Ivory Coast – Bouaké area (August 1984)

During 1970s, low-ground development relied upon irrigated rice cultivation, so the presence of water in the environment became not related to rainfall. The density of anopheline mosquitoes varies within year span according to the steps in rice cultivation. In the center of the pic, the main irrigation ditch was invaded by aquatic vegaetation and became a breeding site for water snails, that are intermediate hosts for schistosomiases.