Establishment of baseline susceptibility data to various insecticides for Anopheles gambiae sensu lato prior to the implementation of insecticide residual spray in the district of Copargo, northern Benin

To establish a baseline data on the susceptibility data to various insecticides for Anopheles gambiae sensu lato prior to the implementation of insecticide residual spray in the district of Copargo, Northern Benin, a study was conducted from June to December 2017 for this purpose. Adult females from field aged 2-5 days were subjected to insecticide- impregnated papers (permethrin 0.75%, delthamethrin 0.05%, DDT 4%, and bendiocarb 0.1%) following WHOPES. The species within An. gambiae complex, and the presence of knock down (kdr) and acetylcholinesterase (ace-1) mutations were searched from the An. gambiae populations subjected to the susceptible test. Results from this study showed that An. gambiae from Copargo district developed strong resistance to DDT (4% of mortality), permethrin (19%) and deltamethrin (43%) but were fully  susceptible  (mortality 100%) to bendiocarb. The PCRs showed the presence of two sub-species of An. gambiae, namely An. coluzzii, and An. arabiensis, with a predominance for An. coluzzii (77%). The kdr mutation was detected in all An. gambiae populations tested in very high frequency (> 95%) whereas the Ace-1 mutation was found at a very low frequency ( 95%), tandis que la mutation ace-1 a ete retrouvee a une frequence tres faible (<2%). Cette etude a montre que An. coluzzii est la sous - espece la plus importante du district de Copargo. Cependant, l’utilisation anarchique des pesticides chimiques dans cette commune cotonniere a contribue a la selection de la resistance de ce vecteur du paludisme vis-a-vis des insecticides. Aussi la faible frequence de la mutation ace-1 retrouvee au sein des populations de An. gambiae de cette commune suggererait l’utilisation du bendiocarb en alternatif aux pyrethrinoides pour les activites de pulverisations intra domiciliaires  d’insecticides pour lutter contre les moustiques. Mots-cles : resistance; espece; insecticide, Anopheles gambiae; copargo; Benin