoni through integrative analysis

Cristian Chaparro — 2024-11-07

Two distinct chronotypes of Schistosoma mansoni, presenting diurnal and nocturnal cercarial emission patterns, have been described (Mouahid et al., 2019). One emits at midday and the other at night. We performed mono-miracidial infections on Biomphalaria pfeifferi, and we sampled the cercarial emission every 4 hours over 2 days. RNA-seq and ChIPmentation were performed on each collected sample for the diurnal and nocturnal chronotypes. We used MOFA2 to integrate the data and obtained factors that are explained by both omics that are related to sex and time of emission respectively. Furthermore, we identified a factor that represents the different sequencing batches.The integrative analysis allowed us to select candidate genes implicated in the differential emission of cercariae by selecting the appropriate factors associated with it. This approach enabled us to remove confounding factors like the sex of the sporocysts which, phenotypically, does not play a role in the differential emission. In this work, we will present the results of the GO term enrichment for the selected factors, as well as the associated pathway enrichment analysis. We will also discuss the challenges presented by the analysis of non-model organisms.Mouahid, G., Mintsa Nguema, R., Al Mashikhi, K.M., Al Yafae, S.A., Idris, M.A., Moné, H., 2019. Host-parasite life-histories of the diurnal vs. nocturnal chronotypes of Schistosoma mansoni: adaptive significance. Trop. Med. Int. Health TM IH 24, 692–700. https://doi.org/10.1111/tmi.13227

Assessing risk factors and hotspots in a rural endemic area for schistosomiasis mansoni in Brazil during three cross-sectional studies between 2014-2022

Bianca Leal de Oliveira — 2024-11-07

Januária is a historically known endemic municipality for schistosomiasis mansoni in northern Minas Gerais, Brazil. Brejo do Amparo, one of its seven districts, holds the rural communities of Pé da Serra, Tocantins, and Santana on the banks of the Tocantins stream, where it previously registered a positivity rate of over 50% for schistosomiasis and the presence of Biomphalaria glabrata infected with Schistosoma mansoni. To identify spatial changes in these communities, we compared parasitological data, sociodemographic data, water contact patterns, and spatial distribution of positive cases in 2014 (T0), 2015 (T12), and 2022 (T96). After ethics approval (CAAE 21824513.9.0000.5091; CAAE 55239522.3.0000.5149), fecal samples were collected from individuals of two years of age or older in 2014 and 2015, and between six and 70 years of age in 2022. The material was processed by Kato-Katz and Helmintex methods. Questionnaires to assess sociodemographic and water contact data were applied and the risk of infection associated with the variables was measured by Odds Ratio (OR) in univariate and multivariate models. For the spatial analysis, the residences were georeferenced (GPS, GARMIN 64s) and the Kernel Density Estimator (KDE) was used to identify potential hotspots. A flexible spatial scan statistic was conducted to confirm these and determine the most likely clusters. The number of participants was 257, 260, and 265 in 2014, 2015 and 2022, respectively; mostly female (2014: 52.9%; 2015: 52.7%; 2022: 52.5%) and between 21-40 years old (2014: 26.5%; 2015: 25%; 2022: 35.1%). There was a decline in prevalence from T0 (45.9%) to T12 (10.38%) after the intervention, followed by an increase in T96 (26.03%). Overall, there was a 43% reduction in prevalence in Brejo do Amparo from 2014 to 2022. Regarding the risk factors, proximity of the residences of less than 200m from the stream (2014: OR=2.93; 95%CI 1.27-6.76; p-value=0.01. 2022: 2.46; 95%CI 1.08-5.59; p-value=0.03) and the absence of bathrooms (2014: OR=10.35; 95%CI 1.90-56.39; p-valuelt;0.01. 2022: OR=6.52; 95%CI 1.13-37.77; p-value=0.03) were significant risk factors for T0 and T96. As for 2022, the lack of water treatment for drinking was also a risk factor (OR=2.27; 95%CI 1.21-4.28; p-value=0.01), while using water for irrigation of gardens or crops was marginally significant (OR=1.85; 95%CI 0.92-3.73; p-value = 0.08). From our spatial analysis, a cluster in Tocantins remained statistically significant in all three periods, with a relative risk varying from 2.03 in 2014 to 4.18 in 2022. From our results, we can verify that even considering the diminishing schistosomiasis prevalence in the rural communities, the district Brejo do Amparo still presents significant risk areas for S. mansoni infection, corroborating the need for WASH (Water, Sanitation, and Hygiene) interventions integrated to local health systems, and adequate health education to mitigate the occurrence of schistosomiasis in the region.

