Rare but highly fatal virus now subject to strict quarantine and reporting measures
South Korea has officially designated Nipah virus infection as a first-tier infectious disease, a classification for the most dangerous outbreaks with a high fatality rate that require immediate reporting and isolation.
The Korea Disease Control and Prevention Agency announced that the revision to the infectious disease classification guidelines will take effect Monday, marking the first time a new disease has been added to the top-tier category since the country introduced the four-tier system in 2020.
Following the revision, patients diagnosed with or suspected to have Nipah virus infection are now subject to public health management measures, including mandatory reporting, isolation, contact tracing and epidemiological investigation.
Nipah virus, first identified at a pig farm in Malaysia in 1998, was named after the region where it was first reported. This zoonotic disease can spread from animals to humans and between people.
Nipah virus belongs to the Henipavirus genus and is carried primarily by infected animals. Infections in humans have occurred through direct contact with infected animals, primarily fruit bats and pigs, or their bodily fluids, including blood, urine, or saliva.
The infection can also occur through consumption of food contaminated by infected animals, such as raw date palm sap or fruit tainted by fruit bats.
Human-to-human transmission has also been reported through close contact with an infected person's respiratory droplets, nasal secretions, urine, or blood.
The virus can survive for days in certain food products under ambient conditions, making it particularly challenging to control in tropical regions.
Its fatality rate is reported to be 40 to 75 percent, and no vaccine or specific treatment is currently available.
South Korea has not reported any Nipah virus cases so far. However, the World Health Organization has included Nipah in its list of priority pathogens with pandemic potential. Bangladesh and India have reported repeated outbreaks in recent years, including eight deaths across the two countries in 2025 alone.
Since 2001, India and Bangladesh have reported over 450 Nipah virus cases, with an average fatality rate of over 70 percent. In India, 78 died out of 108 infected since its first outbreak, and 248 out of 346 in Bangladesh during the same period.
While outbreaks in Malaysia, Singapore and the Philippines occurred in the early 2000s, no recent cases have been reported in those countries.
After an incubation period of four to 14 days, symptoms may begin with fever, headache, muscle pain, nausea, vomiting and a sore throat.
While some patients experience only mild or no symptoms, in severe cases, patients can develop neurological symptoms such as dizziness, drowsiness and changes in state of consciousness, which may progress to seizures and coma within 24 to 48 hours.
Some 20 percent of those who had symptoms of encephalitis were left with long-term neurological complications such as seizures.
"Nipah virus is rare but extremely dangerous," said Lim Joo-hyun, director for endocrine and kidney disease research at the National Institute of Health.
"What makes it especially concerning is the high fatality rate and the fact that it can jump from animals to humans and spread within communities. That's why proactive monitoring and preparation are essential."
With the new designation, all suspected and confirmed cases must be immediately reported to health authorities. Patients will be subject to high-level isolation procedures, including negative-pressure rooms, while close contacts will be tracked and monitored throughout the 45-day maximum incubation period.
To detect and contain any potential cases, the KDCA has established a diagnostic testing system using real-time RT-PCR within biosafety level 4 (BSL-4) laboratories. In addition, travelers arriving from India and Bangladesh, where recent infections have been reported, must report symptoms through the Q-CODE quarantine system.
Hospitals and clinics nationwide have been instructed to report patients with Nipah-like symptoms and recent travel history to high-risk regions. Those showing signs of infection will be isolated and treated according to first-tier protocols.
There are no vaccines or antiviral medications for Nipah virus, but individual precautions can significantly reduce the risk of infection.
Authorities recommend avoiding contact with wild animals such as fruit bats and pigs in endemic regions, refraining from drinking raw date palm sap or consuming damaged fruit, and practicing good hygiene, such as frequent handwashing and mask-wearing.
Travelers returning from high-risk countries who develop a fever, headache or other symptoms within 14 days of arrival should call the KDCA's 1339 hotline or visit a local health center immediately.
"This designation is a preemptive move to guard against the virus's entry into the country, especially in light of its recurrence in several Asian countries," said KDCA Commissioner Lim Seung-kwan.
"The experience of COVID-19 has underscored the importance of early preparation against emerging infectious diseases."