Bangkok, Thailand. Thailand and Malaysia have increased airport screening measures following the detection of two Nipah virus cases in India, as health authorities work to contain the rare but deadly infection.
Regional response and transmission risks
The virus, which spreads primarily from fruit bats to humans through contaminated food products, has prompted regional concern despite its limited capacity for human-to-human transmission. Health experts say outbreaks typically remain small and contained, though the infection’s high fatality rate makes swift detection critical.
Fatality rate and current medical countermeasures
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, the World Health Organisation says.
However, whilst it can also spread from person to person, it does not do this easily, and outbreaks are usually small and fairly contained, according to experts and the European Centre for Disease Prevention and Control. Candidate vaccines are under development, although none have been approved yet.
Outbreak history and case totals
Nipah was first identified in Malaysia in 1999. Since then, there have been small outbreaks almost every year, mostly in Bangladesh. India also sees sporadic outbreaks.
According to the Coalition for Epidemic Preparedness Innovations, a group that tracks emerging disease threats and funds the development of medical tools to protect against them, as of December 750 cases had been recorded in all, and 415 of the patients died.
Reuters traced the spread of Nipah in a 2023 series, Bat Lands.
How infections typically occur
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 what scientists say is its natural host: fruit bats.
More specifically, the 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, the WHO says. Human-to-human spread has been found, mainly after close contact between a sick patient and their family or caregivers.
Symptoms and clinical course
The initial symptoms of Nipah such as fever, headaches and muscle pain are not specific and can be confused with other diseases. These can then be followed by neurological signs indicating acute encephalitis, or inflammation of the brain, and some people experience severe respiratory problems.
Seizures occur in severe cases, progressing to a coma in days. Most people who get better make a full recovery, but some experience long-term neurological problems.
Assessment of wider spread
Whilst Nipah is a dangerous disease with a high fatality rate, it has not yet shown signs of becoming more transmissible amongst humans or spreading easily worldwide, scientists say.
What screening measures are being increased at airports in Thailand and Malaysia?