From field to laboratory: isolation, genetic assessment, and parasitological behavior of Schistosoma mansoni obtained from naturally infected wild rodent Holochilus sciureus (Rodentia, Cricetidae), collected in Northeastern Brazil.

Wild rodent species are naturally infected by Schistosoma mansoni; however, the genetic characterization of the parasite, its parasitological features, and its role in human schistosomiasis are poorly understood. In this study, we isolated and characterized Schistosoma from naturally infected Holochilus sciureus, called HS strain, collected from a schistosomiasis endemic region in Maranhão State, Brazil. To isolate the parasite, miracidia obtained from the livers of H. sciureus were used to infect Biomphalaria glabrata of sympatric (called SB) and allopatric (called BH) strains, and the produced cercariae were subcutaneously inoculated into hamsters and/or BALB/c mice. Parasitological kinetics in experimentally infected hosts were evaluated, and the tRNACys-12S (referred to as 16S herein) and cox 1 regions of mtDNA from isolated worms were amplified and sequenced. Only miracidia obtained from infected mice, but not from hamsters, were capable of infecting B. glabrata, allowing maintenance of the isolated parasite. Cox1 and 16S mtDNA sequences showed 100% similarity with S. mansoni, and phylogenetic analysis showed that the HS strain of S. mansoni forms an assemblage with isolates from America and Kenya, confirming the conspecificity. Experimental infection of B. glabrata SB with S. mansoni HS resulted in two peaks of cercariae shedding at 45 and 70 days post-infection (dpi) and caused higher mortality than in B. glabrata BH. The worm recovery rate in mice was approximately 13%, and the peak of egg elimination occurred at the 10th week post-infection. Therefore, S. mansoni obtained from H. sciureus was successfully isolated, genetically characterized, and maintained in mice, allowing further study of this schistosome strain.

Alterations in blood glucose concentration in wild rodents, Holochilus sciureus, naturally infected with Schistosoma mansoni.

The present study aimed to evaluate the changes in peripheral blood glucose concentrations induced by Schistosoma mansoni infection in Holochilus sciureus rodents, a wild reservoir of the parasite. Glucose concentration was measured in the plasma of blood samples using a colorimetric enzymatic test. Biological parameters and S. mansoni burden in each rodent were also verified and correlated with glucose concentrations. A total of 76 H. sciureus were captured, out of which 20 (26%) were infected with S. mansoni (n=13 males and n=7 females). Although the parasite burden was comparable between the sexes, blood glucose concentration was lower in infected males and almost unchanged in females. Furthermore, histopathological data revealed that male rodents had a greater hepatic granulomatous inflammatory reaction than females. In addition, we also confirmed that the weight and total length of the analyzed animals had no effect on glucose levels. Therefore, natural infection with S. mansoni in H. sciureus may have a lower impact on glycemic homeostasis in females, which will help us understand the role of these rodents as reservoirs of S. mansoni.

Alterations in blood glucose concentration in wild rodents, Holochilus sciureus, naturally infected with Schistosoma mansoni / Alterações na concentração de glicose do sangue periférico de roedores silvestres, Holochilus sciureus, naturalmente infectados com Schistosoma mansoni

The present study aimed to evaluate the changes in peripheral blood glucose concentrations induced by Schistosoma mansoni infection in Holochilus sciureus rodents, a wild reservoir of the parasite. Glucose concentration was measured in the plasma of blood samples using a colorimetric enzymatic test. Biological parameters and S. mansoni burden in each rodent were also verified and correlated with glucose concentrations. A total of 76 H. sciureus were captured, out of which 20 (26%) were infected with S. mansoni (n=13 males and n=7 females). Although the parasite burden was comparable between the sexes, blood glucose concentration was lower in infected males and almost unchanged in females. Furthermore, histopathological data revealed that male rodents had a greater hepatic granulomatous inflammatory reaction than females. In addition, we also confirmed that the weight and total length of the analyzed animals had no effect on glucose levels. Therefore, natural infection with S. mansoni in H. sciureus may have a lower impact on glycemic homeostasis in females, which will help us understand the role of these rodents as reservoirs of S. mansoni.(AU)