Schistosomiasis as an urban disease: summary of 7 years of studies in the city of Salvador, the first capital of Brazil

PEDRO SANTOS MUCCILLO REIS — 2024-11-07

Background: After 114 years of Pirajá da Silva's work, there is still evidence of transmission of Schistosoma mansoni (SM) in Salvador. This study aims to identify areas of focal transmission for schistosomiasis in the metropolis. METHODS: Between 2017 and 2024, we investigated five new communities in Salvador, selected from malacological surveillance data from the Zoonoses Control Center (CCZ), other health data and pilot surveys: DC, SA, PI, LP and BF. A sixth community, SB, was revisited a decade after the last survey. Residents aged 2 years and over were invited to participate in an epidemiological and parasitological survey, providing up to three stool samples on different days for the Kato-Katz (KK) test. Those positive for SM or other helminths were treated and underwent a test of cure with KK after 30 days, with retreatment when necessary. The SA and PI areas, with the highest prevalence, were followed longitudinally for two more periods with recurrent case treatments, comparing the results with those of SB. RESULTS: 5,813 residents participated in the initial studies in the five communities. The majority were female (58.2%), with a mean age of 33.2 ± 20.1 years. The majority were born in Salvador (71.2%), but many had a history of living in other municipalities (20.0%) and traveling in the last year (30.1%). The vast majority reported having running water (96.3%) and a toilet (99.0%) connected to the collection network (96.0%). The global prevalence of schistosomiasis was 4.0% (95%CI 3.5 %-4.5%) with low parasite load (lt;100 opg). In all areas, the prevalence of MS was associated with males, ages between 13 and 49 years, and living close to bodies of water (lt;100 m). Recurrent treatment reduced the prevalence of MS by an average of 70% in SA (1.7%) and PI (1.9%). Practically all prevalent cases during follow-up were incidents, except for the "new" cases that did not undergo regular examinations and, therefore, could not be treated recurrently. Despite the time without follow-up, SB showed a prevalence of 4.1%, equivalent to the initial average of other areas. The prevalence and parasite load demonstrate that there is local transmission of the schistosomiasis in the city of Salvador. Extrapolating to the entire population of the city, we estimate that more than 60,000 individuals may be infected. The Recurrent treatment of positive cases was able to reduce the burden of the disease.

Immunization of malnourished mice with the rSm29 Schistosoma mansoni antigen is not able to reduce the area of hepatic granuloma

