RESUMEN
OBJECTIVE: Diagnose risk environments for schistosomiasis in coastal localities of Pernambuco using geoprocessing techniques. METHODS: A coproscopic and malacological survey were carried out in the Forte Orange and Serrambi areas. Environmental variables (temperature, salinity, pH, total dissolved solids and water fecal coliform dosage) were collected from Biomphalaria breeding sites or foci. The spatial analysis was performed using ArcGis 10.1 software, applying the kernel estimator, elevation map, and distance map. RESULTS: In Forte Orange, 4.3% of the population had S. mansoni and were found two B. glabrata and 26 B. straminea breeding sites. The breeding sites had temperatures of 25ºC to 41ºC, pH of 6.9 to 11.1, total dissolved solids between 148 and 661, and salinity of 1,000 d. In Serrambi, 4.4% of the population had S. mansoni and were found seven B. straminea and seven B. glabrata breeding sites. Breeding sites had temperatures of 24ºC to 36ºC, pH of 7.1 to 9.8, total dissolved solids between 116 and 855, and salinity of 1,000 d. The kernel estimator shows the clusters of positive patients and foci of Biomphalaria, and the digital elevation map indicates areas of rainwater concentration. The distance map shows the proximity of the snail foci with schools and health facilities. CONCLUSIONS: Geoprocessing techniques prove to be a competent tool for locating and scaling the risk areas for schistosomiasis, and can subsidize the health services control actions.
Asunto(s)
Biomphalaria/crecimiento & desarrollo , Monitoreo del Ambiente , Sistemas de Información Geográfica , Esquistosomiasis mansoni/transmisión , Animales , Biomphalaria/parasitología , Brasil/epidemiología , Reservorios de Enfermedades , Humanos , Factores de Riesgo , Esquistosomiasis mansoni/epidemiología , Análisis Espacial , Temperatura , Factores de TiempoRESUMEN
ABSTRACT OBJECTIVE Diagnose risk environments for schistosomiasis in coastal localities of Pernambuco using geoprocessing techniques. METHODS A coproscopic and malacological survey were carried out in the Forte Orange and Serrambi areas. Environmental variables (temperature, salinity, pH, total dissolved solids and water fecal coliform dosage) were collected from Biomphalaria breeding sites or foci. The spatial analysis was performed using ArcGis 10.1 software, applying the kernel estimator, elevation map, and distance map. RESULTS In Forte Orange, 4.3% of the population had S. mansoni and were found two B. glabrata and 26 B. straminea breeding sites. The breeding sites had temperatures of 25ºC to 41ºC, pH of 6.9 to 11.1, total dissolved solids between 148 and 661, and salinity of 1,000 d. In Serrambi, 4.4% of the population had S. mansoni and were found seven B. straminea and seven B. glabrata breeding sites. Breeding sites had temperatures of 24ºC to 36ºC, pH of 7.1 to 9.8, total dissolved solids between 116 and 855, and salinity of 1,000 d. The kernel estimator shows the clusters of positive patients and foci of Biomphalaria, and the digital elevation map indicates areas of rainwater concentration. The distance map shows the proximity of the snail foci with schools and health facilities. CONCLUSIONS Geoprocessing techniques prove to be a competent tool for locating and scaling the risk areas for schistosomiasis, and can subsidize the health services control actions.
RESUMO OBJETIVO Diagnosticar ambientes de risco para esquistossomose em localidades litorâneas de Pernambuco utilizando técnicas de geoprocessamento. MÉTODOS Foi realizado inquérito coproscópico e malacológico nas localidades Forte Orange e Serrambi. Foram coletadas variáveis ambientais (temperatura, salinidade, pH, sólidos totais dissolvidos e dosagem de coliformes fecais da água) relacionadas aos criadouros ou focos de Biomphalaria. A análise espacial foi realizada no software ArcGis 10.1, aplicando-se o estimador kernel, mapa de elevação e mapa de distância. RESULTADOS No Forte Orange, 4,3% da população estava com S. mansoni e existem dois criadouros de B. glabrata e 26 de B. straminea. Os criadouros apresentaram temperaturas de 25ºC a 41ºC, pH de 6,9 a 11,1, sólidos totais dissolvidos de 148 a 661 e salinidade de 1.000 d. Em Serrambi, 4,4% da população estava com S. mansoni e há sete criadouros de B. straminea e sete de B. glabrata. Os criadouros apresentaram temperaturas de 24ºC a 36ºC, pH de 7,1 a 9,8, sólidos totais dissolvidos de 116 a 855 e salinidade de 1.000 d. O estimador de kernel mostra os aglomerados de pacientes positivos e de focos de Biomphalaria, e o mapa de elevação digital indica áreas de concentração de águas pluviais. O mapa de distância mostra a proximidade dos focos dos caramujos em relação às escolas e unidades de saúde. CONCLUSÕES As técnicas de geoprocessamento se mostraram como importantes ferramentas para a localização e dimensionamento das áreas de risco para esquistossomose, podendo subsidiar as ações de controle por parte dos serviços de saúde.
