An outbreak of the Nipah virus in India’s eastern state of West Bengal has heightened concerns in China and several Southeast Asian countries, prompting them to tighten health screening operations at airports as millions prepare to travel for the Lunar New Year holiday.
Since December 2025, two confirmed cases of the virus have been reported in West Bengal, India’s health ministry said on Wednesday. The ministry did not provide details about the people infected but noted that of a total of 196 contacts linked to the confirmed cases, “all traced contacts have been found asymptomatic and have tested negative”, for the virus.
“The situation is under constant monitoring, and all necessary public health measures are in place,” the ministry added.
A district health officer told Reuters that the two people infected in West Bengal in late December were health workers. Both are being treated at a local hospital, the health officer said. The Nipah virus (NiV) is a zoonotic virus – a disease transmitted from animals such as fruit bats and flying foxes to humans. It can also be transmitted to humans via contaminated food products or directly from person to person.
The virus can be deadly. It typically incubates in the human body for five to 14 days, with symptoms occurring within three to four days.
It causes severe respiratory and neurological disease in humans, progressing from fever and headache to acute encephalitis (brain inflammation) in severe cases, Kaja Abbas, associate professor of infectious disease epidemiology and dynamics at the London School of Hygiene & Tropical Medicine and Nagasaki University, said. Symptoms can also include convulsions and mental confusion, and patients can fall into a coma within 24 to 48 hours in severe cases.
“The case fatality rate is high, between 40 percent and 75 percent, among people infected with the Nipah virus,” Abbas told Al Jazeera.
However, the virus’s basic reproduction number, which is the expected number of secondary infections stemming from a primary case, is “typically below one”, he said. This suggests the virus spreads in only a limited way via human-to-human transmission and there is a low likelihood of the virus becoming a widespread pandemic. The first known outbreak of NiV was reported in 1998 when pig farmers and butchers in Malaysia and Singapore contracted it from infected pigs. At least 250 people were infected, with more than 100 deaths.
In 2014, NiV infections in the Philippines were associated with the slaughter of horses and consumption of infected horse meat.
Since 2001, there have been sporadic but recurring outbreaks in South Asia, particularly in Bangladesh and India.
According to the World Health Organization, outbreaks in Bangladesh have been linked to humans consuming contaminated raw palm sap, having close contact with other people’s secretions and excretions, and caring for infected patients.
According to the WHO, the first cases in India were recorded in West Bengal in 2007 but an earlier outbreak was retrospectively identified in the state’s Siliguri city in 2001. The 2001 Siliguri outbreak occurred in a healthcare setting where 75 percent of cases were of hospital staff or visitors, the WHO said.
Since 2018, dozens of deaths have been reported in India’s Kerala state, which is now regarded as the world’s highest-risk region for the virus.
The reasons for other outbreaks in Indian states are unclear. Some medical experts have suggested outbreaks may have been triggered by human consumption of fruit contaminated by bat saliva or urine, while the Indian Council of Medical Research has suggested that while the virus is primarily spread by physical contact, it may also be airborne.
Source: Here