Public health officials are trying to find the whereabouts of two men who came into close contact with an Indian national infected with the coronavirus while he was in Krabi.
Epidemiology Bureau director Walairat Chaifu said on Sunday the officials were searching for a Thai man who travelled with the patient on a round trip from Phuket to Chiang Mai from Oct 30-Nov 2, and an American man who dined with him on Patong beach the night before.
"We are looking for his Thai and American friends," Dr Walairat said.
They are among 79 people considered high-risk, including four family members, due to close contact with the Indian man who tested positive on Wednesday and again on Friday. He is being treated at Krabi Hospital.
Dr Walairat said tests on three of the family members were negative and the Disease Control Department was waiting for the outcome of a test on his wife.
Samples were collected from other people close to him, including those on the ferry from and to Phi Phi island, as well as passengers seated in the two rows in front of and behind him on flights between Phuket and Chiang Mai, she added.
The man's most recent overseas trip was to Singapore, but he returned in February.
He first arrived in Thailand in April last year to set up a restaurant on Phi Phi island. He has a brother on the mainland in Muang district of Krabi.
The department also considered 211 more people to be in a low-risk category, and department director-general Opas Karnkawinpong said they were ordered to stay at home for two weeks to monitor their own conditions.
Dr Opas said that chances the Indian had spread the coronavirus to other people were slim because only a small amount of the virus was found during the tests conducted on him.
The department is trying to find the source of the virus as Singapore was the only country outside Thailand he had travelled to since the outbreak began.
The patient's most recent domestic journey began on Oct 28, when he left Phi Phi island for Phuket. From there he flew to Chiang Mai on Oct 30, drove to Sukhothai on Oct 31 for the Loy Krathong festival and flew back to Phuket on Nov 2. He returned to Phi Phi on Nov 4.
Dr Walairat said health measures, including a face mask requirement, in place during the festival may have been sufficient to prevent him spreading the virus to other revellers.
