Schistosomiasis Mansoni Research Articles

Intestinal schistosomiasis: Can a urine sample decide the infection?

Intestinal schistosomiasis, one of the neglected tropical diseases whose control depends on accurate diagnosis of the disease prevalence. The use of low sensitive Kato Katz (KK) fecal egg detection method as a reference gold standard is not an accurate indication especially in low transmission areas. Latent class analysis frameworks especially the Bayesian could be used instead to compare between different diagnostic tests without the use of a gold standard method as a reference. Thus, this study compared two urine-based tests for the detection of circulating antigen and cell free DNA of Schistosoma mansoni versus KK method using the Bayesian latent class analytical framework and in two models where the trace results of point of contact - assay of circulating cathodic antigen (POC-CCA) were once estimated as positive, and as negative in the other model. The Bayesian framework in the trace CCA positive model showed an estimate of disease prevalence of 26% (95% BCI:0 to 60%). POC-CCA showed the highest sensitivity (74% with BCI: 9 to 91%) and lowest specificity for (20% with BCI: 0% to 37%) and the reverse for KK. For POC-CCA with traces considered negative, it was found that results between the three tests were moderated where the positivity for infection by Schistosoma antigen detection and PCR for cell free DNA approached that estimated by the Bayesian framework (44%), and the specificity for point of contact assay(81%; 95%BCI: 59% to 100%) rose in hand with its sensitivity(77%, 95% BCI:53% to 100%) and with results for PCR test (sensitivity=80%; 95% BCI: 61% to 100%, specificity=69%; 95% BIC: 47% to 100%). KK remains with the highest specificity while its sensitivity in the two models never exceeded 22%. Thus, we conclude that the use of a single urine sample could be very sensitive and highly specific in the diagnosis of intestinal schistosomiasis using either the trace negative model of point of contact assay, or conventional PCR, when compared to the fecal egg detection using duplicate KK. However, the use of a single tool restricts the management of the disease in areas of low endemicity.

Regulation of Liver Fibrosis during Murine Schistosomiasis Mansoni

Background: The main pathology of Schistosoma mansoni (S. mansoni) infection is induced by a granulomatous tissue reaction against the parasite eggs. Unfortunately, no therapy has been proven to prevent the progression of hepatic fibrosis associated with granulomatous hypersensitivity to parasite eggs. Accumulating evidence has demonstrated a critical pathogenic role for both interleukin 17 (IL-17) and interleukin 13 (IL-13) in organ fibrosis. Objective: The present study investigated the role of IL-17 and IL-13 in the pathogenesis of liver fibrosis during S. mansoni infection. Material and Methods: Thirty female C57BL/6 mice were divided into three groups, normal, infected, and anti- mouse IL-17 treated groups. The infected and anti-mouse IL-17 groups were infected with 40±5 cercariae of S. mansoni per mouse. Neutralizing rat anti-mouse IL-17 mAb or an isotype-matched rat IgG mAb was first administered intraperitoneally 3 weeks after S. mansoni infection (62.5μg per mouse) then at the same dose every third day until 2 days before killing. Serum IL-17, IL-13, and proinflammatory cytokines levels were determined by ELISA. Liver granulomas were measured by an ocular micrometer. Results: Serum level of IL-17 was significantly higher in infected mice compared with non-infected animals. Reducing IL-17 activity using anti-IL-17 monoclonal antibodies improves liver functions and reduces the size of the liver granulomas. Meanwhile, Th-2 profibrogenic cytokine IL-13 was also decreased in infected/anti-IL-17 mAB- treated mice. IL-17-induced proinflammatory mediators (IL-1Land TNF-that involved in liver fibrosis were markedly reduced in anti-IL-17 mAB-treated mice. Conclusion: IL-17 and IL-13 contribute to granulomatous inflammatory and fibrosing reactions in murine schistosomiasis.

