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The World Health Organization recommends the use of the Kato-Katz method in the procedures of schistosomiasis control programs. Studies show the importance of a fast reading of the slides due to the decline of their viability, with the appearance of fungi or desiccation of the sample, which hinders diagnosis. It is necessary to establish a procedure to improve the long-term preservation of these Kato-Katz slides in order to accomplish the following: (1) preserve the slides for future quality control procedures and readings; (2) allow for the production of durable materials for training; and (3) train health professionals involved in diagnosing schistosomiasis. Therefore, this study aims to test a slide preservation methodology for these purposes. The results showed that the modifications made to the experimental slides demonstrated that egg loss was within the expected range and the limit accepted by quality control standards, as well as improved the diagnostic durability of the slides during the preservation times tested. We concluded that the application of the preservation technique to the slides promoted stabilization and permanence for long-term storage.

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To present the current epidemiological scenario of schistosomiasis related to urban transmission through an epidemiological risk assessment in Porto de Galinhas, a coastal area of Pernambuco, Brazil. Malacological and parasitological surveys were performed between the years 2018 and 2020. Snails were identified taxonomically and examined to confirm infection by Schistosoma mansoni, and so to identify Schistosomiasis Transmission Foci (STF) by the artificial light exposure technique. Stool samples were examined using the Kato-Katz method to identify schistosomiasis cases. Socioeconomic, environmental, behavioural and health data were collected by a questionnaire applied to participates in the survey and used to predict the schistosomiasis risk occurrence by multivariate logistic regression. In all, a total of 6466 snails of Biomphalaria glabrata were collected and 36 breeding sites were identified, of which 25 % were STF. A total of 2236 individuals took part of the survey which identified 187 cases of schistosomiasis, registering a positivity percentage of 8.36 %. The surveys identified the neighbourhoods with the highest risk for transmission while the socioenvironmental analysis identifies other risk factors for disease occurrence, such as gender, age range, level of education and absence of water drainage. We found that areas with poor sanitation, flooding during winter periods and dwellings located near mangroves should be treated by health authorities as priority areas for health interventions to minimize disease transmission. In addition, efforts to improve the population's educational level could certainly contribute to the adoption of measures to prevent and control this neglected tropical disease.

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The World Health Organization (WHO) recognizes schistosomiasis as one of the Neglected Tropical Diseases targeted for global elimination in the 2030 Agenda of the Sustainable Development Goals. In Brazil, schistosomiasis mansoni is considered a public health problem, particularly prevalent among vulnerable populations living in areas with poor environmental and sanitary conditions. In 2022, the WHO published a Guideline encompassing recommendations to assist national programs in endemic countries in achieving morbidity control, eliminating schistosomiasis as a public health problem, and advancing towards interrupting transmission. The perspectives presented here, collectively prepared by members of the Oswaldo Cruz Foundation's (Fiocruz) Schistosomiasis Translational Program (FioSchisto), along with invited experts, examine the feasibility of the WHO recommendations for the Brazilian settings, providing appropriate recommendations for public health policies applicable to the epidemiological reality of Brazil, and suggests future research to address relevant issues. In Brazil, the provision of safe water and sanitation should be the key action to achieve schistosomiasis elimination goals. The agencies involved in measures implementation should act together with the Primary Care teams for planning, executing, monitoring, and evaluating actions in priority municipalities based on their epidemiological indicators. Host snails control should prioritize judicious ecological interventions at breeding sites. The Information, Education, and Communication (IEC) strategy should be associated with water and sanitation and other control actions, actively involving school community. To identify infected carriers, FioSchisto recommends a two-stage approach of immunological and molecular tests to verify transmission interruption during the intervention and beyond. Praziquantel administration should be done under medical supervision at the Primary Care level. MDA should be considered in exceptional settings, as a measure of initial attack strategy in locations presenting high endemicity, always integrated with water and sanitation, IEC, and snail control. To assist decision-making, as well as the monitoring and evaluation of strategic actions, there is a need for an Information System. FioSchisto considers this systematization essential to make investments in strategic research to support the improvement of schistosomiasis control actions. Efforts toward schistosomiasis elimination in Brazil will succeed with a paradigm shift from the vertical prescriptive framework to a community-centered approach involving intersectoral and interdisciplinary collaboration.

