The virus is difficult to detect and stop at international borders
A deadly infection found in India is “unlikely to pose a significant risk of global spread” although countries should remain vigilant, a UK expert has said. Professor Paul Hunter, an infectious disease expert at the University of East Anglia, said detecting Nipah at borders can be difficult because of the time it takes for people to develop symptoms after contracting the virus.
Indian authorities have said they have contained an outbreak of the Nipah virus after two confirmed cases in the eastern state of West Bengal. Several Asian countries have strengthened health checks and airport surveillance for anyone arriving in their countries from India.
All contacts of the two infected people in India have been quarantined and tested, according to information from the Indian government. Professor Hunter said: “Although Nipah is a very serious infection, it is unlikely to pose a significant risk of global spread as the risk of human-to-human transmission is low.
“The R0 (the number of people to whom an infected person will transmit a virus) is less than 1.0. However, we cannot be complacent, as we have seen recently, some viruses can mutate and increase their infectivity. In addition, the long incubation period makes detection at borders very difficult.”
Nipah has a high mortality rate and has been found before in parts of Asia. According to the UK Health Security Agency (UKHSA), while the risk for most people remains very low, understanding the virus is important for travelers to affected areas. He said no cases have ever been found in the UK. Experts know that Nipah can be transmitted from animals to humans and can also be transmitted through contaminated food or directly from person to person.
It was first identified in 1999 during an outbreak among pig farmers in Malaysia and Singapore. Fruit bats tend to help the virus circulate, although the UKHSA said there is evidence it can infect other animals, including pigs, dogs, cats, goats, horses and sheep.
People tend to show symptoms between four and 21 days after infection, which usually begin with the sudden onset of a flu-like illness or fever. People can also develop pneumonia and other respiratory problems.
The most serious complication is encephalitis (inflammation of the brain) or meningitis, which usually develops between three and 21 days after infection, the UKHSA said. It is estimated that between 40 and 75% of people infected with the Nipah virus will die, while survivors may be left with complex disabilities, such as persistent seizures and personality changes.
Countries with previously reported outbreaks include India, Bangladesh, Malaysia, the Philippines and Singapore. The UKHSA said many infections in people are a result of eating or drinking fruit or fruit products (such as raw or partially fermented date palm juice).
This may be contaminated with droppings, urine or saliva from infected fruit bats. Human-to-human transmission is also possible through close contact with an infected person or their body fluids. This has been documented in Bangladesh and India.
Currently, there is no proven specific treatment for Nipah virus infection and there is no authorized preventive vaccine, although work is underway.
