A police with mask stands guard outside Lady MacLehose Holiday Village in Sai Kung, where people who came into close contact with the South Korean MERS patient will spend two weeks in quarantine, in Hong Kong, May 29, 2015. [Photo/Agencies]

The top health authorities in Guangdong and Hong Kong have issued notices asking people who were onboard Asiana Airlines OZ723 and two buses with the patient to report to them immediately.

Central Hospital in Huizhou has trained 160 nurses for the disease. Guangzhou Daily reported that the nurses were selected by lot to work with the South Korean patient in the intensive care unit.

Lin Jianfeng, a director in charge of infectious disease prevention at the Guangdong Center for Disease Control and Prevention, said the possibility of widespread human-to-human infections is remote.

He said 158 people were on the same flight as the patient and 41 people were on the same buses with him. "The toughest job now is to track all of the passengers on the buses," he added.

The South Korean Health Ministry said the country had 15 patients infected with the virus as of Sunday.

Wang Xiaodong and Xinhua contributed to the story.

Related: ROK apologizes for outbreak of MERS

South Korea's health minister apologized on Sunday for failing to halt an outbreak of the MERS virus, vowing the "utmost efforts" to halt the disease's spread as the number infected rose to 15.

"We apologize for causing concern and anxiety among people due to ... our initial judgment on the contagiousness of MERS," Minister Moon Hyung-pyo said.

Moon added that this week would be a "critical period" to contain the spread of MERS, or Middle East respiratory syndrome, which can cause symptoms ranging from flulike aches and pains to pneumonia and kidney failure.

Health officials have come under fire for allowing an infected man to travel to China despite warnings from doctors.