Nipah virus infection - India
30 January 2026
Situation at a glance
On 26 January 2026, the National IHR Focal Point for India notified WHO of two laboratory‑confirmed cases of Nipah virus (NiV) infection in West Bengal State. Both are healthcare workers at the same private hospital in Barasat (North 24 Parganas district). NiV infection was confirmed at the National Institute of Virology in Pune on 13 January. One case remains on mechanical ventilation as of 21 January, the other case experienced severe neurological illness but has since improved. Authorities have identified and tested over 190 contacts, who all tested negative for NiV with support from a mobile BSL‑3 laboratory deployed by the National Institute of Virology, Pune. No further cases have been detected to date. This event represents the third NiV infection outbreak reported in West Bengal (previous outbreaks reported in Siliguri in 2001 and Nadia in 2007). Enhanced surveillance and infection prevention and control (IPC) measures are in place while investigations into the source of exposure are ongoing. NiV infection is a serious but rare zoonotic disease transmitted to humans through infected animals (such as bats), or food contaminated with saliva, urine, and excreta of infected animals. It can also be transmitted directly from person to person through close contact with an infected person. There are currently no licensed medicines or vaccines for NiV infection, however early supportive care can improve survival. WHO assesses the risk posed by Nipah to be moderate at the sub-national level, and low at the national, the regional and global levels.
Description of the situation
On 26 January 2026, the India IHR NFP notified WHO of two confirmed NiV infection cases that occurred in West Bengal State. Preliminary laboratory testing suggested NiV infection, and confirmation was received from the National Institute of Virology, Pune on 13 January 2026.
The cases were confirmed through Reverse Transcription Polymerase Chain Reaction (RT-PCR) and Enzyme-Linked Immunosorbent Assay (ELISA) testing.
The first case is a female nurse and the second case is a male nurse. Both cases were between 20 – 30 years old, from Barasat, North 24 Parganas district. Both cases developed symptoms typical of severe NiV infection in late December 2025 and were admitted to hospital in early January 2026. As of 21 January 2026, the second case showed clinical improvement, while the first case remained under critical care.
Following the two confirmed cases, Indian health authorities identified and tested over 190 contact persons, including health and care workers and community contacts. All samples from contact persons tested negative for NiV.
The Indian National Centre for Disease Control, announced on 27 January that no further confirmed cases have been detected in West Bengal from December 2025 to date.
Epidemiology
NiV infection is a zoonotic disease transmitted to humans through infected animals (such as bats), or food contaminated with saliva, urine, and excreta of infected animals. It can also be transmitted directly from person to person through close contact with an infected person. Fruit bats or flying foxes (
Pteropus species) are the natural hosts for the virus.
The incubation period ranges from 3 to 14 days. In some rare cases incubation of up to 45 days has been reported. Laboratory diagnosis of a patient with a clinical history of NiV infection can be made during the acute and convalescent phases of the disease by using a combination of tests. The main tests used are RT-PCR from bodily fluids and antibody detection via ELISA.
Human infections range from asymptomatic infection to acute respiratory infection (mild, severe), and fatal encephalitis (brain swelling).
Infected people initially develop symptoms including fever, headaches, myalgia (muscle pain), vomiting and sore throat. This can be followed by dizziness, drowsiness, altered consciousness, and neurological signs that indicate acute encephalitis. Some people can also experience atypical pneumonia and severe respiratory problems, including acute respiratory distress. Encephalitis and seizures occur in severe cases, progressing to coma within 24 to 48 hours.
Further information about NiV infection can be found
here.
The case fatality ratio (CFR) in outbreaks across Bangladesh, India, Malaysia, and Singapore range from 40% to 75%, depending on local capabilities for early detection and clinical management. There are currently no licensed medicines or vaccines specific for NiV infection. Intensive supportive care is recommended to treat severe respiratory and neurologic complications.
Henipavirus nipahense (Nipah virus) is considered a priority pathogen for the acceleration of medical countermeasures (MCMs) to respond to epidemics and pandemics as part of the WHO R&D Blueprint for Epidemics.
Public health response
Several public health measures have been implemented by local authorities, including:
- The Government of India, in close coordination with the Government of West Bengal, initiated prompt and comprehensive public health measures in accordance with established protocols.
- Investigations were conducted in collaboration with other sectors through a One Health coordinated approach.
- Contact tracing has been carried out around the identified cases, with continuous follow-up.
- Surveillance efforts have been strengthened and enhanced to ensure early case detection.
- Health education and awareness campaigns, including community engagement and advocacy, are ongoing.
- Clinicians have been sensitized and alerted to NiV. Infection prevention and control has been strengthened at health-care settings.
- Prompt sample collection, transportation, and testing were conducted at the reference laboratory teams.
The support provided by WHO includes:
- Providing event communication support at national and international levels, including the submission of an official IHR notification.
- Monitoring of the evolving outbreak situation, especially during the ongoing Nipah season, including support for assessment of epidemiological patterns, risk factors, and geographic spread.