Neste presente estudo, objetivou-se avaliar as alterações induzidas pela infecção natural de Schistosoma mansoni nas concentrações de glicose do sangue periférico de roedores Holochilus sciureus, reservatório silvestre do parasito. A dosagem da concentração de glicose foi realizada no plasma de amostras de sangue por meio de teste enzimático colorimétrico. Parâmetros biológicos e carga parasitária de S. mansoni também foram verificados em cada roedor e correlacionados com as concentrações de glicose. Um total de 76 H. sciureus foram capturados, dentre os quais 20 (26%) estavam infectados por S. mansoni (n=13 machos e n=7 fêmeas). Apesar da carga parasitária ter sido semelhante entre os sexos, as concentrações de glicose no sangue foram menores em machos naturalmente infectados e quase inalteradas em fêmeas. Além disso, os dados histopatológicos mostraram uma maior reação inflamatória granulomatosa hepática em roedores machos, quando comparados com as fêmeas. Adicionalmente, também foi confirmado que o peso e o comprimento total dos animas analisados não interferiram nos valores de glicose. Portanto, a infecção natural por S. mansoni em H. sciureus pode induzir menos impacto na homeostase glicêmica em fêmeas, o que pode ajudar a melhor entender o papel desses roedores como reservatórios de S. mansoni.(AU)

A preliminary study on the distribution of breeding sites of BIOMPHALARIA GLABRATA in the municipality of peri mirim, a low endemicity area for schistosomiasis in northeast Brazil

Information on areas colonized by snails that transmit Schistosoma mansoni is essential for planning schistosomiasis control measures. Therefore, the purpose of this study was to map the natural breeding sites of Biomphalaria spp. in the municipality of Peri Mirim, Maranhão, Brazil. The snails were manually collected and the breeding sites were geo-referenced (seven in the urban area and five in flooded fields), from November 2017 to March 2018. In the laboratory, the snails were examined for the presence of larval stages of S. mansoni identified by morphology and internal anatomy analysis. While no snails were found in the urban area, sixteen B. glabrata were collected in the flooded fields. No S. mansoni or other trematode infections were detected. Wild rodents, most likely Holochilus sciureus that could act as S. mansoni reservoirs, were also found in the flooded fields. These data indicate possible risk areas for further outbreaks of schistosomiasis transmission in the municipality of Peri Mirim.

Antiparasitic effects of ethanolic extracts of Piper arboreum and Jatropha gossypiifolia leaves on cercariae and adult worms of Schistosoma mansoni.

New treatment strategies for schistosomiasis should be evaluated, since resistant strains to the only available drug, Praziquantel, have already been described. Thus, we demonstrated antiparasitic effects of ethanolic extracts of Jatropha gossypiifolia and Piper arboreum on cercariae and adult worms of Schistosoma mansoni. The bioassays were performed at 0-10 000 µg mL-1 concentration for 0-72 h. Adult worms were stained with carmine to assess external and internal damage. The chemical screening was performed using high-performance liquid chromatography. P. arboreum displayed the best cercaricidal effect, with a 100% reduction in viability in just 60 min. The extract of J. gossypiifolia was more effective against adult worms, with 100% viability reduction of male and female worms after 12 and 24 h, respectively. P. arboreum and J. gossypiifolia were equally effective in inhibiting the oviposition of S. mansoni (93% reduction) and causing damage to internal and external structures in adult worms. Flavonoids were identified in both the extracts and phenolic compounds and amides only in P. arboreum. Thus, for the first time, it was proven that ethanolic extracts of P. arboreum and J. gossypiifolia leaves are biologically active against cercariae and adult worms of S. mansoni in vitro.

Hydroalcoholic extract of Caryocar brasiliense Cambess. leaves affect the development of Aedes aegypti mosquitoes.

INTRODUCTION: Curtailing the development of the aquatic immature stages of Aedes aegypti is one of the main measures to limit their spread and the diseases transmitted by them. The use of plant extracts is a promising approach in the development of natural insecticides. Thus, this research aimed to characterize the inhibitory effect of the hydroalcoholic extract of Caryocar brasiliense leaves on the emergence of adult A. aegypti and the main substances that constitute this extract. METHODS: C. brasiliense leaf extract was prepared by ethanol (70%) extraction. Bioassays using L3 larvae were performed at concentrations of 200, 300, 400, and 500 ppm. We identified the major secondary metabolites present in this extract, and performed toxicity tests on an off-target organism, Danio rerio. RESULTS: We observed a significant delay in the development of A. aegypti larvae mainly at a concentration of 500 ppm, and estimated an emergence inhibition for 50% of the population of 150 ppm. Moreover, the C. brasiliense leaf extracts exhibited low toxicity in D. rerio. The main compounds found in the extract were quercetin, violaxanthin, myricetin3-O-hexoside, methyl-elagic-3-arabinose acid, and isoquercitrin. CONCLUSIONS: Herein, we demonstrate the inhibition of mosquito development by the hydroalcoholic extract of C. brasiliense and suggest substances that may act as active principles.

