Tokyo: A new strain of coronavirus that emerged in China may have originated in bats or snakes, according to genetic analysis of the virus that has so far killed 17 people.
The theories are based on examination of the genome sequence of the virus released by authorities in the wake of the outbreak, with two studies pointing to the likely role of bats in the outbreak.
One study, published Tuesday in the journal Science China Life Sciences, which is sponsored by Beijing's Chinese Academy of Sciences, looked at the relations between the new strain and other viruses.
It found the coronavirus that emerged from China's Wuhan was closely related to a strain that exists in bats.
"Bats being the native host of the Wuhan CoV (coronavirus) would be the logical and convenient reasoning, though it remains likely there was the intermediate host(s) in the transmission cascade from bats to humans," the researchers from several institutions in China wrote in the paper.
That study did not speculate about which animal could have been an "intermediate host," but a second study published Wednesday in the Journal of Medical Virology identifies snakes as the possible culprit.
"To search for (a) potential virus reservoir, we have carried out a comprehensive sequence analysis and comparison. Results from our analysis suggest that snake is the most probable wildlife animal reservoir," the paper says.
The researchers caution that their conclusions require "further validation by experimental studies in animal models".
Neither study explained how the virus may have been transmitted from animals to humans.
But they could offer clues to Chinese authorities as they hunt for the source of the outbreak that has sickened more than 540 people, some even as far afield as the United States.
The food market where the deadly virus surfaced offered a range of exotic wildlife for sale, including live foxes, crocodiles, wolf puppies, giant salamanders, snakes, rats, peacocks, porcupines, camel meat and other game. The virus strain is believed to have emerged from illegally traded wildlife here at the market.
Gao Fu, director of the Chinese centre for disease control and prevention, said in Beijing on Wednesday that authorities believe the virus likely came from "wild animals at the seafood market" though the exact source remains undetermined.
As it seeks to stop the spread of the virus, Wuhan's local government – the epicentre of the outbreak - said it would close all urban transport networks and suspend outgoing flights from the city as of 10am on Thursday (0200 GMT), state media reported, adding that the government said citizens should not leave the city unless there were special circumstances.
With more than 11 million people, Wuhan is central China's main industrial and commercial centre, home to the country's largest inland port and gateway to its Three Gorges hydroelectric dam.
However, the virus has already spread beyond the city to population centres including Beijing, Shanghai, Macau and Hong Kong.
Contrasting with its secrecy over the 2002-03 Severe Acute Respiratory Syndrome (SARS), which killed nearly 800 people, China's communist government has this time given regular updates to try to avoid panic as millions travel for the Lunar New Year. SARS was linked to Chinese consumption of civet meat.
Kerala ramps up measures to mitigate any outbreak
The Health Department in Kerala has issued an alert in the wake of the new coronavirus outbreak in China. Surveillance in all the four airports in the state -- Thiruvananthapuram, Kochi, Kozhikode and Kannur -- have been stepped up, State Health Minister KK Shailaja said in a press release.
Those who have returned from China should inform district medical officers, the minister added.
Seven major international airports, including Kochi, had been put on high alert by the centre as part of preparations to tackle a possible coronavirus outbreak in the country. The Ministry of Civil Aviation has informed that all tourists arriving from China and Hong Kong will have to undergo thermal screening and if found necessary, even medical examinations.
States have been asked to review their preparedness, identify gaps and strengthen core capacities in the area of surveillance, laboratory support and in particular, hospital preparedness in terms of isolation and ventilator management of patients with severe respiratory illness.
The Indian government had earlier issued a travel advisory asking citizens to follow certain precautionary measures while visiting China in the wake of the outbreak.
The World Health Organization (WHO) urged all countries to be prepared to tackle the spread of the virus. “WHO encourages all countries to continue preparedness activities on the novel coronavirus,” the global health body had tweeted.
After a meeting at its Geneva headquarters on Wednesday, WHO said it would decide on Thursday whether to declare the outbreak a global health emergency, which would step up the international response. If it does so, it will be the sixth international public health emergency to be declared in the last decade.
(With inputs from PTI)