Environmental control of schistosomiasis through community participation in a Moroccan oasis.

Summary Akka oasis, in the province of Tata, southern Morocco, is one of the oldest foci of urinary schistosomiasis in Morocco where transmission is still taking place. We report the results of two studies: a cross-sectional snail survey investigated the distribution of Bulinus truncatus in relation to habitat factors in the Akka traditional irrigation system. The presence of aquatic vegetation, especially Potamogeton sp. was identified as a key factor determining snail occurrence and abundance in canals, impoundments and isolated small puddles and streamlets in the Akka riverbed. In a participatory rapid appraisal, the community identified snail control as a way to reduce transmission of schistosomiasis. Without any further outside incentives, the local irrigation committee implemented repeated cleaning and vegetation removal in canals. A longitudinal study evaluated the effect of these measures on populations of B. truncatus. Snail and egg mass densities showed significant reductions after repeated vegetation clearing in the study sites. The participatory approach led to low-cost, environment-friendly schistosomiasis control measures that were effective and sustainable.