Regulation of Liver Fibrosis during Murine Schistosomiasis Mansoni

Background: The main pathology of Schistosoma mansoni (S. mansoni) infection is induced by a granulomatous tissue reaction against the parasite eggs. Unfortunately, no therapy has been proven to prevent the progression of hepatic fibrosis associated with granulomatous hypersensitivity to parasite eggs. Accumulating evidence has demonstrated a critical pathogenic role for both interleukin 17 (IL-17) and interleukin 13 (IL-13) in organ fibrosis. Objective: The present study investigated the role of IL-17 and IL-13 in the pathogenesis of liver fibrosis during S. mansoni infection. Material and Methods: Thirty female C57BL/6 mice were divided into three groups, normal, infected, and anti- mouse IL-17 treated groups. The infected and anti-mouse IL-17 groups were infected with 40±5 cercariae of S. mansoni per mouse. Neutralizing rat anti-mouse IL-17 mAb or an isotype-matched rat IgG mAb was first administered intraperitoneally 3 weeks after S. mansoni infection (62.5μg per mouse) then at the same dose every third day until 2 days before killing. Serum IL-17, IL-13, and proinflammatory cytokines levels were determined by ELISA. Liver granulomas were measured by an ocular micrometer. Results: Serum level of IL-17 was significantly higher in infected mice compared with non-infected animals. Reducing IL-17 activity using anti-IL-17 monoclonal antibodies improves liver functions and reduces the size of the liver granulomas. Meanwhile, Th-2 profibrogenic cytokine IL-13 was also decreased in infected/anti-IL-17 mAB- treated mice. IL-17-induced proinflammatory mediators (IL-1Land TNF-that involved in liver fibrosis were markedly reduced in anti-IL-17 mAB-treated mice. Conclusion: IL-17 and IL-13 contribute to granulomatous inflammatory and fibrosing reactions in murine schistosomiasis.

Schistosomiasis and Associated Risk Factors Among School-Aged Children in Northern Nigeria

Background: The Jigawa State Ministry of Health in Northern Nigeria undertook a pilot intervention without a follow-up to control schistosomiasis through preventive chemotherapy by ensuring that each child swallows praziquantel from 2009 to 2013 in five primary schools in Dutse metropolis. Previously, the overall prevalence for urinary and intestinal schistosomiasis determined using Sedimentation and Kato Katz methods was 22.9%.
 Methods: A cross sectional study involving 150 randomly selected pupils, aged 6 - 15 years old was conducted using sedimentation and Kato-Katz methods to determine the prevalence of urinary and intestinal schistosomiasis respectively in three schools in July, 2018. Information on demographic and associated risk factors was collected using a structured questionnaire and the data generated was analyzed using SPSS statistics version 18.0.
 Results: The overall prevalence was 10% with S. haematobium 8%, S. mansoni 2.67% and co-infection 0.67%. Males had higher prevalence, 15.10% than females 1.75%. The 11 - 15 years age group had higher prevalence, 10.10% than 6 - 10 years, 9.68%. Nearly all the infections occurred among class 4-6 pupils with 12.10% and 2.94% in 1-3. Based on parental occupations, children of unskilled laborer had the highest prevalence of 16.67% followed by children of civil servants 12.50%, and children of butchers 0%. Kachi School had the highest prevalence of 14.00% while Sir Muhammadu Sunusi had the lowest 4.00%. Schistosomiasis prevalence was found only to be significantly associated with gender; higher among males than females (15.1% vs 1.75%, P = 0.011).
 Conclusion and Implications for Translation: Schistosomiasis is still endemic among school-aged children in Dutse metropolis, but with a drop in overall prevalence from 22.9% to 10.00%. Chemotherapy and health education should be sustained on both in and out of school-aged children in order to control the transmission.
 Key words: • Schistosomiasis • Tropical diseases • Northern Nigeria • Chemotherapy• School-aged Children • Kato - Katz • Sedimentation
 
 Copyright © 2020 Dogara et al. Published by Global Health and Education Projects, Inc. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0) which permits unrestricted use, distribution, and reproduction in any medium, provided the original work, first published in this journal, is properly cited.

Concurrent Intestinal Schistosomiasis and Soil-Transmitted Nematode Infections in Primary School Children, Benue State North Central Nigeria

