Some of the 75 people who had close contact with the first MERS patient in China were released from quarantine on Tuesday with the remainder due to be released on Wednesday, according to the provincial Center for Disease Control and Prevention (CDC).

The patient, a 44-year-old South Korean man, was confirmed as suffering with MERS on May 29. Those who had close contact were potential victims and needed to be kept under close observation for 14 days as the virus has an incubation period of two weeks.

The condition of the patient is improving in hospital in Huizhou, Guangdong province and his blood sample and throat swab have been tested negative for the virus for at least five days, according to Deng Xilong, chief physician of the ICU at Guangzhou Eighth People's Hospital who has been involved with the man's treatment.

"His sputum has been tested negative for the MERS virus twice, but we still keep him in quarantine because his symptoms haven’t disappeared," Deng said.

It took only four hours for the South Korean man to be found and sent to hospital after the health authority in Huizhou was notified of the suspected case, according to Huang Yuliang, deputy director of Huizhou Municipal Central Hospital.

Altogether 78 people had close contact with the man in Guangdong and they had all been located by June 4, a week after the case was confirmed. Three have left the province but the countries and regions where they are staying have been notified of their arrival.

"To prevent last year's Ebola outbreak in Africa from entering Guangdong, we established a disease control and prevention system involving exit-entry administration, CDC and health centers in communities that can quickly track down potential virus carriers. The system proved to be working well when applied to the MERS case," said Zhong Haojie, an emergency management expert from Guangdong CDC.

"The risk of having a second-generation MERS patient will be cleared after those who had close contact with the first patient are out of quarantine," he said.

"The risk of widespread MERS virus brought by the South Korean patient to Guangdong is extremely low, although we still have the risk of newly imported MERS cases from the Middle East and South Korea.

"Keeping people who had close contact with the first MERS patient under close watch is important in preventing the virus from being spread. We are grateful for their cooperation that has reduced the virus’ harm to society.

"Some of the people who had close contact with MERS patients in South Korea weren’t cooperative with the quarantine and wandered off, which brought the risk of spreading the virus."

Many MERS cases around the globe have been cross infections in hospitals. Thanks to strict protective measures, none of the doctors and nurses who have been taking care of the South Korean MERS patient in Huizhou Municipal Central Hospital since May 28 has shown any sign of being infected.

"We combine standard prevention with the measures that prevent the virus from being spread through droplets, body touch and air, a strict prevention system that we also adopted last year to deal with Ebola," said Sun Shumei, director of infection control at Nanfang Hospital affiliated to Southern Medical University.

She added that other patients in the ICU of the hospital in Huizhou had been moved out of the unit before the ICU took in the South Korean MERS patient.