The ability of the coronavirus to spread is getting stronger and infections could continue to rise, China's National Health Commission says, with more than 2000 people globally infected and 56 in China killed by the disease.
National Health Commission Minister Ma Xiaowei, speaking at a press briefing on Sunday, said knowledge of the virus was limited.
Ma said the incubation period for the coronavirus can range from one to 14 days, and that the virus is infectious during incubation, which was not the case with Severe Acute Respiratory Syndrome (SARS), a coronavirus that originated in China and killed nearly 800 people globally in 2002 and 2003.
Containment efforts, which have thus far included transportation and travel curbs and the cancellation of big events, will be intensified, Ma told a crowded news briefing on the second day of the Lunar New Year holiday.
The virus, believed to have originated late last year in a seafood market in the central Chinese city of Wuhan that was illegally selling wildlife, has spread to Chinese cities including Beijing and Shanghai, as well as the United States, Thailand, South Korea, Japan, Australia, France and Canada.
President Xi Jinping said during a politburo meeting on Saturday that China was facing a "grave situation", as health authorities around the world scrambled to prevent a pandemic.
On Sunday, China announced a nationwide ban on the sale of wildlife in markets, restaurants, and e-commerce platforms. Wild and often poached animals packed together in Chinese markets are blamed as incubators for viruses to evolve and jump the species barrier to humans.
Snakes, peacocks, crocodiles and other species can also be found for sale via Taobao, an e-commerce website run by Alibaba.
The US State Department said it will relocate personnel at its Wuhan consulate to the United States and will offer a limited number of seats to private US citizens on a January 28 flight to San Francisco.
The World Health Organisation this week stopped short of calling the outbreak a global health emergency, but some health experts question whether China can continue to contain the epidemic.
On Sunday, China confirmed 1,975 cases of patients infected with the new coronavirus as of Jan. 25, while the death toll from the virus has risen to 56, state broadcaster CCTV reported.
The outbreak has prompted widening curbs on movements within China, with Wuhan, a city of 11 million, on virtual lockdown, with transports links all-but severed except for emergency vehicles.
Health authorities in Beijing urged people not to shake hands but instead salute using a traditional cupped-hand gesture. The advice was sent in a text message that went out to mobile phone users in the city on Sunday morning.
China has called for transparency in managing the crisis, after a cover-up of the spread of the deadly SARS virus eroded public trust.
The outbreak has overshadowed the start of the Lunar New Year, when hundreds of millions of Chinese travel at home and abroad to be with families, with public events cancelled and many tourist sites shut.
On Saturday, Hong Kong declared a virus emergency, scrapped celebrations and restricted links to mainland China.
Hong Kong Disneyland and the city's Ocean Park theme park were closed on Sunday. Shanghai Disneyland, which expected 100,000 visitors daily through the Lunar New Year holidays, has already closed.
On Saturday, Canada declared the first "presumptive" confirmed case of the virus in a resident who had returned from Wuhan. Australia confirmed its first four cases on Saturday, Malaysia confirmed four and France reported Europe's first cases on Friday.
Australian Associated Press