Everything we know about ‘deadly’ Nipah virus as UK health agency issues travel warning

Countries have been warned to remain vigilant.

Health authorities have been put on alert after two cases of the deadly Nipah virus were confirmed in West Bengal, as per Indian authorities.

While cases remain low, authorities are concerned due to the deadly nature of the disease, with the UK Health Security Agency (UKHSA) saying that 40 to 75 per cent of people infected die from the virus.

This has led to multiple Asian countries tightening health screenings and airport surveillance for people arriving from India.

With between 3 to 3.5 million people travelling between the UK and India each year, the UKHSA has issued a warning to British nationals, saying that "understanding this virus is important if you are planning to travel to one of the areas where it circulates."

What is the Nipah virus?

Experts have described the virus as “unlikely to pose a significant risk of global spread”, but warned countries should remain vigilant.

The UKHSA writes on the government website that Nipah can be spread from animals to humans and "the natural hosts of the virus are fruit bats, particularly those of the Pteropus genus." 

It adds that "currently, there is no proven specific treatment for Nipah virus infection, and no preventative vaccine is licensed for use."

How does the virus spread?

The virus can be transmitted through contaminated food or directly from human to human, although is easiest transmitted through bodily fluids, with the virus not being considered easily airborne.

For those travelling to endemic areas, prevention focuses on avoiding exposure, as the UKHSA advises:

• avoid contact with bats and their environments, and sick animals
• don't consume raw or partially fermented date palm sap - if consuming date palm juice, ensure it has been boiled first
• wash all fruit thoroughly with clean water and peel before eating; avoid consuming fruit found on the ground or fruit that appears to have been partially eaten by animals
• wear protective clothing and gloves when handling sick animals and during slaughter and culling procedures
• practise good hand hygiene, particularly after caring for or visiting sick people
• avoid close, unprotected contact with anyone infected with Nipah virus, including contact with their blood or body fluids

What are the symptoms?

The UKHSA writes that the virus can take between 4 to 21 days to incubate (the period between becoming infected and symptoms appearing).

It says: "Symptoms usually begin with the sudden – onset of non-specific flu-like illness or fever. Pneumonia and other respiratory problems may also develop.

"The most serious complication is encephalitis (inflammation of the brain) or meningitis, which typically develops 3 to 21 days after the initial illness begins. This is the hallmark of Nipah infection and is associated with a very high mortality rate.

"It is estimated that between 40 and 75% of people infected with Nipah virus will die. Some survivors may be left with lasting neurological difficulties, including persistent seizures and personality changes. In rare cases, the virus can reactivate months or even years after the initial infection."

Where is the virus found and has a case ever been reported in the UK?

Outbreaks in humans of the virus have only ever been identified in South and South-East Asia, mainly in more rural areas.

Countries where cases have been found include:

• Bangladesh (where cases have occurred almost annually since 2001)
• India (including outbreaks in Kerala in Southern India since 2018, and a current outbreak in West Bengal)
• Malaysia
• The Philippines
• Singapore

No case has ever reported a case in the UK.

The UKHSA has designated the Nipah virus as a "high priority pathogen", urging that it needs "investment in developing tests, treatments and vaccines".

This is due to its "high fatality rate and the fact that there are currently no approved vaccines or specific treatments available."