Impact of Resistance to Pyrehroids on the Incidence of Malaria into Anopheles gambiae (Giles, 1902) in the Southern Forest Area in Cote d'Ivoire

The Levels and mechanisms of resistance to pyrethroids and DDT in field Anopheles gambiae populations and their impact on malaria incidence were investigated from December 2016 to May 2017 in four sites in the southern part of C?te d'Ivoire. Among these sites; two have high incidences of malaria; Jacqueville and Toumodi and two other ones with low incidences of malaria; Tiassale and Adzope. The results showed resistance to pyrethroids and DDT with mortality rates ranging from 32% to 67% with alphacypermethrin 0.05%, from 27% to 64% with deltamethrin 0.05%, from 22% to 47% with permethrin 0.75% and 18% to 28% with DDT 4%. This resistance was not only due to the metabolic mechanisms of detoxification including single oxygen cytochrome P450 activities and esterases, but also to the kdr mutation. The two identified species; An. coluzzii and An. gambiae were sympatric in Tiassal? and Toumodi, while only An. coluzzii was present in Jacqueville. The frequencies of the resistant alleles at the kdr mutation L1014F were high ranging from 0.53 in Tiassale to 0.95 in Toumodi and thoses at the Ace-1R mutation G119S were very low ranging from 0.25 in Toumodi to 0.03 in Tiassal?. This research revealed a link between the kdr mutation and the incidence of malaria and also a link between the Ace-1R mutation and the malaria incidence. Indeed, the kdr and the Ace-1R mutations frequencies were higher into field Anopheles gambiae populations from high malaria incidence areas than those from low malaria incidence areas. These mutations may be favorable for a high malaria transmission.