Overall Prevalence and Distribution of Knockdown Resistance (kdr) Mutations in Aedes aegypti from Mandalay Region, Myanmar

Abstract

Knockdown resistance (<i>kdr</i>) mutations in the voltage-gated sodium channel (VGSC) of mosquitoes confer resistance to insecticides. Although insecticide resistance has been suspected to be widespread in the natural population of <i>Aedes aegypti</i> in Myanmar, only limited information is currently available. The overall prevalence and distribution of <i>kdr</i> mutations was analyzed in <i>Ae. aegypti</i> from Mandalay areas, Myanmar. Sequence analysis of the <i>VGSC</i> in <i>Ae. aegypti</i> from Myanmar revealed amino acid mutations at 13 and 11 positions in domains II and III of <i>VGSC</i>, respectively. High frequencies of S989P (68.6%), V1016G (73.5%), and F1534C (40.1%) were found in domains II and III. T1520I was also found, but the frequency was low (8.1%). The frequency of S989P/V1016G was high (55.0%), and the frequencies of V1016G/F1534C and S989P/V1016G/F1534C were also high at 30.1% and 23.5%, respectively. Novel mutations in domain II (L963Q, M976I, V977A, M994T, L995F, V996M/A, D998N, V999A, N1013D, and F1020S) and domain III (K1514R, Y1523H, V1529A, F1534L, F1537S, V1546A, F1551S, G1581D, and K1584R) were also identified. These results collectively suggest that high frequencies of <i>kdr</i> mutations were identified in Myanmar <i>Ae. aegypti</i>, indicating a high level of insecticide resistance.