Insecticide Susceptibility Tests of Aedes albopictus Skuse in Geothermal Hot Springs, Malaysia

Dengue fever is a major public health concern, including more than 20,000 reported dengue cases annually in Malaysia. Aedes albopictus is the primary vector of chikungunya and secondary vector of dengue and Zika viruses. The susceptibility to dichlorodiphenyltrichloroethane (DDT), dieldrin, fenitrothion, pirimiphos-methyl, propoxur and bendiocarb of Ae. albopictus from four hot springs in Selangor, Malaysia was ascertained in accordance with World Health Organization guidelines. Threeto five -day old female mosquitoes which were reared from eggs collected by ovitraps were exposed to discriminating dosages of insecticides for 1 hr recommended exposure period, and the 24 h mortality was recorded. The Kerling Hot spring (KERL) population was susceptible to six insecticides. All four field populations were susceptible to pirimiphos-methyl 0.25% indicating it could be considered as a replacement insecticide for future vector control operations. Propoxur is the second in line as an alternative insecticide based on mortality > 80.0%. Nevertheless, it is necessary to confirm their crossresistance to pyrethroids and other organophosphates before using them in rotation in the management of insecticide resistance.