Several countries in Asia have increased border health control measures in response to confirmed cases of Nipah virus infection in West Bengal, India.

Last Sunday (Jan 25), Thailand began screening passengers arriving from the region at three airports: Suvarnabhumi, Don Mueang, and Phuket.

Nepal has also started screening at Kathmandu airport and other cross-border checkpoints with India, as reported by the BBC.

Singapore is implementing temperature screening at the airport for flights arriving from affected areas, according to the Communicable Diseases Agency (CDA).

On Tuesday, Malaysia's health ministry stated that they are evaluating the situation and ensuring that border health control measures are consistently enforced.

Meanwhile, Taiwan authorities announced on Wednesday that they will officially classify Nipah virus infection as a category five notifiable infectious disease in March, as reported by Taipei Times.

These actions were prompted by two confirmed cases of the deadly virus in West Bengal since December.

India's Ministry of Health and Family Welfare reported on Tuesday that a total of 196 contacts linked to the two cases have been identified, traced, monitored, and tested. All tested negative for the Nipah virus and showed no symptoms.

"The situation is under constant monitoring, and all necessary public health measures are in place," the ministry added.

According to Bangkok Post, health officials at Suvarnabhumi Airport have not detected any passengers with virus symptoms following the enhanced screening measures.

Last year, Bangladesh recorded four deaths from Nipah virus infection between Jan 1 and Aug 29.

What is Nipah?

The Nipah virus is a zoonotic virus, meaning it can be transmitted from animals to humans. The virus originates from fruit bats, and possibly other species of bats, with pigs potentially serving as intermediate amplifying hosts for outbreaks in humans.

Transmission can occur from animal to human through direct contact with infected animals or consumption of date palm sap or fruits contaminated by infected bats. Limited human-to-human transmission through close contact has also been documented.

The incubation period of the Nipah virus in humans ranges from 4 to 45 days, with 90% of symptoms developing between four to 14 days after exposure. The infectious period likely starts during the incubation period and continues until the patient stops shedding the virus.

Symptoms of Nipah virus infection

Nipah virus infection can lead to mild to severe disease, including encephalitis (inflammation of the brain) and potentially death, according to the US Centres for Disease Control and Prevention. Symptoms may include fever, headache, cough, sore throat, and difficulty breathing.

As the infection progresses, patients may deteriorate and develop encephalitis, which can lead to coma within 24 to 48 hours. Death occurs in 40 to 75% of cases, as stated by the World Health Organisation.

Currently, there are no licensed treatments or vaccines available for the Nipah virus. Singapore has not reported any new cases of the virus since 1999, with outbreaks mainly occurring in western Bangladesh and West Bengal.

Singapore steps up vigilance

The Communicable Diseases Agency (CDA) announced on Wednesday that it is closely monitoring the Nipah virus outbreak in West Bengal, India.

While the virus is primarily transmitted through exposure to bats and consumption of contaminated date palm sap or fruits, human-to-human transmission is rare but possible.

"The outbreak in West Bengal is reportedly between humans, with two cases so far," noted CDA.

The agency mentioned that bio-surveillance programs monitoring Singapore's bat populations since 2011 have not detected the Nipah virus.

Singapore has intensified vigilance through various means, such as requiring immediate notification of confirmed and suspected cases, alerting healthcare facilities to be vigilant, and setting up temperature screening at the airport. They are also spreading health advisories, increasing surveillance of migrant workers, and collaborating with counterparts in South Asia.

CDA stated that additional public health measures may be implemented in Singapore based on new information indicating a heightened public health risk.

To minimize the risk of Nipah virus exposure, travelers to affected areas are advised to avoid contaminated food and drinks, direct contact with sick individuals, animals, and bat roosting areas, and to maintain good personal hygiene.

Anyone experiencing symptoms during or after travel should seek medical attention promptly and inform healthcare providers of their recent travel and potential exposure to the virus.

For more information, contact carol.ong@asiaone.com