Poliane Silva Maciel — 2024-11-07

Introduction: Malnutrition and schistosomiasis are important public health problems. The main pathological alteration in schistosomiasis is a granulomatous reaction in the liver. We have previously demonstrated that malnutrition leads to a reduction in hepatic granuloma area. Also, evidence suggest that malnutrition can impact the efficacy of vaccines. Several S. mansoni antigens have been studied as vaccine candidates, such as Sm29 protein. Studies have shown that immunization with rSm29 reduced parasite load and hepatic granuloma area. However, no work has evaluated the immune response and liver pathology in a malnourished host immunized with a vaccine antigen against schistosomiasis that induces anti-pathology effect. Objective: Evaluate the impact of malnutrition on the efficacy and immune response induced by rSm29 in malnourished mice. Methods: Initially, C57BL/6 mice were separated in 2 groups: Eutrophic: standard 14% protein diet and Malnourished 3% protein diet. The nutritional status was assessed by body weight and biochemical parameters measurements. After the establishment of malnutrition, mice were divided into 4 groups: Eutrophic and Malnourished: inoculated with Saline/CpG/ALUM or immunized with rSm29/CpG/ALUM. Animals received 3 doses of immunization at a 15-day interval. Mice were challenged with 100 cercariae 15 days after the last dose. Fifty days later, mice were perfused to assess the number of worms recovered. Liver sections were collected to assess granuloma area. The egg numbers were assessed in the liver and intestine. Serum was obtained 15 days after each immunization dose to evaluate the levels of specific anti-rSm29 IgG. The spleen was collected 50 days after infection to evaluate the immune response. Results: Malnourished mice showed a significant decrease in body weight and in biochemical parameters. No changes in the proportions of the lymphoid and myeloid population were observed in immunized mice. Immunization induced an increased production of IL-6, IL-4, IL-10 and IL-17 by spleen cells and specific IgG antibodies, regardless of the diet. However, antibody titers were higher in immunized eutrophic mice than in immunized Malnourished group. Only eutrophic immunized mice showed a reduction in the granuloma area in relation to saline group. Furthermore, saline Malnourished group showed a decrease in the granuloma area, compared to the saline Eutrophic. No significant changes were observed in the number of worms recovered and eggs retained in the liver or intestine between groups. Conclusion: We observed an improvement in liver pathology in immunized eutrophic mice. However, vaccination was not able to reduce the granuloma area in malnourished animals to values lower than the diet-induced reduction. Regardless of the diet, immunization induced the production of cytokines and the activation of the humoral immune response. Despite that, we did not observe a reduction in the parasite burden of immunized animals.

ASSESSMENT OF THE ANTHROPOMETRIC STATUS OF ADULTS LIVING IN A SCHISTOSOMIASIS-ENDEMIC RURAL AREA PRE- AND POST-TREATMENT

Ane Caroline Casaes — 2024-11-07

Introduction: The nutritional profile of individuals living in rural areas, many endemic to helminthiases such as schistosomiasis, reflects the nutritional changes observed in the general population. Characteristics of underweight and thinness, once prevalent, have been replaced by an increasing prevalence of overweight and obesity, which currently represent public health concerns. Obesity, in addition to being a risk factor for non-communicable chronic diseases, may worsen the health status of vulnerable populations, such as those infected by Schistosoma mansoni. Thus, this study aimed to assess the anthropometric status of adults living in a rural area endemic for schistosomiasis before and after treatment with praziquantel. Methodology: In Conde, Bahia, Brazil, 189 adult participants were evaluated due to previous records of high parasitic infection rates in 2018. This study involved assessments before (D0) and six months after treatment with Praziquantel, with stool sample collection for Kato-Katz examination. The study included an evaluation of body mass index (BMI) for nutritional status, waist circumference (WC) for cardiovascular risk, and body fat percentage (BF%) and fat-free mass percentage (FFM%) for body composition, using Bioelectrical Impedance Analysis with a tetrapolar Sanny® device. Results: Most participants were female (58.3%) with a median age of 36 (IQR 24-51). Regarding nutritional status, 57.4% were overweight, 83.1% had a high body fat percentage (%BF), and only 1.9% exhibited low fat-free mass (FFM%). Additionally, 58.3% were at cardiovascular risk, and 54.0% were infected with S. mansoni. Regardless of infection status, participants were evaluated at baseline (D0) and six months after treatment (D180). There was a significant increase in BMI (p=0.036) and waist circumference (WC) (p=0.033). Conversely, %BF appeared to decrease (plt;0.0001), with no relevant changes in FFM% (p=0.133). No statistically significant differences were found between infected and non-infected individuals, except for FFM%, which was higher in the infected group (67.6 IQR 61.3-79.3 vs. 72.5 IQR 66.6-79.7; p=0.044). Conclusion: Treatment appears to have influenced body composition, leading to an increase in BMI and WC, along with a possible redistribution of fat, without a substantial impact on lean mass. These findings emphasize the importance of nutritional interventions to enhance the health of this population, as well as the need for studies on the role of S. mansoni infection in the immune system changes associated with low-grade chronic inflammation related to obesity.

