Transmitted from animals to humans

Health officials are scrambling to contain an outbreak of the Nipah virus in India’s eastern state of West Bengal after five confirmed cases, including infections among doctors and nurses. The virus is regarded as extremely dangerous due to its high fatality rate and the absence of any effective treatment.

Almost 100 people have been instructed to self-quarantine at home, while those infected are being treated at hospitals in and around Kolkata. One patient is reported to be in critical condition.

Nipah is a highly dangerous zoonotic virus, meaning it spreads from animals to humans, and there is currently no vaccine or cure. The World Health Organization lists it as a high-risk pathogen, explaining that although human cases are uncommon, infections usually occur when the virus spills over from bats, often through fruit contaminated by bat saliva or droppings. The virus can also spread between people through close contact with infected bodily fluids.

A health official stands outside the Kozhikode Medical College Hospital ward, which has been converted into a Nipah virus isolation ward on September 06, 2021 in Kozhikode, India. (Photo by C. K Thanseer/DeFodi images via Getty Images)

The US Centers for Disease Control and Prevention says Nipah infection typically starts with flu-like symptoms, including fever, headache, muscle aches, and fatigue. In some cases, patients may also develop respiratory problems such as coughing or pneumonia.

Symptoms usually appear within four to 14 days after exposure.

First identified in 1999

The most serious complication linked to Nipah is encephalitis, an inflammation of the brain that can lead to confusion, seizures, or coma. Even those who survive may suffer lasting neurological problems, such as ongoing seizures or changes in personality.

Nipah was first identified in 1999 during an outbreak in Malaysia and Singapore, where pig farmers and others who had close contact with infected pigs became ill.

Since that time, outbreaks have been recorded across parts of South Asia, including Bangladesh, northeastern India, and the southern Indian state of Kerala.

Road blockade due to Nipah affected areas at Chathamangalam panjayat on September 08, 2021 in Kozhikode, India. (Photo by C. K Thanseer/DeFodi images via Getty Images)