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

Abstract

Aedes aegypti 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 (kdr) mutations in the voltage-gated sodium channel (VGSC) are related to pyrethroid resistance in Ae. aegypti. We analyzed the patterns and distributions of the kdr mutations in Ae. aegypti in the Mandalay area of Myanmar. The segment 6 regions of domains II and III of vgsc were separately amplified from individual Ae. aegypti genomic DNA via polymerase chain reaction. The amplified gene fragments were sequenced. High proportions of three major kdr mutations, including S989P (54.8%), V1016G (73.6%), and F1534C (69.5%), were detected in the vgsc of Ae. aegypti from all studied areas. Other kdr mutations, T1520I and F1534L, were also found. These kdr mutations represent 11 distinct haplotypes of the vgsc 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 kdr mutations were observed in vgsc of Myanmar Ae. aegypti, suggesting a high level of pyrethroid resistance in the population. These findings underscore the need for an effective vector control program in Myanmar.

First report of kdr mutations in the voltage-gated sodium channel gene in the arbovirus vector, Aedes aegypti, from Nouakchott, Mauritania

“…More interestingly, a high proportion (45.1%) of Aedes mosquitoes harbored the triple mutations 989SP/1016VG/1534FC with the heterozygous status, suggesting a potentially high level of resistance to pyrethroids. Similar findings were reported from Myanmar [ 36 ]. However, in a study conducted in Senegal [ 37 ], no mutations in the vgsc gene associated with pyrethroid resistance were found despite the phenotypic resistance to pyrethroids observed in Ae.…”

Insecticide Resistance in Aedes aegypti Mosquitoes: Possible Detection of kdr F1534C, S989P, and V1016G Triple Mutation in Benin, West Africa

“…A quadruple mutation, S989P/V1016G/T1520I/F1534C, was also identified in 2022 in Myanmar in Ae. aegypti [24]. High prevalence of the F1534C mutation has been reported previously, but intense phenotypic resistance to pyrethroids is only found when accompanied by the V1016I mutation or V1016G, S989P, and/or V410L [24,25].…”

Molecular analysis of knockdown resistance (kdr) mutations in the voltage-gated sodium channel gene of Aedes aegypti populations from Saudi Arabia

“…They were collected in 2004–2005 when insecticide usage was likely much lower. This fully susceptible genotype was not reported in a more recent study in Myanmar; however, the susceptible haplotype is still present [ 27 , 30 ]. Previous studies have reported the completely susceptible wild type genotype in the Indo-Pacific, including Taiwan [ 33 ], Queensland, Australia [ 67 ] and Malaysia [ 68 ].…”

“…These mutations (S989P, V1016G and F1534C) were reported in the Middle East and Southeast Asia [25]. Kdr mutations at amino acid 1016 have been reported from different geographical locations; for example, V1016G in Southeast Asia since 2009 [26][27][28][29][30][31][32][33], Ghana [34] and Saudi Arabia [17,35]. The mutation S989P is thought not to cause any resistance alone but when co-occurring with V1016G confers resistance against permethrin and deltamethrin [17].…”