Effectiveness of a handmade shell-based substrate for the breeding of Biomphalaria glabrata under laboratory conditions.

Efficient snail production is essential for the proper maintenance of the Schistosoma mansoni life cycle in the laboratory. In order to improve the breeding of Biomphalaria glabrata under laboratory conditions, this study aimed to demonstrate the effectiveness of a handmade shell-based substrate on the physiological performance of B. glabrata. The shells used to make the substrate were cleaned, sterilized and macerated until a powder was obtained (yield of 92.3%). B. glabrata specimens were randomly assigned to three treatment groups: negative control group (NCG) exposed to a clay-only substrate; a positive control group (PCG) containing clay, oyster flour and calcium carbonate; and the test group (TG) with the shell-based substrate and clay. B. glabrata bred in the test group showed improved growth, sexual maturity, fertility, mortality rate, and shell morphology when compared to the NCG, and similar to the PCG. Therefore, the shell-based substrate proved to be efficient and has a low cost for the breeding of B. glabrata.

Community Perceptions on Schistosomiasis in Northeast Brazil.

Schistosomiasis is a serious public health issue in the world infecting more than 200 million people. In Maranhão state, Brazil, the disease has a high prevalence in the Baixada Maranhense microregion, where the socioeconomic conditions, high prevalence of freshwater snails, elevated incidence of human infection, and large rodent populations make the area highly conducive to the life cycle and persistence of schistosomiasis. The objective of this study was to record the perception of residents and health/public education professionals regarding this parasitosis and also understand their knowledge of the relationship between schistosomiasis and the environment. We conducted 53 interviews addressing the socioeconomic, behavioral, and environmental issues surrounding schistosomiasis. It was recorded that the population believed the environment is the main cause of the disease and the fisherman may be stigmatized by their chance of having the disease. Health/public educational professionals in the region indicated that there were no regular educational campaigns, which contributed to the high rates of reinfection and the difficulties in preventing and controlling the spread of the disease. These data clearly demonstrate the need for interdisciplinary work that engages the community in gathering and disseminating knowledge and developing solutions to minimize the occurrence of this major health issue in the region.

Hydroalcoholic extract of Caryocar brasiliense Cambess. leaves affect the development of Aedes aegypti mosquitoes

Abstract INTRODUCTION: Curtailing the development of the aquatic immature stages of Aedes aegypti is one of the main measures to limit their spread and the diseases transmitted by them. The use of plant extracts is a promising approach in the development of natural insecticides. Thus, this research aimed to characterize the inhibitory effect of the hydroalcoholic extract of Caryocar brasiliense leaves on the emergence of adult A. aegypti and the main substances that constitute this extract. METHODS: C. brasiliense leaf extract was prepared by ethanol (70%) extraction. Bioassays using L3 larvae were performed at concentrations of 200, 300, 400, and 500 ppm. We identified the major secondary metabolites present in this extract, and performed toxicity tests on an off-target organism, Danio rerio. RESULTS: We observed a significant delay in the development of A. aegypti larvae mainly at a concentration of 500 ppm, and estimated an emergence inhibition for 50% of the population of 150 ppm. Moreover, the C. brasiliense leaf extracts exhibited low toxicity in D. rerio. The main compounds found in the extract were quercetin, violaxanthin, myricetin3-O-hexoside, methyl-elagic-3-arabinose acid, and isoquercitrin. CONCLUSIONS: Herein, we demonstrate the inhibition of mosquito development by the hydroalcoholic extract of C. brasiliense and suggest substances that may act as active principles.

