RESUMEN
An outbreak of encephalitis in Bellary district of Karnataka state and adjoining areas of Andhra Pradesh which occurred during October 1986 to January, 1987, has been investigated. Out of the 219 patients reported, 110 were from Bellary district and the remaining 109 were from Anantapur and Kurnool districts of Andhra Pradesh; 131 (59.8%) were males and 88 (40.2%) females, while 192 (87.7%) patients were aged 10 yr and below. Sixty one patients died giving a case fatality rate of 27.9 per cent. Virological/serological investigations were carried out on 153 patients. Japanese encephalitis (JE) virus was isolated from the brain tissue of 2 cases. On the basis of the results of serological tests and virus isolation, a flavivirus (JE/WN/DEN) etiology could be established in 116 (75.8%) patients.