Epidemiological aspects of Nipah virus infection Kay-Sin TAN MRCP, Chong-Tin TAN FRCP MD, Khean-Jin GOH MRCP Division of Neurology, Department of Medicine,University of Malaya,Kuala Lumpur Abstract An outbreak of Nipah encephalitis secondary to a new paramyxovirus virus occured among pig

An outbreak of Nipah encephalitis secondary to a new paramyxovirus virus occured among pig farmers in Malaysia from September 1998 to June 1999. The objective of this study was to characterize several epidemiological aspects of the outbreak. The study was based on patients admitted to the University Hospital, Kuala Lumpur and their household members. Fourteen households with 110 members were studied. Thirty out of 110 (27%) of the household members had symptomatic Nipah infection. Another 6 out of 43 (8%) members had subclinical infection with positive serology with a total of 33% of the household members being infected by Nipah virus. There was significant correlation between full time pig farming and the likelihood of Nipah infection. Twenty-five out of 43 members (51%) who had high exposure to pigs had symptomatic Nipah infection whereas 5 out of 24 members (21%) who had minimum exposure to pigs were infected. Half of the 14 households reported sick or dying pigs. There was no correlation between the rate of symptomatic human Nipah infection and history of animals falling sick (p=0.8). The cases indicated that the infection may spread from pig to man via infected body fluid with direct body contact and via respiratory droplets at close range. Animals other than pigs may also transmit the disease to man and from pig-to-pig.