Parasitological and histological aspects of Holochilus sciureus naturally infected by Schistosoma mansoni / Aspectos parasitológicos e histológicos de Holochilus sciureus naturalmente infectados por Schistosoma mansoni

Abstract Schistosomiasis is a neglected disease that affects millions of people around the world, being common in the state of Maranhão. A total of 225 rodents of the Holochilus sciureus species from the Western Lowland Maranhão were studied, of which 144 animals (64%) exhibited Schistosoma eggs in their feces samples. Macroscopic lesions characterized as well-defined whitish areas on the liver and spleen surfaces were observed. Histopathological examination revealed multifocal granulomas in the esophagus, liver, spleen, pancreas and duodenum, with structures compatible with Schistosoma mansoni eggs, as well as severe hepatic micro-vacuolar degeneration, multifocal and coalescent, with proliferation of random bile ducts and associated epithelial hyperplasia to areas of fibrosis. Adult forms of the parasite were observed in the blood vessels of the portal space. The lungs exhibited moderate and diffuse interstitial pneumonia with intralesional S. mansoni eggs. In the kidneys, hyaline cylinders were observed in the pelvis and diffuse hemorrhage. In conclusion, H. sciureus displays a pathological picture similar to human being. This rodent plays a role as sentinel in Baixada Maranhense.

Resumo A esquistossomose é uma doença negligenciada que afeta milhões de pessoas em todo o mundo, sendo comum no estado do Maranhão. Um total de 225 roedores da espécie Holochilus sciureus da Planície Ocidental do Maranhão foram estudados, dos quais 144 animais (64%) apresentaram ovos de Schistosoma em suas fezes. Lesões macroscópicas caracterizadas como áreas esbranquiçadas bem definidas nas superfícies do fígado e baço foram observadas. O exame histopatológico revelou granulomas multifocais no esôfago, fígado, baço, pâncreas e duodeno, com estruturas compatíveis com ovos de Schistosoma mansoni, degeneração micro-vacuolar hepática grave, multifocal e coalescente, com proliferação de ductos biliares aleatórios e hiperplasia epitelial associada a áreas de fibrose. Formas adultas do parasito foram observadas nos vasos sanguíneos do espaço portal. Os pulmões exibiram pneumonia intersticial moderada e difusa com ovos de S. mansoni intralesionais. Nos rins, foram observados cilindros hialinos na pelve e hemorragia difusa. Em conclusão, H. sciureus apresenta um quadro patológico semelhante ao ser humano. Este roedor desempenha um papel de sentinela na Baixada Maranhense.

Parasitological and histological aspects of Holochilus sciureus naturally infected by Schistosoma mansoni.

Schistosomiasis is a neglected disease that affects millions of people around the world, being common in the state of Maranhão. A total of 225 rodents of the Holochilus sciureus species from the Western Lowland Maranhão were studied, of which 144 animals (64%) exhibited Schistosoma eggs in their feces samples. Macroscopic lesions characterized as well-defined whitish areas on the liver and spleen surfaces were observed. Histopathological examination revealed multifocal granulomas in the esophagus, liver, spleen, pancreas and duodenum, with structures compatible with Schistosoma mansoni eggs, as well as severe hepatic micro-vacuolar degeneration, multifocal and coalescent, with proliferation of random bile ducts and associated epithelial hyperplasia to areas of fibrosis. Adult forms of the parasite were observed in the blood vessels of the portal space. The lungs exhibited moderate and diffuse interstitial pneumonia with intralesional S. mansoni eggs. In the kidneys, hyaline cylinders were observed in the pelvis and diffuse hemorrhage. In conclusion, H. sciureus displays a pathological picture similar to human being. This rodent plays a role as sentinel in Baixada Maranhense.

Spatial and Seasonal Distribution of Holochilus sciureus with Schistosoma mansoni Infection in an Endemic Area for Schistosomiasis in Brazil.

INTRODUCTION: The occurrence of wild rodents in the Schistosoma mansoni life cycle may increase the transmission of schistosomiasis and understanding the spatial and seasonal distribution of the natural infection of these reservoirs is essential for the development of more effective control strategies. MATERIAL AND METHODS: In this study, Holochilus sciureus rodents were captured from the flooded fields of São Bento city (an endemic area for schistosomiasis in Northeast Brazil), during the dry and rainy seasons. All these sites were georeferenced and the prevalence of S. mansoni was verified by the presence of adult worms in the mesenteric branches and livers of each animal. RESULTS: It was demonstrated that almost half of the animals collected were naturally infected with S. mansoni (45.45%) and this infection was not related to the distance from urban areas. Furthermore, the temperature, precipitation, sex, and weight did not interfere with the H. sciureus infection rates. Interestingly, we found, for the first time, the natural infection of H. sciureus in another endemic city of S. mansoni in Northeast Brazil. CONCLUSIONS: Therefore, the H. sciureus rodent shows a high natural infection rate for S. mansoni in the flooded fields of São Bento, regardless of the weather station, capture distance, and biological aspects. Additionally, we have demonstrated that H. sciureus naturally parasitized with S. mansoni may inhabit a much more extensive area that is currently described in the literature.

