According to the Centers for Disease Control and Prevention (CDC), the Nipah Virus (NiV) is a zoonotic virus, meaning it can initially spread between animals and humans. It is a member of the family Paramyxoviridae, Henipavirus genus, which is genetically related to Hendra virus, also known to be carried by bats. The fruit bat, or what’s called the flying fox, is the animal host reservoir of the NiV. Infected flying foxes can spread the NiV to other animals like pigs. Humans, on the other hand, get infected in what’s called a spillover event, where a person comes in contact with an infected animal or its body fluid, gets infected, then causes the initial spread.

The first documented Nipah virus outbreak happened in Malaysia in 1999, also affecting Singapore. The initial outbreak, which was among pig farmers, was linked to human contact with infected pigs or their contaminated tissues. Nearly 300 human cases and more than 100 deaths were reported. In an effort to control the outbreak, more than 1 million pigs were culled, substantially impacting the Malaysian economy at the time. NiV has since been reported in Bangladesh, India, and Indonesia. 

In September 2023, Indian authorities once again hastened to contain an outbreak of Nipah in Kerala, India. Reports claim that fruit bats have been identified as the carriers of the virus and the cause of subsequent outbreaks. Eating fruits and other fruit products contaminated with bat urine or saliva most likely facilitated the spread of the infection. According to a Reuters investigation, parts of Kerala are among those at high risk for outbreaks of bat viruses.