What to know about Nipah virus amid outbreak in India

The virus has a fatality rate between 40% and 75%, according to the CDC.

September 18, 2023, 5:04 PM

India's southern state of Kerala is currently facing an outbreak of the rare, but potentially serious Nipah virus with at least two deaths so far, according to local reports.

Health officials have closed schools and offices in Kerala and hundreds of residents are being tested.

Despite Nipah virus's high fatality rate and no specific treatments available, experts said it's very unlikely the virus will lead to a global emergency and that it's a reminder of how habitat destruction has led to animals transmitting the disease to humans.

Here's what you need to know about the virus, including signs and symptoms, how the virus is transmitted and what treatments are available.

What is Nipah virus?

Nipah virus is a type of zoonotic disease, meaning it's primarily found in animals and can initially spread between animals and people.

It was first discovered in 1999 after a disease affected both pigs and people in Malaysia and Singapore, according to the Centers for Disease Control and Prevention.

Nipah viruses binding receptors on human cells, an initial stage of Nipah infection.
Dr_microbe/Getty Images

The virus is most often spread by fruit bats, also known as flying foxes, and it can spread through direct or indirect contact.

"People can become infected if they have close contact with an infected animal or body fluids such as, for example, the fruit bat saliva on a fruit, and then it flies off and then a person eats the fruit," Dr. Diana Finkel, an associate professor of medicine in the division of infectious disease at Rutgers New Jersey Medical School, told ABC News.

The virus can also spread from person to person by being in close contact or coming into contact with the bodily fluids of an infected person.

What are the symptoms?

Symptoms typically occur between four and 14 days after exposure. The most common symptom is fever followed by headache, cough, sore throat, difficulty breathing and vomiting.

Diagnosing the virus in the early stages is often difficult because the symptoms resemble many other illnesses, the CDC said.

The virus can lead to severe symptoms, including disorientation, drowsiness, seizures or encephalitis, which is inflammation of the brain. These can progress to a coma within 24 to 48 hours, according to the CDC.

Deaths range anywhere between 40% and 75% among all cases, the federal health agency said. Some permanent changes among survivors have been noted, including persistent convulsions.

What are the treatments available?

Currently there are no specific treatments available for Nipah virus with treatment limited to supportive care, including rest and fluids.

Experts said there are treatments currently under development. One is a monoclonal antibody, which is are immune system proteins that are manufactured in a lab and mimic the antibodies the body naturally creates when fighting the virus.

Finkel said the drug has already completed phase I clinical trials and is currently being used on a compassionate basis.

Researchers are also studying the potential benefit of remdesivir -- the intravenous medication used to treat COVID-19 -- which has been shown to work well in nonhuman primates with Nipah virus.

What is the likelihood of Nipah virus spreading?

Experts said that while anything is possible, it's very unlikely that the outbreak in India will lead to global spread.

There has been limited person-to-person spread amid the outbreak in India.

Nipah viruses binding receptors on human cells, an initial stage of Nipah infection.
Dr_microbe/Getty Images

"The world is small, but the likelihood that somebody's infected, or an infected fruit bat with Nipah virus would be here, right now, is very unlikely," Finkel said.

She said when people are exposed in the healthcare settings, it's often because proper standard precautions were not followed such as not wearing gloves or masks.

Experts say the outbreak is also a reminder of the potentially devastating effects of habitat destruction and climate change, possibly leading to more interaction between infected animals and humans.

"If you take this current outbreak in Kerala, as an example, you have to think about why are fruit bats that harbor this Nipah virus, why are they coming into contact with people?" Dr. Peter Rabinowitz, director of the University of Washington Center for One Health Research, told ABC News. "What is changing in terms of the movement of the bat populations? Are they leaving [a] habitat where there were not very many people? Are they now spending more time close to people?"