UK expert urges vigilance over deadly Nipah virus found in India

Professor Paul Hunter, an infectious diseases expert at the University of East Anglia, said detecting Nipah at borders can be difficult owing to the length of time it takes for people to develop symptoms after catching the virus.

Indian authorities have said they have now contained a Nipah virus outbreak there following two confirmed cases in the eastern state of West Bengal.

Several Asian countries have tightened health screenings and airport surveillance for anyone arriving into their countries from India.

All the contacts of the two people infected in India have been quarantined and tested, according to information from the Indian government.

Read More: What is the Nipah virus that has led to 100 quarantining in India?

Prof Hunter said: "Although Nipah is a very serious infection, it is unlikely to pose a significant risk of global spread as the risk of person-to-person transmission is low.

"The R0 (the number of people that one infected person will pass on a virus to) is less than 1.0.

"Nevertheless, we cannot be complacent as we have seen recently, some viruses can mutate to increased infectivity.

"Also the long incubation period makes detection at borders very difficult."

Nipah has a high fatality rate and has been found before in parts of Asia.

According to the UK Health Security Agency (UKHSA), while the risk to most people remains very low, understanding the virus is important for travellers to affected areas.

It said no cases have ever been found in the UK.

Experts know that Nipah can be spread from animals to humans, and it 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, though the UKHSA said there is evidence it can infect other animals, including pigs, dogs, cats, goats, horses and sheep.

People tend to show symptoms four to 21 days after infection, which usually begin with the sudden onset of flu-like illness or fever.

People may also develop pneumonia and other respiratory issues.

The most serious complication is encephalitis (inflammation of the brain) or meningitis, which typically develops three to 21 days after infection, the UKHSA said.

It is estimated that between 40 and 75% of people infected with Nipah virus will die, while survivors can 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 result from eating or drinking fruits or fruit products (such as raw or partially fermented date palm juice).

This can be contaminated with the poo, urine or saliva of infected fruit bats.

Person-to-person spread 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 no preventative vaccine is licensed, though work is ongoing.

Ian Jones, professor of virology at the University of Reading, said: "Nipah is a bat virus that causes occasional zoonotic outbreaks, most of which are associated with the seasonal consumption of foodstuffs contaminated by bat urine.

"Like other zoonotics such as avian flu or Ebola, the case fatality rate is high, but the virus does not transmit effectively person to person.

"The at-risk groups are therefore close family members and the healthcare workers who treat the primary cases.

"The risk to the general public from Nipah is essentially nil as the virus has never shown any evidence of general spread."