The house fly (Musca domestica Linnaeus) is an important disease vector. Insecticide resistance is an obstacle to effective house fly control. Previous studies have demonstrated that point mutations in acetylcholinesterase (Ace), carboxylesterase (MdαE7) and voltage-sensitive sodium channel (Vssc), and over-expression of CYP6D1v1 confer insecticide resistance in the house fly. However, information about the status and underlying mechanisms of insecticide resistance in Kazakhstani house flies is lacking. In this study, we investigated the occurrence of genetic mutations associated with insecticide resistance in field house flies collected at six different locations in southern Kazakhstan. Four mutations (V260L, G342A/V, and F407Y) in Ace and three mutations (G137D and W251L/S) in MdαE7 were detected with appreciable frequencies. Notably, haplotypes carrying triple-loci mutations in Ace and double mutations in MdαE7 were found in Kazakhstan. The L1014H and L1014F mutations in Vssc, and CYP6D1v1 resistance allele were detected at a low frequency in some of the six investigated house fly populations. Phylogenetic analyses of haplotypes supported multiple origins of resistance mutations in Ace and MdαE7. These observations suggest that house flies in southern Kazakhstan may exhibit significant resistance to organophosphates and carbamates. Regular monitoring of insecticide resistance is recommended to achieve effective house fly control by chemical agents in southern Kazakhstan.

Graphical Abstract