Henipavirus is a genus of the family paramyxoviridae containing two members, Hendra virus and Nipah virus. The henipaviruses are characterised by their large size (18.2 kilobases; Wang et al., 2001), their natural occurrence in fruit bats, and their recent emergence as zoonotic pathogens capable of causing illness and death in domestic animals and humans.
Hendra virus was discovered in 1994 when it caused the deaths of thirteen horses, a trainer and a stablehand at a training complex in Hendra, a suburb of Brisbane, Australia. A second outbreak occurred in McKay, 1000km north of Brisbane resulting in the death of two horses and their owner (Field et al., 2001). Symptoms of infection include respiratory illness and encephalitis. The route of transmission from bats to horses and humans is unknown, however, as there is no evidence that Hendra virus is transmitted directly to humans, it is believed that human infection occurs via exposure to an infected intermediate host.
Nipah virus was identified in 1999 when it caused an outbreak of neurological and respiratory disease on pig farms in peninsular Malaysia, resulting in 105 human deaths and the culling of one million pigs (Field et al., 2001). Symptoms of infection are primarily encephalitic in humans and respiratory in pigs. Like Hendra virus, Nipah virus is believed to be transmissible to humans only via an intermediate host.
References
Field, H., Young, P., Yob, J. M., Mills, J., Hall, L., Mackenzie, J. (2001). The natural history of Hendra and Nipah viruses. Microbes and Infection 3, 307–314.Wang, L., Harcourt, B. H., Yu, M., Tamin, A., Rota, P. A., Bellini, W. J., Eaton, B. T. (2001). Molecular biology of Hendra and Nipah viruses. Microbes and Infection 3, 279–287.
