GUANGZHOU, June 5 -- China's first confirmed Middle East Respiratory Syndrome (MERS) patient was still in serious condition, the health and family planning commission of Guangdong Province said Thursday.

A man from the Republic of Korea (ROK) tested positive for MERS in Guangdong on May 29. He is being treated at Huizhou Municipal Central Hospital.

The commission said they had quarantined 75 people who had close contact with the man, and none of them showed any MERS symptoms.

The man, 44, had visited a MERS patient at a ROK hospital and expressed discomfort as early as May 21.

Despite a doctor recommending that he cancel his travel plans, he flew to Hong Kong on May 26 and entered Huizhou City via Shenzhen.

Zhong Nanshan, a renowned respiratory expert, said a massive outbreak of MERS in China was unlikely given a lack of evidence on sustained human-to-human transmission of the virus.

Local officials and doctors have also expressed confidence in controlling the virus, citing experience gained from outbreaks of bird flu and Severe Acute Respiratory Syndrome (SARS).

SARS was first reported in 2002 in Guangdong, which borders Hong Kong. It killed around 800 people in the world. In addition, Guangdong is one of the Chinese provinces that has dealt with the bulk of H7N9 bird flu cases since it emerged in 2013.

MERS is a respiratory illness caused by a coronavirus, similar to SARS. The first human case emerged in Saudi Arabia in 2012. There is no vaccine or treatment for the disease, which has a fatality rate of about 40 percent.