The country's 14th case involves a 40-year-old Chinese woman who is the wife of a man diagnosed with the new coronavirus strain here Saturday.
The Chinese man, the country's 12th case, worked as a tour guide in Japan and came in contact with a Japanese national who was also diagnosed with the infection. The guide arrived in South Korea on Jan. 19, but he was symptom-free upon arrival and had freely moved about the country.
The center said it has identified 138 people the man ran into while in the country and various places he visited, and is scrambling to contact those that could have been infected to see if they are feeling sick. It said the man's daughter is in isolation although showing no symptoms yet.
The 15th case is a 43-year-old South Korean man who was in Wuhan, the epicenter of the current outbreak, and returned Jan. 20.
Authorities said he is under observation.
The KCDC said it is tracking the movements of all new patients to determine where they were and whom they met, with information to be made public as soon as possible.
The public health agency said it has determined that four of the confirmed patients here worked at or visited a Korean fashion and accessory shopping mall in Wuhan called The Place and asked anyone who has been there recently to notify quarantine workers so they can be checked.
Regarding broader measures, the government, which announced restrictions on the entry of people from Wuhan and the surrounding Hubei Province earlier in the day, said it will take stringent measures to isolate anyone who may pose a health risk to society until the disease is contained.
"There is consensus in the government to go beyond levels that scientific and medical communities think are adequate to curb the spread of the illness," Minister of Health and Welfare Park Neung-hoo said in a briefing on future action.
He said that while the 15 confirmed cases here do not mean the illness is spreading out of control, much more must be done to deal with the contagious virus.
Park then confirmed person-to-person transmission had taken place here and that a few instances even involved people getting sick because they came into contact with a person who had, in turn, had contact with someone who had recently visited Wuhan.
On worries of the spread of the illness by people who are asymptomatic, the minister pointed out that there has been no such confirmed case. But he conceded that it could be spread by a person with few symptoms.
Sources have said that in some cases the virus has been detected even when a person did not feel ill at all.
The minister said that Seoul has decided to place everyone who has come into contact with an infected person into self-quarantine, requiring them to not leave their homes for at least 14 days.
People who follow the guidelines will be compensated and allowed to go on paid leave, while those who break this order could be fined 3 million won (US$2,510) and be criminally charged.
In particular, people who work in public facilities such as schools, welfare centers and hospitals will be barred from reporting for duty.
The policymaker said that Seoul has decided to subject everyone who has come from China in the two weeks to viral testing if he or she complains of even mild fever or coughing. In the past, people with pneumonia were screened.
Park said such a step was precautionary and aimed at reducing risks.
Since Jan. 3, Seoul has screened 429 people for potential contagion. It said 327 turned out not to be infected, while 87 are undergoing tests.
Authorities are also monitoring 683 people who have been in close proximity to virus-infected patients.
Seoul said that as of early Sunday, the new coronavirus has been reported in 26 countries and has affected over 14,500 people.
It said the death toll stands at 304, with all fatalities occurring in China. (Yonhap)