What is the deadly Nipah virus?

A deadly virus that spreads to humans from contact with infected bats, pigs or other people has in its latest outbreak killed 17 of 18 people confirmed to be infected and has led to the quarantine of 1,400 people in their homes.

The new outbreak of the Nipah virus in the state of Kerala in southern India began just a few weeks ago.

What is the Nipah virus?

It is a zoonotic virus, which means it is spread from animals to humans and infects both. Nipah likes to live in fruit bats, its natural host.

How does one get infected with Nipah?

The virus can spread to humans who come into direct contact with infected bats, pigs or other infected people, the World Health Organization says.

The spread of Nipah to humans from close contact with infected pigs -- that were infected by bats -- has occurred in Malaysia and Singapore. Person-to-person transmission has been known to occur in Bangladesh and India when people have contact with someone who is sick from Nipah. Eating certain foods, especially fruit such as raw date-palm sap, that are contaminated with urine or saliva from infected fruit bats, has been the most likely source of infection in recent outbreaks.

What are the signs and symptoms of Nipah virus?

Common initial symptoms are headaches and fever, followed by drowsiness, disorientation, and confusion. This leads to encephalitis, inflammation of the brain, and can progress to a coma. The virus can also cause respiratory illness, the Centers for Disease Control and Prevention (CDC) says.

For those who survive Nipah, long-term consequences of the virus can include persistent shaking and personality changes. Even after being exposed, the virus can live inside and be reactivated years later.

How long has been Nipah been around?

The virus was first identified in an outbreak in 1998 to 1999 among pig farmers and other people in close contact with pigs in Malaysia and Singapore. It got its name from the Kampung Sungai Nipah village in Malaysia where the outbreak occurred.

Of nearly 300 people who were infected, more than 100 died. In contrast, the virus caused a relatively mild disease in infected pigs. To stop the spread of Nipah, more than a million pigs were killed, causing a significant trade loss for Malaysia, the CDC says. No cases of Nipah have since been reported in Malaysia or Singapore.

Two years later, in 2001, a different strain of Nipah caused an outbreak in Bangladesh, and outbreaks have since occurred there almost annually. Also in 2001, a Nipah outbreak happened in Siliguri, India. Several other outbreaks have since occurred in India.

Other areas where fruit bats are found may be at risk for Nipah, including Cambodia, Ghana, Indonesia, Indonesia, Madagascar, the Philippines, and Thailand.

Is there a test for Nipah?

A Nipah infection can be diagnosed through a combination of tests. Tests of throat and nose swabs and of urine, blood, and the cerebrospinal fluid that surrounds the brain can detect the virus in the early stages of infection. Later, testing for antibodies can be performed.

Is there a vaccine or treatment for Nipah?

There is no vaccine to protect against Nipah infection in either humans or animals. There is also as yet no treatment to fight the virus in infected people. A drug, ribavirin, has shown some promise against the virus in the laboratory, but its effectiveness for humans carrying Nipah is still uncertain. There is a vaccine that has shown to help ferrets after they are exposed to Nipah, but it has not been tested on humans.