Nipah virus infection is a zoonotic viral disease caused by a paramyxovirus of the genus Henipavirus, naturally hosted by fruit bats of the Pteropodidae family [1][3][4]. It is transmitted to humans from animals, through contaminated food, or directly between people, and is classified as a Biosafety Level-4 agent endemic in South Asia [1][4][5].
Disease overview
Evidence-backed information EN 5/7 applicable sections · ZH 5/7 applicable sections Updated Oct 23, 2026
Nipah virus infection is a zoonotic illness first identified in 1998 among pig farmers in Malaysia and subsequently reported in Bangladesh, India, the Philippines, and Singapore [1][2]. The disease causes a spectrum from asymptomatic infection to severe respiratory and neurological illness, with case fatality estimates ranging from 40% to 80% [2][3][4]. It is recognized as a WHO priority pathogen with high pandemic potential, and preparedness relies on surveillance, infection control, and a One Health approach [1][3][5].
Read the full clinical and epidemiological profile 6
Infection produces a range from asymptomatic cases to acute respiratory illness and encephalitis in the most severe presentations [2]. Most patients develop fever with neurological symptoms such as headache or confusion and respiratory symptoms such as cough or breathing difficulty, alongside chills, fatigue, vomiting, and diarrhoea [2]. The incubation period is typically 3 to 14 days, rarely up to 45 days, and severe disease with brain swelling and frequent death is especially associated with neurological involvement [2].
Outbreaks were first detected in 1998–1999 among pig-associated settings in Malaysia and Singapore, with no further reports from those countries since [1][2]. From 2001 onward, annual or periodic outbreaks have occurred in Bangladesh and India, and a 2014 event was reported in the Philippines [1][2]. The virus shows sporadic outbreak patterns, high case fatality of roughly 40%–80%, and is considered endemic in South Asia with pandemic potential [3][4][5].
The natural reservoir is fruit bats of the Pteropodidae family, with transmission to humans via direct contact with infected bats, pigs, or horses and via consumption of bat-contaminated fruit products such as raw date palm juice [1][2]. Human-to-human spread occurs through close contact, including in healthcare settings and among family caregivers, with increased risk in overcrowded or poorly ventilated facilities [1][2]. Contaminated food and direct interpersonal exposure are additional routes [1][2].
Public-health prevention emphasizes strengthening surveillance, laboratory services, infection prevention and control in healthcare, and community engagement supported by WHO and partners [1]. A One Health approach addressing bat-to-human chains is considered necessary, and rapid diagnosis with implementation of infection control measures is essential to contain outbreaks [5]. No approved vaccines or antivirals are available, so preparedness depends on technical guidance, training, and cross-country exchange of expertise [1][3][5].
- 1 World Health Organization. Nipah virus fact sheet [Internet]. cited 4 Sept 2026. Available from: https://www.who.int/news-room/fact-sheets/detail/nipah-virus
- 2 World Health Organization. Nipah virus infection [Internet]. cited 4 Sept 2026. Available from: https://www.who.int/health-topics/nipah-virus-infection
- 3 Madhukalya R et al. Nipah virus: pathogenesis, genome, diagnosis, and treatment. Appl Microbiol Biotechnol. 2025 Jul 1. PMID: 40593310. doi: 10.1007/s00253-025-13474-6. PubMed: https://pubmed.ncbi.nlm.nih.gov/40593310/
- 4 Angeletti S et al. Molecular epidemiology and phylogeny of Nipah virus infection: A mini review. Asian Pac J Trop Med. 2016 Jul. PMID: 27393089. doi: 10.1016/j.apjtm.2016.05.012. PubMed: https://pubmed.ncbi.nlm.nih.gov/27393089/
- 5 Aditi et al. Nipah virus infection: A review. Epidemiol Infect. 2019 Jan. PMID: 30869046. doi: 10.1017/S0950268819000086. PubMed: https://pubmed.ncbi.nlm.nih.gov/30869046/
- B33.8
- 1D64
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Epidemiology and Infection
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