Background: Culex pipiens has a significant public health importance since it is an important vector of West Nile virus and Rift Valley fever virus. We, therefore, aimed to determine the in- secticide resistance level in Cx. pipiens populations in the Aegean and Mediterranean regions of Turkey.
Methods: Bioassays have been carried out against Dichlorodiphenyltrichloroethane (DDT) (4%), Malathion (5%), Fenitrothion (1%), Propoxur (0.1%), Bendiocarb (0.1%), Permethrin (0.75%) and Deltamethrin (0.05%). Biochemical analyses have been performed to detect non-specific esterase, mixed function oxidase, glutathione-s-transferase and acetylcholinesterase levels. A knockdown resistance (kdr) (L1014F) and Acetylcholinesterase (Ace-1) (G119S) mutations have been detected by using allele-specific primers and a polymerase chain reaction (PCR) amplifica- tion of specific alleles (PASA) diagnostic test was performed for detection of F290V mutation.
Results: Bioassay results showed that all Cx. pipiens populations were resistant to DDT, Mal- athion, Fenitrothion, Bendiocarb, Propoxur and some of the populations have started to gain Permethrin and Deltamethrin resistance. Biochemical analyses results revealed that altered glu- tathione-s-transferases, P450 monooxygenases, esterase levels might be responsible for DDT, or- ganophosphate, carbamate and pyrethroid resistance in Cx. pipiens populations. Results showed mild to high frequency of L1014F, low frequency of F290V but no Ace-1 G119S mutation within the populations. Additionally, acetylcholinesterase insensitivity was not significantly high within the most of these populations.
Conclusion: Overall results may help to fulfil the lacking information in the literature regarding insecticide resistance status and underlying mechanism of Culex pipiens populations of the Mediter- ranean and Aegean region of Turkey by using all bioassays, molecular tests and biochemical assays.