Virological study of an epidemic of febrile illness with haemorrhagic manifestations at Kanpur, India, during 1968.

Several epidemics of febrile illnesses associated with haemorrhagic manifestations occurred in India during 1963 and 1964. These epidemics were restricted to the eastern coastal areas. However, in northern India, for the first time, a widespread epidemic of febrile illness associated with haemorrhagic manifestations occurred at Kanpur in 1968. In the present study, the virological findings of the epidemic are reported.The role of dengue type 4 virus in the epidemic is demonstrated by the isolation of the virus from a number of cases, including one with haematemesis, and conversion of antibody titres with dengue type 4 virus in the paired sera.