Intestinal schistosomiasis and soil-transmitted nematode (STN) infections are among the major public health problems globally, especially in sub-Saharan Africa, Nigeria inclusive. School-aged children carry the highest burden of both infections with significant morbidities in Nigeria. Data on co-endemicity of these infections especially amongst internally displaced persons (IDP) is scarce. To fill this gap, we performed a school-based cross sectional study in three rural communities in North Central Nigeria in which internally displaced persons co-existed. The study aimed to determine the co-endemicity of Schistosoma mansoni and soil-transmitted nematodes infections among primary school children in six primary schools in Guma Local Government area, Benue State, north central Nigeria. Four hundred and forty three primary school pupils were included in the study between January and March 2018 by using simple random technique. A single stool specimen was collected from each participant, and a portion about 1 gram of each specimen was processed by Kato Katz technique. Of the 443 pupils examined, 219(49.4%) were found positive for the characteristic egg of at least one STN. Of the total children, 46(10.4%) had Schistosoma mansoni infection. Co-infection of atleast one STN and S.mansoni occurred in 21(4.7%) of the 443 pupils sampled. Co-infection of Schistosoma mansoni and Ascaris lumbricoides was observed in 11(23.9%) while Schistosoma mansoni and hookworm occurred in 10(21.7%) of the children. There was higher intensity in the total egg count among the males (51.99±60.67) than the females (48.42±59.89) in both genders. The intensity of egg count was highest in age group 7-9 years (55.27±65.03). The lowest intensity was observed in age group 13-15 (41.47±46.08).Integrated interventions such as health education, school feeding program for improved nutrition and mass chemotherapy is advocated.

Clinicopathologic Features of Chronic Intestinal Schistosomiasis and Its Distinction From Crohn Disease

Chronic intestinal schistosomiasis (CIS) can mimic chronic colitis of other etiologies, particularly inflammatory bowel disease. Recognizing clinical and pathologic features unique to schistosomiasis can facilitate differential diagnosis. Clinical, endoscopic, imaging, macroscopic, and histologic features of 40 CIS cases were reviewed and compared with 40 cases of Crohn disease (CD). The most common symptoms of CIS were abdominal pain, distention, bloody stool, weight loss, and anemia. Lesions were mainly located in the rectum and/or left colon in 67.5% of patients. Polyps were seen colonoscopically in 57.1% and yellow granular hyperplasia in 40% of patients. Spotty or linear calcifications were radiographically seen in 21.7% of patients. Macroscopically mural thickening and stricture with erosions or ulcerations were seen in resected specimens of CIS. Four patients were initially diagnosed as having ulcerative colitis and 3 as CD (a misdiagnosis rate of 17.5%). The key microscopic feature was calcified ova in the submucosa, some accompanied by fibrosis, granulomas, or multinucleated giant cells. Crypt distortion, ulceration, and transmural lymphoid aggregates were less frequent in CIS than CD (P<0.05). Pyloric gland metaplasia was absent in CIS. Interestingly, eosinophilic counts were not significantly increased in tissue in CIS as compared with CD. Thus, clinical, endoscopic, imaging, and macroscopic manifestations are not specific for CIS. Correct diagnosis relies on increased awareness of this disease and rigorous search for parasitic eggs in tissue, particularly in patients from endemic areas who are suspected to have inflammatory bowel disease.

Caracterização epidemiológica dos casos de infecção por Schistosoma mansoni no estado de Sergipe, Brasil, 2008-2017

A Esquistossomose é uma doença assintomática causada pelo Schistossoma mansoni(S.mansoni) que pode provocar graves problemas no organismo do hospedeiro. Em Sergipe, foram registrados 946 casos na última década. Visto que o estado está numa posição endêmica referente à doença, há necessidade de realizar uma caracterização epidemiológica dos casos de esquistossomose mansônica com o objetivo realizar uma caracterização epidemiológica dos casos de Schistosoma mansoni no estado de Sergipe, entre 2008 e 2017. Este estudo de abordagem quantitativa e caráter descritivo teve como embasamento dados secundários disponíveis no Sistema de Informação de Agravos de Notificação (SINAN), pelo Departamento de Informática do Sistema Único de Saúde (DATASUS), no período de 2008 a 2017. Após análise das informações disponíveis, não houve diferença significativa entre os sexos acometidos. As faixas etárias 10 a 14, 40 a 59 e 60 a 79 foram iguais estatisticamente aos indivíduos com idade entre 20 e 39 anos. A raça parda foi a mais acometida. O desfecho “morte por esquistossomose” não apresentou diferença significativa em relação à “cura”, sendo um dado preocupante para a saúde pública. A região de saúde mais atingida foi Itabaiana e Aracaju. É necessário a urgência do fortalecimento e estímulo aos programas de combate à esta patologia no estado de Sergipe.

