At first, doctors thought the 68-year-old man might have simple pneumonia. He coughed and wheezed his way through three hospitals before officials figured out, nine days later, that he had something far more serious and contagious.
Along the way, health officials said the man has infected dozens who then became potential carriers themselves and infected dozens more and counting.
The original diagnosis that missed what became South Korea's first case of Middle East respiratory syndrome, or MERS, was possibly caused by incomplete information from the patient about his travels. The World Health Organization acknowledged that MERS was not an easy virus to identify early because its symptoms are similar to other respiratory infections, like a common cold.
But it was especially problematic in South Korea because of peculiarities in the hospital system, health experts said Monday.
Patients jostle, cajole and name-drop to get referrals into the biggest hospitals, which they believe attract the best doctors. Family members and outside caregivers commingle with the sick in crowded emergency wards. They often stay with the patients in their rooms and do much of the nursing work - wiping sweat, emptying bedpans, changing sheets and exposing themselves to infections.
"Our crowded hospital environment is a weakness," said Cho Sung-il, a professor of epidemiology in the Graduate School of Public Health at Seoul National University. "Chances of close contact are higher in a South Korean hospital emergency room, for example, where seats and beds are usually arranged close together."
As of Tuesday morning, the South Korean authorities had confirmed at least 95 MERS cases and were monitoring more than 2,500 people under quarantine for symptoms. At least seven patients have died.
So many patients, including those in rural towns, seek medical care at large hospitals that securing a bed in a mega-hospital in Seoul, the capital, for a relative or friend has become a test of a person's networking ability. Patients often visit small hospitals to get a referral to a bigger hospital.
The two hospitals where the vast majority of MERS cases have occurred were among the biggest in their cities.
"Many people want to check into famous hospitals, some even waiting in their emergency rooms until a bed gets available," said Kim Woo-joo, head of the Korean Society of Infectious Diseases, who is leading the government's epidemiological study of the MERS outbreak. "In big hospitals, we see bottlenecks. This is a very Korean thing, and I think this is not a good situation when we have a new contagious virus breaking out."
In many ways South Korea is one of the world's most technologically advanced countries, where most of the population is connected to the Internet and nearly everyone has a smartphone. But within a matter of days, it also has become known for the largest caseload of MERS outside of Saudi Arabia, where the disease first emerged in 2012.
Researchers have traced MERS to a virus that is believed to have jumped from camels to humans. The virus can be spread by breathing the same air as an infected and coughing person in close proximity. It causes high fevers and pneumonialike symptoms, and there is no cure.
The hospital odyssey of the first infected patient, known as the index case, began after May 11, when he developed a fever and began coughing. He visited a clinic in his hometown of Asan, south of Seoul, on May 12, 14 and 15. Perplexed doctors, not knowing he had even visited Saudi Arabia and the United Arab Emirates in early May, sent him to a bigger hospital, St. Mary's, in Pyeongtaek, 37 miles south of Seoul.
With no improvement, he went to Seoul to seek better medical care, visiting a relatively small hospital there on May 17, where X-rays suggested pneumonia. The next day he was referred to the Samsung Medical Center in Seoul, one of the largest in South Korea, where doctors suspected he had MERS, learned of his Middle East visit, and isolated him. The correct diagnosis was confirmed May 20.
Kim said the crowded conditions at St. Mary's had been ideal for the virus to spread. So far, 37 St.Mary's patients have been confirmed as having caught the virus - nearly 40 per cent of the known total.
One of the St. Mary's patients infected by the index case later checked into the emergency ward of the Samsung hospital in Seoul, infecting at least 35 people there. Nearly 700 people who had been at the emergency ward have been quarantined.
There has been no sign of a panic among the wider public. But fears of the virus have led to the closings of nearly 2,000 kindergartens and schools and the cancellation of concerts and religious and social gatherings. Sales of face masks and hand sanitizer have soared. Baseball stadium attendance has plummeted.
In a sign of widening fear in Asia, the authorities in Hong Kong raised their three-stage response level Monday from "alert" to "serious," which means ports of entry will exert tighter arrival controls. The Hong Kong Center for Health Protection posted an advisory about the raised response on its website, urging people to "avoid unnecessary travel" to South Korea.
The WHO appeared to be less concerned, saying that it was not advising special actions at ports and airports in South Korea or travel or trade restrictions, "given the lack of evidence of sustained human-to-human transmission in the community."
Alison Clements-Hunt, a spokeswoman for the health organization, said the virus pattern found in South Korea was in line with those monitored elsewhere. The testing on a virus sample in South Korea "shows nothing alarming in terms of mutations and change in what would be the transmittablity of the virus."
Nonetheless, she said the organization was sending a team of experts to South Korea. She also said frequent visits to patients at hospitals in some Asian cultures are "something that may need to be looked at in the light of MERS."
Some experts have faulted the South Korean government for the way it initially handled information on the outbreak. None of the hospitals where patients were infected had been alerted about the possibility of MERS.
"Doctors were diagnosing the patients without knowing anything about MERS," said Jee Sun-ha, a professor of public health at Yonsei University in Seoul. "Once the authorities detected the first case, they should have taken more aggressive steps, revealing the names of the hospitals the patients had visited and trying as much as possible to localize the outbreak."
It was only Sunday that the government revealed the names of all 24 hospitals the confirmed cases had visited - 2 1/2 weeks after the first case was discovered. They have since added five more to the list.
The government said it had been reluctant to release the names, fearing possible panic in the neighborhoods around the hospitals. After their names were released, some of the hospitals reported a plunge in the number of outpatients and even closed down temporarily.
But Choi Chang-woo, head of the civic group Citizens' Solidarity for Safe Society, said the government's "monopoly on information," which he said was rooted in South Korea's authoritarian past, was partly to protect the business interests of big hospitals and keep people ignorant about mistakes.
"They haven't learned from the Sewol disaster," Choi said, referring to the 304 deaths in the sinking of the Sewol ferry in April last year, often blamed on the government's fumbled rescue. "This is what you get when your government's top priority is not the safety of the people."
President Park Geun-hye's weekly approval rating dropped 6 percentage points to 34 per cent last week in the aftermath of the MERS outbreak, according to a survey released Friday by Gallup Korea. On Monday, Park vowed an "all-out national response."
Efforts included exploiting South Korea's advanced cellphone network, tracing the signals of people who had defied quarantine in order to find them.
"Now the government is belatedly trying to mend the fence after the cow had already been stolen," Choi said.