The first cases of human-to-human transmission of the deadly coronavirus outside of China have taken place, health authorities have confirmed.
Two people, one in Germany and one in Japan, have contracted the virus even though they had not travelled to China. They contracted the virus from visitors from the Wuhan region.
One of them is a Japanese tour bus driver in his 60s who had driven two groups of Chinese tourists from Wuhan earlier this month.
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He was diagnosed with pneumonia on Saturday and has now been hospitalised.
Another man — who is in his 40s, lives in Wuhan and arrived in Japan on January 20 — is also confirmed to have contracted the virus, bringing the total confirmed cases in Japan to six.
In Germany, a man is believed to have been infected by a Chinese colleague who visited his workplace.
The 33-year-old took part in a training session at his workplace last Tuesday which also included an employee of the same company visiting from China, Andreas Zapf, the head of Bavaria's office for health and food safety told The Independent.
The woman who was visiting had not previously shown any symptoms and flew home on Thursday.
However, she went to a doctor after feeling ill on the flight and tested positive for the new virus.
The woman lives in Shanghai, but had been visited a few days earlier by her parents, who come from the worst-affected Wuhan area.
The German man, who lives in the Starnberg area south of Munich is in isolation as a precaution, officials in Bavaria said. They said his condition was good.
The World Health Organisation said a case in Vietnam also involved human-to-human transmission outside China.
This all comes as the United States and several other nations prepare to airlift citizens out of Wuhan — the epicentre of the disease that has killed more than 100 people.
Hong Kong's leader said it will cut all rail links to mainland China and halve the number of flights as authorities in China and overseas sought to stem the spread of the new virus.
The number of confirmed cases rose to more than 4500.
The US government chartered a plane to fly out diplomats from the US Consulate in Wuhan, where the outbreak started, and other Americans.
The plane will make a refuelling stop in Alaska before flying on to Ontario, California, the US Embassy said.
A Japanese-chartered Boeing 767 departed for Wuhan to fly out its citizens, the first of two possible flights, and South Korea also said it will send a plane to the city in central China. France, Mongolia and other governments also planned evacuations.
China has cut off access to Wuhan and 16 other cities in Hubei province to prevent people from leaving and spreading the virus further. The lockdown has trapped more than 50 million people in the most far-reaching disease control measures ever imposed.
The Japanese flight was bringing 20,000 face masks as well as protective gear, all in short supply as hospitals grapple with a growing number of patients. The city is building two hospitals in a matter of days to add more than 2000 beds.
US health officials expanded their recommendation for people to avoid non-essential travel to any part of China, rather than just Wuhan and other areas most affected by the outbreak.
Asian stock markets tumbled for a second day, dragged down by worries about the virus's global economic impact.
Hong Kong leader Carrie Lam, wearing a green surgical mask, told a news conference that train service would stop at midnight Thursday and that the two stations connecting to the mainland would be closed.
She stopped short of a total closing of the border, as North Korea and Mongolia have done, but said ferry and bus service to the mainland would also be suspended.
China's death toll from the new viral disease rose to 106, including the first death in Beijing, the Chinese capital, and 24 others in Hubei province, where the first illnesses were detected in December.
There were 1771 new cases confirmed in China, raising the national total to 4515, according to the National Health Commission. It said 976 people were in serious condition.
The sharp rise in infections in recent days suggests there has been significant human-to-human spread of the virus, though it could also be explained by expanded monitoring efforts, said Malik Peiris, chairman in virology at the University of Hong Kong.
Experts worry that the new virus may spread more easily than originally thought, or may have mutated into a form that does so. It is from the coronavirus family, which also can cause the common cold as well as more serious illnesses such as SARS.
Mr Peiris, an adviser on the World Health Organisation's coronavirus emergency committee, said it is reassuring that outside of China the disease has not spread widely beyond the people who brought it from Wuhan.
China has reported eight cases in Hong Kong and five in Macao, and more than 45 cases have been confirmed elsewhere in the world. Almost all involve mainland Chinese tourists or people who visited Wuhan.
Thailand reported six members of a family from Hubei were new cases, raising its total to 14. Taiwan confirmed three new cases Tuesday, including two 70-year-old tourists from Wuhan, raising its total to eight.
Infections also have been confirmed in the United States, South Korea, Vietnam, Singapore, Malaysia, Nepal, France, Canada, Australia and Sri Lanka.