Mosquito Distribution and Japanese Encephalitis Virus Infection in a Bat Cave and Its Surrounding Area in Lopburi Province, Central Thailand

Mosquito distribution and Japanese encephalitis virus (JEV) infection were studied in a bat cave and its surrounding area in Lopburi province, central Thailand. Mosquitoes were collected from May 2009 to April 2010 by using CO2-baited CDC-light traps, and dry ice as a source of CO2 to attract mosquitoes. Mosquitoes were identified and tested for JEV infection by using reverse transcription polymerase chain reaction (RT-PCR). Five genera of mosquitoes collected from the bat cave include Aedes, Anopheles, Armigeres, Culex and Uranotaenia, and eight genera of mosquitoes collected from the area close to the bat cave include Aedes, Aedeomyia, Anopheles, Armigeres, Coquillettidia, Culex, Mansonia and Uranotaenia. The dominant species of the collected mosquitoes from these two areas were Cx. quinquefasciatus, Cx. tritaeniorhynchus and Ar. subalbatus. There was only one species of blood-fed mosquitoes collected from the bat cave in this study, which was Cx. quinquefasciatus. Blood meal identification based on cytochrome b sequences in this study indicated that all mosquito blood meals were blood from the fruit bat, Rousettus leschenaulti. A total of 61 pools of mosquitoes were collected from the bat cave: six pools of Ar. subalbatus, one pool of Cx. gelidus, 39 pools of Cx. quinquefasciatus and 15 pools of Cx. tritaeniorhynchus. A total of 110 pools of mosquitoes were collected from the area close to the bat cave: six pools of Ae. albopictus, three pools of An. stephensi, 23 pools of Ar. subalbatus, two pools of Cx. gelidus, 36 pools of Cx. quinquefasciatus and 40 pools of Cx. tritaeniorhynchus. Each of these pools in this study, which contains 10 mosquitoes was tested for JEV infection by using RT-PCR, and all of them were negative.