Asunto(s)
Humanos , Animales , Biomphalaria/crecimiento & desarrollo , Esquistosomiasis mansoni/transmisión , Monitoreo del Ambiente , Sistemas de Información Geográfica , Temperatura , Factores de Tiempo , Biomphalaria/parasitología , Esquistosomiasis mansoni/epidemiología , Brasil/epidemiología , Reservorios de Enfermedades , Factores de Riesgo , Análisis EspacialRESUMEN
The occurrence of schistosomiasis is directly linked to the presence of its snail intermediate host Biomphalaria spp. Knowledge of geographical distribution, habitats and behaviour of these snails in relation to the climate is essential for guiding measures for disease prevention and control. This study aims to model the distribution of B. glabrata and B. straminea in schistosomiasis non-endemic areas of the metropolitan region of Recife (MRR) based on environmental data and estimates of snail distributions in endemic and neighbouring areas. We applied Kriging with the aim of determining the spatial distribution of these two snail species and MaxEnt for modelling their ecological behaviour. Kriging showed that the North and the Centre of the MRR were generally either snail-free or contained only B. straminea, while both snail species could be found in the South. MaxEnt supported our observation that the northern and southern coastal regions were favoured by B. glabrata and diurnal mean temperature variation; July rainfall and November rainfall were the three variables favouring Biomphalaria breeding sites that contributed the most in the predictive model we developed. The study showed the location of areas suitable to Biomphalaria spp. and therefore at potential risk, first for invasion of these snails and later for the development of new schistosomiasis- endemic areas. This information should be useful, not only to estimate expansion possibilities of this disease in the MRR, but also to point out the climatic variables that would contribute to this expansion, thereby allowing timely application of prevention and control measures.
Asunto(s)
Biomphalaria/crecimiento & desarrollo , Biomphalaria/parasitología , Esquistosomiasis mansoni/epidemiología , Animales , Brasil , Vectores de Enfermedades , Vigilancia de la Población , Schistosoma mansoni , Esquistosomiasis mansoni/transmisión , Caracoles/crecimiento & desarrollo , Caracoles/parasitologíaRESUMEN
INTRODUCTION: The expansion of schistosomiasis to previously unaffected areas is being monitored by identifying new cases and georeferencing outbreaks of vector snails. METHODS: In 2014, the Laboratório de Esquistossomose began an epidemiological survey in Serrambi and registered 2,574 people living there. RESULTS: Of these subjects, 1,414 (54.9%) underwent feces examination and 63 (4.5%) were diagnosed with Schistosoma mansoni infection. At this locality, seven breeding sites each were identified for Biomphalaria straminea and Biomphalaria glabrata. At two sites, B. glabrata were shedding cercariae. CONCLUSIONS: Implementing preventive measures is necessary to avoid the establishment of schistosomiasis in yet another tourist locality, Pernambuco.
