The UK Health Security Agency (UKHSA) has warned the public to be aware of Nipah virus symptoms after two cases were confirmed in the Indian state of West Bengal, prompting a mass quarantine of around 200 people who had contact with the infected patients. The virus has been designated a "high priority pathogen" because of its high fatality rate and the lack of a proven treatment.
Symptoms typically appear between four and 21 days after exposure, though longer incubation periods have occasionally been observed. According to the UKHSA, between 40 and 75 per cent of those infected may die, with the most serious complication being brain inflammation or meningitis, which can develop three to 21 days after the illness begins. Some survivors may experience lasting neurological effects, including persistent seizures and personality changes, and in rare cases the virus can reactivate months or even years later.
Most infections result from consuming fruit or fruit products contaminated with the faeces, urine or saliva of infected fruit bats. Person-to-person transmission is possible through close contact with an infected individual or their body fluids, and outbreaks have been documented in India and Bangladesh, often affecting family members and caregivers. There is currently no proven specific treatment for the infection, nor any licensed preventative vaccine.
Professor Paul Hunter, an infectious diseases expert at the University of East Anglia, said that while Nipah is a serious infection, it is unlikely to spread globally because the risk of person-to-person transmission is low. "The R0, the number of people one infected person passes the virus to, is less than 1.0," he said. "Nevertheless, we cannot be complacent, as some viruses can mutate to increased infectivity. The long incubation period also makes detection at borders very difficult."
Several Asian countries have introduced tightened health screenings and airport surveillance for travellers arriving from India in response to the outbreak.