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OBJECTIVE: To verify the agreement of data on severe forms and deaths from schistosomiasis recorded in the Brazilian Notifiable Diseases Information System and the Mortality Information System, sociodemographic variables with the occurrence of severe forms and deaths, and the temporal trend of the disease in the state of Pernambuco, Brazil. METHODS: This is an ecological, descriptive, time series study with data on severe forms and deaths from schistosomiasis in Pernambuco, from 2007 to 2017. For the linkage between databases, a function was developed in python programming language, using the Soundex method. To identify sociodemographic and health factors that correlated with the dependent variables, Pearson's correlation test was applied. For trend analysis, linear regression was applied. RESULTS: We identified 9,085 severe cases, 1,956 deaths, and 186 cases in the linkage. The correlation between the average positivity rate with the general water supply and waste collection was 0.22 and 0.26 respectively. We verified a correlation of the average cumulative mortality rate with water supply by well or spring (r=0.27), water supply by the general network (r=0.3), waste collection (r=0.42), and road urbanization (r=0.29). We found 3,153 severe forms in 2007 with a decrease trend and 205 deaths in 2010, without a trend pattern. CONCLUSION: There is a need for greater investments in disease control and in the quality of information, especially in the record of severe forms, considering that, due to the pathophysiology of the disease, death only occurs when the individual develops the chronic form, and its notification on the Notifiable Diseases Information System is imperative.

OBJETIVO: Verificar a concordância dos dados relacionados às formas graves e aos óbitos por esquistossomose registrados no Sistema de Informação de Agravos de Notificação e no Sistema de Informação Sobre Mortalidade, as variáveis sociodemográficas com a ocorrência das formas graves e óbitos e a tendência temporal da doença em Pernambuco. MÉTODOS: Trata-se de um estudo ecológico, descritivo, de série temporal com dados referentes às formas graves e aos óbitos por esquistossomose em Pernambuco, de 2007 a 2017. Para o linkage entre as bases de dados, foi desenvolvida uma função em linguagem python de programação, utilizando o método soundex. Para identificar fatores sociodemográficos e sanitários que se correlacionaram com as variáveis dependentes, foi aplicado o teste de correlação de Pearson. Para a análise de tendência, aplicou-se a regressão linear. RESULTADOS: Identificaram-se 9.085 casos graves, 1.956 óbitos e 186 casos no linkage. A correlação entre a taxa média de positividade com o abastecimento hídrico rede geral e coleta de lixo foi 0,22 e 0,26 respectivamente. Houve correlação da taxa média de mortalidade acumulada com abastecimento hídrico por poço ou nascente (r=0,27), abastecimento hídrico por rede geral (r=0,3), coleta de lixo (r=0,42), urbanização das vias (r=0,29). Ocorreram 3.153 formas graves em 2007, com tendência a redução, e 205 óbitos em 2010, sem um padrão de tendência. CONCLUSÃO: Há necessidade de maiores investimentos no controle da doença e na qualidade da informação, especialmente no registro das formas graves, pois, dada a fisiopatologia da doença, o óbito só ocorre quando o indivíduo desenvolve a forma crônica, sendo imperativo sua notificação no Sistema de Informação de Agravos de Notificação.

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RESUMO Objetivo: Verificar a concordância dos dados relacionados às formas graves e aos óbitos por esquistossomose registrados no Sistema de Informação de Agravos de Notificação e no Sistema de Informação Sobre Mortalidade, as variáveis sociodemográficas com a ocorrência das formas graves e óbitos e a tendência temporal da doença em Pernambuco. Métodos: Trata-se de um estudo ecológico, descritivo, de série temporal com dados referentes às formas graves e aos óbitos por esquistossomose em Pernambuco, de 2007 a 2017. Para o linkage entre as bases de dados, foi desenvolvida uma função em linguagem python de programação, utilizando o método soundex. Para identificar fatores sociodemográficos e sanitários que se correlacionaram com as variáveis dependentes, foi aplicado o teste de correlação de Pearson. Para a análise de tendência, aplicou-se a regressão linear. Resultados: Identificaram-se 9.085 casos graves, 1.956 óbitos e 186 casos no linkage. A correlação entre a taxa média de positividade com o abastecimento hídrico rede geral e coleta de lixo foi 0,22 e 0,26 respectivamente. Houve correlação da taxa média de mortalidade acumulada com abastecimento hídrico por poço ou nascente (r=0,27), abastecimento hídrico por rede geral (r=0,3), coleta de lixo (r=0,42), urbanização das vias (r=0,29). Ocorreram 3.153 formas graves em 2007, com tendência a redução, e 205 óbitos em 2010, sem um padrão de tendência. Conclusão: Há necessidade de maiores investimentos no controle da doença e na qualidade da informação, especialmente no registro das formas graves, pois, dada a fisiopatologia da doença, o óbito só ocorre quando o indivíduo desenvolve a forma crônica, sendo imperativo sua notificação no Sistema de Informação de Agravos de Notificação.

