Camilla Jessen
Why scientists say Nipah is deadly but not easily spread.
Health authorities across parts of Asia have stepped up surveillance as reports of the Nipah virus draw renewed attention.
With its high fatality rate, questions are growing about whether the disease could pose a wider global threat.
The current concern follows a Nipah virus outbreak in West Bengal, India. Airports in Thailand, Nepal and Taiwan have introduced screening measures for travelers who may be infected.
Since December, two confirmed cases have been identified, both reportedly among health workers. According to the BBC, Indian health officials said 196 people who had contact with those cases were traced and tested negative.
Kathmandu’s airport is among those carrying out additional checks, reflecting regional caution as authorities monitor the situation.
What the virus does
The Nipah virus is known to spread from animals to humans, particularly through pigs and fruit bats. Health experts estimate its fatality rate ranges between 40% and 75%, and there is currently no approved vaccine or specific treatment.
The incubation period can last from four days to two weeks. Early symptoms often include fever, headache, muscle pain, vomiting and sore throat.
In more severe cases, patients may experience drowsiness, altered consciousness, pneumonia or encephalitis, a potentially fatal inflammation of the brain.
Why WHO is watching
The World Health Organization has classified Nipah virus as one of its top ten priority diseases, alongside illnesses such as Zika and Covid-19, due to its epidemic potential.
According to Unilad, many infections in India and Bangladesh are linked to people drinking raw date palm sap. The sap is harvested in winter and can be contaminated by bats.
These so-called spillover events occur when the virus jumps from animals to humans.
Expert view on pandemic risk
Speaking to Unilad, Doctor Emily Gurley, Professor of Epidemiology of Infectious Diseases at Johns Hopkins University, said fatality rates vary depending on how the virus is transmitted.
She said infections contracted directly from bats have a fatality rate of around 90%, while human-to-human transmission results in death rates closer to 40% to 50%.
Dr Gurley, who serves on the WHO’s Nipah Virus Taskforce, said a global pandemic remains unlikely.
“If this is like past Nipah outbreaks, then no – the virus just isn’t very transmissible,” she said, noting that each infected person passes the virus to an average of 0.3 others.
“Sometimes you do see variation, where one person infects multiple others, and that’s when larger outbreaks happen,” she added. “But typically it returns to the average, and the outbreak ends.”
Sources: BBC, Unilad, World Health Organization, Newsner
