Dengue and chikungunya are important arboviral
infections in the Andaman Islands. Competent vectors viz. Aedes aegypti and Aedes albopictus are widely prevalent. The most effective proven method for interrupting the transmission of these arboviruses is vector control, mediated through
insecticides. Currently,
DDT and
temephos are the
insecticides used for vector control in these islands. Lack of information on susceptibility necessitated assessing the susceptibility profile of A. aegypti and A. albopictus. F1 generation of adult and larvae were assayed, and LT50 and LT90 values were interpreted following the World Health Organization (WHO) protocol. Adults were found resistant to
DDT-4 % while susceptible to
dieldrin-0.4 %. Against
organophosphates, both showed resistance to
fenitrothion but susceptible to
malathion-5 %. Both species showed resistance to
carbamate and
bendiocarb-0.1 % while susceptible to
propoxur-0.1 %. Of the four synthetic
pyrethroids, both were susceptible to
deltamethrin-0.05 %, while resistant to
permethrin-0.75 %,
lambdacyhalothrin-0.05 % and
cyfluthrin-0.15 %. Larvae of both species showed resistance to
temephos at 0.02 mg/L but susceptible to
malathion at 1 mg/L and
fenthion at 0.05 mg/L. Currently, there is no prescribed WHO dose for adult-
insecticide susceptibility testing. The emergence of resistance to
DDT and
temephos in the vector population poses a challenge to the on-going vector control measures. The results highlight the need for monitoring resistance to
insecticides in the vector population. Impetus for source reduction and alternative choices of control measures are discussed for tackling future threat of arboviral
infections in these islands.