Parasitological and histological aspects of Holochilus sciureus naturally infected by Schistosoma mansoni / Aspectos parasitológicos e histológicos de Holochilus sciureus naturalmente infectados por Schistosoma mansoni

Schistosomiasis is a neglected disease that affects millions of people around the world, being common in the state of Maranhão. A total of 225 rodents of the Holochilus sciureus species from the Western Lowland Maranhão were studied, of which 144 animals (64%) exhibited Schistosoma eggs in their feces samples. Macroscopic lesions characterized as well-defined whitish areas on the liver and spleen surfaces were observed. Histopathological examination revealed multifocal granulomas in the esophagus, liver, spleen, pancreas and duodenum, with structures compatible with Schistosoma mansoni eggs, as well as severe hepatic micro-vacuolar degeneration, multifocal and coalescent, with proliferation of random bile ducts and associated epithelial hyperplasia to areas of fibrosis. Adult forms of the parasite were observed in the blood vessels of the portal space. The lungs exhibited moderate and diffuse interstitial pneumonia with intralesional S. mansoni eggs. In the kidneys, hyaline cylinders were observed in the pelvis and diffuse hemorrhage. In conclusion, H. sciureus displays a pathological picture similar to human being. This rodent plays a role as sentinel in Baixada Maranhense.(AU)

A esquistossomose é uma doença negligenciada que afeta milhões de pessoas em todo o mundo, sendo comum no estado do Maranhão. Um total de 225 roedores da espécie Holochilus sciureus da Planície Ocidental do Maranhão foram estudados, dos quais 144 animais (64%) apresentaram ovos de Schistosoma em suas fezes. Lesões macroscópicas caracterizadas como áreas esbranquiçadas bem definidas nas superfícies do fígado e baço foram observadas. O exame histopatológico revelou granulomas multifocais no esôfago, fígado, baço, pâncreas e duodeno, com estruturas compatíveis com ovos de Schistosoma mansoni, degeneração micro-vacuolar hepática grave, multifocal e coalescente, com proliferação de ductos biliares aleatórios e hiperplasia epitelial associada a áreas de fibrose. Formas adultas do parasito foram observadas nos vasos sanguíneos do espaço portal. Os pulmões exibiram pneumonia intersticial moderada e difusa com ovos de S. mansoni intralesionais. Nos rins, foram observados cilindros hialinos na pelve e hemorragia difusa. Em conclusão, H. sciureus apresenta um quadro patológico semelhante ao ser humano. Este roedor desempenha um papel de sentinela na Baixada Maranhense.(AU)

Spatial distribution and seasonality of Biomphalaria spp. in São Luís (Maranhão, Brazil).

Two of the three vector species of Schistosoma mansoni Sambon, 1907 in Brazil occur in the state of Maranhão: Biomphalaria glabrata (Say, 1818) and Biomphalaria straminea (Dunker, 1848). For the implementation of effective measures to combat schistosomiasis, it is necessary to identify the spatial and seasonal dynamics of these snails. Therefore, this work brought together information from malacological survey carried out in São Luís (Maranhão, Brazil) to identify the spatial and seasonal distribution patterns of Biomphalaria spp. snails. We used data from malacological surveys of the Municipal Health Secretary of São Luís, conducted between 2006 and 2013 in 23 neighborhoods. We also used data from the mollusk surveys that we conducted for 2 years (2012-2014) in four of these neighborhoods. During the 8-year period (2006-2013), 15,990 specimens of Biomphalaria spp. were collected. There was a positive association between precipitation and the abundance of mollusks of the genus Biomphalaria. During 2012-2014, a total of 2487 snail specimens were obtained (B. glabrata: 1046 specimens; B. straminea: 1426 specimens). There was a positive correlation between precipitation and B. straminea abundance. High density of human occupation and high precipitation are two factors that affect the distribution and density of Biomphalaria spp.

