A new virus that has killed nine people, infected hundreds and already reached the United States could mutate and spread, China warned Wednesday, as authorities scrambled to contain the disease during the Lunar New Year travel season.
The coronavirus has caused alarm for its similarity to SARS (Severe Acute Respiratory Syndrome), which killed nearly 650 people across mainland China and Hong Kong in 2002-2003.
In Wuhan, the epicenter of the outbreak, authorities cancelled large public events and urged visitors to stay away, telling residents not to leave the central Chinese city of 11 million people.
The illness is mainly transmitted via the respiratory tract and there "is the possibility of viral mutation and further spread of the disease," National Health Commission vice minister Li Bin said at a news conference in Beijing.
The World Health Organization (WHO) will hold an emergency meeting Wednesday to determine whether to declare a rare global public health emergency over the disease, which has now been detected in the United States, Taiwan, Thailand, Japan, South Korea and Macau.
The Chinese government has classified the outbreak in the same category as the SARS epidemic, meaning compulsory isolation for those diagnosed with the illness and the potential to implement quarantine measures.
But they still have not been able to confirm the exact source of the virus, which has infected 440 people across the country.
"We will step up research efforts to identify the source and transmission of the disease," Li said, although he said experts believe "the cases are mostly linked to Wuhan."
Plane passengers are facing screening measures at five US airports and a host of transport hubs across Asia.
North Korea will ban foreign tourists entirely to protect itself against the virus, according to a major tour operator.
A prominent expert from China's National Health Commission confirmed this week that the virus can be passed between people.
However, animals are suspected to be the primary source of the outbreak, as a seafood market where live animals were sold in the Wuhan was identified as ground zero for the virus.
"We already know that the disease originated from a market which conducted illegal transactions of wild animals," said Gao Fu, director of the Chinese center for disease control and prevention.
"This might be the cause, so the disease could be on an animal, and then passed on from this animal to a human."
He said it was clear "this virus is adapting and mutating."
Countries have been intensifying efforts to stop the spread of the pathogen – known by its technical name 2019 Novel Coronavirus (2019-nCoV) – as the number of cases jumped, raising concerns in the middle of a major Chinese holiday travel rush.
This week, China celebrates the Lunar New Year, the most important event in the Chinese calendar, with hundreds of millions of people travelling across the country to celebrate with family. Many also venture abroad.
On Wednesday, the commission announced measures to contain the disease, including sterilization and ventilation at airports and bus stations, as well as inside planes and trains.
People are being urged to wash their hands regularly, avoid crowded places, open windows to allow in fresh air, and wear a mask if they have a cough.
Anyone with a cough or fever should go to a hospital, Li said.
At Beijing's main international airport on Wednesday, the majority of people were wearing masks.
In Wuhan, Mayor Zhou Xianwang urged residents not to leave the city and visitors to stay away if there is no reason for them to come.
"If it's not necessary we suggest that people don't come to Wuhan," Wang told state broadcaster CCTV.
Police were conducting spot checks for live poultry or wild animals in vehicles leaving and entering the city, state media said.
The local government has cancelled public activities during the holiday, including the annual prayer-giving at the city's Guiyan Temple – which attracted 700,000 tourists during last year's holiday.
Tour groups heading out of the city have also been cancelled.
Hong Kong and British scientists have estimated that between 1,300 and 1,700 people in Wuhan may have been infected.