Pharmacogenetics and Praziquantel: CYP2C19 phenotypes frequencies in Alagoas state, Brazil

Müller Ribeiro Andrade — 2024-11-07

Human schistosomiasis is a chronic parasitic disease resulting from infection by trematode worms of the Schistosoma genus. It mainly affects impoverished populations who are unaware of its potential for transmission from water sources. In Brazil, an estimated 2.1 million people live in schistosomiasis-endemic areas. The treatment used for symptomatic cases and schistosomiasis prophylaxis is based exclusively on Praziquantel. Studies have shown significant variability in the cure rate and effectiveness of treatment for schistosomiasis in different countries. Recent studies in populations from schistosomiasis-endemic African countries have shown that part of this variability is due to genetic variants in the cytochrome P450 isoforms. Pharmacokinetics studies with children of southern Ethiopia, Rwanda, and Tanzania who received Praziquantel preventive chemotherapy showed that carriers of CYP2C19 defective variant alleles *2 and *3 had significantly higher mean Praziquantel plasma concentration than CYP2C19 *1/*1 homozygotes or *17 carriers, which could lead to a higher risk to toxicity. The impact of genetic variants on the population treated in schistosomiasis-endemic regions in Brazil is unknown. The study aims to estimate the frequencies of the CYP2C19 phenotypes in a population of the Alagoas state, Brazil. A total of 423 healthy subjects were genotyped for the CYP2C19 *2 (rs4244285), *3 (rs4986893), and *17 (rs12248560) functional alleles with TaqMan™ assays by real-time PCR. The subjects were primarily males (63.5%), with a mean age of 39.5. In the study population, the CYP2C19 alleles *1, *2, and *17 showed frequencies of 64.2%, 17.4%, and 18.4%, respectively. The *3 allele was not present in the population. Based on the *1, *2 and *17 haplotypes, the population presented the phenotypes of 40.9% extensive metabolizer (*1/*1), 28.6% intermediate metabolizer (*1/*2 + *2/*17), 3.1% poor metabolizer (*2/*2), 24.1% rapid metabolizer (*1/*17), and 3.3% ultrarapid metabolizer (*17/*17). The results indicate that only 40% of the population should metabolize Praziquantel at the expected rates. Approximately 30% of the population may have a slower rate of metabolization of Praziquantel, which may raise its plasma concentration and increase the chance of adverse effects with treatment. Similarly, up to 27% of the population may metabolize Praziquantel more quickly than expected, thus not reaching the desired concentration, which could reduce the effectiveness of the treatment. Further studies are needed to investigate these phenotype impacts on schistosomiasis-treated patients in Brazilian endemic regions.

Characterization of Biomphalaria glabrata's miRNAs: Rhythmicity and Differential Expression in Interaction with its Parasite Schistosoma mansoni

