Data analysis
Univariate comparisons between S. mansoni infection and categorical variables were performed by a chi-square test with Yates’ correction or Fisher’s Exact test when appropriate, and continuous variables were performed using Kruskal-Wallis’s test. The crude odds ratio (OR) and 95% confidence interval (CI) was obtained as a measure of the strength of association with and schistosomiasis. Adjusted OR was obtained from multivariate logistic regression analysis. All descriptive, univariate, and multivariate analyses were performed in Epi Info 7.2.2.6 (https://www.cdc.gov/epiinfo/index.html). We also performed Student’s t test to evaluate differences between Dics from immigrants and natives and Mann-Whitney to assess differences between Dics for percent of lifetime spent in Salvador.