“We sprang right into action, and we have since been working round the clock,” said Kwon Mi-gyeong, a Sunchang health official. The county sent the widow to a bigger hospital with a proper quarantine chamber. It isolated 40 people who visited the hospital while the widow had been there. It also closed all but one of 25 schools in Sunchang.

And Jangdeok was placed under total quarantine.

“People there were not happy at all,” Ms. Kwon said. “They refused to open the door for us when we went to check their conditions.” She added: “They refused to be monitored and insisted that they were O.K. It took a lot of explaining before they understood why this had to be done.”

Cheongdam said the outbreak had shaken village life. Residents wore masks outdoors. They avoided shaking hands and chatted from a distance.

“It came out of the blue, bringing everything to a halt,” the monk said.

Thirty-seven people have been infected in the Pyeongtaek hospital, either by the first MERS case or by people infected by him there. Four of them carried the virus out of Pyeongtaek when they visited hospitals in Seoul and other cities. In those hospitals, they infected dozens more, some of whom, in turn, spread the virus to other hospitals, sometimes without telling doctors that they had passed through infected clinics.

Fear of infection and public anger escalated as the government refused to release the names of hospitals visited by confirmed cases, even when their numbers kept growing.

South Koreans felt increasingly incensed by their government’s inability to contain the virus, with the crisis coming just a year after another: the sinking of a ferry that killed 304 people, mostly teenagers.

“The government was a super-spreader of mistrust,” an editorial writer of the mass-circulation conservative daily Chosun Ilbo wrote in his column on Wednesday, in which he also compared big local hospitals to “infection chambers.” An editorial in another leading daily, the JoongAng Ilbo, stated that the “authoritarian leadership” of President Park Geun-hye, who scrapped plans to visit Washington next week because of the MERS crisis, had helped prove that South Korea remained “an undeveloped country.”