WHO risk assessment
Nipah virus (
Henipavirus nipahense) is a rare zoonotic pathogen with a high CFR (40-75%) and no licensed vaccine or treatment. Its reservoirs are fruit bats or flying foxes (bats in the Pteropus genus), which are distributed in the coastal regions and on several islands in the Indian ocean, India, south-east Asia and Oceania. The virus can be transmitted to humans from wild and domestic animals, however, as the disease can be transmitted by domesticated animals, secondary human-to-human transmissions are also possible. Cases of Nipah virus infection were first reported in 1998 and since then have been reported in Bangladesh, India, Malaysia, Philippines and Singapore. The virus is present in India, with seasonal outbreaks linked to bat activities and cultural practices such as the consumption of raw date palm sap. Seasonal outbreaks occur between December and May, coinciding with the harvesting of date palm sap.
This event represents the third Nipah outbreak reported in West Bengal, while multiple Nipah outbreaks were also documented in Kerala since 2018. In West Bengal, previous outbreaks occurred in 2001 (Siliguri) and 2007 (Nadia district). Based on the current available information, WHO assesses the overall public health risk posed by NiV at the sub-national level to be moderate, taking into consideration no availability of specific drugs or vaccines for NiV infection and the difficulty of early diagnosis. Although sensitive and specific laboratory methods exist, the symptoms during the first phase are not specific and could potentially delay a timely diagnosis, outbreak detection and response. In addition, fruit bats (
Pteropus spp.) are the natural reservoir of NiV, and they are present in India and repeated spillover of the virus from its reservoir to the human population has been demonstrated.
Human-to-human transmission has been documented in previous outbreaks, mostly reported in health-care settings and among family and caregivers of sick people through close contact with bodily fluids. Implementation of adequate infection prevention and control measures in health care facilities is critical to mitigate health care associated infection.
The yearly number of NiV infection cases reported in India has remained relatively low since 2001, except for 2001, when 66 cases were reported and 2018 when 18 cases were reported. Over the past 5 years, a dozen confirmed cases were reported in India, all in Kerala State. Strong public health measures are implemented in India to detect and control outbreaks, including established NiV surveillance, and the availability of Rapid Response Teams (RRT) at both the Central and State levels, along with the capacity to rapidly test samples.
For neighbouring countries, WHO assesses the public health risk posed by NiV at the regional level to be low. There have been no reports of cross‑border transmission, and the current outbreak remains geographically limited. Nevertheless, the risk of disease occurrence persists due to the shared ecological corridor of fruit bats and the history of human cases previously reported in the region. India has demonstrated strong capacity and experience in managing past NiV outbreaks.
WHO assesses the public health risk posed by NiV at the global level to be low, as there has been no confirmed spread of cases outside India.
WHO advice
In the absence of a licensed vaccine or specific therapeutic treatment for Nipah virus disease, reducing or preventing infection in people relies on raising awareness of the risk factors. This includes providing guidance on and reinforcing risk communication messages about the measures that people can take to reduce exposure to the Nipah virus. This is also important in the context of mass gatherings, where attendees come from different countries and may be unfamiliar with disease and its mode of transmission, as well as actions they can take to protect themselves. and case management should focus on delivering timely supportive care, supported by an effective laboratory system and adequate infection prevention and control measures in health facilities. Intensive supportive care is recommended for treatment of severe respiratory and neurologic complications.
Public health educational messages should focus on:
Reducing the risk of bat-to-human transmission
- Efforts to prevent transmission should first focus on decreasing bat access to date palm sap and other fresh food products. Freshly collected date palm juice should be boiled, and fruits should be thoroughly washed and peeled before consumption. Fruits with signs of bat bites should be discarded. Areas where bats are known to roost should be avoided.
Reducing the risk of human-to-human transmission.
- Close unprotected physical contact with NiV-infected people should be avoided. Regular hand washing should be carried out after caring for or visiting sick people along other preventive measures.
- People experiencing Nipah-like symptoms should be referred to a health facility, as early supportive care is key in the absence of treatment. Contact tracing and monitoring are also key to mitigate human-to-human transmission.
Controlling infection in health care settings
- Health and care workers caring for patients with suspected or confirmed infection, or handling specimens from them, should always implement standard precautions for infection prevention and control at all times, for all patients.
- When caring for patients with suspected or confirmed NiV, WHO advises the use of contact and droplet precautions including a well-fitting medical mask, eye protection, a fluid-resistant gown, and examination gloves. Airborne precautions should be implemented during aerosol-generating procedures, including placing the patient in an airborne-infection isolation room and the use of a fit-tested filtering facepiece respirator instead of a medical mask. Suspected or confirmed cases of NiV should be placed in a single-patient room. For family members and caregivers visiting patients with suspected or confirmed Nipah virus, similar precautions should be applied.
- Samples taken from people and animals with suspected NiV infection should be handled by trained staff working in suitably equipped laboratories.
Based on the currently available information, WHO does not recommend any travel and/or trade restrictions.
...
https://www.who.int/emergencies/disease-outbreak-news/item/2026-DON593
.svg "Location of Nadia district in West Bengal")