Molluscicidal effect of Euphorbia umbellata (Pax) Bruyns latex on Biomphalaria glabrata, Schistosoma mansoni host snail.

Euphorbia umbellata (Pax) Bruyns is an easily cultivated shrub, with occurrence in the tropical regions of the American and African continents. Chemical studies have revealed that the latex of this plant is rich in terpene compounds, which are highly toxic to snails Biomphalaria glabrata (Basommatophora: Planorbidae). The aim of this study was to evaluate the chemical composition and molluscicidal activity of the latex produced by E. umbellata, as well as the safety of its application in aquatic environments. The concentration of latex that killed 90% of the exposed snails after 24 h exposure (LC90) was 3.69 mg/L. Toxicity bioassays using Danio rerio (zebrafish) revealed that these animals were less susceptible to latex than planorbids. However, it is important to perform other toxicity tests to ensure the feasibility of using latex to control populations of mollusks that contribute to schistosomiasis transmission. A phytochemical screening performed with the E. umbellata latex identified the triterpenoid and coumarin class. Further studies are warranted to isolate, identify, and test the active compounds of E. umbellata latex in B. glabrata.

Distribuição dos moluscos transmissores da esquistossomose no município endêmico de São Bento, Maranhão, Brasil / Distribution of mollusks that transmit schistosomiasis in the endemic municipality of São Bento, Maranhão, Brazil

Neste estudo, objetivou-se mapear os criadouros de Biomphalaria spp., transmissoras da esquistossomose mansoni, presentes no município de São Bento, localizado na região da Baixada Maranhense, área na qual esta doença é endêmica. Foram visitados 16 dos 22 bairros existentes na cidade durante o período de agosto de 2012 a julho de 2013. Os caramujos foram coletados com auxílio de conchas de captura e pinças, armazenados e transportados para o Laboratório de Parasitologia Humana da Universidade Estadual do Maranhão, em São Luís, onde foram acondicionados em aquários de vidro e alimentados com folhas de alface. Os moluscos foram submetidos à análise parasitológica à procura de estágios larvais de Schistosoma mansoni e identificados pela conquiliologia e por meio de dissecções. Em 18 criadouros mapeados foram obtidos 1.195 exemplares de Biomphalaria glabrata e de B. straminea. Nenhum molusco eliminou cercárias de S. mansoni. Considerando os resultados obtidos e os aspectos epidemiológicos relacionados à transmissão da esquistossomose, o mapeamento das espécies vetoras no município permitirá a localização e identificação dos criadouros, o que poderá auxiliar substancialmente os serviços de saúde locais nas atividades de vigilância e controle da esquistossomose, além de nortear futuros estudos epidemiológicos sobre a esquistossomose mansoni na região da Baixada Maranhense

Biological aspects of rodent Holochilus sp., natural host of schistosomiasis / Aspectos biológicos de Holochilus sp., hospedeiro natural da esquistossomose

In the present study, we aimed to analyze the reproductive aspects (seasonal period and number of embryos) and positivity for S. mansoni in rodent of Holochilus gender, in São Bento - MA. For this, monthly captures of up to 10 Holochilus sp. rodents were conducted, randomly for sex, taking notes of the seasonal period of São Bento in each month of capture. At the laboratory, rodents had feces analyzed for S. mansoni infection by Kato-Katz method. After the analysis, they were adequately anesthetized for obtaining full length, weight and sex determination. In females, an incision of the ventral portion of the body was carried out to verify the presence of embryos and to count them. Among the captured rodents, there was male dominance in almost all months and they tended to be heavier and had larger bodies than the females. The animals showed high reproductive potential. The positivity for S. mansoni and the reproduction of Holochilus sp. were greater in the rainy season of São Bento. As for the number of embryos, we observed that, in the rainy season, more males were found than female. In short, the intense reproductive activity, along the susceptibility to S. mansoni presented by rodents are factors that help to maintain and aggravate schistosomiasis in Baixada Maranhense

