Schistosoma mansoni IgG antibody response and Kato-Katz infection among pre-school aged children in Mbita, Western Kenya 2012-2014

We compared serological measures of transmission based on antibody response to S. mansoni soluble egg antigen (SEA) with stool-based measures of infection among 3,663 preschool-age children in an area endemic for S. mansoni in western Kenya. We estimated force of infection among children using the seroconversion rate examined how it varied geographically and by age.

Methods
The analysis included 3,663 children ages 2 months to 5.5 years who were originally enrolled from 30 communities that participated in a cluster randomized controlled trial to measure the effect of community-wide versus school-based mass distribution of praziquantel to reduce S. mansoni infection in Mbita, western Kenya. Villages were selected within 5 km of Lake Victoria from among those with ≥ 25% S. mansoni prevalence that had not received mass treatment with praziquantel. Preschool age children ≤5 years were assessed annually from 2012-2014 in repeated cross-sectional surveys that collected blood and stool specimens, and samples were tested for the presence of infection (in stool) and for antibodies to S. mansoni soluble egg antigen (SEA).