ABSTRACT Objective: To verify the agreement of data on severe forms and deaths from schistosomiasis recorded in the Brazilian Notifiable Diseases Information System and the Mortality Information System, sociodemographic variables with the occurrence of severe forms and deaths, and the temporal trend of the disease in the state of Pernambuco, Brazil. Methods: This is an ecological, descriptive, time series study with data on severe forms and deaths from schistosomiasis in Pernambuco, from 2007 to 2017. For the linkage between databases, a function was developed in python programming language, using the Soundex method. To identify sociodemographic and health factors that correlated with the dependent variables, Pearson's correlation test was applied. For trend analysis, linear regression was applied. Results: We identified 9,085 severe cases, 1,956 deaths, and 186 cases in the linkage. The correlation between the average positivity rate with the general water supply and waste collection was 0.22 and 0.26 respectively. We verified a correlation of the average cumulative mortality rate with water supply by well or spring (r=0.27), water supply by the general network (r=0.3), waste collection (r=0.42), and road urbanization (r=0.29). We found 3,153 severe forms in 2007 with a decrease trend and 205 deaths in 2010, without a trend pattern. Conclusion: There is a need for greater investments in disease control and in the quality of information, especially in the record of severe forms, considering that, due to the pathophysiology of the disease, death only occurs when the individual develops the chronic form, and its notification on the Notifiable Diseases Information System is imperative.

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Schistosoma mansoni infections, particularly egg antigens, induce Th2-dominant granulomatous responses accompanied by remarkable immunoregulatory mechanisms that avoid intense fibrosis. Interleukin (IL)-33 is a cytokine that stimulates the early activation of Th2 responses, and its soluble ST2 receptor (sST2) avoids granulomatous response, as well as CXCL9 and CXCL10 chemokines that have antifibrotic activity. However, in schistosomiasis, these molecules have not been suitably studied. Therefore, this study aimed to measure IL-33 and sST2 RNA, cytokines, and chemokines in peripheral blood cultures from individuals living in schistosomiasis-endemic areas. Peripheral blood cells from individuals with S. mansoni (n = 34) and non-infected individuals (n = 31) were cultured under mitogen stimulation. Supernatant chemokines and cytokines were evaluated using a cytometric bead array, and IL-33 and sST2 mRNA expression was measured using qPCR. Infected individuals showed higher levels of CXCL8, CXCL9, CXCL10, IFN-γ, TNF-α, IL-6, IL-2, IL-4, and IL-10; there was a lower expression of IL-33 mRNA and similar expression of sST2mRNA in infected than non-infected individuals. In conclusion, for the first time, we demonstrated lower IL-33mRNA expression and high levels of the antifibrotic chemokines CXCL9 and CXCL10 in schistosomiasis mansoni, which could control exacerbations of the disease in individuals from endemic areas.

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Background: Social and environmental vulnerabilities contribute to the persistence and increase of Schistosomiasis, which has been a public health problem in Brazil and worldwide. In this study, we aimed to monitor the entry, installation, and maintenance of schistosomiasis transmission in an urban area on the Brazilian coast over two decades (2000-2010/2010-2020). Methods: This population-based cross-sectional study was conducted in Porto de Galinhas, state of Pernambuco, Brazil, to investigate the dynamics of schistosomiasis transmission in the urban area. Through 3 malacological and parasitological surveys and using geoprocessing technologies, schistosomiasis transmission foci (STF), as well as cases of the disease were identified and quantified. Statistical and geoprocessing tools were used to analyse the data. Findings: Overall, the number of STF decreased from 15 (2000) to 11 (2010) and then to 9 (2020). Although the infection ratio of snails in 2000 has decreased from 16·1% to 5·8% in 2010, we observed an increase to 7·2% in 2020. Additionally, 6,499 individuals were analysed (2012 in 2000; 2459 in 2010, and 2028 in 2020) and the prevalence of human infection has decreased over years, from 32·5% (2000), 16·6% (2010) to 8·8% (2020). The disorderly urbanization process was directly related to the spatial distribution of STF and schistosomiasis cases, causing a new scenario where people became infected by walking on unpaved and flooded streets. Interpretation: Although we observed a decreasing in schistosomiasis cases and STF, this NTD became a health problem related to urbanization in the study area. The challenge to overcome this new sort of transmission will require a greater understanding of the disorderly migration, spatial occupation, and degradation of the environment. Funding: National Council for Scientific and Technological Development (CNPq), Ministry of Science, Technology, Innovations and Communications, Brazil.

