Japanese encephalitis (JE) caused by Japaneseencephalitis virus (JEV) is widely spread in the eastand southeast part of Asia and number of human casesare estimated approximately 20000 annually in theworld. The epidemic area is expanding recently as anewly emerging disease in the Oceanic countries. JEV is transmitted by a variety of mosquitoesspecified in the area, main vector being culicinespecies. Seasonal incidence of human cases is noted inthe epidemic regions influenced by the emergingseason of vector mosquitoes. Evidence is accumulatedthat pigs plays an important role is the natural historyof JEV. Indeed, infected human cases are observedmore frequently in countries where pigs arecommonly domesticated. It was recorded in Japan thatJE epidemic is parallel to the number of farms and notto the absolute numbe of pig population showing Japanese encephalitis (JE) was widely spread in the east and southeast part of Asia and number of human cases were estimated about 20000 annually in theworld. JEV is transmitted by a variety of mosquito-specified in the area, the main vector being culicinespecies. The main vector being culicinespecies. The main vector being culicinespecies. The main vector being culicinespecies. infected people cases were observed more frequently in countries where pigs arecommonly domesticated. It was recorded in Japan thatJE epidemic is parallel to the number of farms and notto the absolute numbe of pig population showing