South Korean health authorities said Sunday they were tracing the route of infection for the most recent case of the Middle East respiratory syndrome, whose symptoms may have manifested a week after the estimated maximum incubation period of the disease.

The country’s 186th patient, a 50-year-old cancer patient who was diagnosed with the disease Saturday, is the wife of a 55-year-old MERS patient, according to the MERS special response team at the Health Ministry. Her husband was confirmed to have caught the disease on June 12, and was discharged Thursday after making a full recovery.

According to the officials, the woman began showing her first symptom, a fever, on Thursday, 21 days after being isolated from her husband on June 11. The disease was thought to have a maximum dormancy period of 14 days.

After her husband was confirmed to have been infected, she was quarantined but was released after 14 days.

“It is likely she acquired the virus from her husband, and the symptoms belatedly showed up after her cancer treatment compromised her immune system,” Jeong Eun-gyeong of the MERS special response team said.

If this is the case, the disease would have manifested about a week after the accepted maximum incubation period. While there have been similar cases of belated symptoms, the authorities have maintained that there is no evidence that the state-approved incubation period is inaccurate, and the patients are likely to have been belatedly diagnosed.

But the three-week gap between her husband’s isolation and the manifestation of her symptoms raised the possibility that she may have been infected by MERS at Samsung Medical Center in Gangnam district, southern Seoul. Last Monday, she visited the Samsung hospital to receive cancer treatment, three days before first expressing symptoms.

“We believe there is no possibility that patient No. 186 was exposed to medical staff infected with MERS. ... We are conducting further investigation on (her being infected via) other medical staff or patients, but such a possibility is low, for now,” Jeong said.

If the latest patient turns out to have been infected at SMC, she will be the 91st person to have been infected at the facility. The hospital ― considered among the best in the country ― has accounted for nearly half of the 186 MERS cases in the country.

As of Sunday, 15 of 16 MERS patients that were being treated at the facility had been transferred to other hospitals, and one was discharged after making a full recovery.

Jeong explained that the extensive number of hospital medical staff who were exposed to MERS patients, and subsequently removed from duty, overburdened the remaining staff. As of Sunday, 12 members of the SMC staff were infected, while over 900 were being tested for infection.

While the authorities did not say that the latest measure was intended to penalize SMC, it effectively removed the hospital from the frontlines of the MERS outbreak.

The recent MERS outbreak has put the hospital’s capacity to deal with infectious diseases into question. The hospital was recently revealed to have failed to supply its staff with sufficient protective gear to, which is required in the handling of infectious diseases.

As of Sunday, 37 of the 186 patients diagnosed with MERS had been hospitalized, with 12 in an unstable condition. Another 116 have fully recovered and been discharged.

The MERS death toll stood at 33 for the fifth straight day.

Prime Minister Hwang Kyo-ahn urged the Health Ministry to swiftly provide financial support for hospitals who have suffered from the MERS outbreak. The government on Saturday announced it would allocate 16 billion won ($14.2 million) to support the hospitals.

By Yoon Min-sik
(minsikyoon@heraldcorp.com)