Nipah virus (NiV) is among the most dangerous zoonotic viruses known to public health authorities. Although outbreaks are relatively rare, the virus is associated with extremely high fatality rates and severe disease affecting the brain and lungs. Its ability to spill over from animals to humans and, in certain situations, spread between people makes it a continuing concern in South and Southeast Asia, particularly in India.
The World Health Organization has repeatedly warned that Nipah virus is a serious public health threat. In one of its official communications, WHO stated that Nipah virus infection is “a newly emerging zoonotic disease that causes severe illness in both animals and humans,” and emphasized the need for early detection, rapid isolation, and strong infection-control measures.
This study provides a detailed and updated explanation of Nipah virus, including its origin, global spread, Indian outbreaks with a timeline of cases and deaths, symptoms, causes, treatment options, prevention strategies, and the latest confirmed cases in India based on official government statements and verified news reports.
Origin and identification of Nipah virus
Nipah virus was first identified during an outbreak in 1998–1999 in Malaysia. The outbreak primarily affected pig farmers and slaughterhouse workers who developed acute fever, respiratory distress, and encephalitis. Investigations later confirmed that pigs had become infected after exposure to fruit bats, which are the natural hosts of the virus. The virus then spread from pigs to humans through close contact.
Singapore also reported cases during the same period, linked to imported pigs from Malaysia. More than 300 human infections were recorded across both countries, and over 100 deaths occurred. To stop the outbreak, Malaysian authorities ordered the culling of more than one million pigs, causing major economic loss but successfully halting transmission.
Scientists later confirmed that fruit bats of the Pteropus genus carry Nipah virus without showing symptoms. These bats shed the virus through saliva, urine, and feces, enabling contamination of food sources or infection of other animals. WHO has noted that the presence of these bats across large geographic areas makes complete elimination of the virus impossible.
Global spread and countries affected
Following the initial outbreak in Malaysia and Singapore, Nipah virus re-emerged in Bangladesh in 2001. Since then, Bangladesh has reported nearly annual outbreaks, many of which were linked to the consumption of raw date palm sap contaminated by bat secretions. Human-to-human transmission was documented frequently in Bangladesh, especially among family members and healthcare workers.
Apart from Malaysia, Singapore, Bangladesh, and India, sporadic human infections have been reported in the Philippines. Surveillance studies have detected Nipah virus antibodies in fruit bat populations across several Asian countries, indicating that the virus is geographically widespread in animals even when human cases are rare.
The World Health Organization has placed Nipah virus on its list of priority pathogens due to its high mortality rate, lack of specific treatment, absence of an approved vaccine, and potential to cause outbreaks with serious consequences.
Nipah virus in India: timeline of outbreaks, cases, and deaths
India has experienced multiple Nipah virus outbreaks since 2001. These outbreaks have mainly occurred in West Bengal and Kerala and have varied in scale and severity.
In 2001, the first documented Nipah outbreak in India occurred in Siliguri, West Bengal. The outbreak involved significant person-to-person transmission, particularly in hospital settings. Official investigations later confirmed 66 cases and 45 deaths, resulting in a fatality rate of nearly 70 percent. Many of the infected individuals were healthcare workers or caregivers.
In 2007, another outbreak was reported in the Nadia district of West Bengal. Five confirmed cases were identified, and all five patients died. This outbreak occurred close to the Bangladesh border and raised concerns about cross-border circulation of the virus through bat populations.
After more than a decade without reported cases, Nipah virus reappeared in India in 2018 in Kerala. The outbreak affected Kozhikode and Malappuram districts. Eighteen laboratory-confirmed cases were reported, with 17 deaths. The outbreak gained nationwide attention because of its severity and the involvement of healthcare facilities. The Kerala government, with support from central authorities, implemented aggressive containment measures, including isolation, contact tracing, and strict infection-control protocols. These measures successfully brought the outbreak under control.
In 2019, Kerala reported a single Nipah case in Ernakulam district. The patient survived, and no secondary transmission was detected. Health officials described this as evidence of improved surveillance and rapid response capacity.
In 2021, another isolated Nipah case was reported in Kozhikode, Kerala. The patient, a young boy, died from the infection. Immediate containment measures were implemented, and no additional cases were confirmed.
In 2023 and 2024, Kerala again reported small clusters of Nipah cases, including fatalities. Although limited in size, these outbreaks reinforced the pattern of repeated spillover events in regions with dense fruit bat populations.
