Mosquito distribution and Japanese encephalitis virus infection in the immigration bird (Asian open-billed stork) nested area in Pathum Thani province, central Thailand

Abstract

Japanese encephalitis virus infection is a mosquito-borne emerging or re-emerging infectious disease in several countries. The ecology of this virus in nature includes amplifying avian or mammal hosts and mosquito vectors. Infected immigration birds from epidemic areas may play important roles in the outbreak of the disease. The prevalence is high during the raining season in Thailand and human cases have been reported from several provinces including Bangkok suburbs. This study was conducted to investigate the mosquito distribution and Japanese encephalitis virus infection in the immigration bird (Asian open-billed stork) nested area, Pathum Thani province, central Thailand. Mosquitoes were collected by using CO(2)-baited Centers for disease control and prevention (CDC) light traps, and dry ice was used as a source of CO(2) to attract mosquitoes from March 2008 to January 2009. Eight traps were operated from 4 p.m. until 7 a.m. on each study day. There were seven genera collected: Aedes, Anopheles, Armigeres, Coquillettidia, Culex, Mansonia, and Uranotaenia. Culex tritaeniorhynchus was the most collected species in each month, except November, in which Culex gelidus was the most collected species. Sixty pools of C. gelidus and of C. tritaeniorhynchus, each of which had 50 mosquitoes, were tested for Japanese encephalitis virus infection by using reverse transcription polymerase chain reactions; however, none of them was infected with the virus.