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Nipah virus


Nipah is a zoonotic disease that can be transmitted between humans and animals. It was first identified in 1999 during a human outbreak in Malaysia and Singapore and was named after the village in Malaysia where pig farmers first became ill with the disease. Additional human outbreaks have since been reported in Bangladesh and India.


Fruit bats of the Pteropus genus, also known as flying foxes, are the natural reservoir for the Nipah virus and play a pivotal role in its maintenance and transmission. These bats live in the tropics and subtropics of Asia (including the Indian subcontinent), Australia, East Africa, Madagascar and several island chains in both the Indian and Pacific Oceans, thus potentially placing the countries within these areas at risk for spread of the disease. Bats infected with Nipah virus show no clinical signs of disease, but are able to shed the virus in their bodily fluids, such as urine, feces and saliva, and spread it to pig and human populations. Outbreaks have been associated with consuming raw date palm sap as well as drinks (including fermented drinks) made from it, which were contaminated with infectious bat feces, urine or saliva.


Pigs infected with Nipah virus can be asymptomatic or develop respiratory or neurologic disease, eliminating the virus in urine, saliva, and respiratory secretions. These secretions, along with raw pig tissues, serve as sources of infection for other pigs and humans. Human-to-human transmission of Nipah virus can occur following close contact with infected humans or their saliva, respiratory secretions or urine. Clinical signs in humans range from asymptomatic to mild or severe respiratory infection, and/or fatal inflammation of the brain (i.e. encephalitis).