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Sustainable Development Goals
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SOURCES AND DISTRIBUTION OF SURFACE WATER FECAL CONTAMINATION AND PREVALENCE OF SCHISTOSOMIASIS IN A BRAZILIAN VILLAGE
Infecção
Contaminação
Fezes
Transmissão
Saneamento
Limpeza ambiental
Prevenção & Controle
Author
Affilliation
Mercer University School of Medicine. Macon, Georgia, USA / Case Western Reserve University. Center for Global Health and Diseases. Cleveland Ohio, USA
University of Wisconsin. School of Freshwater Sciences. Great Lakes Water Institute. Milwaukee, Wisconsin, USA
Fundação Oswaldo Cruz. Centro de Pesquisa Gonçalo Moniz. Laboratório de Patologia e Biologia Molecular. Salvador, BA, Brasil
University of Wisconsin. School of Freshwater Sciences. Great Lakes Water Institute. Milwaukee, Wisconsin, USA
Case Western Reserve University. Center for Global Health and Diseases. Cleveland Ohio, USA
University of Wisconsin. School of Freshwater Sciences. Great Lakes Water Institute. Milwaukee, Wisconsin, USA
Fundação Oswaldo Cruz. Centro de Pesquisa Gonçalo Moniz. Laboratório de Patologia e Biologia Molecular. Salvador, BA, Brasil
University of Wisconsin. School of Freshwater Sciences. Great Lakes Water Institute. Milwaukee, Wisconsin, USA
Case Western Reserve University. Center for Global Health and Diseases. Cleveland Ohio, USA
Abstract
BACKGROUND: The relationship between poor sanitation and the parasitic infection schistosomiasis is well-known, but still rarely investigated directly and quantitatively. In a Brazilian village we correlated the spatial concentration of human fecal contamination of its main river and the prevalence of schistosomiasis. METHODS: We validated three bacterial markers of contamination in this population by high throughput sequencing of the 16S rRNA gene and qPCR of feces from local residents. The qPCR of genetic markers from the 16S rRNA gene of Bacteroides-Prevotella group, Bacteroides HF8 cluster, and Lachnospiraceae Lachno2 cluster as well as sequencing was performed on georeferenced samples of river water. Ninety-six percent of residents were examined for schistosomiasis. FINDINGS: Sequence of 16S rRNA DNA from stool samples validated the relative human specificity of the HF8 and Lachno 2 fecal indicators compared to animals. The concentration of fecal contamination increased markedly along the river as it passed an increasing proportion of the population on its way downstream as did the sequence reads from bacterial families associated with human feces. Lachnospiraceae provided the most robust signal of human fecal contamination. The prevalence of schistosomiasis likewise increased downstream. Using a linear regression model, a significant correlation was demonstrated between the prevalence of S. mansoni infection and local concentration of human fecal contamination based on the Lachnospiraceae Lachno2 cluster (r2 0.53) as compared to the correlation with the general fecal marker E. coli (r2 0.28). INTERPRETATION: Fecal contamination in rivers has a downstream cumulative effect. The transmission of schistosomiasis correlates with very local factors probably resulting from the distribution of human fecal contamination, the limited movement of snails, and the frequency of water contact near the home. In endemic regions, the combined use of human associated bacterial markers and GIS analysis can quantitatively identify areas with risk for schistosomiasis as well as assess the efficacy of sanitation and environmental interventions for prevention.
Keywords in Portuguese
EsquistossomoseInfecção
Contaminação
Fezes
Transmissão
Saneamento
Limpeza ambiental
Prevenção & Controle
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