Serodiagnosisby the ELISAon Encephalitis in

One hundred forty two serum specimens from 114 encephalitis cases in Chiang Mai, Thailand collected during epidemic period in 1983, were measured for their antibody titers against Japanese encephalitis (JE) and dengue virus type 2 antigens by the ELISA. Seventeen cases were diagnosed as JE, while 12 were considered as possible dengue en- cephalopathy by IgM-ELISA. Age distribution of JE cases showed its peak in the group of 10-14 years old, while possible dengue encephalopathy distributed from 10 up to 49 years old. Indirect IgG-ELISA using JE antigen detected 26 cases of secondary flavivirus infections, with highest incidence in 10-14 years old.