Here's What An Infectious Disease Expert Wants You To Know About Nipah Virus

A recent outbreak of Nipah virus in India has led some to worry the disease could spread, calling the prospect “scary”. 

The UK Health Security Agency (UKHSA) said that though it isn’t in the UK, “understanding this virus is important if you are planning to travel to one of the areas where it circulates” as it is a “serious infection”. 

But what exactly is Nipah virus, and where is it? 

What is Nipah virus? 

Professor Paul Hunter, an expert in infectious diseases at the University of Anglia, said, “Nipah virus infection is a rare infectious disease, but one that can pose a significant risk of death.

“The death rates vary between and have been as low as 9% or as high as 90% of known cases. However, up to about half of infections may not cause any symptoms. So, the mortality rates per infection may be lower than reported.” 

The incubation period is around two weeks, he added, but can be longer.

What are the symptoms of Nipah virus? 

It starts off as a “non-specific” flu-like fever, UKHSA said. This can sometimes turn into pneumonia. 

Nipah virus can also carry complications, like meningitis or inflammation of the brain (encephalitis). 

This typically happens three to 21 days after the onset of the virus; it is “the hallmark of Nipah infection and is associated with a very high mortality rate”.  

It’s believed that 40-75% of those with the disease may die from it.

Where is Nipah virus found? 

Professor Hunter said, “Outbreaks have been most years in Southeast Asia since the first one was identified in Malaysia in 1998/99. Most outbreaks have been reported from Bangladesh. This is not the first time that outbreaks have been identified in West Bengal.” 

Per UKHSA, the disease has never been reported in the UK. 

“While antibodies against Nipah virus have been detected in bat species across Asia, Ghana and Madagascar, human outbreaks have not occurred outside the South and South-East Asian region,” they added. 

How is Nipah virus spread? 

It is a zoonotic virus (can be spread from animals to humans), and it can be spread among people and through food, too. 

Its natural hosts are fruit bats, but goats, cats, pigs, and other animals can carry it too. 

“The infection usually spreads from animals to humans either through direct contact or consumption of contaminated food. The primary source of infection is bats, and people have been infected from consumption of fruit or fruit products – such as raw date palm juice – contaminated with urine or saliva from infected fruit bats,” he said.

“However, the first outbreak was associated with contact with infected pigs. Those pigs probably got infected by bats.” 

And while person-to-person spread is less common, “spread from infected patients to their health professionals is a particular concern”.

Will Nipah virus be a global pandemic? 

“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 is less than 1.0,” said Professor Hunter.

“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”. 

As of the time of writing, UKHSA said, “the risk to most people remains very low,”