A mystery virus that has infected eight patients from different parts of the country claimed its first known victim yesterday morning after a 36-year-old, nine-months pregnant woman died in a Seoul hospital of multiple organ failure triggered by pulmonary fibrosis and a stroke.

The Korea Centers for Disease Control and Prevention said yesterday that the woman had received intensive care treatment in a general hospital in Seoul for a month before her death. Doctors managed to save the baby.

According to the KCDC, the victim was one of the eight patients in the hospital receiving treatment for various conditions suspected to be caused by the same unidentified virus. All patients initially received treatments at different clinics around the country, but were later transferred to the Seoul hospital to receive intensive care, the KCDC said. The patients were not infected because they were at the same hospital, it said.

Seven of the eight patients, including the victim, were pregnant or had recently given birth. One was an adult male in his 40s.

One patient was treated and released on May 4, and another received a lung transplant after treatments failed.

The KCDC said the 36-year-old victim visited a clinic on April 8 after showing severe cold- or flu-like symptoms. On April 11, she was rushed to the Seoul hospital.

Despite the hospital's efforts, pulmonary fibrosis, or scarring of the lungs, developed rapidly. After suffering from cerebral hemorrhage, the patient died 7 a.m. yesterday.

As anxiety spreads over the mysterious disease, health authorities said they are trying to identify the virus. Other possibilities, including bacterial infections and other immunological diseases, are being investigated.

Initial tests by the hospital discovered adenovirus and coronavirus, common cold causes, in two patients. But the KCDC said they may not be the cause of the pulmonary fibrosis.

"So far, we have found viruses that are often discovered in common cold patients," said Yang Byeong-guk, head of infectious diseases at the KCDC. "What's important is to identify whether the pulmonary fibrosis is triggered by a new kind of virus or not."