The continued absence of an effective and safe
tetravalent dengue vaccine and the lack of specific anti-viral treatment have made mosquito vector control using chemical
insecticides as the mainstream for
dengue prevention and control. However, the long-term use of chemical
insecticides may induce resistance. Hence detection of insecticide resistance in
dengue vectors is crucially important in ensuring the
insecticide-based intervention in
dengue control program is still effective and reliable. In this study, the susceptibility status of Aedes aegypti from five selected
dengue hotspots in Klang Valley, Malaysia against
pyrethroids was determined by employing the World Health Organization (WHO) protocol of adult bioassay. Four types of
pyrethroids were tested against adult female Aedes aegypti to determine the knockdown rate, post 24-h adult mortality and resistance ratio. All field-collected Aedes aegypti strains were resistant to the four
pyrethroids tested, except for the Taman Sungai Jelok (TSJ) strain.
Permethrin exhibited the lowest knockdown rate against Aedes aegypti, followed by
deltamethrin,
cyfluthrin and
lambda-cyhalothrin. This present study indicated the widespread of
pyrethroid resistance in Aedes aegypti in Klang Valley, indicating the needs of implementing alternative measures in vector control program. The data in this study can be utilised as an input for insecticide resistance management of Aedes aegypti in Malaysia.