Airports across parts of Asia have begun tightening health surveillance and travel screening after an outbreak of Nipah virus in an Indian state.

Thailand, Nepal and Taiwan are among the countries and territories that have stepped up precautionary measures after five Nipah virus cases were confirmed in India’s West Bengal.

Nipah is a zoonotic disease that mainly spreads to humans from infected pigs and bats, but can also be passed on through close person-to-person contact.

In West Bengal, some 100 people are being quarantined after the virus was detected in a hospital. A doctor, a nurse and another staff member tested positive after the first two confirmed cases in a male and female nurse from the same district.

In Thailand, the ministry of public health has stepped up health screening at major airports for passengers arriving from West Bengal, using techniques that became established during the Covid-19 pandemic.

Passengers at the Suvarnabhumi, Don Mueang and Phuket airports are being monitored for fever and symptoms associated with the virus, and health “beware” cards are being issued to guide travellers on what to do if they fall ill.

A health worker wearing protective gear disposes of biohazard waste from a Nipah virus isolation centre at a government hospital in Kozhikode, in India’s southern state of Kerala (AFP/Getty)

Officials have also increased cleaning and disease-control preparedness at Phuket International Airport as part of the preventive measures. The Indian airline, Indigo, operates a daily direct flight between Kolkata’s international airport in West Bengal and Phuket.

Addressing public concern on Monday, Thai prime minster Anutin Charnvirakul said no Nipah cases had been recorded domestically but surveillance levels would remain high.

“Thailand’s Department of Disease Control screens travellers from West Bengal, India at Suvarnabhumi & Don Mueang airports starting 25 January amid Nipah virus outbreak. Health officials implement strict measures as passengers show excellent cooperation at checkpoints,” the Thai government said.

Travellers who arrive with high fever or symptoms that may indicate Nipah infection will be transferred to quarantine facilities, according to local media reports.

The department for public parks and wildlife has also ordered stricter screenings for in cave areas and natural tourist attractions in Thailand amid concern about the outbreak in India.

Thailand’s Department of Disease Control screens travellers from West Bengal, India, at Suvarnabhumi & Don Mueang airports (Thai government)

It urged tourists to follow the strict rule: “Don’t hunt, don’t forage, don’t eat.”

In Nepal, the government has raised alert levels and intensified health checks at Tribhuvan International Airport in Kathmandu, and at key land border crossings with India, in a bid to prevent the virus from entering the country.

Health desks have been set up to screen travellers for symptoms, and hospitals and border health points have been instructed to report and manage suspicious cases. Officials highlighted the challenge posed by open borders and the daily movement of people from neighbouring West Bengal.

A spokesperson for the ministry of health, Dr Prakash Budhathoki, said adequate measures to prevent the spread of the virus have been put in place.

He said that the government has begun individual screening of passengers arriving in Nepal through Tribhuvan International Airport (TIA) and border points with India.

Travellers who arrive in Thailand with high fever or symptoms that may indicate Nipah infection will be transferred to quarantine facilities (Thai government)

“We have specifically intensified surveillance at border points in Koshi Province. Health checks have also been ordered for people entering Nepal through other border crossings,” he stated.

Meanwhile, health authorities in Taiwan are planning to list Nipah virus infection as a Category 5 notifiable disease, the highest classification for serious emerging infections under local law.

This move – subject to a 60-day public comment period before taking effect – would require immediate reporting and special control measures if cases occur, reflecting concerns over the virus’s high fatality rate and epidemic potential.

Taiwan’s Centres for Disease Control (CDC) said Taiwan is maintaining its Level 2 “yellow” travel alert – that alerts travellers to exercise caution – for Kerala state in southwestern India.

The CDC’s deputy director-general Lin Ming-cheng said travel advisories will be updated as the outbreak evolves.

The World Health Organisation has described the Nipah virus as a priority pathogen because of its potential to trigger an epidemic.

Thailand’s Department of Disease Control screens travellers from West Bengal (Thai government)

The initial symptoms of an infection can include fever, headaches, muscle pain, vomiting and sore throat and its more serious symptoms are dizziness or drowsiness, altered consciousness, severe atypical pneumonia and respiratory problems.

People infected with the virus may show no symptoms at all, while others develop acute respiratory distress. In severe cases, Nipah can lead to fatal encephalitis – an inflammation of the brain.

Nipah virus outbreaks have been associated with a high death rate in the past, with fatality levels reported between 40 and 75 per cent depending on the outbreak and the viral strain involved.

The virus has been documented in Bangladesh, India, Malaysia, the Philippines and Singapore, with Bangladesh recording the highest number of 341 cases and 241 deaths, according to the International Society for Infectious Disease.