Employees from Asiana Airlines disinfect the interior of its airplane in Incheon, South Korea, June 4, 2015. [Photo/Agencies]

The third patient, who had been confirmed positive on May 21 as he shared a hospital room with the first patient, passed away Thursday.

When the 76-year-old was infected, he was suffering from asthma and chronic obstructive pulmonary disease, the health ministry said.

He is the father of the 44-year-old man who went to China on May 26 against the medical advice of dropping his travel plan.

The death toll has risen to four as of Friday, raising the fatality rate to 9.8 percent.

An 83-year-old man passed away Wednesday, and he was confirmed positive for the MERS on Thursday night.

Another confirmation after death was a 57-year-old woman who passed away on Monday and received the MERS confirmation a day later.

The MERS is a respiratory illness caused by a new type of corona-virus that is similar to the one causing Severe Acute Respiratory Syndrome (SARS). There is no vaccine or treatment for the disease, with its fatality rate reaching 40.7 percent.

The first case was spotted in Saudi Arabia in 2012. The World Health Organization has reported more than 1,000 cases of MERS globally and more than 400 deaths.