Temporal Pattern of Mutations in the Knockdown Resistance ( kdr ) Gene of Aedes aegypti Mosquitoes Sampled from Southern Taiwan

• Published in: The American journal of tropical medicine and hygiene Vol. 101; no. 5; pp. 973 - 975
• Main Authors: Biduda, Sandrine, Lin, Chia-Hsien, Saleh, Fatma, Konradsen, Flemming, Hansson, Helle, Schiøler, Karin L, Alifrangis, Michael
• Format: Journal Article
• Language: English
• Published: United States Institute of Tropical Medicine 01-01-2019; The American Society of Tropical Medicine and Hygiene
• Subjects: Aedes - genetics; Animals; Genotype; Insecticide Resistance - genetics; Insecticides; Insecticides - pharmacology; Mosquitoes; Mutation; Polymorphism, Single Nucleotide; Pyrethrins - pharmacology; Seasons; Taiwan; Time Factors; Taiwan
• ISSN: 0002-9637; 1476-1645
• DOI: 10.4269/ajtmh.19-0289

mosquitoes are the principal dengue vector in Taiwan, where the use of insecticides is a key element in the national control strategy. However, control efforts are constrained by the development of resistance to most insecticides, including pyrethroids. In this study, mutations in the voltage-gated sodium channel (VGSC) gene resulting in knockdown resistance (
) were examined in
. Fragments of the VGSC gene were polymerase chain reaction (PCR)-amplified followed by restriction fragment length polymorphism analysis in samples from various settings in Southern Taiwan covering dry and wet seasons from 2013 to 2015. Three
mutations were identified: V1023G, D1794Y, and F1534C, with observed frequencies of 0.36, 0.55, and 0.33, respectively, in the dry season of 2013-2014. Exploring for temporal changes, the most important observation was the 1534C allele frequency increment in the following season to 0.60 (
< 0.05). This study suggests that continued insecticide pressure is driving the mutational changes, although the selection is ambiguous in the mosquito population.