| Background: Geographic Information Systems (GIS) methods have been particularly appropriate for data analyses and spatial representations of schistosomiasis infection in highly endemic areas. Descriptive mapping has proven invaluable in elucidating spatial patterns of risk at the household and community levels. Several risk factors for schistosomiasis infection have been identified in Brazil over the last 10 years, including poverty, population density, water contact behavior, and source of household water. This study examines exposure-related risk factors for infection and spatial clustering of schistosomiasis cases in an endemic area in Brazil.;Methods: A population-based household survey was combined with GPS locations of study households in the Conde area, a schistosomiasis endemic area in Bahia, Brazil, in a Geographic Informations System (GIS). Spatial-statistical methods were employed to examine patterns of infection at the community-wide and sub-community levels. Logistic regression models were developed using individual-level and household data to identify risk factors of infection.;Results: The spatial distribution of infection was largely heterogeneous, with one major focus of transmission in the southern region of the Conde area. Community cluster membership, frequency of piped water in the home, and drinking water from the river were significantly associated with presence of schistosomiasis infection by unadjusted analysis. Once adjusted for covariates, only the frequency of publically provided water, specifically alternate days of frequency, was significantly associated with schistosomiasis infection. Other socioeconomic factors, other water contact behaviors, household sanitation and hygiene, and population density were not associated with infection.;Conclusion: These results implicate individual-level, household-level and community-level risk factors in schistosomiasis infection, most notably, the role of reliable publically provided water. |