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OBJECTIVES: We measured the production of cytokines, chemokines and antibodies involved in allergic responses and sCD23 levels during Schistosoma mansoni infection. METHODS: Individuals (n = 164) were selected using the ISAAC questionnaire and parasitological exams. The subjects were divided as follows: those infected individuals with allergy-related symptoms (A-I), those with allergy-related symptoms only (A-NI); those only infected (NA-I); and those non-infected individuals without allergy-related symptoms (NA-NI). We used supernatants from cell culture (mitogenic stimulation) to measure cytokine and chemokine levels using cytometric bead arrays. Serum levels of anti-Ascaris lumbricoides (Asc) and anti-Blomia tropicalis IgE were measured using ImmunoCAP, and sCD23 was measured using ELISA. RESULTS: Schistosoma mansoni infection was associated with a lower risk of allergy-related symptoms. In A-I, there were higher levels of TNF-α, IL-10, IL-6, IFN-γ and CXCL8 than in NA-NI group, with TNF-α and IL-6 also at higher levels compared to A-NI group. Levels of IL-6, CXCL8, total and anti-Asc IgE, as well as the numbers of eosinophils, were higher in NA-I than in NA-NI, and the antibodies were also lower in A-NI than in NA-I group. In AI and NA-I, there was less production of CCL2 than in NA-NI. There were no differences in the levels of IL-2, IL-4, IL-17, CCL5, sCD23 and anti-Blomia IgE. CONCLUSIONS: Patients with allergy-related symptoms and infected (simultaneously) had higher levels of IL-10; due to the infection, there was increased production of IL-6 and CXCL8 and less CCL2. These data may characterize deviation to Th1 or attenuation of the Th2 response in allergy sufferers in areas endemic for schistosomiasis.

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High-throughput profiling of metabolites has been used to identify metabolic changes in murine models as a response to the infection by the parasitic trematode Schistosoma. These investigations have contributed to our understanding on the pathogenesis of this tropical neglected disease, with a potential of helping diagnosis. Here, our study aimed to investigate the application of gas chromatography-mass spectrometry (GC/MS) on the profiling of urine metabolites from mice carrying infections by Schistosoma mansoni. Two larval infection doses created distinctive infection intensities in mice, whereby the heavily infected animals were found to release 25 times more eggs in faeces than lightly infected animals. Over 200 urine metabolites were identified from these animals by GC/MS, following two complementary derivatisation methods. A list of 14 individual metabolites with altered relative abundances between groups were identified. Most of the altered metabolites showed a trend of increased abundances in response to infection intensity, indicating host-specific metabolic alterations as a result of the disease. Hippurate, a metabolite which concentration is intimately modulated by the gut microbiota, was found to be highly correlated to infection intensity. Our study showed that urine metabolic profiling by GC/MS can distinguish non-infected animals from those carrying light and heavy infections by S. mansoni, revealing metabolites associated to the infection and providing insights on the pathogenesis of schistosomiasis.

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BACKGROUND: Spinal neuroschistosomiasis (SN) is one of the most severe clinical presentations of schistosomiasis infection and an ectopic form of the disease caused by any species of Schistosoma. In Brazil, all cases of this clinical manifestation are related to Schistosoma mansoni, the only species present in the country. Although many cases have been reported in various endemic areas in Brazil, this is the first time in the literature that SN is described in two brothers. CASE PRESENTATION: Two cases of SN were accidentally diagnosed during an epidemiological survey in an urban area endemic for schistosomiasis transmission. Both patients complained of low back pain and muscle weakness in the lower limbs. Sphincter dysfunction and various degrees of paresthesia were also reported. The patients' disease was classified as hepato-intestinal stage schistosomiasis mansoni at the onset of the chronic form. A positive parasitological stool test for S. mansoni, clinical evidence of myeloradicular damage and exclusion of other causes of damage were the basic criteria for diagnosis. After treatment with praziquantel and corticosteroid, the patients presented an improvement in symptoms, although some complaints persisted. CONCLUSIONS: It is important to consider SN when patients come from areas endemic for transmission of schistosomiasis mansoni. Clinical physicians and neurologists should consider this diagnostic hypothesis, because recovery from neurological injuries is directly related to early treatment. As, described here in two brothers, a genetic predisposition may be related to neurological involvement. Primary care physicians should thus try to evaluate family members and close relatives in order to arrive at prompt schistosomiasis diagnosis in asymptomatic individuals and propose treatment in an attempt to avoid progression to SN.

