ABSTRACT

Schistosoma mansoni infections in the Lake Victoria basin in western Kenya are associated with lake water contact. Previous studies demonstrated an association between school proximity to the lake and the prevalence of schistosomiasis, suggesting that the lake is the primary source of S. mansoni transmission in this area.  In order to determine the best combination of strategies for controlling schistosomiasis, we propose to use this information to help us identify 150 communities with schools that have a prevalence of schistosomiasis ≥ 25% among 9-11 year old students. Prevalence and intensity of S. mansoni infection will be determined by Kato-Katz examination of 3 consecutive stool samples for 100 randomly selected 9-12 year old students, 100 randomly selected Standard one students, and 50 randomly selected adults from the community.  Selected communities will be randomized into 6 study arms.  In the first year, half of the communities will receive community wide treatment (CWT) and half will receive school based treatment (SBT). Over years 2-4, a combination of CWT, SBT or drug holiday will be employed in the various study arms and infection levels in 9-12 year old students will be evaluated. Children in communities or schools scheduled for drug holiday will not be evaluated for infection in holiday years. In year 5, a final evaluation of communities in all study arms will be performed and positive individuals will be treated. The primary outcome will be comparison of S. mansoni infection prevalence and intensity levels among treatment arms. Other samples will be collected as necessary to integrate with SCORE morbidity projects and projects evaluating snails and transmission.