West Nile Virus Surveillance Project in Thailand

Abstract

This cross sectional study was held during year 2005-2006, to survey the West Nile virus in Culex mosquitoes, serum of birds and horses. The ELISA and PCR technique were adopted to detect the parasite. The positive IgM West Nile virus specimens will be confirmed by technique of Plaque Reduction Neutralization Test (PRNT) at Unité des virus émergents, Faculté de Médecine, Marseille Institute de Recherché pour le Development (IRD). France. In year 2005, all of mosquitoes and serum of birds from Nakhon Sawan, Pathum Thani, Prachin Buri and Ayutthaya provinces had shown negative. In year 2008, collecting of mosquitoes and birds were still being done in the same areas and also to survey in horses from open farm at Kanchanaburi, Nakhon Ratchasima, Saraburi and Phuket province. The result had shown a pool of Culex vishnui from Nakhonsawan had infected the harmless Wang Thong virus, and the horses from Kanchanaburi province had infected with positive IgM West Nile virus at the infection rate of 6%. So that the active survey for West Nile virus surveillance should be done in birds and mosquitoes during rainy season, and the passive survey in horse for 2 times every 1 or 2 weeks after season stop.