The study of using and insecticide resistant in the Eastern Thailand

Insecticide uses continue to be the main method for dengue and malaria vector control in Thailand, but may cause mosquitoes developing resistance to insecticide. This study aimed to identify insecticide resistant situation in Eastern Thailand. The survey questionnaires were used for collecting data of used insecticide of Local Administrative Organizations (LAO) of 9 provinces in the East, and found that 92.7% of LAO have been using insecticide 100% to control Aedes, 11.8% for Anopheles which were organophosphate and pyrethroid. Cypermethrin was the most utilized for adulticide and temephos was the most used for larvicide in Aedes control. The insecticide susceptibility of Aedes aegypti adult from four provinces (Sakaew, Rayong, Chanthaburi and Trat) were conducted under the WHO susceptibility test, the results indicated that all populations of Ae. aegypti resist to permethrin 0.75% and lambdacyhalothrin 0.05%. Almost all Ae. aegypti were incipient resistant or resistant to cyfluthrin 0.15% and deltamethrin 0.05%., but for malathion 5% and fenitrothion 5% were high susceptibility. However, the result of insecticide susceptibility of An. minimus adult from all provinces was high susceptibility to permethrin 0.75% and deltamethrin 0.05%. The diagnostic dose for temephos susceptibility test of Ae. aegypti larvae found that all provinces were high susceptibility to temephos and resistance ratio (RR50 and RR95) of all Ae. Aegypti were 2.47-3.08. Therefore there should be insecticide regularly monitoring and guideline for using insecticide for such period of time that will be applied by every organizations.