COMPARISON OF BEDNETS TREATED WITH ALPHACYPERMETHRIN, PERMETHRIN OR LAMBDACYHALOTHRIN AGAINST ANOPHELES-GAMBIAE IN THE GAMBIA

In the Gambian village of Saruja, where malaria is transmitted mainly by mosquitoes of the Anopheles gambiae complex, a trial was undertaken of the acceptability and efficacy of bednets treated with one of thre e pyrethroid insecticides alphacypermethrin 40 mg/m(2). permethrin 500 mg/m(2) and lambdacyhalothrin 10 mg/m(2). Fewer mosquitoes were found alive under nets treated with insecticide than under control nets. Si gnificantly more dead mosquitoes were found under nets treated with al phacypermethrin than under nets treated with permethrin or lambdacyhal othrin. Side-effects were reported by a proportion of the users of net s treated with each of the insecticides, but none were severe and thei r prevalence was similar between treatment groups, Unwashed nets treat ed with alphacypermethrin were more effective at killing anopheline mo squitoes in bioassays than nets treated with permethrin or lambdacyhal othrin. Killing activity was reduced when nets were washed, irrespecti ve of which insecticide was used, Bednets treated with alphacypermethr in are well accepted, effectively killed anopheline mosquitoes and sho uld therefore be evaluated for personal protection against malaria tra nsmission.