Fig. 1

Communities sampled (black dots) in Bunkpurugu-Yunyoo district across all 2011–2013 surveys. The observed prevalence rates are displayed from low (green) to high (red) on the elevation surface and major roads. Four ecological zones defined by study design are highlighted by the elevation as rocky uplands, transition vegetation, riverine plains and urban zones. Inset map shows all the districts within Ghana, highlighting the Bunkpurugu-Yunyoo district