Abstract

Permanet 2.0 distribution was made free in October, 2008 and May, 2009 in Oueme Department. OlysetNet distribution was also made free in July, 2011 throughout the entire country by Beninese National Malaria Control Programme to increase coverage of long-lasting insecticidal nets (LLINs). We investigated the dynamics of insecticide resistance in Anopheles gambiae from southern Benin and the metabolic resistance mechanisms involved. Larvae and pupae of A. gambiae s. l. were collected from the breeding sites in Littoral and Oueme Departments. Centers for Disease Control and Prevention (CDC) susceptibility tests were conducted on unfed female mosquitoes aged 2 to 5 days old with stock solutions of permethrin, deltamethrin and dichlorodiphenyltrichloroethane (DDT). CDC biochemical assays using synergists were also carried out. A. gambiae Ladji populations were resistant to permethrin and DDT in 2008 and in 2013. A. gambiae Sekandji populations were susceptible to deltamethrin in 2008 and in 2013 whereas these populations were resistant to this product in 2010. A. gambiae Sekandji populations were resistant to DDT in 2008 and in 2013. The DDT resistance level in A. gambiae Ladji and Sekandji populations recorded in 2013 was higher than the one observed in 2008. The metabolic resistance conferred by detoxifying enzymes is an indication of phenotypic resistance to both DDT and pyrethroids.

Key words: Dynamics, piperonyl butoxide, S.S.S-tributylphosphorotrithioate, ethacrynic acid, insecticide, vectors, resistance.