Of the 17 new cases in the central city of Wuhan - believed to be the epicentre of the outbreak - three were described as "severe", of which two patients were too critical to be moved, authorities said.
The new virus is from the same large family of coronaviruses that includes Severe Acute Respiratory Syndrome (Sars), which killed almost 800 people globally during a 2002/03 outbreak that also started in China.
According to the KCDC, the woman - a 35-year-old resident of Wuhan in China's Hubei province - arrived at Incheon International Airport on Sunday. For one, the virus that spread to Japan and Thailand could as well spread to this land.
Coronaviruses cause diseases ranging from the common cold to SARS, or severe acute respiratory syndrome.
Health department's report states: "The World Health Organization (WHO) is already alarmed because of the unknown virus".
Finding cases elsewhere in China is to be expected at this point, said Ferguson, who released a modeling study late last week that suggested that there may have been hundreds of infections at this point.
Officials are concerned the disease may spread more widely as millions of Chinese workers travel during next week's Lunar New Year. They added that the virus was "still preventable and controllable". He was hospitalized a week after arriving in the southern city, and his biosample was sent to the Chinese Center for Disease Control and Prevention, where it tested positive on January 19 for the Wuhan coronavirus.
More than 200 cases of the new coronavirus, a SARS-like illness, have been reported throughout China. It is the most populous city in Central China with a population of almost 20 million people in the metro area. He said the CDC wants to be prepared and they are taking precautions in the event of an outbreak but also says the risks to the American public are low.
In Guangdong, a 66-year-old man from Shenzhen was quarantined on January 11 after contracting fever and showing other symptoms after visiting relatives in Wuhan, the provincial health commission said in a statement. "It is likely that we are examining patients affected for several days by multiple animal sources and with some degree of human-to-human transmission", said Farrar. In at least two of those three cases, the patients had recently traveled to Wuhan, the epicenter of the outbreak.