The Prevalence, Biting Time of Anopheles spp. and its Susceptibility to Synthetic Pyrethroids in Ratchaburi Province

Abstract

The objectives of this research were to delineate the prevalence biting time and susceptibility of Anopheles moquitoes to synthetic pyrethroids (Permetrin 0.75% and Deltamethrin 0.05%) in transmission areas of Ratchaburi province. The mosquitoes were collected in June July and October by light trap during 18.00-24.00 PM inside and outside the houses. The susceptibility test was done following WHO methods. The results showed that the most common species were A. minimus, A. maculates, A. dirus and A. barbirostris with prevalence rates of 48.15, 25.93, 14.81 and 11.11 percent, respectively. The susceptibity of A. minimus in all areas to Permethrin 0.75% . The mortality rates after exposure to Permethrin 0.75% were 98-100 percent while those of Deltamethrin 0.05% were 99-100 percent. The using synthetic pyrethroids (Permethrin and Deltamethrin) for Anopheles mosquitoes control is still effective in these areas. Therefore Malaria vectors and susceptibility test to insecticides should be should be studied as a sentinel surveillance. However, chemical using to control Malaria should be under control of experts to avoid the chemical resistance of .vectors.