The risk of human Nipah virus infection directly from bats (Ptoropus hypomelanus) is low

Nipah virus was responsible for the outbreak of fatal encephalitis in Malaysia and Singapore in 1998 – 1999. The migratory pteropid fruit bats, which are probably the natural hosts of the virus, are found ubiquitously throughout South East Asia. In many rural areas in South East Asia, humans live close to the natural habitats of the bats. We report a serological survey of residents in an island off the east coast of Peninsula Malaysia, who live in close proximity to a roosting colony of island flying foxes (Pteropus hypomelanus) from which Nipah virus has been isolated. The objective was to determine the relative risk of Nipah virus infection in humans directly from the bats. One hundred and fifty three adults in Tioman island (8 % of the adult population) were surveyed. The mean age was 37 years, 52 % were males. Fifty-eight subjects resided in Air Batang, a village with the roosting colony of Pteropus hypomelanus. This constituted 39 % of the village adult population. Most of the subjects were employed in tourism related industry and 50 % has resided in the island for more than 5 years. Ten percent has previous physical contact, and 19 % has consumed fruits partially eaten by the bats. None has a history of previous central nervous system infection. The Nipah serology in all of the subjects was negative. Conclusion: The risk of human contracting infection of Nipah virus from bats is low. insectivorous bats. This included 31 % positive antibody status to Pteropus hypomelanus (island flying foxes) and 17 % positive antibody status to Pteropus vampyrus (Malayan flying foxes) in Peninsular Malaysia.12 The virus was later isolated from the urine and swabs of a partially eaten ‘jambu air ’ fruit (Eugenia aquea) of the island flying foxes (Pteropus hypomelanus) in Tioman island off the east coast of Peninsula Malaysia.13 Therefore, the pteropid bats could have served as the natural reservoir of the virus and might have infected the pigs when they fed on fruits in trees planted within the pig farms.14 The infected pigs in turn transmitted the virus to man and other animals.7,10,14 Fruit trees are common throughout the village