Knockdown Resistance Mutations in the Voltage-Gated Sodium Channel of (Diptera: Culicidae) in Myanmar.

is an important mosquito vector transmitting diverse arboviral diseases in Myanmar. Pyrethroid insecticides have been widely used in Myanmar as the key mosquito control measure, but the efforts are constrained by increasing resistance. Knockdown resistance () mutations in the voltage-gated sodium channel (VGSC) are related to pyrethroid resistance in . We analyzed the patterns and distributions of the mutations in in the Mandalay area of Myanmar. The segment 6 regions of domains II and III of were separately amplified from individual genomic DNA via polymerase chain reaction. The amplified gene fragments were sequenced. High proportions of three major mutations, including S989P (54.8%), V1016G (73.6%), and F1534C (69.5%), were detected in the of from all studied areas. Other mutations, T1520I and F1534L, were also found. These mutations represent 11 distinct haplotypes of the population. The S989P/V1016G/F1534C was the most prevalent, followed by S989P/V1016V and V1016G/F1534C. A quadruple mutation, S989P/V1016G/T1520I/F1534C, was also identified. High frequencies of concurrent mutations were observed in of Myanmar , suggesting a high level of pyrethroid resistance in the population. These findings underscore the need for an effective vector control program in Myanmar.