What Is Nipah Virus? Symptoms, Risks Explained After West Bengal Outbreak

India has placed health authorities on high alert after confirming five Nipah virus cases in West Bengal, including infections among healthcare workers, triggering an intensified public health response and regional travel screening measures.

Nearly 100 close contacts have been placed under home quarantine, while patients are receiving treatment at hospitals in and around Kolkata. Officials said one patient remains in critical condition. Authorities are also investigating an additional 100 to 200 potential contacts as part of an expanded tracing effort.

Senior health officials confirmed that Kerala and West Bengal are endemic regions for Nipah virus, prompting heightened monitoring and rapid-response protocols.

Limited treatment supplies under review

Officials have raised concerns about the limited global supply of monoclonal antibodies used in Nipah treatment. The government said securing adequate stocks has become a priority and expects improved availability in the coming weeks.

Regional response: Airport screenings ramped up

Several Asian countries, including Thailand, Nepal and Taiwan, have introduced stricter airport health screenings for travellers arriving from West Bengal. Measures include temperature checks, health declarations and isolation protocols for symptomatic passengers.

Thailand has strengthened cleaning and disease-control procedures at airports with direct flights from Kolkata, while Taiwan plans to classify Nipah as a top-level notifiable disease, allowing faster reporting and stricter containment measures.

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What is Nipah virus?

Nipah virus (NiV) is a highly infectious zoonotic disease with a fatality rate ranging from 40 to 75 percent, depending on the outbreak and healthcare response. The virus is primarily transmitted from fruit bats to humans through contaminated food and can also spread between people through close contact. There is currently no approved vaccine or specific antiviral treatment.

Nipah virus symptoms

Early symptoms are often non-specific, making detection challenging. Common signs include:

• Fever, headache, muscle pain, sore throat and vomiting

• Respiratory distress or atypical pneumonia

• Severe cases may cause encephalitis (brain swelling), confusion, seizures and coma

The incubation period typically ranges from 4 to 14 days, but can extend up to 45 days. Survivors may experience long-term neurological complications.

How does Nipah virus spread?

• Animal-to-human transmission: Contact with infected fruit bats or pigs, contaminated fruit or raw date palm sap

• Human-to-human transmission: Exposure to body fluids of infected patients

• Occupational risk: Healthcare workers and caregivers face higher exposure risks

How to prevent Nipah infection

Health authorities recommend the following preventive measures:

• Wash hands frequently and maintain personal hygiene

• Avoid contact with fruit bats, sick animals and contaminated food

• Wash fruits thoroughly and avoid consuming damaged produce

• Boil raw date palm sap before consumption

• Use protective gloves and equipment when handling animals or patients

In healthcare settings

• Use contact and droplet precautions

• Apply airborne precautions during aerosol-generating procedures

• Isolate patients in single rooms

• Improve ventilation and sanitation in patient areas

• Handle samples only in specialised laboratories

Is there a treatment for Nipah virus?

There is no licensed cure or vaccine for Nipah virus. Treatment remains supportive and focuses on managing symptoms, hydration and addressing severe respiratory or neurological complications. Early diagnosis and rapid medical intervention remain critical.

Which animals carry Nipah virus?

Fruit bats of the Pteropus genus are the natural hosts and often show no symptoms. Domestic animals, especially pigs, can also become infected and transmit the virus to humans.

Preventive measures include farm quarantines, routine disinfection, safe disposal of infected carcasses and restricting animal movement from affected areas.

Public health measures underway

Authorities are focusing on:

• Reducing bat-to-human transmission by protecting food sources

• Limiting human-to-human spread through isolation and hygiene protocols

• Active case detection, contact tracing and quarantine

The World Health Organization (WHO) has not recommended any travel or trade restrictions at this stage, noting that the general public risk remains low.

What travellers should know

Travellers arriving from affected areas may face health screenings and questionnaires. Officials advise passengers to:

• Report fever, headache, respiratory symptoms or confusion

• Disclose recent travel history accurately

• Follow isolation or testing instructions if required

While Nipah virus remains a serious health concern, experts say the risk to most travellers is low without direct exposure. Targeted airport screenings and public health surveillance aim to prevent wider spread while maintaining normal travel operations.