Bendiocarb resistance selection pressure: What happen after his massive use for Indoor residual spraying (IRS) in areas under universal coverage of long lasting insecticidal nets (LLINs) in southern Benin?

Abstract

The present study was aimed to determine the relative impact of indoor residual spraying intervention on the development of insecticide resistance by looking for Kdr and Ace-1 mutations in An. gambiae s.l. as marker of insecticide pressure. Anopheles larvae were collected from Adjohoun, Dangbo, Misserete and Seme, four districts previously under IRS and in control area (Adjara) between June 2010 to November 2011. An. gambiae s.l. was tested to susceptibility to insecticide. The results revealed that An. gambiae s.l. showed a strong resistant to permethrin 0.75%, DDT 4% and deltamethrin 0.05% throughout the IRS period and after IRS cessation in all districts. But after 3 years of bendiocarb use in areas study, no resistance to this insecticide was recorded. Furthermore, the Kdr mutation frequency was very high, about 80% in 2010 and 2011. The Ace-1 alleles frequencies were homogeneous and worthless for two years in all four districts. This study demonstrates that An. gambiae s.l. in the Oueme department have maintained and developed their resistance to pyrethroids, but are still susceptible to bendiocarb, mainly in districts under IRS.