A new coronavirus that has claimed 17 lives in Wuhan, China, may have been transmitted to people from snakes, according to a genetic analysis. The snakes may have caught the virus from bats in the food market in which both species were sold.
As of 22 January, there are 555 confirmed cases of the infection, which can cause fever, difficulty breathing and pneumonia. To contain the virus, Wuhan has effectively been placed under quarantine, with public transport being temporarily closed, according to reports.
While 444 of the cases have been reported in Wuhan, cases have also been confirmed in the surrounding regions, with 26 in Guangdong province, 14 in Beijing and 9 in Shanghai. Internationally, confirmed cases have been reported in Thailand, Japan, South Korea and the US. Hundreds more are suspected, and attempts to diagnose the cases are underway.
The source of the infection is suspected to be a food market in Wuhan visited by several of those first infected with the virus. The market is known to sell live wild and farmed animals, including marmots, birds, rabbits, bats and snakes.
To find out if the virus might have come from one of these species, Wei Ji and colleagues at Peking University in China compared the genomes of five samples of the new virus with 217 similar viruses collected from a range of species.
The team’s analysis suggests that the new virus looks similar to those found in bats, but is most like viruses seen in snakes, genetically speaking. “Results derived from our sequence analysis suggest for the first time that snake is the most likely wildlife animal reservoir,” the team wrote.
“We are excited about this new speculation,” says Haitao Guo at the University of Pittsburgh in Pennsylvania, who reviewed the study. “We need more experimental evidence, but it gives us a clue,” he says.
The new virus may have formed as a result of viruses from bats and snakes combining, which can happen when two species of animal are kept in close quarters as can happen in food markets, says Peter Rabinowitz at the University of Washington in Seattle.
The virus may then have passed to people through the air, says Rabinowitz. “It’s still speculation, but if the virus is in the secretions or faeces of the snakes, it would be possible to aerosolise and be breathed in if there were enough snakes and enough people,” he says.
On 22 January, the World Health Organization held an emergency committee on the new virus, which is in the same family as SARS and MERS. Following the meeting, director general Tedros Adhanom Ghebreyesus said that he needed more information on the virus and its spread before he could declare the outbreak a public health emergency.
“This is an evolving and complex situation,” Ghebreyesus said. “The decision about whether or not to declare a public health emergency of international concern is one I take extremely seriously, and one I am only prepared to make with appropriate consideration of all the evidence.”
The emergency committee will meet again tomorrow, and Ghebreyesus promises they “will have much more to say” then.
Journal reference: Journal of Medical Virology, DOI: 10.1002/jmv.25682
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