Assessment of the Grain Store as an Unbaited Outdoor Shelter for Mosquitoes of the Anopheles Gambiae Complex and Anopheles Funestus (Diptera: Culicidae) At Kisumu, Kenya

Abstract

Following observations that considerable numbers of the Anopheles gambiae complex were resting in grain stores in the unsprayed comparison zone of the large-scale epidemiological trial of fenitrothion (OMS-43) at Kisumu, Kenya, collections were made from these grain stores within rural family compounds and compared with collections from Muirhead-Thomson pit shelters over the course of 1 year. An. gambiae complex numbers were 6.8× greater in the grain stores than in the pit shelters and represented 40% of the numbers observed in the larger sleeping huts. The ratio of An. gambiae to An. arabiensis, and precipitin test results and blood-fed:gravid ratio for the An. gambiae complex were similar from both sources. The distribution of specimens between sleeping huts and other structures in the compound was 94:6 in An. gambiae and 58:42 in An. arabieensis. An. funestus collections, although still small, were larger in the grain stores. The grain store thus provided a good collection site for assessing the extradomiciliary component of the An. gmnbiae complex population.