RESUMEN
The role of irrigated areas for the spread of schistosomiasis is of worldwide concern. The aim of the present study was to investigate the spatial distribution of the intermediate snail host Biomphalaria in an area highly endemic for schistosomiasis due to Schistosoma mansoni, evaluating the relationship between irrigation and types of natural water sources on one hand, and the influence of place and time of water exposure on the intensity of human infection on the other. A geographical information system (GIS) was used to map the distribution of the intermediate snail hosts in Ilha das Flores, Sergipe, Brazil, combined with a clinical/epidemiological survey. We observed a direct correlation between the intensity of human infection with S. mansoni and irrigation projects. Malacological studies to identify snail species and infection rates showed that B. glabrata is the main species responsible for human schistosomiasis in the municipality, but that B. straminea also plays a role. Our results provide evidence for a competitive selection between the two snail species in rice fields with a predominance of B. glabrata in irrigation systems and B. straminea in natural water sources.
Asunto(s)
Riego Agrícola , Biomphalaria , Sistemas de Información Geográfica , Oryza , Esquistosomiasis mansoni/epidemiología , Animales , Brasil/epidemiología , Intervalos de Confianza , Estudios Transversales , Bases de Datos Factuales , Estudios Epidemiológicos , Humanos , Prevalencia , Esquistosomiasis mansoni/transmisión , Caracoles , Estadísticas no ParamétricasRESUMEN
INTRODUCTION: Schistosomiasis is endemic in Brazil, with high prevalence in the State of Sergipe, despite the existence of the Schistosomiasis Control Program (PCE). METHODS: The data from Sergipe's PCE between 2005 and 2008 were surveyed. From the raw information, a database was created on a spreadsheet using the Access software. The frequency and geographic distribution of infections due to Schistosoma mansoni and other intestinal parasites were analyzed. These data were exported to the Spring 5.0.5 software for georeferencing and preparation of thematic maps of the spatial and temporal distribution according to year of evaluation. RESULTS: In 2005, 13.6% (14,471/106,287) of the tests were positive for S. mansoni, 11.2% (16,196/145,069) in 2006, 11.8% (10,220/86,824) in 2007 and 10.6% (8,329/78,859) in 2008. Analysis on the maps showed that there was high prevalence of the disease in Sergipe, and particularly in the municipalities of Ilha das Flores, Santa Rosa de Lima, Santa Luzia do Itanhi and São Cristóvão. Furthermore, we evaluated the association between the frequencies of these parasitic diseases and social and developmental indicators in the different municipalities, according to data from the Brazilian Institute for Geography and Statistics (IBGE) and the Department of Water Resources (SRH). We found that municipalities with schistosomiasis prevalence higher than 15% had lower coverage of sewage systems (hygiene index) (p = 0.05). Additionally, municipalities with hookworm prevalence higher than 10% had lower educational HDI (p = 0.04). CONCLUSIONS: The importance of greater control over environmental risk and educational factors needs to be emphasized in attempts to reduce the prevalence of these parasitic diseases.
Asunto(s)
Programas Nacionales de Salud , Esquistosomiasis mansoni/epidemiología , Animales , Brasil/epidemiología , Geografía , Helmintiasis/epidemiología , Helmintiasis/prevención & control , Humanos , Recuento de Huevos de Parásitos , Prevalencia , Evaluación de Programas y Proyectos de Salud , Factores de Riesgo , Esquistosomiasis mansoni/prevención & control , Índice de Severidad de la Enfermedad , Factores SocioeconómicosRESUMEN
INTRODUÇÃO: A esquistossomose é endêmica no Brasil, com elevada prevalência no Estado de Sergipe, apesar da existência do Programa de Controle da Esquistossomose (PCE). MÉTODOS: Foi realizado levantamento de dados do PCE-Sergipe de 2005 a 2008. A partir da matriz bruta formulou-se planilha de dados no software Access e analisou-se frequência e distribuição geográfica das infecções por Schistosoma mansoni e outros enteroparasitos. Estes dados foram exportados para o software Spring 5.0.5 para georreferenciamento e confecção de mapas temáticos de distribuição espacial e temporal por ano de avaliação. RESULTADOS: Foram positivos para S. mansoni 13,6 por cento (14471/106287) de exames nos anos de 2005, 11,2 por cento (16196/145069) em 2006, 11,8 por cento (10220/86824) em 2007 e 10,6 por cento (8329/78859) em 2008. A análise de mapas mostrou elevada prevalência da doença em Sergipe, em particular nos municípios Ilha das Flores, Santa Rosa de Lima, Santa Luzia do Itanhi e São Cristóvão. Além disso, avaliamos a associação entre as frequências dessas doenças parasitárias com indicadores sociais e de desenvolvimento dos diferentes municípios, de acordo com os dados do Instituto Brasileiro de Geografia e Estatística (IBGE) e da Superintendência de Recursos Hídricos (SRH). Observamos que os municípios com prevalência da esquistossomose maior do que 15 por cento têm menor concentração de rede de esgotos (índice de higiene); p = 0,05. Adicionalmente, os municípios com prevalência de infecção por ancilostomídeos maior do que 10 por cento apresentam um menor IDH educacional; p = 0,04. CONCLUSÕES: Ressalta-se a importância de maior controle dos fatores de risco ambientais e educacionais, na tentativa de reduzir prevalências dessas doenças parasitárias.
INTRODUCTION: Schistosomiasis is endemic in Brazil, with high prevalence in the State of Sergipe, despite the existence of the Schistosomiasis Control Program (PCE). METHODS: The data from Sergipe's PCE between 2005 and 2008 were surveyed. From the raw information, a database was created on a spreadsheet using the Access software. The frequency and geographic distribution of infections due to Schistosoma mansoni and other intestinal parasites were analyzed. These data were exported to the Spring 5.0.5 software for georeferencing and preparation of thematic maps of the spatial and temporal distribution according to year of evaluation. RESULTS: In 2005, 13.6 percent (14,471/106,287) of the tests were positive for S. mansoni, 11.2 percent (16,196/145,069) in 2006, 11.8 percent (10,220/86,824) in 2007 and 10.6 percent (8,329/78,859) in 2008. Analysis on the maps showed that there was high prevalence of the disease in Sergipe, and particularly in the municipalities of Ilha das Flores, Santa Rosa de Lima, Santa Luzia do Itanhi and São Cristóvão. Furthermore, we evaluated the association between the frequencies of these parasitic diseases and social and developmental indicators in the different municipalities, according to data from the Brazilian Institute for Geography and Statistics (IBGE) and the Department of Water Resources (SRH). We found that municipalities with schistosomiasis prevalence higher than 15 percent had lower coverage of sewage systems (hygiene index) (p = 0.05). Additionally, municipalities with hookworm prevalence higher than 10 percent had lower educational HDI (p = 0.04). CONCLUSIONS: The importance of greater control over environmental risk and educational factors needs to be emphasized in attempts to reduce the prevalence of these parasitic diseases.