Temephos susceptibility status of field-collected Aedes aegypti (L.) larvae from different regions of Thailand.

Abstract

At present, container breeding reduction strategies involve in the control of Aedes aegypti larvae through physical and chemical methods. Currently, the common chemical used for controlling Ae. aegypti (L.) larvae is temephos. The WHO recommends a concentration of 1 ppm, which is safe for mammalian consumption and can be put in drinking water. However, temephos has been used for a long period of time and in the past a variety of concentrations had been used. Therefore, monitoring temephos resistance must be done periodically to ensure treatment efficacy. The goal of this research was to study the susceptibility status of field-collected Ae. aegypti (L.) larvae from different regions of Thailand to temephos by using the WHO susceptibility test at the diagnostic concentration of 0.02 milligrams/liter. The study was conducted during 2010-2012. The results showed that most of the field-collected Ae. aegypti larvae were susceptible to temephos (mortality 98±2.00-100%), while 15 of 60 field strains in the study had incipient resistance (mortality 82±7.57- 97±1.92%). We concluded that most of the tested Ae. aegypti field strains were still susceptible to the chemical compound that has been used to control dengue vectors.The chemical compound used to control larvae therefore still ought to be effective in controlling dengue vectors in Thailand.