Anopheles pharoensis and transmission of Plasmodium falciparum in the Senegal River delta, West Africa.

1. Anopheles pharoensis Theobald was found to be the prevalent man-biting anopheline mosquito in the central area of the Senegal River delta. 2. Blood-fed females of An. pharoensis were obtained during September-December 1987 from mosquito bednets in the village of Souhloul, near the Boundoum dam, 70 km NE of St Louis. 3. Dried mosquito specimens were identified morphologically and each thorax processed using monoclonal antibody against the circumsporozoite protein of Plasmodium falciparum. 4. Five An. pharoensis out of 912 examined were sporozoite positive, while ninety-eight An. gambiae Giles sensu lato were all negative. This finding strongly supports the local importance of An. pharoensis as a malaria vector. 5. Successful use of pyrethroid-impregnated bednets against malaria transmission in this situation has helped to achieve more than 90% reduction of malaria prevalence.