The Public Health Ministry on Sunday announced the country's second confirmed case of Middle East Respiratory Syndrome Coronavirus (Mers-CoV).
The patient is a 71-year-old man from Oman who travelled to Thailand last Friday after he was treated at a hospital in that country for about one week for fever and a cough, according to Public Health Minister Piyasakol Sakolsatayadorn.
The man tested positive for Mers at Bumrungrad and Chulalongkorn hospitals.
The man was referred to the Bamrasnaradura Infectious Diseases Institute on Saturday at 6:20pm and another laboratory test by the Medical Science Department confirmed he had contracted Mers.
Dr Piyasakol said the Omani man is now being quarantined at the Institute's Diseases Control Department.
The Public Health Ministry is looking for people who had contact with the patient. They include a relative who accompanied the man, 218 crew and passengers who are still in Thailand, a taxi driver, a hotel employee, and 30 hospital staff.
These people will be kept under close surveillance for 14 days. Of this group, 37 are categorised as high-risk. They are the patient's relative, 23 air passengers, the taxi driver, the hotel employee, and 11 hospital staff, Dr Piyasakol said.
Those in the high risk grouping will be quarantined, he said.
Government spokesman Sansern Kaewkamnerd said Prime Minister Prayut Chan-o-cha has been informed of the latest case in Thailand and asked Thais not to panic about it because steps in place to detect the disease and prevent its outbreak are effective and internationally recognised.
Maj Gen Sansern said the prime minister asked people to pay more attention to their own health.
If they have a fever, a cough, a feeling of vibrations in the chest when breathing and diarrhoea, they should consult a doctor or call the Disease Control Department hotline at 1422 around the clock.
Thailand confirmed its first case of Mers on June 18 last year. The patient was also a 75-year-old male who travelled en route from Oman to Thailand. He was treated and declared free of the virus and was eventually allowed to leave the kingdom. The disease did not spread to anyone other person.