An outbreak of intestinal schistosomiasis, alongside increasing urogenital schistosomiasis prevalence, in primary school children on the shoreline of Lake Malawi, Mangochi District, Malawi

BackgroundIntestinal schistosomiasis was not considered endemic in Lake Malawi until November 2017 when populations of Biomphalaria pfeifferi were first reported; in May 2018, emergence of intestinal schistosomiasis was confirmed. This emergence was in spite of ongoing control of urogenital schistosomiasis by preventive chemotherapy. Our current study sought to ascertain whether intestinal schistosomiasis is transitioning from emergence to outbreak, to judge if stepped-up control interventions are needed.MethodsDuring late-May 2019, three cross-sectional surveys of primary school children for schistosomiasis were conducted using a combination of rapid diagnostic tests, parasitological examinations and applied morbidity-markers; 1) schistosomiasis dynamics were assessed at Samama (n = 80) and Mchoka (n = 80) schools, where Schistosoma mansoni was first reported, 2) occurrence of S. mansoni was investigated at two non-sampled schools, Mangochi Orphan Education and Training (MOET) (n = 60) and Koche (n = 60) schools, where B. pfeifferi was nearby, and 3) rapid mapping of schistosomiasis, and B. pfeifferi, conducted across a further 8 shoreline schools (n = 240). After data collection, univariate analyses and Chi-square testing were performed, followed by binary logistic regression using generalized linear models, to investigate epidemiological associations.ResultsIn total, 520 children from 12 lakeshore primary schools were examined, mean prevalence of S. mansoni by ‘positive’ urine circulating cathodic antigen (CCA)-dipsticks was 31.5% (95% confidence interval [CI]: 27.5–35.5). Upon comparisons of infection prevalence in May 2018, significant increases at Samama (relative risk [RR] = 1.7, 95% CI: 1.4–2.2) and Mchoka (RR = 2.7, 95% CI: 1.7–4.3) schools were observed. Intestinal schistosomiasis was confirmed at MOET (18.3%) and Koche (35.0%) schools, and in all rapid mapping schools, ranging from 10.0 to 56.7%. Several populations of B. pfeifferi were confirmed, with two new eastern shoreline locations noted. Mean prevalence of urogenital schistosomiasis was 24.0% (95% CI: 20.3–27.7).ConclusionsWe notify that intestinal schistosomiasis, once considered non-endemic in Lake Malawi, is now transitioning from emergence to outbreak. Once control interventions can resume after coronavirus disease 2019 (COVID-19) suspensions, we recommend stepped-up preventive chemotherapy, with increased community-access to treatments, alongside renewed efforts in appropriate environmental control.

Intestinal Schistosomiasis and Giardiasis Co-Infection in Sub-Saharan Africa: Can a One Health Approach Improve Control of Each Waterborne Parasite Simultaneously?

Both intestinal schistosomiasis and giardiasis are co-endemic throughout many areas of sub-Saharan Africa, significantly impacting the health of millions of children in endemic areas. While giardiasis is not considered a neglected tropical disease (NTD), intestinal schistosomiasis is formally grouped under the NTD umbrella and receives significant advocacy and financial support for large-scale control. Although there are differences in the epidemiology between these two diseases, there are also key similarities that might be exploited within potential integrated control strategies permitting tandem interventions. In this review, we highlight these similarities and discuss opportunities for integrated control of giardiasis in low and middle-income countries where intestinal schistosomiasis is co-endemic. By applying new, advanced methods of disease surveillance, and by improving the provision of water, sanitation and hygiene (WASH) initiatives, (co)infection with intestinal schistosomiasis and/or giardiasis could not only be more effectively controlled but also better understood. In this light, we appraise the suitability of a One Health approach targeting both intestinal schistosomiasis and giardiasis, for if adopted more broadly, transmission of both diseases could be reduced to gain improvements in health and wellbeing.

Corrigendum to: Evaluation of hepatic fibrosis by elastography in patients with schistosomiasis mansoni.

Corrigendum to: Evaluation of hepatic fibrosis by elastography in patients with schistosomiasis mansoni.

Granuloma formation and tissue pathology in Schistosoma japonicum versus Schistosoma mansoni infections.

