Susceptibility of Anopheles gambiae sensu lato to different insecticide classes and mechanisms involved in the South-North transect of Benin

Monitoring vector resistance to insecticides is a major component of resistance management. Adults of Anopheles gambiae s.l. from larvae collected at thirteen sites were tested with papers impregnated with bendiocarb, permethrin; deltamethrin; pirimiphos-methyl and induced bottles of insecticide including bendiocarb; deltamethrin, permethrin and pirimiphos-methyl. Molecular analyses were performed and detoxification enzyme levels were determined for each study site. This study revealed a generalized distribution of resistance of An. gambiae s.l. to pyrethroids (permethrin and deltamethrin) and a clear resistance to carbamates (bendiocarb) especially in the northern region of the country. This vector is still susceptible to organophosphates, especially pirimiphos-methyl, but resistance is a dynamic phenomenon and it would be necessary to monitor the susceptibility of these anopheles to pyrimiphos-methyl and to find alternative vector control methods to slow down the spread of resistance genes.