Use of polymerase chain reaction to identify Anopheles gambiae Giles (Dipt., Culicidae) sibling species composition

Abstract

Abstract: In an entomological study conducted in two high altitude malaria endemic sites in Kakamega district, western Kenya (1995–96), Anopheles gambiae sensu lato (A. gambiae s.l.) and Anopheles funestus were the only two anopheline species collected and identified based on morphological criteria. Anopheles gambiae s.l. was the predominant species forming 83% (n = 2667) of the total female anopheline mosquitoes collected indoors. In both ecogeographical sites, the two species showed different seasonal patterns in population densities and Plasmodium falciparum infectivity rates both which are responsible for variation in malaria transmission in the two sites. To establish the sibling species composition of the A. gambiae Giles complex 30% of the total A. gambiae collected were analysed by the DNA‐based polymerase chain reaction (PCR). All 802 mosquito specimens tested belonged to one sibling species, A. gambiae sensu stricto (A. gambiae s.s). No A. arabiensis was present from the specimens tested. The results suggest that A. gambiae s.s. may be the only member of the gambiae complex represented in the high altitude sites in western Kenya. This species, unlike A. arabiensis, is highly anthropophagic and endophilic, and these behavioural trends may be useful in targeting specific control measures for this species in the high altitude sites such as indoor residual spraying and destruction of breeding sites. The present study is the first logitudinal entomological study to be carried out in highlands of western Kenya where malaria epidemics are frequent.