Asunto(s)
Biomphalaria/parasitología , Vectores de Enfermedades , Schistosoma mansoni/aislamiento & purificación , Esquistosomiasis mansoni/epidemiología , Adolescente , Adulto , Animales , Brasil/epidemiología , Niño , Preescolar , Heces/parasitología , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Persona de Mediana Edad , Esquistosomiasis mansoni/diagnóstico , Adulto JovenRESUMEN
OBJECTIVE: Investigate breeding sites with host snails and autochthonous human cases of schistosomiasis. METHODS: Between July 2010 and September 2012 were performed: (1) malacological survey searching for breeding sites, collection and identification of Biomphalaria snails positive for Schistosoma mansoni in Recife, PE, Northeastern Brazil; (2) prevalence survey in 2,718 schoolchildren aged from seven to 14 years old to identify cases of schistosomiasis, clinical examination and ultrasound in positive cases of S. mansoni. The autochthony of the cases was investigated and the case were clinically evaluated. The cases and breeding sites were georeferenced and spatially described. RESULTS: The results identified 30 breeding with B. straminea, four of which were potential foci of transmission, as molecular testing identified snails with S. mansoni DNA. There were 14 children diagnosed with schistosomiasis, of which five were considered to be autochthonous cases of the disease. CONCLUSIONS: Urgent measures are required in order to avoid schistosomiasis becoming endemic to Recife, as has happened in other coastal areas of the state of Pernambuco.
Asunto(s)
Biomphalaria/parasitología , Enfermedades Endémicas/estadística & datos numéricos , Schistosoma/crecimiento & desarrollo , Esquistosomiasis mansoni/epidemiología , Animales , Biomphalaria/crecimiento & desarrollo , Brasil/epidemiología , Preescolar , Vectores de Enfermedades , Enfermedades Endémicas/prevención & control , Humanos , Prevalencia , Características de la Residencia , Esquistosomiasis mansoni/diagnóstico , Esquistosomiasis mansoni/prevención & control , Población UrbanaRESUMEN
OBJETIVO : Investigar criadouros com moluscos hospedeiros e casos humanos autóctones para esquistossomose. MÉTODOS : Entre julho de 2010 e setembro de 2012 foram realizados: (1) levantamento malacológico para busca ativa de criadouros, coleta e identificação de caramujos Biomphalaria positivos para Schistosoma mansoni em Recife, PE; (2) inquérito de prevalência com 2.718 escolares, de sete a 14 anos, para diagnóstico de casos de esquistossomose; (3) exame clínico e ultrassonografia nos casos positivos para S. mansoni. Os casos foram investigados quanto à sua autoctonia e avaliados clinicamente. Os casos e criadouros foram georreferenciados e espacializados. RESULTADOS : Foram identificados 30 criadouros de B. straminea , quatro deles potenciais focos de transmissão, uma vez que os testes moleculares identificaram DNA de S. mansoni nos caramujos coletados. Foram diagnosticadas 14 crianças com esquistossomose; entre elas, cinco foram consideradas casos autóctones da doença. CONCLUSÕES : Ações emergenciais pela vigilância em saúde são necessárias para evitar que a esquistossomose se endemize em Recife, como acontece em localidades litorâneas do estado de Pernambuco. .
OBJETIVO Investigar criaderos con moluscos hospedadores y casos humanos autóctonos para esquistosomiasis. MÉTODOS Se ejecutaron: estudio malacológico para búsqueda activa de criaderos, colecta e identificación de caracoles Biomphalaria positivos para S. mansoni en Recife, PE, entre julio de 2010 y septiembre de 2012, pesquisa de prevalencia con 2.718 escolares, de siete a 14 años, para diagnóstico de casos de esquistosomiasis, examen clínico y de ultrason en los casos positivos para S. mansoni. Los casos fueron investigados con respecto a su autoctonía y evaluados clínicamente. Los casos y criaderos fueron geo-referenciados y espacializados. RESULTADOS Se identificaron 30 criaderos de B. straminea, cuatro de ellos potenciales focos de transmisión, luego que las pruebas moleculares identificaron DNA de S. mansoni en los caracoles colectados. Se diagnosticaron 14 niños con esquistosomiasis, entre ellas cinco fueron considerados casos autóctonos de la enfermedad. CONCLUSIONES Acciones de emergencia para vigilancia de salud son necesarias para evitar que la esquistosomiasis se vuelva endémica en Recife como sucede en localidades del litoral de Pernambuco. .
OBJECTIVE : Investigate breeding sites with host snails and autochthonous human cases of schistosomiasis. METHODS : Between July 2010 and September 2012 were performed: (1) malacological survey searching for breeding sites, collection and identification of Biomphalaria snails positive for Schistosoma mansoni in Recife, PE, Northeastern Brazil; (2) prevalence survey in 2,718 schoolchildren aged from seven to 14 years old to identify cases of schistosomiasis, clinical examination and ultrasound in positive cases of S. mansoni. The autochthony of the cases was investigated and the case were clinically evaluated. The cases and breeding sites were georeferenced and spatially described. RESULTS : The results identified 30 breeding with B. straminea, four of which were potential foci of transmission, as molecular testing identified snails with S. mansoni DNA. There were 14 children diagnosed with schistosomiasis, of which five were considered to be autochthonous cases of the disease. CONCLUSIONS : Urgent measures are required in order to avoid schistosomiasis becoming endemic to Recife, as has happened in other coastal areas of the state of Pernambuco. .
