Japanese Encephalitis Virus Vaccine.

Endemic viral encephalitis in Asia is caused by a flavivirus, Japanese encephalitis virus, carried by niosquitoes. Japanese encephalitis may present as a subclinical infection or as an acute meningoencephalomyelitis with cortical lesions similar to those of poliomyelitis. It is transmitted through an enzootic cycle among mosquitoes, pigs, and wading (Ardeid) birds. Culex mosquitoes are the main vectors. In fact, estimates of the prevalence of this virus in mosquitoes range from less than 1 to 3%’ Ground pools and rice paddies are well known larval development sites for these mosquitoes.