BANGKOK (Reuters) - Thailand confirmed its first case of Middle East Respiratory Syndrome (MERS) on Thursday, becoming the fourth Asian country to register the deadly virus this year.

Public Health Minister Rajata Rajatanavin told a news conference that a 75-year-old businessman from Oman had tested positive for MERS.

"From two lab tests we can confirm that the MERS virus was found," Rajata said, adding the man had traveled to Bangkok for medical treatment for a heart condition.

"The first day he came he was checked for the virus. The patient ... contracted the MERS virus."

The health minister said 59 others were being monitored for the virus, including three of the man's relatives who traveled with him to Bangkok.

MERS is caused by a coronavirus from the same family as the one that triggered China's deadly 2003 outbreak of Severe Acute Respiratory Syndrome (SARS).

The vast majority of MERS infections and deaths have been in Saudi Arabia, where more than 1,000 people have been infected since 2012, and about 454 have died.

Last month, a MERS outbreak erupted in South Korea resulting in 23 deaths so far. A total of 165 people have been infected and 6,700 people are in quarantine.

But there have been signs that the outbreak, the largest outside of Saudi Arabia, may be slowing in South Korea. The daily number of new cases has dropped to single digits this week compared to as many as 23 last week. Three were reported on Thursday - the lowest number since June 1.

All of the infections known to have occurred in South Korea have taken place in healthcare facilities. Three hospitals have been at least partially shut and two have been locked down with patients and medical staff inside.

China and the Philippines have also reported one MERS case this year.

Earlier, Thailand's Disease Control Department said it was screening travelers at 67 points of entry.

"We are checking 67 ports including land, sea and air," said Sophon Mekthon, secretary-general of Thailand's Disease Control Department.

"We've told all hospitals in Thailand to be on alert. Those who come back from the Middle East and South Korea must be checked thoroughly."

(Reporting by Pracha Hariraksapitak and Amy Sawitta Lefevre; Editing by Jeremy Laurence)