Epidemiology of Japanese encephalitis

Seven hundred and sixty-two cases of Japanese Encephalitis (JE) were studied during the last 5 years (1985-1989) in relation to age, sex, religion, nutritional status, living habits, exposure to domestic animals and mosquitos, clinical profile, seasonal variation and mortality pattern. The maximum occurrence was in 1987-1988 and it showed a preponderance in males (51-82%). The disease is progressively decreasing in Muslims (3-7%) and gradually increasing in tribes (25-60%). Children in the age-group of 6-7 years (19-25%) were maximally affected and the disease was rare in infancy. The common features were coma, convulsions, neck rigidity and fever (88-97%). Gastrointestinal manifestations were rare (3.6%) but were associated with the highest mortality. About 80-95% had exposure to domestic animals directly or indirectly and 95% of the patients were not using mosquito nets. The CSF protein and sugar content were normal, with or without slight leucocytosis while the lymphocyte count was variable. The CSF and blood picture had no significant relation with clinical presentation and prognosis.