Schistosomiasis is the most important helminth disease in the world from a public health perspective. Smansoni and Sjaponicum account for the majority of global intestinal schistosomiasis cases, and the pathogenesis is widely assumed to be fundamentally similar. However, the majority of research on schistosomiasis has been carried out on Smansoni and comparisons between the two species are rarely made. Here, we will discuss aspects of both older and recent literature where such comparisons have been made, with a particular focus on the pathological agent, the host granulomatous response to the egg. Major differences between the two species are apparent in features such as egg production patterns and cellular infiltration; however, it is also clear that even subtle differences in the cascade of various cytokines and chemokines contribute to the different levels of pathology observed between these two main species of intestinal schistosomiasis. A better understanding of such differences at species level will be vital when it comes to the development of new treatment strategies and vaccines.

Esquistossomose mansônica: uma análise de indicadores epidemiológicos no Município de Bacuri, Maranhão, Brasil

Objetivo: descrever os principais indicadores epidemiológicos para Esquistossomose mansoni (EM) no município de Bacuri, Maranhão, Brasil. Metodologia: Para isso, realizou-se uma pesquisa documental e quantitativa destes indicadores da EM no município escolhido. O recorte temporal escolhido para a pesquisa foi de 2007 a 2016. Os dados utilizados foram coletados do Programa de Controle da Esquistossomose (PCE) que está contido na seção de Informações de Saúde do Tabulador Genérico de Domínio Público (TABNET) do Departamento de Informática do Sistema Único de Saúde (DATASUS). Resultados e Discussão: Verificou-se que o ano de 2007 apresentou o maior número de pessoas com suspeita de infecção por Schistosoma (n= 8123). Quanto à realização de exames para os casos suspeitos de infecção por Schistosoma mansoni, os anos de 2017 (n= 7237), 2009 (n= 4805), 2010 (n= 4789) e 2014 (n= 6443) foram os que apresentaram maior quantidade. Em 2007 foram registrados 1166 (16,10%) casos positivos, seguido de 2009 com 1122 (23,30%) e 2014 com 901 (13,90%). A baixa carga parasitária (1 a 4 ovos) representou 68% (n= 3.947) da totalidade dos casos, sendo que houve uma cobertura de tratamento para esses indivíduos superior a 95%. Conclusão: Mediante os resultados obtidos, é válido ressaltar que a Esquistossomose mansoni ainda possui foco endêmico em municípios afastados dos centros urbanos, como a cidade avaliada neste trabalho. Dessa forma, tornam-se necessárias condutas do poder público que visem à redução desses casos.

Spatiotemporal clusters of schistosomiasis mortality and association with social determinants of health in the Northeast region of Brazil (1980–2017)

The Northeast region of Brazil includes the states with the highest prevalence for schistosomiasis mansoni (SM). This study aimed to evaluate the spatiotemporal patterns of SM mortality and to analyze this association with social determinants in health. We conducted an ecological time series study (1980–2017), using spatial analysis tools. Time trend analysis was performed by joinpoint regression. Maps representing mortality rates for SM were constructed and Moran Index was calculated to analyze spatial autocorrelation. A total of 13,720 deaths from SM were reported in this period. The states of Pernambuco (PE) (50.62%) and Alagoas (AL) (22.09%) had the highest mortality percentages. The mortality rate decreased from 1.28 to 0.63 along the time. Although most states showed a stable trend, Sergipe (SE) and Bahia (BA) showed increasing trends in the latest years. Additionally, the spatial analysis showed the concentration of municipalities that presented high risk in the coastal region of the states of PE, AL, SE, and BA. Lastly, mortality rates were correlated with social and educational indicators and hospitalizations for diarrhea. Altogether, these results demonstrate that some states showed stable or increasing trends of SM mortality in the last period of the studied time interval.

Granulomas in parasitic diseases: the good and the bad.

Parasitic diseases affect more than one billion people worldwide, and most of them are chronic conditions in which the treatment and prevention are difficult. The appearance of granulomas, defined as organized and compact structures of macrophages and other immune cells, during various parasitic diseases is frequent, since these structures will only form when individual immune cells do not control the invading agent. Th2-typering various parasitic diseases are frequent, since these structures will only form when individual immune cells do not control the invading agent. The characterization of granulomas in different parasitic diseases, as well as recent findings in this field, is discussed in this review, in order to understand the significance of the granuloma and its modulation in the host-parasite interaction and in the immune, pathological, and parasitological aspects of this interaction. The parasitic granulomatous diseases granulomatous amebic encephalitis, toxoplasmosis, leishmaniasis, neurocysticercosis, and schistosomiasis mansoni are discussed as well as the mechanistic and dynamical aspects of the infectious granulomas.

