Two cases of the deadly Nipah virus in India have prompted authorities in Thailand and Malaysia to step up airport screening. Pakistan has also ordered strict and enhanced health surveillance at all entry points following regional alerts.
What is the Nipah virus?
Nipah is a rare viral infection that spreads largely from infected animals, mainly fruit bats, to humans. It can be asymptomatic but it is often very dangerous, with a case fatality rate of 40% to 75%, depending on the local healthcare system’s capacity for detection and management, according to the World Health Organisation (WHO).
How common is it?
Nipah was first identified in Malaysia in 1999. Since then, there have been small outbreaks almost every year, mostly in Bangladesh and India. As of December, the Coalition for Epidemic Preparedness Innovations (CEPI) reported 750 cases globally, with 415 patients having died.
How does it spread?
When first identified in Malaysia, Nipah spread largely through direct contact with sick pigs or contaminated tissues. Since then, it more commonly spreads from contact with the natural host: fruit bats. More specifically, consumption of fruit or fruit products like raw date palm juice containing urine or saliva from infected fruit bats has been the most likely source of infection.
Human-to-human transmission has also been found, mainly after close contact between a sick patient and their family or caregivers.
What are the symptoms?
The initial symptoms such as fever, headaches, and muscle pain are not specific and can be confused with other diseases. These may then be followed by neurological signs indicating acute encephalitis, some people experience severe respiratory problems. Seizures occur in severe cases, progressing to a coma within days. Most people who get better make a full recovery; however, some experience long-term neurological issues.
How worried should we be?
While Nipah is a dangerous disease with a high fatality rate, it has not yet shown signs of becoming more transmissible among humans or spreading easily worldwide. However, it remains a significant public health concern according to the WHO, particularly in countries where outbreaks are more common.
It can also lead to mass culling of farm animals such as pigs that are susceptible to the virus. Scientists say however, that it is unlikely to spread globally and also point out that airport screening may be ineffective due to the virus having a long incubation period.
What vaccines or treatments are available?
There are currently no approved vaccines or treatments for Nipah, although several candidates are undergoing testing including one developed by Oxford University’s scientists involved in developing one of the Covid-19 vaccines. Their Nipah vaccine uses similar technology and began phase II testing in Bangladesh in December, collaborating with the International Centre for Diarrhoeal Disease Research, Bangladesh, and funded by CEPI.