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The presence of anti-Ascaris (anti-Asc) immunoglobin isotypes alters the risk of allergic asthma. In this study, we analyzed the relationships between serum levels of anti-Asc IgE, IgG1, and IgG4, without concurrent infection by the parasite, and the presence of asthma. We measured cytokine levels from Th1, Th2, and Th17 profiles. Children aged 2-14 years old, asthmatics (n = 64), and non-asthmatics (n = 40) were selected according to the International Study of Asthma and Allergies in Childhood criteria. Asthmatic patients who had positive skin allergy tests were considered to have allergic asthma. Stool exams were performed to exclude children who were parasitized by helminths/protozoans and blood samples were collected in non-parasitized individuals. We performed peripheral blood leukocyte counts and in vitro culture following mitogenic stimulation. Levels of cytokines (IL-2, IL-4, IL-6, IL-10, TNF-α, IFN-γ, and IL-17) in the supernatants were measured using a cytometric bead array. Titration of serum total IgE and IgE specific to Ascaris were obtained using ImmunoCAP; IgG1 and IgG4 titers were measured using enzyme-linked immunosorbent assays. Anti-Asc IgE was associated with a higher risk of asthma and an increase in the number of eosinophils and neutrophils. By contrast, anti-Asc IgG1 could be considered a protective factor against asthma, associated with lower levels of circulating neutrophils. There were high levels of IL-6 and TNF-α in asthmatics. Levels of IL-6, but not TNF-α, depended on the presence of anti-Asc IgG1 in serum. Anti-Asc IgE appears to increase risk of asthma, and anti-Asc IgG1 appears to favor decreased neutrophil counts and increased IL-6 levels.

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BACKGROUND: Maternal exposure to antibodies, cytokines or parasitic antigens during gestation may alter the degree of immune competence of offspring. Here we describe the production of cytokines and chemokines, and the ability to activation of the immune response in infants from mothers sensitized to helminths. METHODS: It were selected five infants born to helminth-seropositive mothers but who were negative for current helminth infection. Whole blood was cultured without stimulus, with phytohemagglutinin mitogen (5 µg/ml, 24 h) or with purified protein derivative (PPD) (1 µg/ml, 24 h), and the supernatant was assessed for presence of Th1/Th2 cytokines (IFN-γ, TNF-α, IL-10, IL-5, IL-4 and IL-2) and chemokines (CXCL10, CCL2, CXCL9, CCL5 and CXCL8) by cytometric bead array. RESULTS: All infants produced CCL5. Two infants demonstrated a mixed profile of Th1 (CXCL9) and Th2 (CCL2) chemokines in the presence of CXCL10, while one infant showed skewing towards Th2 without CXCL10 and two of them had been impaired immune response (children from sensitized to Schistosoma mansoni mothers). CONCLUSION: Infants with Th1 and Th2 profile chemokines demonstrated a good response to vaccination, indicated by CXCL10 levels, but not infants predominantly Th2-skewed profile. These results highlight that children from mothers sensitized to S. mansoni may lead to ineffective immune response to PPD, while mothers sensitized to Ascaris lumbricoides showed no such impairment.

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The relationship between the cellular immune response during Trichuris trichiura infection and asthma has not yet been established. In this study, the cytokines interleukin (IL)-2, IL-4, IL-6, IL-10, TNF-α, IFN-γ and IL-17A were evaluated in asthmatic children harboring T. trichiura. For this assessment, asthmatic and non-asthmatic children (ISAAC questionnaire) were submitted to parasitological tests and blood samples were cultured (mitogen stimulation) for cytokine measurements in the supernatant. Asthma frequencies were similar in infected and uninfected children, but IL-4, IL-6, TNF-α and IL-10 levels were high in the infected asthmatic children. Additionally, infected non-asthmatic children exhibited high levels of these cytokines in relation to uninfected non-asthmatic children; however, cytokine levels were lower when compared with infected and asthmatic children. Therefore, T. trichiura infection positively modulated the pro- and anti-inflammatory cytokines in asthmatic children, but a background of asthma seemed to narrow the production of cytokines induced by this helminth.

