Nipah virus outbreak in India 'definitely a concern,' Canadian scientist says
Much is unknown about the virus that is spread by bats, but here are some answers
Health officials are working to treat those infected with a rare, brain-damaging virus in southern India. It is the first reported outbreak in the country.
The first death happened May 18, said a state health minister in Kerala, the state at the epicentre of the outbreak blamed for the 12 deaths, including a nurse.
"The Nipah virus disease is not a major outbreak and is only a local occurrence," the government said in a statement on Friday, adding that a team of experts continued to monitor the situation.
Three victims, members of one family, are suspected to have been infected by bats that crowded a well near their home, a local government official said.
"It's in the southern part of India, in Kerala, where it has never been seen before," said Dr. Isaac Bogoch, an infectious disease specialist at Toronto General Hospital who treats tropical diseases.
Much is unknown about Nipah virus and the details of this outbreak. Here are some answers.
What is the virus?
Nipah virus was discovered in humans in 1999 in Malaysia. It caused mild disease in pigs but the country experienced nearly 300 human cases and 100 deaths, according to the U.S. Centers for Disease Control and Prevention.
The virus is named after the Malaysian village where it was first identified, the World Health Organization says.
What happens when people are infected?
Initial signs include fever, chills, muscle aches and pains. Ultimately, Bogoch said, the virus causes encephalitis, inflammation of the brain. People can have seizures and headaches. Severe inflammation can cause a coma.
The death rate ranges from 40 per cent to 75 per cent, he said. Fortunately, it is rare.
Many people who survive are left with continuing problems. "Those can include cognitive deficits, some people are left with a seizure disorder afterwards and there's been reports of hearing and vision changes," Bogoch said.
Where does it come from?
How can people be exposed?
Bats shed the virus in their saliva, urine, semen and feces, but they don't have symptoms of the virus.
People who eat fruit that's been in contact with bat secretions can pick up the infection, Bogoch said.
Nipah virus is highly contagious among pigs, and the animals have infected people. Swine spread it by coughing, and the virus may also be in their urine or feces. People who work closely with pigs may pick up the virus.
Health-care providers or family members can also get it through close contact with an infected person, if they have not taken precautions such as avoiding the patient's secretions.
Scientists still need to work out the details of exactly how Nipah and related viruses, the fruit bat host and their environment all interact.
How is it treated?
Is a vaccine available?
There is no commercial vaccine for humans or animals.
At the Canadian Food Inspection Agency's National Centre for Foreign Animal Disease in Winnipeg, researchers started studying the Nipah virus after the attacks of Sept. 11, 2001, when there were concerns it could be used in bioterrorism.
The goal of the research is to rapidly detect the virus in swine herds, develop diagnostic tests, understand how pigs respond to the disease and to assist in the development of vaccines, said Hana Weingartl, a research scientist and head of the special pathogens unit at the centre.
"In a way it's work which is a little bit invisible because we don't have Nipah virus in Canada, so people are not aware about the danger," Weingartl said in an interview. "But internationally, it is important to be able to work with the virus and be prepared because the virus is changing, and similarly to influenza it is quite possible it can … obtain the ability to readily transmit from humans to humans."
The lab has tested three candidate vaccines in animals, one intended for eventual use in humans and the others for veterinary use.
"The vaccine is not an attractive proposition for companies," Weingartl said. Of the three, the first was excellent, she said, but the company decided not to follow up, and the second needs more work, which is being done in England and Australia. Weingartl and her team are testing the third.
The Coalition for Epidemic Preparedness Innovations (CEPI), a global alliance of governments and non-profits, pledged $25 million US in collaboration with two pharmaceutical firms towards the development and manufacture of a vaccine against the Nipah virus.
Given how emerging viruses like Nipah can show up unexplained, Weingartl said there's reason to be on guard.
The Kerala outbreak "is definitely a concern," Weingartl said. "As a scientist, I would like to know how bad it is, what it is, what is the transmission route."
"This is what we would term a neglected tropical infection," Bogoch said.
A travel advisory hasn't been issued, and Bogoch said he doesn't think people should be concerned about travel to the area. Beaches in the tourist areas of Kerala are not as busy as normal, and travel agents there report cancellations.
With files from CBC's Marcy Cuttler and Reuters