DETECTION OF PYRETHROID RESISTANCE IN ANOPHELES MOSQUITOS

Although pyrethroid insecticides are a promising means of controlling Anopheles malaria vectors, there is a need to monitor for resistance. It has been proposed that the results of the WHO-recommended testing m ethod involving exposure to impregnated paper for 1 hour, might be mis leading because of knockdown during this period, and that exposure to a higher dose of pyrethroid for 2 minutes might be preferable. However , comparative tests with a susceptible and a permethrin-resistant stra in of A. stephensi showed that exposure for 1 hour was at least as sen sitive in detecting resistance as was the short exposure method.