About Nipah Virus

Key points

  • Nipah is a serious, and sometimes deadly, viral disease.
  • Nipah virus is spread by fruit bats and can make people and other animals sick.
  • Nipah virus can be spread from person to person.
  • Nipah outbreaks occur nearly every year in parts of Asia, often in Bangladesh and India.
  • Around 40%–70% of people with Nipah die.
Flying fox fruit bat in the sky

What it is

Nipah virus causes disease that can spread between animals and people. Nipah virus is carried by fruit bats (genus Pteropus), also known as flying foxes.

In 1999, Nipah was first discovered following an outbreak in pigs and people in Malaysia and Singapore. Three hundred people got sick and more than one hundred of those people died. In this first outbreak, bats initially spread the Nipah virus to pigs. People who worked closely with the infected pigs got sick, as well.

Nipah outbreaks have only been reported from Bangladesh, India, Malaysia, Philippines, and Singapore. However, the fruit bats that carry the Nipah virus are found throughout Asia, the South Pacific, and Australia.

Map showing presence of fruit bats and Nipah outbreaks
Fruit bats (yellow) are even found where Nipah outbreaks (red) haven't occurred.

Signs and symptoms

Nipah can cause mild to severe disease, including swelling of the brain and death.

People with Nipah are typically sick for 3 to 14 days with fever, headache, cough, sore throat, and difficulty breathing. Later in the infection, some people may experience brain swelling, or encephalitis, where severe symptoms can include confusion, drowsiness, and seizures. People with these symptoms can fall into a coma within 24-48 hours.

How long it takes for signs to show

People with Nipah usually start getting sick 4-14 days after they were infected with the virus.

How it spreads

People can be infected with Nipah from:

  • Direct contact with infected animals, like bats or pigs
  • Consuming food or drinks, like fruit or raw date palm sap, that are soiled by infected animals
  • Close contact with body fluids of an infected person

A person may become infected by drinking raw date palm sap or eating fruit that is contaminated by an infected bat. This initial spread from an animal to a person is known as a spillover event.

Once a person is infected with Nipah, the virus can spread from person to person.

Reducing risk

Caregivers and healthcare providers caring for a patient with Nipah are at a higher risk of becoming infected.

If you travel to or live in an area where Nipah virus outbreaks have occurred, you should:

  • Wash your hands regularly with soap and water.
  • Avoid contact with flying fox bats or sick pigs.
  • Avoid areas where bats roost or
  • Avoid touching anything that could be soiled by bats.
  • Avoid eating raw date palm sap or fruit that could be soiled by bats.
  • Avoid contact with the blood or body fluids of someone with Nipah.

Tesing and diagnosis

Healthcare providers should consider Nipah for people with relevant symptoms who have been where the disease occurs, like Bangladesh or India.

Healthcare providers can test people for Nipah while they're sick or after they've recovered.

Treatment and recovery

Currently there are no licensed treatments for Nipah. Treatment is limited to supportive care, including rest, hydration, and treatment of other symptoms.