Neste estudo objetivou-se analisar os aspectos reprodutivos (período estacional e quantidade de embriões) e a positividade para S. mansoni em roedores do gênero Holochilus, no município de São Bento MA. Para isso, foram realizadas capturas mensais de até 10 roedores Holochilus sp., aleatoriamente quanto ao sexo, anotando-se o período estacional do município de São Bento nos meses de captura. Em laboratório, os roedores tiveram as fezes analisadas quanto à positividade para S. mansoni pelo método Kato-Katz. Após a análise, os animais foram anestesiados para a obtenção do comprimento total, peso corporal e determinação do sexo. Nas fêmeas, foi realizada a incisão da porção ventral do corpo, para a verificação da presença de embriões e contagem dos mesmos. Dentre os roedores capturados, ocorreu dominância de machos em quase todos os meses e eles tenderam a ser mais pesados e apresentaram maior porte que as fêmeas. Os animais mostraram elevado potencial reprodutivo. A positividade para S. mansoni e a reprodução dos Holochilus sp. foram maiores no período chuvoso de São Bento. Quanto ao número de embriões, constatou-se que, no período chuvoso, foram encontrados em maior quantidade por fêmea. Em suma, a intensa atividade reprodutiva juntamente à suscetibilidade para S. mansoni apresentada pelos roedores são fatores que ajudam na manutenção e agravam a esquistossomose na Baixada Maranhense

ASPECTOS BIOLÓGICOS DE Holochilus sp., HOSPEDEIRO NATURAL DA ESQUISTOSSOMOSE

Abstract In the present study, we aimed to analyze the reproductive aspects (seasonal period and number of embryos) and positivity for S. mansoni in rodent of Holochilus gender, in São Bento - MA. For this, monthly captures of up to 10 Holochilus sp. rodents were conducted, randomly for sex, taking notes of the seasonal period of São Bento in each month of capture. At the laboratory, rodents had feces analyzed for S. mansoni infection by Kato-Katz method. After the analysis, they were adequately anesthetized for obtaining full length, weight and sex determination. In females, an incision of the ventral portion of the body was carried out to verify the presence of embryos and to count them. Among the captured rodents, there was male dominance in almost all months and they tended to be heavier and had larger bodies than the females. The animals showed high reproductive potential. The positivity for S. mansoni and the reproduction of Holochilus sp. were greater in the rainy season of São Bento. As for the number of embryos, we observed that, in the rainy season, more males were found than female. In short, the intense reproductive activity, along the susceptibility to S. mansoni presented by rodents are factors that help to maintain and aggravate schistosomiasis in Baixada Maranhense.

Resumo Neste estudo objetivou-se analisar os aspectos reprodutivos (período estacional e quantidade de embriões) e a positividade para S. mansoni em roedores do gênero Holochilus, no município de São Bento - MA. Para isso, foram realizadas capturas mensais de até 10 roedores Holochilus sp., aleatoriamente quanto ao sexo, anotando-se o período estacional do município de São Bento nos meses de captura. Em laboratório, os roedores tiveram as fezes analisadas quanto à positividade para S. mansoni pelo método Kato-Katz. Após a análise, os animais foram anestesiados para a obtenção do comprimento total, peso corporal e determinação do sexo. Nas fêmeas, foi realizada a incisão da porção ventral do corpo, para a verificação da presença de embriões e contagem dos mesmos. Dentre os roedores capturados, ocorreu dominância de machos em quase todos os meses e eles tenderam a ser mais pesados e apresentaram maior porte que as fêmeas. Os animais mostraram elevado potencial reprodutivo. A positividade para S. mansoni e a reprodução dos Holochilus sp. foram maiores no período chuvoso de São Bento. Quanto ao número de embriões, constatou-se que, no período chuvoso, foram encontrados em maior quantidade por fêmea. Em suma, a intensa atividade reprodutiva juntamente à suscetibilidade para S. mansoni apresentada pelos roedores são fatores que ajudam na manutenção e agravam a esquistossomose na Baixada Maranhense.

Biological aspects of rodent Holochilus sp., natural host of schistosomiasis / Aspectos biológicos de Holochilus sp., hospedeiro natural da esquistossomose

