Coronavirus: China orders 'unprecedented' lockdown of cities at virus epicentre

China put on lockdown on Thursday two cities at the epicentre of a new coronavirus outbreak that has killed 56 people and infected nearly 2,000, as health authorities around the world scramble to prevent a global pandemic.

Health officials fear the transmission rate will accelerate as hundreds of millions of Chinese travel at home and abroad during week-long holidays for the Lunar New Year, which begins on Saturday.

The previously unknown virus strain is believed to have emerged late last year from illegally traded wildlife at an animal market in the central Chinese city of Wuhan.

Most transport in Wuhan, a city of 11 million people, was suspended on Thursday morning and people were told not to leave.

Hours later, neighbouring Huanggang, a city of some 7 million people, announced a similar lockdown. Another city, Ezhou, also imposed restrictions, according to municipal officials.

As of Friday, travel restrictions were also placed on cities of Chibi, Zhijiang, Huanggang, Xiantao, Enshi, Qianjiang and Xianning.

China ramped up measures to contain a virus that has killed 56 people and infected more than 2,000, suspending public transport in 10 cities, shutting temples over the Lunar New Year and even closing the Forbidden City and part of the Great Wall.

The risks persuaded Shanghai Disneyland theme park to close from Saturday until further notice.

There is no vaccine for the virus, which can spread through respiratory transmission. Symptoms include fever, difficulty in breathing and cough, similar to many other respiratory illnesses.

Preliminary research suggested the virus was passed on to humans from snakes, but government medical adviser Zhong Nanshan has also identified badgers and rats as possible sources.

The WHO has said it will decide on Thursday whether to declare the outbreak a global health emergency, which would step up the international response.

Chinese authorities gave no new details on the numbers of virus infections but it has been reported in Beijing, Shanghai and Hong Kong, and several other countries including the United States, stoking fears it is already spreading worldwide.

Wuhan's city government said it would shut down all urban transport networks and suspend outgoing flights.

Authorities in Huanggang ordered indoor entertainment venues including cinemas and internet cafes to close and were asking citizens not to leave other than under special circumstances.

Authorities had confirmed more than 2,000 cases and 56 deaths as of January 26.

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

Some experts believe the new virus is not as dangerous as previous coronaviruses such as SARS and Middle East Respiratory Syndrome (MERS), which has killed more than 700 people since 2012.

Airports globally stepped up screening of passengers from China and the European Centre for Disease Control and Prevention said the further global spread of the virus was likely.

Travellers arrive at the nearly-deserted Wuhan train station.