Insecticide Susceptibility of Aedes aegypti in Heath Region 7 in 2018

Abstract

This study was an experimental study. The objective was to determine the insecticide

susceptibility of Aedes aegypti (L.) larvae and adults, the vector of dengue fever. Aedes aegypti larva were collected from urban and rural of Heath Region 7, from 2013 - 2017. Insecticide susceptibility tests were performed with 0.012% (a diagnostic concentration) and 1% (an operational concentration) temephos for larval stages, while diagnostic concentrations of 0.05% deltamethrin, 0.22% cypermethrin, 0.08 % alphacypermethrin, 5% malathion, 1% fentitrothion and 0.05% deltamethrin + 4 % piperonyl butoxide (PBO) were tested with adult stage using WHO tube bioassay.

The results showed strong resistance of Ae. aegypti in all population to 0.012 % temephos, whilst an operational concentration at 1% temephos still efficient kill all mosquitoes. Aedes aegypti has developed resistance to deltamethrin in some areas with mortality ranging from 75%-100%. However, when 0.05% deltamethrin was mixed with 4% piperonyl butoxide (PBO), mortality rate was increase between 96% to 100%. Most areas were resistance to 0.22% cypermethrin, with mortality rates at 50 - 76 %, and resistance with 0.08 % alpha-cypermethrin were mortality rates at 45 % - 88 %. Some areas were resistance to 5% malathion, with mortality rates at 67% - 77%. Most areas were resistance to 1% fenitrothion, with mortality rates ranging from 35% to 75%. These findings indicate Ae. aegypti resistance to various chemicals, expanding across different areas. One contributing factor is the widespread use of various chemicals for dengue fever control in these regions. The findings of this study indicate a growing trend of Ae. aegypti resistance to insecticides. The potential of insecticides resistances may be due to improper use or the repeated use of the same chemicals over time, which can reduce the effectiveness of disease control efforts. Therefore, it is crucial for the Office of Disease Prevention and Control 7 Khon Kaen (ODPC 7) to monitor systematically and continuously. This information is vital for selecting the most effective chemicals to control the vector. However, the most efficient, cost-effective, safe, and easy-to-implement measure for dengue fever prevention are the reduction and elimination of mosquito breeding sites, which offers a permanent solution by controlling Aedes larvae.