Nipah virus disease is caused by the Nipah virus (NiV). The virus is carried by fruit bats, also known as flying foxes. The virus can be spread directly from bats to people through consuming fruits or fruit products (such as raw date palm juice) contaminated with urine or saliva from infected fruit bats, or through contact with domestic animals that have been infected with the virus. Person-to-person transmission is also possible through close contact with an infected person, for example by caring for patients with Nipah virus disease.
Human infection can range from no symptoms to mild or acute respiratory infections. In some cases, it can result in fatal encephalitis (brain infection). The interval from infection to illness is estimated to range from 4 to 14 days but can be longer.
The first identified outbreak of Nipah virus was in 1999 among pig farmers in Malaysia and Singapore. The virus was initially spread from fruit bats to pigs, however other domestic animals including horses, goats, sheep, cats and dogs were also infected. Nipah virus outbreaks are reported most years in Bangladesh. Periodic outbreaks have also been reported from India, Malaysia, the Philippines and Singapore. The fruit bats that carry the virus are found throughout Asia, the South Pacific and Australia.
There is no specific antiviral treatment available for people or animals. Mild symptoms can be treated with rest, drinking fluids to prevent dehydration, and taking over the counter pain relief to reduce pain and fever.
Prevention
There is no vaccine or medication to prevent or treat Nipah virus disease. Risk of infection can be reduced through taking steps to minimise exposure to the virus. The following will help reduce the risk of infection:
- Avoid contact with sick animals or their tissues, particularly during slaughtering procedures. If contact is unavoidable, gloves and protective clothing should be worn.
- Freshly collected date palm juice should be boiled, and fruits should be thoroughly washed and peeled before consumption. Fruits with sign of bat bites should be discarded.
- Avoid close or unprotected contact with people known to be infected with Nipah virus. Wash hands thoroughly after caring for or visiting people with the virus.
Information about NiV transmission can be found in the 'Outbreaks' section of our Country Information pages. Nipah virus disease cases may not always be diagnosed or consistently reported in some countries.