Prevalence and clustering of soil-transmitted helminth infections in a tribal area in southern India

Objectives: To estimate the prevalence, spatial patterns and clustering in the distribution of soil-transmitted helminth (STH) infections, and factors associated with hookworm infections in a tribal population in Tamil Nadu, India. Methods: Cross-sectional study with one-stage cluster sampling of 22 clusters. Demographic and risk factor data and stool samples for microscopic ova/cysts examination were collected from 1237 participants. Geographical information systems mapping assessed spatial patterns of infection. Results: The overall prevalence of STH was 39% (95% CI 36%-42%), with hookworm 38% (95% CI 35-41%) and Ascaris lumbricoides 1.5% (95% CI 0.8-2.2%). No Trichuris trichiura infection was detected. People involved in farming had higher odds of hookworm infection (1.68, 95% CI 1.31-2.17, P<0.001). In the multiple logistic regression, adults (2.31, 95% CI 1.80-2.96, P