Asunto(s)
Animales , Preescolar , Humanos , Biomphalaria/parasitología , Enfermedades Endémicas/estadística & datos numéricos , Schistosoma/crecimiento & desarrollo , Esquistosomiasis mansoni/epidemiología , Biomphalaria/crecimiento & desarrollo , Brasil/epidemiología , Vectores de Enfermedades , Enfermedades Endémicas/prevención & control , Prevalencia , Características de la Residencia , Esquistosomiasis mansoni/diagnóstico , Esquistosomiasis mansoni/prevención & control , Población UrbanaRESUMEN
INTRODUCTION: The prevalence and intensity of geohelminth infections and schistosomiasis remain high in the rural areas of Zona da Mata, Pernambuco (ZMP), Brazil, where these parasites still represent a significant public health problem. The present study aimed to spatially assess the occurrences of schistosomiasis and geohelminthiasis in the ZMP. METHODS: The ZMP has a population of 1,132,544 inhabitants, formed by 43 municipalities. An ecological study was conducted, using secondary data relating to positive human cases and parasite loads of schistosomiasis and positive human cases of geohelminthiasis that were worked up in Excel 2007. We used the coordinates of the municipal headquarters to represent the cities which served as the unit of analysis of this study. The Kernel estimator was used to spatially analyze the data and identify distribution patterns and case densities, with analysis done in ArcGIS software. RESULTS: Spatial analysis from the Kernel intensity estimator made it possible to construct density maps showing that the northern ZMP was the region with the greatest number of children infected with parasites and the populations most intensely infected by Schistosoma mansoni. In relation to geohelminths, there was higher spatial distribution of cases of Ascaris lumbricoides and Trichuris trichiura in the southern ZMP, and greater occurrence of hookworms in the northern/central ZMP. CONCLUSIONS: Despite several surveys and studies showing occurrences of schistosomiasis and geohelminthiasis in the ZMP, no preventive measures that are known to have been effective in decreasing these health hazards have yet been implemented in the endemic area.
Asunto(s)
Enfermedades Endémicas , Helmintiasis/epidemiología , Enfermedades Desatendidas/epidemiología , Salud Rural , Esquistosomiasis mansoni/epidemiología , Brasil/epidemiología , Niño , Heces/parasitología , Encuestas Epidemiológicas , Humanos , Recuento de Huevos de Parásitos , Densidad de Población , Prevalencia , Población Rural , Esquistosomiasis mansoni/parasitología , Esquistosomiasis mansoni/prevención & control , Instituciones Académicas/estadística & datos numéricos , Estadísticas no ParamétricasRESUMEN
INTRODUCTION: The prevalence and intensity of geohelminth infections and schistosomiasis remain high in the rural areas of Zona da Mata, Pernambuco (ZMP), Brazil, where these parasites still represent a significant public health problem. The present study aimed to spatially assess the occurrences of schistosomiasis and geohelminthiasis in the ZMP. METHODS: The ZMP has a population of 1,132,544 inhabitants, formed by 43 municipalities. An ecological study was conducted, using secondary data relating to positive human cases and parasite loads of schistosomiasis and positive human cases of geohelminthiasis that were worked up in Excel 2007. We used the coordinates of the municipal headquarters to represent the cities which served as the unit of analysis of this study. The Kernel estimator was used to spatially analyze the data and identify distribution patterns and case densities, with analysis done in ArcGIS software. RESULTS: Spatial analysis from the Kernel intensity estimator made it possible to construct density maps showing that the northern ZMP was the region with the greatest number of children infected with parasites and the populations most intensely infected by Schistosoma mansoni. In relation to geohelminths, there was higher spatial distribution of cases of Ascaris lumbricoides and Trichuris trichiura in the southern ZMP, and greater occurrence of hookworms in the northern/central ZMP. CONCLUSIONS: Despite several surveys and studies showing occurrences of schistosomiasis and geohelminthiasis in the ZMP, no preventive measures that are known to have been effective in decreasing these health hazards have yet been implemented in the endemic area.
