Schistosoma mansoni infection in a rural area of the Jequitinhonha Valley, Minas Gerais, Brazil: Analysis of exposure risk

This study examines the relative contribution of age-specific total IgE levels, eosinophils and water contact behavior to the prevalence and intensity (geometric mean egg counts) of Schistosoma mansoni infection in the poor rural population of Virgem das Graças in northern Minas Gerais State. In bivariate analysis, age was strongly correlated with both prevalence and intensity of infection, while eosinophil levels with prevalence only (p < 0.0001); IgE levels and 5 demographic and socioeconomic variables were moderately correlated with prevalence (p < 0.05), as were number of persons per room and TBM (total body minutes) with egg counts. In multivariate analysis, after controlling for demographic and socioeconomic factors, only total IgE levels were significantly correlated with both prevalence (p = 0.248, 95% CI = 1.01-1.11) and intensity (p = 0.0217, 95% CI = 0.01-0.14) of infection and eosinophil levels with prevalence (p = 0.0005, 95% CI = 1.07-1.24). Although any causal relationship cannot be confirmed by a cross-sectional study, we demonstrated an associated decrease in prevalence and intensity of S. mansoni infection with increased IgE levels.