Outbreak of Japanese encephalitis in Manipur during 1982--some epidemiological features
Chakraborty, A.K.; Chakraborty, S.K.; Chakraborty, M.S.; Singh, N.C.
Journal of Communicable Diseases 16(3): 227-233
1984
ISSN/ISBN: 0019-5138 PMID: 6096442 Document Number: 227605
The first outbreak of Japanese encephalitis in Manipur State, India, occurred in 1982. There were 99 cases, and the case fatality rate was 53.53%. The outbreak started in May, reached a peak in August and was over by the end of November. The highest number of cases (33.3%) occurred in the age group 15-24 years. About 23.9% of household contacts had Japanese encephalitis antibody in their blood, and all 5 blood samples of pigs taken showed a high titre of antibody. Mosquito collections revealed the presence of Culex vishnui, the main vector of the virus in India, C. fatigans [C. quinquefasciatus], Anopheles hyrcanus, A. annularis and Mansonia annulifera. The virus was not, however, isolated from the mosquito pools. This report describes the first major epidemic of Japanese encephalitis in Manipur (north-eastern India). There was a case fatality rate of 54%; epidemiological studies showed the presence of past infection in pigs, although virus could not be recovered. Japanese encephalitis virus was not recovered from mosquito pools.R.N.P. Sutton.