The previously unknown and contagious coronavirus strain emerged from the central city of Wuhan in China, with cases now detected as far away as the United States, leaving deaths due to virus. Officials believe the origin to be a market where wildlife is traded illegally, Reuters wrote.

The latest death toll in Hubei province, of which Wuhan is the capital, had risen to 17 by 1200 GMT on Wednesday, the provincial government said.

Hours earlier, officials had put the toll at nine dead, all in Wuhan, and more than 470 cases confirmed in China.

Contrasting with its secrecy over the 2002-03 Severe Acute Respiratory Syndrome (SARS) that killed nearly 800 people, China has this time given regular updates to try to head off panic as millions travel at home and abroad for the Lunar New Year.

“The rise in the mobility of the public has objectively increased the risk of the epidemic spreading,” National Health Commission vice-minister Li Bin said.

The World Health Organization (WHO) began an emergency meeting to rule if the outbreak was a global health emergency.

After official appeals to stay calm, many Chinese were canceling trips, buying face masks, avoiding public places such as cinemas and shopping centers, and even turning to an online plague simulation game or watching disaster movie “The Flu” as a way to cope.

The virus has spread from Wuhan around China to population centers including Beijing, Shanghai, Macau, and Hong Kong.

Abroad, Thailand has confirmed four cases, while the United States, Taiwan, South Korea, and Japan have each reported one.

Li said the virus, which can cause pneumonia, was being spread via breathing. Symptoms include fever, coughing and difficulty breathing. About 2,200 people in contact with infected people were in isolation.

There is no vaccine for the virus.

With more than 11 million people, Wuhan is central China’s main industrial and commercial center and an important transport hub, home to the country’s largest inland port and gateway to its giant Three Gorges hydroelectric dam.

WHO spokesman Tarik Jasarevic said new cases would appear as China stepped up monitoring. But Li said there was no evidence of “super-spreaders” capable of disseminating the virus more widely, as happened during the SARS outbreak. SARS was thought to have crossed to humans from civet cats sold for food.