SEOUL/BANGKOK (Reuters) - A South Korean woman has tested positive for coronavirus after visiting Thailand, South Korean officials said on Tuesday, the first foreign tourist reported to have been infected after a visit to the southeast Asian nation.

The 42-year-old, identified only as Patient 16, flew back to South Korea on Jan. 19 after traveling in Thailand, the Korea Centers for Disease Control and Prevention (KCDC) said in a statement.

Treated since developing chills and other symptoms from Jan. 25, the woman did not improve until Sunday, the KCDC added in a statement, and was confirmed positive on Tuesday.

The statement did not explicitly rule out a visit to China by the patient, and KCDC Director Jeong Eun-kyeong declined to comment further.

Tanarak Plipat, deputy director-general of the Thai Department of Disease Control, said the woman could have contracted the virus in Thailand.

“It’s possible because the virus is already spreading domestically in Thailand,” Tanarak said.

Thailand has reported 19 cases of coronavirus, among the highest number of infections outside of China. It confirmed the first case of human-to-human transmission of the virus inside the country on Friday, when a taxi driver tested positive.