Nipah virus (NiV) can spread to people from:
- Direct contact with infected animals, such as bats or pigs, or their body fluids (such as blood, urine or saliva)
- Consuming food products that have been contaminated by body fluids of infected animals (such as palm sap or fruit contaminated by an infected bat)
- Close contact with a person infected with NiV or their body fluids (including nasal or respiratory droplets, urine, or blood)
In the first known NiV outbreak, people were probably infected through close contact with infected pigs. The NiV strain identified in that outbreak appeared to have been transmitted initially from bats to pigs, with subsequent spread within pig populations. Then people who worked closely with infected pigs began falling ill. No person-to-person transmission was reported in that outbreak.
However, person-to-person spread of NiV is regularly reported in Bangladesh and India. This is most commonly seen in the families and caregivers of NiV-infected patients, and in healthcare settings. Transmission also occurs from exposure to food products that have been contaminated by infected animals, including consumption of raw date palm sap or fruit that has been contaminated with saliva or urine from infected bats. Some cases of NiV infection have also been reported among people who climb trees where bats often roost.