Association between Three Mutations, F1565C, V1023G and S996P, in the Voltage-Sensitive Sodium Channel Gene and Knockdown Resistance in Aedes aegypti from Yogyakarta, Indonesia.

Juli Rochmijati Wuliandari,Ary Anthony Hoffmann,Siu Fai Lee,Vanessa Linley White,Nancy Margaret Endersby-Harshman,Warsito Tantowijoyo

doi:10.3390/insects6030658

Juli Rochmijati Wuliandari, Ary Anthony Hoffmann + Show 4 more

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https://doi.org/10.3390/insects6030658

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Journal: Insects	Publication Date: Jul 23, 2015
Citations: 71	License type: CC BY 4.0

Affiliation: University of Melbourne

Abstract

Mutations in the voltage-sensitive sodium channel gene (Vssc) have been identified in Aedes aegypti and some have been associated with pyrethroid insecticide resistance. Whether these mutations cause resistance, alone or in combination with other alleles, remains unclear, but must be understood if mutations are to become markers for resistance monitoring. We describe High Resolution Melt (HRM) genotyping assays for assessing mutations found in Ae. aegypti in Indonesia (F1565C, V1023G, S996P) and use them to test for associations with pyrethroid resistance in mosquitoes from Yogyakarta, a city where insecticide use is widespread. Such knowledge is important because Yogyakarta is a target area for releases of Wolbachia-infected mosquitoes with virus-blocking traits for dengue suppression. We identify three alleles across Yogyakarta putatively linked to resistance in previous research. By comparing resistant and susceptible mosquitoes from bioassays, we show that the 1023G allele is associated with resistance to type I and type II pyrethroids. In contrast, F1565C homozygotes were rare and there was only a weak association between individuals heterozygous for the mutation and resistance to a type I pyrethroid. As the heterozygote is expected to be incompletely recessive, it is likely that this association was due to a different resistance mechanism being present. A resistance advantage conferred to V1023G homozygotes through addition of the S996P allele in the homozygous form was suggested for the Type II pyrethroid, deltamethrin. Screening of V1023G and S996P should assist resistance monitoring in Ae. aegypti from Yogyakarta, and these mutations should be maintained in Wolbachia strains destined for release in this city to ensure that these virus-blocking strains of mosquitoes are not disadvantaged, relative to resident populations.

Highlights

As in many tropical countries around the world, dengue continues to be a major public health concern in Indonesia
We found a suggestion of a synergistic effect of the S996P mutation when it occurred in conjunction with V1023G, in relation to the Type II pyrethroid, deltamethrin which is similar to the findings of Hirata et al [37]
An association between resistance to permethrin and deltamethrin was identified for the V1023G mutation

Summary

Introduction

As in many tropical countries around the world, dengue continues to be a major public health concern in Indonesia. While dengue vaccine development has been an area of active research, the main way to prevent and control dengue virus transmission is to target its primary vector, the mosquito, Aedes aegypti (L.). Current dengue control in Indonesia focuses on community-based elimination of mosquito breeding sites [3,4,5,6], chemical insecticides have been an important tool for more than 40 years of dengue vector control [6,7,8,9]. The two classes of insecticide that have been utilized intensively to prevent or reduce dengue transmission are organophosphates (temephos and malathion) and pyrethroids. Malathion fogging to control adult mosquitoes has been in use since 1973 [10] and, starting in 1980, was supplemented with use of temephos larvicides [7]

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