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This is an analysis of the risk of schistosomiasis transmission in the city of Recife in the Northeast of Brazil based on the number of schistosomiasis cases (Schistosoma mansoni) registered for the period 2007-2017 together with data resulting from active search of breeding sites of the Biomphalaria snail intermediate host. The analyses were performed using Kernel Density Estimation (KDE), SaTScan and Map Algebra methodology using human socio-demographic data and biotic and abiotic data from the snail breeding sites. Investigating 44 breeding sites resulted in a total of 3.800 snails, 31.8% of which were positive for S. mansoni DNA. These data were considered in relation to total of 652 schistosomiasis cases. The KDE showed two high-risk and two medium-risk clusters, while three significant clusters were identified by SaTScan. Combining these data with the Map Algebra methodology showed that all high-risk neighbourhoods had breeding sites with snails positive for S. mansoni. It was concluded that schistosomiasis transmission cannot be controlled without basic sanitation and sewage management in the presence of Biomphalaria snails. The technique of Map Algebra was found to be fundamental for the analysis and demonstration of areas with a high probability of schistosomiasis transmission.

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Neuroschistosomiasis is a severe form of presentation of schistosomiasis in which Schistosoma spp. affects the central nervous system. This is the first study performed to analyze whether there is any relationship between physical effort and the appearance of neuroschistosomiasis, through clinical, molecular and immunological evaluations. An experimental controlled study using 64 male Balb/c inbred mice divided into four groups according to presence or absence of S. mansoni infection and submitted to physical effort or resting was conducted. Thirteen weeks after exercise training, S. mansoni DNA was detected in the brain or spinal cord in about 30% of the infected animals moreover, only S. mansoni-positive samples showed positive labeling for S. mansoni antigens in the brain or spinal cord, with a striking reaction inside the microglia. However, the behavioral tests did not show any clinical symptoms of neuroschistosomiasis in animals submitted to physical effort or in resting. In animals with S. mansoni-positive DNA, immunohistochemical data revealed astrogliosis and microgliosis, elevated IL-10 levels and decreased TNF-α expression. This study demonstrated that isometric exercise does not promote neuroschistosomiasis, furthermore, ectopic forms of schistosomiasis in the central nervous system were largely asymptomatic and exhibited a Th2 immune response profile. More experimental studies are necessary in order to characterize the pathological process of experimental neuroschistosomiasis.

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OBJECTIVE: to describe schistosomiasis cases and deaths among residents of the city of Recife, Pernambuco, Brazil, from 2005 to 2013. METHODS: this was a descriptive epidemiological study using data from the Mortality Information System (SIM) (2005-2013) and the Notifiable Diseases Information System (SINAN) (2007-2013); active tracing of the relatives of the dead was undertaken and probabilistic linkage of the databases (2007-2013) was performed using the Reclink program. RESULTS: 297 schistosomiasis deaths were recorded on the SIM system; through active tracing, 130 relatives were contacted and 20.8% autochthony was identified; 388 cases resident in Recife were registered on the SINAN system; through probabilistic linkage, 23 matching records were identified on SIM and SINAN. CONCLUSION: investigation of deaths showed that some individuals had never traveled outside Recife and progressed to the chronic stage of the disease; 23.8% of the cases registered on SINAN had Recife as the municipality in which infection occurred.

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Laboratory maintenance of the Schistosoma mansoni cycle is necessary for developing studies regarding the diagnosis, treatment and control of schistosomiasis. Within this perspective, it is paramount that mice infected by the parasite should present a minimum survival of six months. However, between October 2016 and May 2017, early deaths were observed among infected animals kept in the vivarium of the Schistosomiasis Reference Service of IAMFIOCRUZ. Therefore, the purpose of the present study was to present the results obtained after investigating the main cause of death among these animals. To achieve this, animals that died or that needed to be euthanized due to clinical distress caused by parasite infection were necropsied to investigate the cause of death and clinical condition. Fragments from the intestines, mesenteric vessels and livers were removed and were subjected to histopathological studies. In addition, mouse feces were collected and analyzed using the hydrogen peroxide reaction to detect occult blood. Over an eight-month period, 70 deaths were noted. Forty two animals presented mesenteric ischemia, a vascular insufficiency syndrome that causes a reduction in the nutrient supply to the intestinal viscera. There is, therefore, a need to reduce the infective parasite load in mice to increase their survival, reduce distress caused by the infection and ensure maintenance of the S. mansoni cycle, thus enabling continuity of scientific studies on this parasitosis.