INTRODUÇÃO: A prevalência e intensidade das infecções produzidas por geohelmintos e esquistossomose continuam elevadas na Zona da Mata de Pernambuco (ZMP), onde essas parasitoses se apresentam como relevante problema de saúde pública. O presente estudo objetivou espacializar a ocorrência da esquistossomose e geohelmintoses na ZMP. MÉTODOS: A ZMP apresenta uma população de 1.132.544 habitantes, composta por 43 municípios. Um estudo ecológico foi desenvolvido, utilizando dados secundários referentes aos casos humanos positivos e cargas parasitárias para esquistossomose e casos humanos positivos para geohelmintoses que foram trabalhados no Excel 2007. Foram utilizadas as coordenadas das sedes municipais para representar o município o qual serviu de unidade de análise deste estudo. Para análise espacial dos dados e identificação de padrões de distribuição e densidade dos casos, foi adotado o estimador de Kernel, sendo as análises feitas no software ArcGIS. RESULTADOS: A análise espacial, a partir do estimador de intensidade de Kernel, permitiu a construção de mapas de densidade mostrando a Mata Norte como a região onde se concentra o maior número de crianças parasitadas e as populações mais intensamente infectadas pelo Schistosoma mansoni. Com relação aos geohelmintos, há uma maior distribuição espacial dos casos de Ascaris lumbricoides e Trichuris trichiura na Mata Sul, destacando a maior ocorrência de ancilostomídeos entre as Matas Norte e Centro de Pernambuco. CONCLUSÕES: Apesar dos inquéritos e dos vários estudos mostrando a ocorrência de esquistossomose e geohelmintoses na ZMP ainda se desconhecem medidas preventivas que tenham sido implementadas na área endêmica mostrando efetividade na redução destes agravos.
Asunto(s)
Niño , Humanos , Enfermedades Endémicas , Helmintiasis/epidemiología , Enfermedades Desatendidas/epidemiología , Salud Rural , Esquistosomiasis mansoni/epidemiología , Brasil/epidemiología , Heces/parasitología , Encuestas Epidemiológicas , Recuento de Huevos de Parásitos , Densidad de Población , Prevalencia , Población Rural , Estadísticas no Paramétricas , Esquistosomiasis mansoni/parasitología , Esquistosomiasis mansoni/prevención & control , Instituciones Académicas/estadística & datos numéricosRESUMEN
Em Pernambuco as geohelmintoses e esquistossomose apresentam prevalências elevadas em áreas rurais e atualmente a esquistossomose tem se expandindo para áreas litorâneas. Em Recife nenhuma investigação epidemiológica confirmou casos autoctónes, consequentemente esta cidade não é atendida pelo Programa de Controle da Esquistossomose (PCE). Em 2008 foi registrada a 1ª ocorrência de caramujos infectados pelo Schistosoma mansoni na cidade do Recife. Diante disto, o presente estudo teve como objetivos: estimar a positividade da esquistossomose e geohelmintoses em Recife; determinar a intensidade de infecção por S. mansoni; conhecer o perfil clínico e investigar a autoctonia dos casos de S. mansoni; espacializar a ocorrência desses agravos. O estudo foi realizado entre maio-11 a maio-12 com crianças entre 7-14 anos em escolas sorteadas. O exame de Kato-Katz permitiu o cálculo da prevalência e intensidade da infecção esquistossomótica. As crianças positivas para S. mansoni fizeram exames clínico e ultrassonográfico e a investigação de autoctonia foi realizada mediante entrevistas. Os casos foram localizados espacialmente utilizando o GoogleEarth e o processamento dos dados realizado no ArcGIS 10.0. Foram feitos 2.718 exames, com 246 crianças infectadas por Ascaris lumbricoides, 235 por Trichuris trichiura, 30 por ancilostomídeos e 12 por S. mansoni. A intensidade de infecção por S. mansoni variou de 24-816 OPG. Oito crianças apresentaram fígado e baço normais, 3 hepatomegalia e 1 hepatoesplenomegalia. A investigação de autoctonia descartou 9 crianças diante da menção de exposição fora do Recife. A distribuição espacial dos casos mostra maior concentração no norte e centro da cidade. As evidências deste estudo devem alertar a Vigilância Epidemiológica para promover a busca de novos casos para que a doença não se propague no Recife. Uma investigação malacológica está em curso para tentar fechar o ciclo de transmissão desta doença no Recife.