Qualidade de Vida e Doenças de Veiculação Hídrica: a invisibilidade da Esquistossomose mansoni nos municípios turísticos da Chapada Diamantina, Estado da Bahia, Brasil

As Doenças de Veiculação Hídrica (DVH’s) são uma constante ameaça à qualidade de vida. Entre elas, a Esquistossomose mansoni (EM) é uma das mais comuns a se manifestar no homem. Em 2017, foram registrados 944 casos da doença em Lençóis, na Chapada Diamantina, mas somente após a contaminação de um grupo de turistas mineiros, as atenções da opinião pública se voltaram para essa realidade. Dessa forma, esta pesquisa teve como objetivo investigar qual a prevalência da EM nos municípios turísticos da região e de que modo a doença tem sido abordada conforme estabelecido pelo Ministério da Saúde. Possuindo perfil qualitativo e tendo como procedimentos as pesquisas bibliográfica e documental somadas à realização de entrevistas semiestruturadas, este estudo identificou que inexistem notificações sobre os casos da doença e as ações para o seu enfrentamento se desenvolvem de maneira heterogênea nos municípios, sendo influenciadas por questões de ordem administrativa, econômica e política. A interferência destes fatores fragiliza o êxito das atividades para o manejo da Esquistossomose mansoni e, consequentemente, comprometem a qualidade de vida dos seus habitantes. Para a melhoria do cenário é necessário um melhor planejamento das ações e distribuição dos recursos destinados às estratégias para combater a doença nesses municípios.

Spironolactone: A promising anti-schistosomal drug as revealed by scanning electron microscopy of adult worms

Background: Schistosomiasis mansoni is still a widespread parasitic infection especially among poor developing countries. Depending on praziquantel (PZQ) as a single medication for treatment and control, causes the emergence of isolates resistant to this drug. Continuous efforts are needed for the introduction of new effective therapies. Some diuretics including spironolactone, showed promising anti-parasitic effects. Objectives: In this study, spironolactone, a potassium-sparing diuretic, was evaluated regarding its in vitro lethal effect on Schistosomamansoni (S. mansoni) adult worms using scanning electron microscopy (SEM). Material and Methods: A total of 144 worms; 72 males and 72 females were exposed to a concentration of 10 μg/ml of spironolactone for 5 days at 37±0.5°C in 5% CO2 incubator. A pure medium and a medium containing 0.5% of dimethyl sulfoxide (DMSO) (vehicle) were used as negative controls, while PZQ at 10 μg/ml was used as a reference drug. The compound was then retested using the same technique by successive descending dilutions of the solution. Mortality rate of 50% (lethal concentration) (LC50) and 100% (lethal concentration) (LC100) were calculated after 72 h and 5 days exposure. Results: Our results highlighted the potent anti-schistosome effect of spironolactone as it showed 100% mortality of worms at 6.4 μg/ml and 5 μg/ml after 72 h and 5 days exposure, respectively. While 50% mortality of worms was obtained at 4.5 μg/ml and 3 μg/ml after 72 h and 5 days exposure, respectively. Moreover, SEM of male and female S. mansoni worms exposed to spironolactone in vitro, showed disintegration and sloughing of the tubercles on the dorsal surface of males, erosion of the tegument with exposure and appearance of the sub-tegumental tissue in males and females. Conclusion: Being a safe, oral, inexpensive, and well tolerated drug, spironolactone is capable of being a potent future anti-schistosome drug.

Analysis and spatial distribution of schistosomiasis mansoni in a historically endemic area of northeastern Brazil.

To perform a descriptive analysis of the activities of the Schistosomiasis Control Program, as well as the spatial distribution of the condition in the state of Alagoas, Brazil, for the period from 2007 to 2016. Descriptive ecological study. Data from positive human cases and operational data were collected in the Information System of the Schistosomiasis Control Program, and data for spatial analysis were collected on the website of the Brazilian Institute of Geography and Statistics. An analysis of spatial autocorrelation (Moran statistics) was performed, where a spatial pattern was established, which showed the Q1 and Q2 patterns to be the most important, and Q3 and Q4 representing transition areas. In the years under study, at least 85% (n=60/70) of the municipalities carried out the activities recommended by the PCE (Schistosomiasis Control Program). Alagoas presented an average positivity rate of 7.1%, which is very high compared to the prevalence of 3.3% at the last national schistosomiasis survey conducted between 2010 and 2015. Moran's statistics showed 22/70 municipalities forming a Q1 cluster, of high/high pattern, and 32/70 municipalities forming a Q2 cluster, of low/low pattern, with the others in a transition area. Moran Map data, however, showed only 7/70 municipalities in the endemic area with a spatial autocorrelation, with these municipalities having the Mundau River as a common element. Schistosomiasis mansoni is of great importance for public health in Alagoas and that the use of spatial analysis can identify priority areas for preventive and control measures against schistosomiasis mansoni.

