Isolation of Japanese encephalitis virus was attempted from Culex tritaeniorhyncus and the blood from slaughtered swines during the summer from 1967 to 1970 in Oita Prefecture. Virus was isolated 7 days in 1967, 3 days in 1968, 13 days in 1970 earlier from the swines than from the pools of collected Culex tritaeniorhynchus.
Only in 1969, the virus was isolated from the mosquitoes 7 days earlier than from the swines.
Isolation of the virus from slaughtered swines may provide an adequate tool in the local laboratories for a certain purpose of the epidemiological study of Japanese encephalitis comparing with the laborious works of virus isolation from mosquitoes collected in the field.