A new pneumonia-like virus has spread outside China for the first time.
A tourist in Thailand has been quarantined after landing in Bangkok from Wuhan in central China where the outbreak began.
According to China's Xinhua News Agency, the woman arrived in Thailand on January 8 and was hospitalised.
No one else was infected and the woman is now ready to return to Wuhan.
One person has died and 41 cases have been recorded since the virus took hold in December, reports the BBC.
The virus was traced back to a large animal and seafood market in Wuhan and until Wednesday had not been recorded outside of the city.
"The present outbreak in Wuhan City in China is certainly severe, with one fatality and six other people reported to be severely ill with pneumonia out of about 40 confirmed cases," said University of Otago's professor of public health Michael Baker in a statement.
"However, it does not appear to be highly transmissible. Cases are largely confined to people who have had exposure to a live-animal market there."
The World Health Organization (WHO) told reporters in Geneva on Tuesday the virus appears to have transferred from person to person for the first time.
"From the information that we have it is possible that there is limited human-to-human transmission," said Maria Van Kerkhove, acting head of WHO's emerging diseases unit.
She says there is a possibility of a wider outbreak.
"It's still early days, we don't have a clear clinical picture."
The virus is a coronavirus which can cause a range of illnesses from colds to Severe Acute Respiratory Syndrome (SARS).