Sarah Dametto — 2024-11-07

MiRNAs are short, single-stranded non-coding sequences that play crucial roles in the regulation of gene transcription in many biological processes such as embryonic development, cell proliferation or apoptosis. Even if miRNAs have been founded conserved in the Eumetazoan, some are dissociated or specific to a species or even to an individual. Indeed, some studies have identified isomiRNAs that can specifically respond to stress or potentially lead to new miRNAs within a species. miRNAs were known to regulate the host's internal defense system and immune cell response, which are a crucial process of host-parasite interactions. Herein, we describe the complete and constitutive set of miRNAs, referred to as the miRNome, in Biomphalaria glabrata snails, the primary intermediate host of the trematode parasite Schistosoma mansoni, the causative agent of schistosomiasis. The B. glabrata miRNome is characterized from the hemolymph, that is known as the main immune-related tissue of the snail, which contains hemocytes, the snail innate immune cells. Using a massive sequencing approach of small RNAs, we characterize their expression and specificity between strains of B. glabrata selected for their extreme compatibility phenotype with the parasite and differential geographical isolate. Our results uncover specific miRNAs and abundant isomiRNAs that are expressed exclusively in one strain or another, suggesting a specificity of the expression for the miRNAs derived by the local co-evolution with the parasite. As expected, expressed common core of miRNAs between naive strains have been founded and constitute thus a conserved cluster of miRNAs. Others points remain to explore : what is the intrinsic expression of these miRNAs in immune cells but also in animal? Could their expression regulation be misinterpreted as a response to the parasite? The expression behavior of three miRNAs, bgl-miR-8-3p, bgl-miR-1985-5p, and bgl-miR-184-3p, was investigated over a 48-hour period in two tissues, hemolymph and head-foot, using qPCR. It was found that these miRNAs exhibit different dynamic expression patterns between the tissues and over time.

Advancing Drug Discovery for Schistossoma mansoni with Siamese Networks and Attention-Based Deep Learning Models

Igor Henrique Sanches Silva — 2024-11-07

Schistosoma mansoni is a parasitic worm responsible for schistosomiasis, a neglected tropical disease impacting millions in regions with inadequate sanitation. Infection occurs through contaminated water, resulting in symptoms like fever, abdominal pain, diarrhea, and serious liver damage. The primary treatment, praziquantel, is ineffective against young schistosomes and newly transformed schistosomula (NTS), and rising drug resistance underscores the critical need for new treatment options.Our goal was to train a deep learning model to identify drug candidates against both adult S. mansoni and NTS. We collected compounds with phenotypic in vitro IC50 data from the literature, removed duplicates, standardized the structures, and a randomly stratified split of the data into training and test sets were performed, where 80% of the data were dedicated to training and 20% to testing. Using a Siamese network architecture, we trained the model to recognize structural similarities between compounds. To enhance performance, we incorporated ChemBERTa, a pre-trained transformer model from ChEMBL, as the initial layer to leverage its understanding of chemical structures. Additionally, we implemented a multi-head attention mechanism to capture a wide range of molecular interactions and fine-tuned the model using Optuna to achieve better performance.Two models were developed—one for adult S. mansoni worms and another for NTS—and validated using an independent external dataset of 263 compounds provided by Prof. de Morais’ group. The adult worm model achieved an accuracy of 0.85, a Matthew's correlation coefficient (MCC) of 0.73, a sensitivity of 0.83, and a specificity of 0.86. In comparison, the NTS model attained an accuracy of 0.82, an MCC of 0.71, a sensitivity of 0.81, and a specificity of 0.84. These strong results are impressive considering the validation dataset included chemically distinct compounds, as revealed by t-SNE analysis indicating that these compounds were located in different regions of chemical space. Despite this challenge, both models demonstrated robust performance and generalizability. Additionally, Monte Carlo uncertainty was calculated for all predictions, providing an extra layer of confidence in the model's outputs.In conclusion, the Siamese AI models developed for adult worms and NTS demonstrate robustness and the ability to generalize to unseen and chemically diverse data. Moving forward, we will conduct an interpretative analysis of the model predictions utilizing techniques such as SHapley Additive exPlanations (SHAP) and uncertainty estimation. Subsequently, we will perform virtual screening of CRAFT’s and commercial databases using these models, incorporating uncertainty values to prioritize the most promising candidates. The top compounds identified will be subjected to phenotypic in vitro testing, thereby contributing to accelerating the discovery of new candidates for schistosomiasis.

