More than 2,700 people in China are now said to have been infected by the fast-spreading coronavirus while more countries have reported their first confirmed cases.
Chinese officials said, as of the end of Sunday, there are 2,744 confirmed cases, including 461 people in critical condition, as the death toll rose to 80.
The deadly pneumonia-like virus comes from a large family of viruses known as coronaviruses, according to the World Health Organization.
They are known to cause illness ranging from the common cold to more severe diseases such as the 2002-2003 outbreak of SARS, or severe acute respiratory syndrome.
In a press briefing, the National Health Commission said the incubation period for the virus is about 10 days and that it is contagious even during this stage, putting additional pressure on prevention control. That is said to be a major difference compared to SARS, where victims became contagious after they showed symptoms.
The national new year holiday has been extended by three days to Sunday, in an attempt to contain the spread.
On Monday, Chinese Premier Li Keqiang visited Wuhan, the capital of Hubei province and centre of the outbreak.
Wuhan is in lockdown and several other cities have imposed travel bans.