Schistosoma mansoni

Schistosoma mansoni is the causative agent of intestinal schistosomiasis and infects ~54 million people annually, causing significant mortality and morbidity. This parasitic trematode is endemic in sub-Saharan Africa and the Middle East, and colonized South America during the transatlantic slave trade. Parasites transition between five distinctive body plans, with asexual proliferation in the snail host and sexual proliferation in the vertebrate host, and motile free-living stages. Transmission results from contact with water containing infected Biomphalaria spp. snails. Infection prevalence and intensity peaks in school-age children; both reduced water contact and acquired immunity reduces infection in adults. Pathology in the human host results from granulomas that form around eggs trapped in the liver and gut. There is no effective vaccine available: treatment of infected patients with praziquantel is the mainstay of control efforts.

Dinâmica espaço-temporal da Esquistossomose Mansônica em Alagoas (2007-2017)

A esquistossomose é uma doença parasitária frequente nos países tropicais e subtropicais. Objetivo da pesquisa foi analisar a dinâmica espaço-temporal da esquistossomose mansônica no estado de Alagoas, entre os anos de 2007 a 2017. Trata-se de um estudo ecológico misto, com o tratamento estatístico realizado em três etapas: modelagem temporal; análise descritiva simples (frequências absolutas e relativas); modelagem espacial. Foram notificados 827 casos novos de esquistossomose mansônica em Alagoas, com taxa de incidência de 2,37/100 mil habitantes. Ao longo da série temporal, o modelo de regressão mostrou dois comportamentos distintos, sendo o primeiro de declínio entre 2007 e 2012, cuja taxa de incidência decresceu de 5,75/100 mil para 0,88/100 mil (APC-29,78%; p&lt;0,001), e o segundo estacionário a partir de 2012. O perfil epidemiológico foi caracterizado pelo acometimento da população adulta em idade produtiva, uma vez que 60,58% (n=501) possuíam idade entre 20 e 59 anos, seguida da população com menos de 15 anos (15,24; n=126). Adicionalmente, 63,12%(n=522) eram da raça parda e 49,58% (n=410) autóctones. A taxa de cura observada foi de apenas (35,43%; n=293) e a letalidade 8,34% (n=69). Desta forma, esquistossomose no estado de Alagoas apresenta um elevado registro de municípios com alta taxa de incidência para a doença; quantidade considerável de municípios em que a população não foi trabalhada no período, permitindo que ocorra ausência e/ou subnotificação de dados importantes sobre a doença; e o estado exibe uma alta endemicidade, tendo em vista que doze municípios excederem o percentual estadual.

Future schistosome hybridizations: Will all Schistosoma haematobium hybrids please stand-up!

nterrogating the genetic make-up of schistosome larvae (i.e. eggs, miracidia and cercariae) originating from definitive or intermediate snail hosts with molecular DNA methods has, by noting unexpected inter-species hybrids, started a revolution in our appraisal of African schistosomiasis [1-4]. Here, two dominant species of human schistosome exist, Schistosoma haematobium and S. mansoni, which are transmitted by specific intermediate freshwater snails, Bulinus spp. for the former and Biomphalaria spp. for the latter. The two schistosomes cause either urogenital or intestinal schistosomiasis, respectively [5] and depending on local snail distributions, schistosome transmission zones in the aquatic habitat may or may not overlap [6]. Within the S. haematobium group, a further 8 sister species are described with S. intercalatum and S. guineensis of medical importance, causing intestinal schistosomiasis while others, such as S. bovis, S. curassoni and S. mattheei occur in livestock, with the remaining species infecting wildlife. Schistosoma mattheei is also of medical interest for occasional infection and associated disease [7]. In contrast, S. mansoni has a single sister species, S. rodhaini, typically found in small rodents which can hybridise with S. mansoni, if given sufficient opportunity [2].