Asunto(s)
Humanos , Niño , Adolescente , Diseño de Investigaciones Epidemiológicas , Esquistosomiasis/epidemiología , Helmintiasis/epidemiología , Sistemas de Información Geográfica , Características de la Residencia , Schistosoma mansoni/parasitologíaRESUMEN
A malacological survey of permanent and temporary breeding sites was conducted in the Piedade neighborhood of Jaboatão dos Guararapes, Pernambuco, between November 2006 and November 2007, with the aim of determining the malacological fauna at this locality, along with the potential for Schistosomiasis mansoni transmission. In addition to Biomphalaria glabrata (Say, 1818), the molluscs Drepanotrema cimex (Moricand, 1837), Pomacea sp and Melanoides tuberculatus (Muller, 1774) were collected. Among the specimens of Biomphalaria glabrata that were collected, 1,490 were found alive, and 74 (5%) were positive for Schistosoma mansoni. The largest numbers of molluscs collected, and all of the specimens that were positive for Schistosoma mansoni, were collected during the annual rainy season. The presence of larvae of other trematodes infecting the Biomphalaria glabrata molluscs was also observed. These trematodes were from the families Strigeidae and Diplostomatidae and, at first sight, they presented morphology that could lead to confusion with Schistosoma mansoni cercariae. Thus, knowledge of these trematodes becomes essential for the differential diagnosis of the etiological agent for schistosomiasis.
Asunto(s)
Biomphalaria/parasitología , Vectores de Enfermedades , Schistosoma mansoni/aislamiento & purificación , Animales , Brasil , Densidad de Población , Esquistosomiasis mansoni/transmisión , Estaciones del AñoRESUMEN
Realizou-se um inquérito malacológico em criadouros, permanentes e temporários, no bairro de Piedade, Jaboatão dos Guararapes, Pernambuco, entre novembro de 2006 e novembro de 2007 com o objetivo de conhecer a fauna malacológica dessa localidade, bem como o potencial de transmissão da esquistossomose mansoni. Além de Biomphalaria glabrata (Say, 1818), foram coletados moluscos Drepanotrema cimex (Moricand, 1837), Pomacea sp e Melanoides tuberculatus (Muller, 1774). Do total de Biomphalaria glabrata coletado, 1.490 exemplares encontraram-se vivos, sendo que 74 (5 por cento) estavam positivos para Schistosoma mansoni. O maior número de moluscos capturados e todos aqueles positivos para Schistosoma mansoni foram coletados na estação anual das chuvas. Foi observada também a presença de outras larvas de trematódeos infectando os moluscos Biomphalaria glabrata. Pertencentes às famílias Strigeidae e Diplostomatidae, apresentam, a primeira vista, morfologia que pode levar a confusão com as cercárias do Schistosoma mansoni, tornando-se indispensável seu conhecimento para o diagnóstico diferencial do agente causador da esquistossomose.
A malacological survey of permanent and temporary breeding sites was conducted in the Piedade neighborhood of Jaboatão dos Guararapes, Pernambuco, between November 2006 and November 2007, with the aim of determining the malacological fauna at this locality, along with the potential for Schistosomiasis mansoni transmission. In addition to Biomphalaria glabrata (Say, 1818), the molluscs Drepanotrema cimex (Moricand, 1837), Pomacea sp and Melanoides tuberculatus (Muller, 1774) were collected. Among the specimens of Biomphalaria glabrata that were collected, 1,490 were found alive, and 74 (5 percent) were positive for Schistosoma mansoni. The largest numbers of molluscs collected, and all of the specimens that were positive for Schistosoma mansoni, were collected during the annual rainy season. The presence of larvae of other trematodes infecting the Biomphalaria glabrata molluscs was also observed. These trematodes were from the families Strigeidae and Diplostomatidae and, at first sight, they presented morphology that could lead to confusion with Schistosoma mansoni cercariae. Thus, knowledge of these trematodes becomes essential for the differential diagnosis of the etiological agent for schistosomiasis.