Nipah Virus | India outbreak: understand symptoms and prevention methods

What is Nipah virus? Why has the WHO listed it as a priority pathogen for research? In January 2026, an outbreak re-emerged in India, with at least five confirmed cases and two deaths, prompting neighbouring countries to strengthen their preventive measures. This article compiles the latest Nipah virus outbreak updates, symptoms, transmission routes, preventive measures, and Hong Kong risk assessment to help you gain a comprehensive understanding of this highly fatal virus.

In January 2026, cases of Nipah virus infection were reported in West Bengal, eastern India. At least five confirmed cases have been identified so far, including two deaths, and nearly 100 people have been instructed to isolate at home.

As a result, neighbouring countries have stepped up their vigilance, with Thailand and Nepal successively strengthening health screening measures for travellers from India. The World Health Organization has listed Nipah virus as a priority pathogen because of its epidemic potential.

Nipah virus infection is an emerging zoonotic disease and belongs to the genus Henipavirus. Fruit bats are the natural host of Nipah virus. Nipah virus was first identified in the 1998–99 outbreak in Malaysia and Singapore involving pig farm workers and people with close contact with pigs. It can affect a wide range of animals, including pigs, horses, goats, sheep, cats and dogs.

Outbreaks of Nipah virus have been reported in Malaysia, Singapore, Bangladesh and India. Bangladesh has recorded the highest fatality rate from Nipah virus, with outbreaks usually occurring in winter.

Since 2001, India has experienced 10 to 12 Nipah virus outbreaks, with approximately 100 to 120 people infected and 70 to 80 deaths, representing a fatality rate of around 70%. Major outbreaks in the past include: West Bengal in 2001 (66 infected, 45 deaths), West Bengal in 2007 (5 infected, 5 deaths), and multiple outbreaks in Kerala in 2018, 2019, 2021 and 2023.

Nipah virus is mainly transmitted through the following routes:

Animal-to-human transmission: Nipah virus infection is mainly spread through direct contact with respiratory droplets, nasal secretions and tissues from infected animals. In the first confirmed outbreak in Malaysia, most human infections were caused by direct contact with sick pigs or their contaminated tissues.

Food transmission: Nipah virus can also be transmitted through consuming food contaminated with the urine, faeces or saliva of infected bats, usually fruit or fruit products, especially raw date palm sap. In subsequent outbreaks in Bangladesh and India, eating fruit or fruit products contaminated with the urine or saliva of infected fruit bats was the most likely route of infection.

Human-to-human transmission: Nipah virus infection can also spread from person to person, mainly through close contact with the secretions and excretions of infected patients, and has been reported in patients' households and healthcare settings.

Incubation period: Nipah virus symptoms usually appear about 4 to 14 days after infection, but may take as long as 45 days to develop.

Early symptoms: Patients may have no symptoms. Early symptoms include flu-like symptoms such as fever, headache, vomiting, sore throat and muscle aches. Other symptoms include dizziness, drowsiness and reduced consciousness.

Severe symptoms: Severe cases may develop complications such as pneumonia, seizures, encephalitis, coma, and even death. In severe cases, coma may occur within 24 to 48 hours.

Fatality rate: The case fatality rate of Nipah virus is about 40% to 75%. Among patients who recover from acute encephalitis, around 20% may continue to experience neurological problems.

Diagnostic methods: During the acute and convalescent phases of the disease, RNA detection can be performed by reverse transcription polymerase chain reaction (RT-PCR) from throat swabs, cerebrospinal fluid, urine and blood. After recovery, IgG and IgM antibody tests can be used to confirm prior infection with Nipah virus.

Treatment methods: As of 2026, there is no targeted treatment for Nipah virus infection. Treatment is mainly supportive care. Standard infection control measures and appropriate barrier nursing techniques are recommended to avoid person-to-person transmission. All suspected Nipah virus cases should be isolated.

Although there is preliminary evidence supporting the use of ribavirin, this drug has not been studied in patients with the disease. Animal model studies have shown that specific antibodies may offer potential benefits. Acyclovir, favipiravir and remdesivir have been evaluated as potential anti-Nipah virus drugs.

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There is currently no vaccine available to prevent Nipah virus infection. When travelling to areas affected by Nipah virus, members of the public should take the following preventive measures to reduce the risk of infection:

Avoid contact with animals: Avoid contact with wild animals or infected farm animals, especially bats, farmed pigs, horses, domestic cats and feral cats. Avoid visiting bat habitats.

Maintain good personal hygiene: Wash hands frequently with hand sanitiser and clean water, especially after contact with animals or their secretions/faeces, and after caring for or visiting patients.

Pay attention to food hygiene: Fruit should be thoroughly washed and peeled before consumption. Do not eat fruit that may have been bitten by bats or picked up from the ground. Avoid drinking raw date palm sap, palm juice or other fruit juices.

Take appropriate protective measures: Anyone who needs to handle animals or their tissues should wear gloves and appropriate protective clothing. Healthcare workers should always adopt suitable infection control precautions when caring for suspected or confirmed patients.

In view of reports of a cluster of Nipah virus infections in certain areas of India, the Centre for Health Protection of the Department of Health stated on 26 January 2026 that it had proactively sought further information from the World Health Organization and the health authorities in India, and had conducted health screening for arriving travellers from the affected outbreak areas who presented with suspected symptoms, so that suspected cases could be referred to hospitals for investigation as soon as possible.

At present, no imported or local cases of Nipah virus infection have been recorded in Hong Kong. The Centre for Health Protection’s risk assessment considers the risk of Nipah virus being introduced into Hong Kong to be low.

The Thai Ministry of Public Health has launched Nipah virus screening for travellers entering from India at Suvarnabhumi Airport and Don Mueang Airport, with particular attention on people from West Bengal.

Nepal has also raised its national epidemic prevention alert level, and has introduced health screening at Tribhuvan International Airport and major border checkpoints along its border with India.

China’s newly revised Law of the People’s Republic of China on Frontier Health and Quarantine, implemented a year ago, has already included Nipah virus in its testing.

Will Nipah virus cause a large-scale outbreak?

Officials have said that this outbreak is "not a major outbreak", but given the severity of Nipah virus infection — as a zoonotic disease with a high fatality rate and the potential for rapid spread — the authorities are handling the situation with the highest priority.

Is it safe to travel to India or South-East Asia?

At present, there is no travel ban for India, but neighbouring countries have begun implementing tracking and preventive measures similar to those used during the COVID-19 pandemic. Experts say the overall risk to travellers going to areas where cases have been reported remains low, despite the virus's high fatality rate.

Is there a vaccine or medicine for Nipah virus?

At present, there is no vaccine or specific antiviral treatment for Nipah virus. Treatment mainly relies on supportive care.

Summary

Although Nipah virus has a high fatality rate, its transmissibility is relatively limited and it is mainly spread through close contact. The Centre for Health Protection in Hong Kong currently assesses the risk of Nipah virus being imported into Hong Kong as low. The public need not be overly alarmed, but should remain vigilant. If you plan to travel to affected areas, pay attention to personal and food hygiene, and avoid contact with wild animals and drinking fruit juice. If you develop symptoms such as fever, headache, drowsiness or confusion after returning to Hong Kong from an affected area, seek medical attention as soon as possible and inform the doctor of your travel history.

This English version of this article has been generated by machine translation powered by AI. It is provided solely for reference purposes. In the event of any discrepancy or inconsistency between this translation and the original Chinese version, the Chinese version shall prevail.