South Korean health authorities confirmed the country’s third case of Influenza A Thursday about a week after the first confirmed infection was identified.

The 62-year-old woman was found to have been infected with the H1N1 virus after returning from a recent trip to the United States, Yonhap News Agency reported Thursday, quoting the Korea Center for Disease Control and Prevention (KCDC).

This marked the third confirmed influenza A case in South Korea after a 51-year-old nun was confirmed to contract the contagious disease Saturday. On Tuesday, another case was reported after a fellow nun tested positive for the virus, raising concerns over a possible person-to-person transmission.

Both were released from the hospital after showing no sign of flu symptoms.

The latest flu patient, reportedly on the same plane as the two nuns, will be discharged from the hospital Thursday since she is no longer showing symptoms of the illness. She has been quarantined and treated with anti-viral drugs at a state-designated hospital since Sunday, the KCDC said.

The disease control center said that it has tracked down all those who may have had contact with the patient since her return to South Korea. It added, however, that there is slim chance the disease will spread through person-to-person infections.

As of late Wednesday, 172 people have been tested for suspected flu symptoms here, most of which turned out to be negative. The number of additional confirmed and suspected cases has died down in recent days.

Since the outbreak was reported in Mexico last month, the Seoul government has been stepping up efforts to stem its spread by intensifying monitoring of inbound travelers, while advising people not to travel to affected nations.