A survey of species A and B of theAnopheles gambiaeGiles complex in the Kisumu area of Kenya prior to insecticidal spraying with OMS-43 (fenitrothion)

Throughout 1972 surveys were made in Kenya on the Anopheles gambiae Giles complex in an area near Kisumu, part of which was to have all houses sprayed with OMS-43 (fenitrothion) the following year. Pre-spray data was collected on monthly hut densities, man-biting rates, parity and the human blood indices and sporozoite rates of A. gambiae caught in both an area designated for spraying (evaluation zone) and a comparison zone which was to remain unsprayed. The sporozoite rates, host preferences, and population size of the A. gambiae comples in relation to the human population were similar in the two zones. Few adults were collected from artificial pit-shelters in either zone. Cytotaxonomic identifications showed that although species A of the A. gambiae comples predominated throughout the year, the population of species B decreased relatively less in the drier months than that of species A. No marked differences were found between the host preferences or sporozoite rates of the two species.