LSHTM experts comment on Nipah virus outbreak in West Bengal, measures to control it, and risk to the wider region
After two cases of Nipah virus were confirmed in West Bengal, India, media reports suggest countries including Singapore, Hong Kong, Thailand and Malaysia have instituted airport screening measures over concerns the outbreak could spread.
Nipah virus can be spread from animals to humans, with infections usually accompanied by flu-like symptoms and fever that can lead to complications such as encephalitis (inflammation of the brain) or meningitis. Between 40 and 75% of people infected with Nipah virus will die and there is no approved vaccine or cure.
Indian authorities have moved quickly to contain the outbreak with traced contacts of the confirmed cases so far testing negative and the risk outside the affected area considered low.
Dr Kaja Abbas, Associate Professor of Infectious Disease Epidemiology and Dynamics at the London School of Hygiene & Tropical Medicine and Nagasaki University, said:
"Nipah virus is a zoonotic RNA virus first identified in 1999 that causes severe respiratory and neurological disease in humans, potentially progressing from fever and headache to acute encephalitis. Since 2001, sporadic but recurring outbreaks have occurred, especially in Bangladesh and India. In addition to zoonotic transmission from animals such as fruit bats to humans, human-to-human transmission and transmission from contaminated fruit products (such as date palm juice) to humans also occur.
"India's health ministry has confirmed two cases in West Bengal, India, since December 2025 among healthcare workers, and traced contacts have tested negative for Nipah infection.
"To prevent international spread, countries such as Thailand and Nepal have initiated screening passengers from India at the point of entry through air or land, and other countries such as Kazakhstan has issued guidance through their health ministries to follow medical observation for 14 days upon arrival. General prevention focuses on good hygiene, proper ventilation, avoiding crowds and sick contacts, staying home when ill, seeking timely medical advice, and maintaining a healthy lifestyle to support immunity.
"The basic reproduction number of the Nipah virus is typically below 1, suggesting limited human-to-human transmission and a low likelihood of widespread pandemic spread."
Ms Sol Kim, PhD student at the London School of Hygiene & Tropical Medicine and Nagasaki University studying Nipah virus epidemiology and dynamics, said:
"Based on publicly available information so far, the current Nipah outbreak in India appears to have been contained. Two cases have been confirmed, and contact tracing has identified close to 200 contacts, all of whom have tested negative. This suggests that onward spread has been effectively stopped.
"India has seen Nipah outbreaks before. In West Bengal (eastern India, near the Bangladesh border), this is the first reported outbreak since 2007. More recently, outbreaks have occurred in Kerala in southern India (far from the West Bengal area), where rapid detection, isolation of cases, and thorough contact tracing have helped stop the virus quickly, usually with very small numbers of cases.
"For the general public, especially outside the affected area, the risk is considered low. There is no evidence of ongoing person-to-person spread, and the response measures in place are appropriate for the situation.
"That said, the virus can cause serious illness, such as encephalitis, or even death when infected. It is important that people in affected areas follow public-health advice, including good hand hygiene and avoiding contact with bats or fruit that may have been contaminated by bats."
No cases of Nipah virus have ever been reported in the UK.
This article is a rapid reaction to a breaking news story