In the present study, we aimed to analyze the reproductive aspects (seasonal period and number of embryos) and positivity for S. mansoni in rodent of Holochilus gender, in São Bento - MA. For this, monthly captures of up to 10 Holochilus sp. rodents were conducted, randomly for sex, taking notes of the seasonal period of São Bento in each month of capture. At the laboratory, rodents had feces analyzed for S. mansoni infection by Kato-Katz method. After the analysis, they were adequately anesthetized for obtaining full length, weight and sex determination. In females, an incision of the ventral portion of the body was carried out to verify the presence of embryos and to count them. Among the captured rodents, there was male dominance in almost all months and they tended to be heavier and had larger bodies than the females. The animals showed high reproductive potential. The positivity for S. mansoni and the reproduction of Holochilus sp. were greater in the rainy season of São Bento. As for the number of embryos, we observed that, in the rainy season, more males were found than female. In short, the intense reproductive activity, along the susceptibility to S. mansoni presented by rodents are factors that help to maintain and aggravate schistosomiasis in Baixada Maranhense(AU)

Neste estudo objetivou-se analisar os aspectos reprodutivos (período estacional e quantidade de embriões) e a positividade para S. mansoni em roedores do gênero Holochilus, no município de São Bento MA. Para isso, foram realizadas capturas mensais de até 10 roedores Holochilus sp., aleatoriamente quanto ao sexo, anotando-se o período estacional do município de São Bento nos meses de captura. Em laboratório, os roedores tiveram as fezes analisadas quanto à positividade para S. mansoni pelo método Kato-Katz. Após a análise, os animais foram anestesiados para a obtenção do comprimento total, peso corporal e determinação do sexo. Nas fêmeas, foi realizada a incisão da porção ventral do corpo, para a verificação da presença de embriões e contagem dos mesmos. Dentre os roedores capturados, ocorreu dominância de machos em quase todos os meses e eles tenderam a ser mais pesados e apresentaram maior porte que as fêmeas. Os animais mostraram elevado potencial reprodutivo. A positividade para S. mansoni e a reprodução dos Holochilus sp. foram maiores no período chuvoso de São Bento. Quanto ao número de embriões, constatou-se que, no período chuvoso, foram encontrados em maior quantidade por fêmea. Em suma, a intensa atividade reprodutiva juntamente à suscetibilidade para S. mansoni apresentada pelos roedores são fatores que ajudam na manutenção e agravam a esquistossomose na Baixada Maranhense(AU)

Monitoramento de positividade para Schistosoma mansoni em roedores Holochilus sp. naturalmente infectados / Monitoring positivity for Schistosoma mansoni in rodents Holochilus sp. naturally infected

The occurrence of non-human mammals such as schistosomiasis reservoir has always been an aggravating factor to be studied. Family cricetidae rodents like Nectomys sp, seem to have an important role in the potentiation of the spread of it. However, for Holochilus sp. (Rodentia: Cricetidae), found in Maranhão, studies with this function seem scarce. Thereby, we aimmed to analyze the infection rate of these animals for S. mansoni in São Bento MA, endemic area for the parasite. These rodents were monitored during 12 months, by the Tomahawk traps for caught and triplicates of stool tests blades, made by KatoKatz kit, for parasitogical exam. A total of 101 rodents were captured, of which 28.7% were naturally infected by S. mansoni (17.3% females and 82.7% males). This analysis showed that an average of 2.4 rodents was infected for one year, being possible to find positive animals in almost all the collects. Therefore, the rodent Holochilus sp. is a potential candidate in ensuring the maintenance of the schistosomiasis cycle in the region under study.

A ocorrência de mamíferos não humanos como reservatório da esquistossomose sempre foi um fator agravante a ser estudado. Roedores da família dos cricetídeos, como o Nectomys sp, parecem  desempenhar importante papel na potencialização da disseminação da mesma. No entanto, para Holochilus sp (Rodentia: Cricetidae), encontrado no  Maranhão, estudos com essa finalidade parecem pouco elucidativos. Desse modo, objetivou-se analisar o índice de infecção desses animais por S. mansoni na cidade de São Bento MA, área endêmica para o parasito. Para tanto, foi realizado um monitoramento desses roedores durante 12 meses, através de armadilhas do tipo Tomahawk para captura e triplicatas de lâminas cropológicas, confeccionadas por meio do kit Kato-Katz, para exame parasitológico. Foram contabilizados um total de 101 roedores, sendo que 28,7% apresentaram- se naturalmente infectados para S. mansoni, (17,3% fêmeas e 82,7% machos).  Tal análise evidenciou que, por mês, uma média de 2,4 roedores estavam infectados para o período de um ano. Sendo possível encontrar animais positivos em quase todas as coletas. Portanto, o roedor Holochilus sp. é um possível candidato à manutenção do ciclo da esquistossomose na região em estudo.