Health authorities in India have intensified disease surveillance after two suspected cases of the Nipah virus were flagged in the eastern state of West Bengal. The development has drawn international attention due to the virus’s high fatality rate and lack of a specific cure, although follow-up testing later indicated the cases were not confirmed as Nipah. Despite this, health agencies remain on alert, given the virus’s history and potential to cause serious outbreaks.
The UK Health Security Agency (UKHSA) said it is closely monitoring the situation while assessing the risk to the UK population as very low. According to its latest update on outbreaks in India, the two individuals in the Kolkata area initially tested positive at a local laboratory, but subsequent tests at a national reference facility returned negative results. UKHSA added that it would revise its assessment should new evidence emerge.
Nipah virus is classified as a zoonotic disease, meaning it can spread from animals to humans. It can cause a wide spectrum of illness, ranging from mild or symptom-free infection to severe respiratory disease and encephalitis, which is inflammation of the brain and can be fatal. The World Health Organization (WHO) estimates that Nipah outbreaks have a case fatality rate of between 40 and 75 per cent, depending on healthcare access and outbreak response.
WHAT MAKES NIPAH VIRUS SO DANGEROUS
The virus is naturally carried by fruit bats from the Pteropodidae family and has been detected across parts of South and Southeast Asia. Human infections have previously been linked to direct contact with infected animals, consumption of food contaminated by bat saliva or droppings, and in certain outbreaks, close human-to-human transmission.
WHO has repeatedly stressed that there is no approved vaccine or antiviral treatment for Nipah virus. Medical care focuses on managing symptoms and complications, making early detection and strong hospital infection control essential. In past outbreaks, transmission has occurred among family members and healthcare workers who had close, unprotected contact with infected patients.
UKHSA guidance notes that human-to-human spread has been observed in both India and Bangladesh, particularly in caregiving or clinical settings. The typical incubation period is believed to range from four to 21 days, although longer periods have occasionally been reported, complicating contact tracing efforts.
WHY WEST BENGAL IS UNDER CLOSE WATCH
While confirmed Nipah outbreaks in India have been more common in Kerala, the West Bengal alert has raised concern due to the state’s proximity to Bangladesh, where repeated spillover events have occurred. Indian authorities responded by isolating suspected patients, testing close contacts, and monitoring healthcare workers as a precaution.
Historical outbreaks highlight why such caution is taken. During a 2001 outbreak in Siliguri, a significant number of infections were reported among hospital staff and visitors, underscoring the risk of transmission in healthcare environments. Surface contamination in hospitals has also been documented in past outbreaks, reinforcing the importance of strict infection prevention measures.
For Singapore and the wider region, health experts note that while Nipah virus is severe, it does not spread easily through casual community contact like common respiratory viruses. Activities most associated with infection, such as exposure to bat habitats or consuming raw date palm sap, are not typically undertaken by tourists.
SYMPTOMS AND PUBLIC HEALTH RESPONSE
Early symptoms of Nipah infection can resemble many common illnesses, including fever, headache, muscle pain and vomiting. In more severe cases, patients may develop respiratory symptoms and neurological complications, including seizures and coma. Some survivors have experienced long-term neurological effects.
Public health agencies emphasise that rapid laboratory testing, transparent reporting and robust healthcare systems are key to preventing widespread transmission. Although the suspected West Bengal cases were not confirmed, authorities continue to maintain vigilance, reflecting global concern over emerging infectious diseases with epidemic potential and significant public health impact.