Sensitivity of Culex quinquefasciatus to Insecticides Used in Brazzaville (Republic of Congo)

Culex quinquefasciatus is a major source of culicidian nuisance in the city of Brazzaville.To fight against this nuisance, the populations use different means of control, in particular the insecticide sprays sold on the market.This study was carried out in August and October 2016, and in January 2017.The objective was to assess the sensitivity of Culex quinquefasciatus to insecticides used in public health in order to adopt effective control strategies against this mosquito.Culex quinquefasciatus larvae bred to obtain adult mosquitoes were collected from different waste water collections in the city.Susceptibility tests were carried out according to the WHO protocol (1998) with Culex females aged 2 to 5 days.The insecticides used were DDT 4%, permethrin 0.75%, deltamethrin 0.05%, carbosulfan 0.6%, bendiocarb 0.1%, fenitrothion 1%, lambdacyhalothrin 0.05%, malathion 5% and cylfluthrin 0.15%.Susceptibility tests showed high levels of resistance to all insecticides used.Culex quinquefasciatus being resistant to these insecticides, the identification of the mechanisms that support this resistance is necessary to put in place an effective strategic plan.