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BACKGROUND: In Brazil, schistosomiasis is a parasitic disease of public health relevance, mainly in poor areas where Schistosoma mansoni is the only human species encountered and Biomphalaria straminea is one of the intermediate host snails. A nested-PCR based on a specific mitochondrial S. mansoni minisatellite DNA region has been successfully developed and applied as a reference method in Brazil for S. mansoni detection, mainly in host snails for epidemiological studies. The amplification efficiency of LAMP is known to be higher than PCR. The present work aimed to assess the utility of our previously described SmMIT-LAMP assay for S. mansoni detection in human stool and snail samples in a low-transmission area of schistosomiasis in the municipality of Umbuzeiro, Paraíba State, Northeast Region of Brazil. METHODOLOGY/PRINCIPAL FINDINGS: A total of 427 human stool samples were collected during June-July 2016 in the municipality of Umbuzeiro and an overall prevalence of 3.04% (13/427) resulted positive by duplicate Kato-Katz thick smear. A total of 1,175 snails identified as Biomphalaria straminea were collected from 14 breeding sites along the Paraíba riverbank and distributed in 46 pools. DNA from human stool samples and pooled snails was extracted using the phenol/chloroform method. When performing the SmMIT-LAMP assay a total of 49/162 (30.24%) stool samples resulted positive, including 12/13 (92.31%) that were Kato-Katz positive and 37/149 (24.83%) previously Kato-Katz negative. By nested-PCR, only 1/46 pooled DNA snail samples was positive. By SmMIT-LAMP assay, the same sample also resulted positive and an additional one was positive from a different breeding site. Data of human and snail surveys were used to build risk maps of schistosomiasis incidence using kernel density analysis. CONCLUSIONS/SIGNIFICANCE: This is the first study in which a LAMP assay was evaluated in both human stool and snail samples from a low-transmission schistosomiasis-endemic area. Our SmMIT-LAMP proved to be much more efficient in detection of S. mansoni in comparison to the 'gold standard' Kato-Katz method in human stool samples and the reference molecular nested-PCR in snails. The SmMIT-LAMP has demonstrated to be a useful molecular tool to identify potential foci of transmission in order to build risk maps of schistosomiasis.

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BACKGROUND & OBJECTIVES: : Schistosomiasis is a rural endemic disease that has been expanding to urban and coastal areas in the state of Pernambuco, Brazil. The aim of this study was to characterize the distribution of breeding sites of the causative vector, Biomphalaria straminea in an endemic municipality for schistosomiasis and to present the predictive models for occurrences and dispersal of this vector snail to new areas. METHODS: : A malacological survey was conducted during January to December 2015 in the municipality of São Lourenço da Mata, Pernambuco, Brazil to identify the breeding sites of Biomphalaria. Faecal contamination was determined by means of the Colitag™ diagnostic kit. Rainfall data were collected, and correlated with snail distribution data. Kernel density estimation, kriging and maximum entropy (MaxEnt) modeling were used for spatial data analysis, by means of the spatial analysis software packages. RESULTS: : Out of the 130 demarcated collection points, 64 were classified as breeding sites for B. straminea. A total of 5,250 snails were collected from these sites. Among these 64 sites, four were considered as foci of schistosomiasis transmission and 54 as potential transmission foci. An inverse relationship between rainfall and snail density was observed. Kernel spatial analysis identified three areas at higher risk of snail occurrence, which were also the areas of highest faecal contamination and included two transmission foci. Kriging and MaxEnt modeling simulated the scenarios obtained through the kernel analyses. INTERPRETATION & CONCLUSION: : Use of geostatistical tools (Kriging and MaxEnt) is efficient for identifying areas at risk and for estimating the dispersal of Biomphalaria species across the study area. Occurrence of B. straminea in the study area is influenced by the rainy season, as it becomes more abundant during the period immediately after the rainy season, increasing the risk of dispersal and the appearance of new transmission foci.

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