In 2025, Kerala recorded further Nipah infections. According to official statements from the Union Ministry of Health, four confirmed cases were reported during the year, with two deaths. Investigations suggested that these cases were likely caused by independent spillover events rather than sustained human-to-human transmission.
Latest confirmed Nipah cases in India (2025–2026)
The most recent Nipah cases in India were confirmed between December 2025 and January 2026 in West Bengal. The Union Ministry of Health and Family Welfare officially confirmed that two healthcare workers from the Barasat area near Kolkata tested positive for Nipah virus.
A senior government health official stated that “only two laboratory-confirmed cases have been identified, and extensive contact tracing has been completed.” The National Centre for Disease Control reported that all identified contacts were placed under medical observation and tested negative at the time of reporting.
Authorities emphasized that there was no evidence of community transmission and that the situation was under control. Enhanced surveillance was implemented in affected areas, and hospitals across the state were advised to follow strict infection-control measures. International news agencies reported that some Asian countries increased health screening of travelers from India as a precautionary step.
How Nipah virus spreads
Nipah virus spreads through well-established transmission routes. The most common route is animal-to-human transmission. Fruit bats can contaminate fruits, fruit juices, or palm sap with saliva or urine. Humans may become infected after consuming contaminated food or through direct contact with bats.
In certain outbreaks, pigs have served as intermediate hosts. Humans became infected through close contact with infected pigs or their bodily secretions.
Human-to-human transmission can occur through close physical contact with infected individuals, particularly exposure to respiratory droplets or bodily fluids. This form of transmission has been documented in several Indian outbreaks, especially in hospital and household settings.
WHO has stated that human-to-human transmission “has been observed among family members and caregivers of infected patients,” highlighting the importance of infection-control practices.
Symptoms of Nipah virus infection
Nipah virus infection often begins with non-specific symptoms, making early diagnosis difficult. Initial symptoms commonly include fever, headache, muscle pain, sore throat, cough, vomiting, and fatigue.
As the disease progresses, severe symptoms may develop, including acute respiratory distress, confusion, seizures, and encephalitis. Many patients experience rapid neurological deterioration, which can lead to coma and death.
The incubation period typically ranges from four to fourteen days, though longer periods have been reported. Fatality rates have ranged from 40 percent to more than 70 percent in different outbreaks, depending on healthcare access and response speed.
Diagnosis
Laboratory confirmation of Nipah virus infection requires specialized testing. Diagnostic methods include real-time PCR testing to detect viral genetic material and serological tests to identify antibodies. In India, confirmation is often carried out by national reference laboratories such as the National Institute of Virology.
Early diagnosis is critical for patient management and outbreak control, as it allows rapid isolation and contact tracing.
Treatment
There is currently no approved antiviral treatment or licensed vaccine for Nipah virus infection. WHO has clearly stated that “there are no specific treatments or vaccines currently available for Nipah virus infection.”
Clinical management focuses on supportive and symptomatic care. This includes maintaining fluid and electrolyte balance, providing respiratory support such as oxygen or mechanical ventilation when required, and managing neurological complications.
Several experimental therapies and vaccine candidates are under research, but none have yet been approved for widespread use.
Prevention and protection
In the absence of a vaccine or specific treatment, prevention remains the most effective strategy against Nipah virus.
Reducing exposure to bats and contaminated food is critical. Health authorities advise against consuming raw date palm sap and recommend washing fruits thoroughly before consumption. Domestic animals should be kept away from areas frequented by bats.
In healthcare and household settings, strict infection-control measures are essential. These include the use of personal protective equipment, isolation of suspected cases, proper hand hygiene, and safe handling of bodily fluids.
Public health measures such as surveillance, early detection, contact tracing, and community awareness campaigns play a central role in preventing outbreaks. WHO has emphasized that strengthening health systems and educating communities are key to reducing the impact of Nipah virus.
Nipah virus remains a persistent and unpredictable public health threat in India and neighboring regions. Its high fatality rate, repeated outbreaks, and continued presence in animal reservoirs underline the importance of vigilance, early detection, and rapid response.
The recent cases in West Bengal during 2025–2026 demonstrate that even limited clusters can trigger widespread concern but also show that timely government action and strong surveillance can prevent further spread. Until effective vaccines or treatments become available, prevention, awareness, and robust public health systems remain the strongest defenses against Nipah virus.