The snow-capped peaks of Idaho’s Wood River Valley are a magnet for movie stars and other wealthy tourists who throng to the area each winter bearing their skis, their appetites and their cash. They come for the soft powder, stay for the parties at top-class restaurants and pump money into an otherwise remote wilderness region where the howl of wolves echoes through the night.

But this year, somewhere between the lifts and the lodge, the tourists left behind something else: a deadly virus.

Now the valley is a coronavirus hot spot, registering one of the highest infection rates per capita in the country. With 192 cases in a county of just 22,000 people — including two deaths — the share of the population testing positive is greater than even in New York City.

The impact has been dramatic: The small hospital in Ketchum, the region’s hub, has partially shut down after four of its seven emergency doctors were quarantined. Patients are being ferried to facilities hours away. The fire department is relying on fresh-faced volunteers, trained in a day, to drive ambulances.

Everyone in town knows someone who has fallen ill.

The coronavirus “tore through this valley like a wildfire,” said Brent Russell, one of the emergency room doctors.

“I would say about a quarter of the people I know here have symptoms consistent with covid,” he added, referring to covid-19, the disease caused by the coronavirus.

Russell, 50, would normally be treating them. But he was one of the first in the region to come down with the virus. After an agonizing 3½ weeks — including nights when he woke up barely able to breathe — Russell is only now returning to work to help cope with the ever-growing influx of new patients.

Along with a handful of other ski hubs in the western United States, the Wood River Valley — whose population density is about 3,000 times less than New York City’s — offers a preview of what happens when the novel coronavirus escapes cities and attacks rural America.

Although scarcely populated areas offer some protection for a virus that thrives on social contact, they are hardly immune. And once infection creeps in, the effect in rural communities could be more severe given threadbare health systems, long distances to hospitals and elderly populations.

“The epidemic hasn’t really hit many rural communities yet. But it will. And they know that if it does hit them, it’s going to hit them harder,” said Olugbenga Ajilore, a senior economist at the Center for American Progress, a liberal think tank.

The vast majority of American coronavirus patients remain clustered in and around cities. That’s where the disease got its start in the United States, as infected travelers arrived from abroad.

But there are few areas — even remote ones — that remain untouched by the coronavirus as it continues its relentless spread.

Montana and North Dakota recently recorded their first coronavirus deaths. In Washington state on Monday, Gov. Jay Inslee (D) noted a “disturbing” pattern of rural counties that had recorded remarkably high positive test rates — including one that was up to 21 percent. In rural Alabama, meanwhile, residents are bracing for bigger outbreaks of a virus that “could pop up anywhere,” said Rep. Robert B. Aderholt (R-Ala.), who represents a wide, thinly populated region in the northern half of the state.

When it does, he said, he fears an impact that “exposes the vulnerabilities in all of rural America,” including underfunded health systems and patchy broadband networks.

For now, at least, the virus’s early forays into the countryside have come with a silver lining: They’re hitting areas that are better able to withstand them than most.

Some of the worst affected areas, per capita, are recreation centers renowned for their natural beauty that attract large numbers of tourists and have thrived during the past decade of economic growth. The counties surrounding Vail and Crested Butte in Colorado and Park City in Utah — skiing meccas, all — have seen especially high concentrations of patients.

So has Blaine County, home to the Sun Valley ski resort, the city of Ketchum and Idaho’s largest coronavirus outbreak. Many celebrities have second homes in the region. The skiing is reputed to be some of the best in the country, and it’s a top destination on the conference circuit.

But the same factors that have helped the region thrive have also made it vulnerable to the coronavirus.

“We were doing so well, with lots of tourism,” said Scott Mason, who owns three restaurants in Ketchum. “But that’s why we’re getting so hard hit now.”

The area is particularly popular among tourists from Seattle, with direct flights to the small regional airport. Health experts say visitors from the area with the nation’s first coronavirus outbreak probably brought it to Idaho in the early days of the pandemic, before states and municipalities nationwide began to implement extreme restrictions intended to slow the spread.

Russell, the doctor, said he believes he contracted the virus before there were any confirmed cases in Idaho. An avid skier, he said innocuous-seeming conversations with visitors may have been the culprit.

“People think that skiing is a low-risk activity,” he said. “But you’re on a chairlift for two-thirds of the time, and you’re turning to face people to talk to them.”

Blaine County had its first two positive test results on March 14.

Sun Valley — the region’s major ski resort — announced the next day that it was closing for the season, weeks earlier than planned. The day after, Ketchum Mayor Neil Bradshaw did something he never thought he would: He wrote an open letter telling tourists to stay away.

“For a town used to welcoming visitors, that is hard to do,” he acknowledged in his piece for the Idaho Mountain Express. “But we must reduce the number of people visiting our area. . . . The message is clear: This is not a place for a virus vacation.”

The city immediately began to clear out. Hotels emptied. Restaurants shuttered.

“Normally, we’d be bustling,” Bradshaw said in an interview. “It’s very much a ghost town right now.”

But it was too late. At Blaine County’s only hospital, the 25-bed St. Luke’s Wood River Medical Center, the virus had hit the staff hard. Two emergency doctors, Russell included, tested positive. Two others were believed to have been exposed and were in quarantine.

Without enough staff to keep the hospital running at full strength, administrators decided to transfer patients to other facilities and halt inpatient services.

Because nearby areas of Idaho are still relatively unaffected, it’s a strategy that’s working — for now.

“If the rest of the state were as hard-hit as we are, we’d be in a real disaster here. It would be like Italy,” Russell said.

Even with those additional resources, the health system is under strain. Bill McLaughlin, the local fire chief, said about 10 percent of first responders have tested positive for the coronavirus. With patients being transported as far away as Boise — a five- or six-hour round trip — he has had to sign up and train volunteer ambulance drivers in as little as a day to keep the system running.

All the while, there’s the personal toll.

In a city like Ketchum — population 2,700 — the impact of so many people falling ill at once has been deeply personal.

“Everybody here knows somebody who has gotten sick, or in some cases, has passed away,” McLaughlin said.

“It’s not six degrees of separation,” Bradshaw said. “It’s one degree.”

There’s also the impact on livelihoods. Tourists may have brought the coronavirus to the region. But without them, the local economy falls apart.

Mason, the restaurant owner, was cleaning the kitchen at the Ketchum Grill by himself one recent afternoon, with only the occasional to-go order to tend to. This time of year, his three restaurants would normally be packed. But with so little food to serve, he has gone from about 80 employees to 11.

“The numbers are drastic,” said Mason, who opened his first restaurant in the city 29 years ago. “Right now, we’re losing money. We’ll do what we can, but this can’t go on for months and months.”

Authorities say they don’t know if the worst of the pandemic has passed or if it’s still to come. But they say they are heartened by the fact that the community appears to be rallying together. Social distancing rules are being followed. People are volunteering to help. The tourists, everyone seems convinced, will one day return.

And each night, at 8 p.m., the region puts its own spin on a global phenomenon of breaking the isolation and thanking health-care workers — not with pots and pans or cheers or a song. But with a howl.

“The whole valley,” Russell said, “lets out a giant wolf roar.”