Figure 1. Map of Upper River Region in The Gambia, with location of study clinical facilities.

Study samples are collected at one of the clinical facilities, Yorrobawol health center, Darsilami community health post, Konkuba community health post, Taibatu health post and Chamoi Health Center, and transported to the study laboratory in Basse for sample processing and analysis, and from there to other laboratories for further analysis. Map adapted from the Atlas of the Gambia 2004.