Different strategies for Schistosomiasis diagnosis and implications for mass drug treatment recommendation

Natalia de Melo Nasser Fava — 2024-11-07

Schistosomiasis is the second most significant parasitic infection in the world in terms of public health and economic impact (WHO, 2021). Brazil, as a signatory to the 2030 Agenda, has committed to eliminating neglected diseases, including schistosomiasis, by the end of this decade. To achieve this goal, two fundamental pillars are essential: effective diagnosis and appropriate environmental interventions. In the context of endemic areas, Brazilian Ministry of Health recommends the preparation and examination of two Kato-Katz slides per stool sample. Additionally, in situations where the infection prevalence exceeds 25%, mass treatment of the population with Praziquantel is recommended (Brazil, 2022). This study aimed to compare the prevalences obtained from analyzing two Kato-Katz slides with those obtained from analyzing 18 Kato-Katz slides, in order to inform the discussion about thresholds for mass drug treatment. The study included 50 participants randomly selected, aged seven years or older, of both sexes, excluding pregnant and lactating women, residing in the Usina João de Deus community in the municipality of Capela, Alagoas, Brazil In the municipality's routine schistosomiasis control program, one slide is prepared for each stool sample. In the past year, the prevalence in the João de Deus community was 2%. In this study, each participant provided a stool sample, from which 18 slides were prepared using the Kato-Katz method for parasitic diagnosis. To estimate the empirical distribution of prevalence in the case of using two slides (α = 5%), an algorithm was applied with the following steps: a) Randomly selecting two of the 18 slides for each individual; b) Considering the individual positive for the presence of the parasite if at least one of the slides indicated its presence; c) Estimating the total prevalence among the 50 participants; d) Repeating the previous steps 1,000 times. To ensure the reproducibility of the simulation, the seed used was the number of the first prize of the federal lottery drawn on June 1, 2024. At the conclusion of the analysis of 18 Kato-Katz slides, 17 participants tested positive for Schistosoma mansoni, resulting in a prevalence rate of 34%. According to statistical simulations, the prevalence rate obtained with a single Kato-Katz slide, as performed by the schistosomiasis control program, was 8.4%. In contrast, using two slides, as recommended by the Ministry of Health, yielded a prevalence rate of 12.8%. The confidence interval for this estimate did not encompass 25%. According to the Ministry of Health's guidelines, these results do not justify the need for mass drug treatment. However, the varying prevalence rates obtained with one, two, or 18 slides highlight the need for more effective and urgent measures for disease surveillance and control. These actions are crucial to meet the objectives outlined in the 2030 agenda and to enhance the living conditions of the population.

