An outbreak of the Nipah virus in India’s eastern state of West Bengal has raised concern across parts of Asia, prompting several countries to introduce precautionary health screenings for travellers arriving from the region.
At least five confirmed cases have been reported so far, including infections among doctors and nurses, leading authorities to quarantine about 100 people and hospitalize others in Kolkata. While Indian health officials say nearly 200 known contacts have tested negative, neighbouring countries are taking preventive steps. Airports in Thailand and Nepal have begun screening passengers arriving from affected areas, reflecting growing regional vigilance.
Nipah virus is a rare but highly dangerous disease transmitted primarily from animals to humans, most commonly through fruit bats. People can become infected by consuming food contaminated by bats, through direct contact with infected animals, or via close contact with bodily fluids from an infected person. Human-to-human transmission has been documented, particularly in healthcare and family settings.
The virus can cause a wide range of illness, from mild or asymptomatic infection to severe respiratory disease and inflammation of the brain, known as encephalitis. Early symptoms often resemble the flu and include fever, headache, muscle pain, vomiting and sore throat. As the disease progresses, some patients develop breathing difficulties, pneumonia, dizziness, confusion and altered consciousness.
In the most severe cases, Nipah infection can lead to seizures, coma, respiratory failure and death. The incubation period is typically between four and 14 days, though cases have been reported with delays of up to 45 days before symptoms appear.
Nipah virus is considered one of the deadliest infectious diseases known, with fatality rates ranging from 45 to 75 per cent depending on the outbreak and access to medical care. There is currently no approved vaccine or specific treatment for humans or animals. Medical care focuses on managing symptoms, supporting breathing, and preventing complications.
Survivors of severe Nipah infection may face long-term health effects. While many recover fully, some experience ongoing neurological problems such as seizures, personality changes, or memory issues. A small number of patients have suffered relapses or delayed-onset brain inflammation months or years after apparent recovery.
The virus was first identified during a 1999 outbreak in Malaysia and has since appeared sporadically in parts of South and Southeast Asia, including Bangladesh, Singapore and India. Previous outbreaks in India have proven fatal, including a 2018 incident in which multiple members of the same family died.
Although Nipah virus has never been detected in Canada, global health authorities consider it a priority disease because of its high mortality rate, lack of treatment options and potential to spread through close contact. Researchers are working to change that. In late 2025, scientists launched the world’s first phase-two clinical trial of a Nipah vaccine, marking a major step toward long-term prevention.
For now, health officials stress early detection, infection control, and surveillance as the most effective tools to limit the spread of the virus and protect public health.