Insecticides resistance in the Culex quinquefasciatus populations from northern Thailand and possible resistance mechanisms

摘要: The mosquito vector Culex quinquefasciatus is known to be resistant insecticides worldwide, including Thailand. This study was the first investigation of insecticide resistance mechanisms, involving metabolic detoxification and target site insensitivity in C. from Adult females reared field-caught larvae six provinces northern Thailand were determined for status by exposing 0.05% deltamethrin, 0.75% permethrin 5% malathion papers using standard WHO susceptibility test. overall mortality rates 45.8%, 11.4% 80.2%, respectively. A fragment voltage-gated sodium channel gene amplified sequenced identify knock down (kdr) mutation. ace-1 mutation PCR-RFLP. L1014F kdr observed all populations, but homozygous mutant F/F1014 genotype found only two where significantly correlated with deltamethrin resistance. However, none mosquitoes had G119S gene. laboratory strain, Cq_CM_R, has been established showing a highly level after selection few generations. F1014 allele frequency increased one generation selection. synergist assay performed assess detoxifying enzymes. Addition bis(4-nitrophenyl)-phosphate (BNPP) diethyl maleate (DEM), inhibitors esterases glutathione S-transferases (GST), respectively, into larval bioassay Cq_CM strain showed no significant reduction. By contrast, addition piperonyl butoxide (PBO), an inhibitor cytochrome P450 monooxygenases, 9-fold reduction Resistance pyrethroids widely distributed reports time detection wild populations At least major confer Thai populations.