Biological and proteomic differences of two Schistosoma mansoni strains

Marilia Valentini — 2024-11-07

Different strains of Schistosoma mansoni may exhibit variations in pathology and drug susceptibility. These differences can impact parasite distribution, control measures and the search for new therapeutic alternatives for schistosomiasis. In this study, we aimed to compare two strains of S. mansoni: BH (Belo Horizonte) and SE (Sergipe). To understand differences in pathology and praziquantel (PZQ) treatment response in the vertebrate host, BALB/c mice were infected with 80 cercariae of each strain and treated 45 days post infection (dpi) with either a subcurative dose of a 50 mg/kg, a curative dose of 150 mg/kg, or a higher dose of 300 mg/kg PZQ. Fecal egg count was performed weekly starting at 30 dpi, and euthanasia was performed at 60 dpi. BH strain presented higher infection rates, with a larger number of worms recovered from the mesenteric veins, a greater number of fecal eggs and intestine’ retained eggs (oogram). Liver granuloma from SE strain infections were significantly smaller than those from the BH strain, which also had a higher number of granuloma, suggesting increased pathogenicity. No significant differences in parasite burden were found when mice were treated with a subcurative dose. However, in groups infected with BH strain and treated with 150 or 300 mg/kg PZQ we found a significant reduction in parasite burden and fecal egg count, a lower number of immature and mature eggs and a higher number of dead eggs in the oogram as well as a reduced number of hepatic and intestinal granuloma. SE strain showed significant differences only in the number of fecal eggs at 60 dpi following treatment with 300 mg/kg PZQ. To explore differences in pathology and susceptibility to praziquantel, we performed a comparative shotgun proteomic analysis of male and female worms from both strains using label-free quantification. Proteins were extracted from pools of parasites, followed by peptide digestion with trypsin and mass spectrometry analysis. We identified over 1000 proteins across groups. In untreated males, 16 proteins showed differential expression. PZQ treatment did not alter protein expression in BH strain males or females. In contrast, SE strain females showed upregulation of 3 proteins post-treatment, and SE strain males exhibited 74 differentially expressed proteins. Among treated females from both strains, subtle adaptations were observed, especially in SE strain, with structural proteins of the cytoskeleton and musculature suggesting potentially less PZQ-induced damage in this strain. Overall, results indicate that the BH strain produces and retains more eggs, which has implications for pathology, but is more susceptible to PZQ. In contrast, the SE strain appears to exhibit characteristics of PZQ resistance or tolerance in vivo. We also identified proteins upregulated in the SE strain related to adaptive mechanisms against oxidative stress induced by PZQ, potentially enhancing parasite survival and adaptation post-treatment.

Biomphalaria glabrata, a new model to investigate the evolution of meiotic recombination

Julie Clement — 2024-11-07

Meiotic recombination is a conserved mechanism that plays an important role in genetic diversity and genome evolution. By shuffling parental alleles to produce novel haplotype, recombination increases the efficiency of selection at linked loci and thus facilitates population adaptation. During meiosis, DNA double-strand breaks initiates homologous recombination at specific loci called hotspots. In many mammals, their localization corresponds to specific DNA sequences bound by the zinc finger (ZnF) array of PRDM9. These hotspots are also marked with specific epigenetic modifications (H3K4me3 and H3K36me3) that are catalyzed by PRDM9 itself. A remarkable property of PRDM9 is the high diversity and fast evolution of its ZnF domain. The consequence is the fast evolution of recombination map for species having a PRDM9 for hotspot localisation and thus a potentially higher evolvability.
PRDM9 appears in the last common ancestor of metazoans but its partial or complete loss have been surprisingly reported in many taxa. Species lacking a full-length PRDM9 have evolutionary stable hotspots that are located near promoter-like regions, that are evicted by PRDM9. The involvement of PRDM9 in meiotic recombination has not been yet explored outside vertebrate species, one reason being that invertebrate model species (drosophila, nematode) have no PRDM9. Here, we propose to fill these gaps by investigating PRDM9 function in meiotic recombination in closely-related species of freshwater snails, including Biomphalaria glabrata and Biomphalaria pfeifferi and Bulinus truncatus, for which we recently identified full-length PRDM9 conservation by exploring their recently published genome assemblies.
This project will address the following questions: Where are meiotic hotspots located along the genome of freshwater snails? Is PRDM9 essential for meiotic progress and fertility? Can we find evidence of PRDM9 function in the localisation of hotspots?
We will use complementary approaches such as population genomics, genotyping of PRDM9 zinc finger array, molecular mapping of histone modifications and DNA breaks in snail gonads (ChIPseq approaches), histology and genetic manipulation of snail.
Preliminary results about PRDM9 ZnF diversity showed hypervariable amino-acid at positions contacting DNA and diversity in number and order of ZnF between individuals and populations. This indicates a probable involvement of PRDM9 in specifying recombination hotspot. The epigenetic profiling is currently being optimized and will be applied to our snails lines already selected for different Prdm9 alleles.
This project should help to identify the molecular bases behind the adaptation of freshwater snails to their biotic and abiotic environments.