ROME — The attract of the turquoise waters, extravagant villas and unique dance golf equipment of the Emerald Coast of Sardinia proved stronger than ever in August, as Italian vacationers hungry for virus-free air mingled with regulars of the worldwide occasion circuit hopping throughout from locations just like the Spanish island of Ibiza and Mykonos within the Aegean Sea.

They joined Silvio Berlusconi, the mogul who dominated Italian politics for a quarter-century and whose Sardinian refuge is worthy of a Roman emperor; and his businessman pal Flavio Briatore, an acquaintance of President Trump, organic father to Heidi Klum’s first little one and proprietor of the island’s unapologetically hedonistic membership Billionaire.

Now Mr. Berlusconi, 83, lies in a Milan hospital with pneumonia after contracting the coronavirus. Mr. Briatore, who dropped in to pay him a go to at his Sardinian property and who had publicly complained about what he mentioned was an overreaction by the federal government to the pandemic, is quarantined in Milan with Covid-19, too.

It’s not clear when or how Mr. Berlusconi or Mr. Briatore have been contaminated. However native officers say that Billionaire and a few different golf equipment ignored well being rules and have become the petri dish of an island epidemic that contaminated soccer coaches, socialites and showgirls because it unfold to the mainland.

Mr. Briatore’s membership says that it did greater than was requested of it and blamed a sensationalist information media for leaping to conclusions.

What’s for positive is that the number of cases in Sardinia shot up from a few dozen before the summer to more than 1,000 in the space of a month and that the authorities have attributed more than 750 cases in Lazio, the region that includes Rome, to people returning from the island.

Roberto Ragnedda, the mayor of the Sardinian town of Arzachena, where many of the clubs are, said “10 days of madness” in August had caused “enormous damage to our image and to economy.”

“If the owners of the clubs were more careful these outbreaks could have been avoided,” he said, adding that, despite having gotten the outbreak under control, “we are seen as the source of everything wrong.”

For the authorities in Sardinia, the summer realized their worst nightmare.

In March, as infections and deaths exploded in the country’s north, the southern island’s governor, Christian Solinas, pleaded with the authorities in Rome to ban travel to Sardinia because Italians, especially those with a second home there, kept arriving. The government obliged.

As a result, Sardinia essentially dodged the Covid-19 disaster. In mid-April, when Italy reached more than 170,000 total cases for the virus, Sardinia had about 1,000.

Over the ensuing months, the virus all but vanished from the island, with zero new infections on May 14. Mr. Solinas vowed to keep it that way and at the time proposed requiring a “sanitary passport,” essentially a sticker certifying a negative coronavirus test result attached to a boat or plane ticket. The government called it unconstitutional, and ultimately, tourists only had to register via an online form on the region’s website.

Still, it seemed sufficient. Mr. Solinas, using powers given by the national government, decided to reopen outdoor nightclubs, as long as people danced at a distance. On Aug. 1, the island’s cases had ticked up only slightly, to 39.

But August has been Sardinia’s hot season since the 1960s, when the Aga Khan, the spiritual leader of some 20 million Ismaili Muslims worldwide and an enthusiastic jet-setter, banded together with friends to buy miles of northeastern coastal land from herders and developed luxurious hotels, yacht and golf clubs and a village in medieval Moorish style along what became known as the Emerald Coast.

This year, it became Italy’s viral hot spot; “the Emerald Covid,” according to one headline in the newspaper Corriere della Sera.

The authorities are investigating partygoers for leaving false names and numbers at clubs to avoid contact tracing. The Italian civil protection agency complained about a 5 a.m. incident at the Just Cavalli nightclub of the zebra-print fashion house Roberto Cavalli, in which a man broke the nose of a volunteer for blocking his yellow Mercedes and “ruining his holiday.” Johnny Micalusi, a Rome-based celebrity chef known as the King of Fish and for schmoozing with his famous guests at their tables, was hospitalized with Covid-19 after working out of a Sardinian club.

But according to Mr. Ragnedda, the “most egregious” offender was Mr. Briatore, at whose club he once delivered drinks while working his way through law school.

Mr. Briatore declined a request for an interview through Patrizia Spinelli, a spokeswoman for his Billionaire Life brand. (“We didn’t just create a company, we built a lifestyle” is its motto.) She said the club was not responsible: “We are victims of the situation, too, and took all the precautions.”

She noted that the club had gone above and beyond health regulations, limiting its season to a single month, specially training its staff and halving the number of tables for the dinner show it developed to replace the usual disco.

She said Mr. Ragnedda forced the club to close early by banning the loud music necessary in a song and dance performance that people expected with their dinner.

“We are all about music and energy,” she said.

She said that 27 infected members of the club’s staff were isolated in single rooms at the company’s expense in the Billionaire residences, and confirmed that about 30 contractors had also been infected.

Mr. Briatore is in quarantine after discovering his infection during an Aug. 22 checkup for an unrelated ailment. This week, he assured his Instagram followers, “I have not disappeared,” and said that he was in “super form.”

Mr. Briatore, a convicted card cheat and fixer of Formula 1 motor races, is also the star of the Italian version of “The Apprentice.”

“There was only one person that I wanted. And that was Flavio,” Mr. Trump said in a promo for the Italian show. In another spot, the two men appear together at Trump Tower, firing each other. Mr. Briatore once claimed of Mr. Trump that he had been “the first to bring him to Europe” but has since downgraded their relationship status to a publicity stunt.

Mr. Briatore, who usually wears a white beard and black T-shirts, has bristled at the attacks on Billionaire, telling Italian reporters that his club “always respected the rules.”

But videos on social media depicting less-than-quiet sit-down dinners have caused an uproar.

In one, a train of women transport champagne bottles loaded with sparklers by means of thumping music and a sweaty crowd. Nearly no one is carrying a masks.

In a social media publish a few days earlier than his coronavirus analysis, Mr. Briatore, 70, attacked a virologist for talking badly about his membership, saying that such scientists had “terrorized Italy.”

“Allow us to work,” Briatore mentioned in one other publish on Might 31. “The coronavirus gives insurance coverage for this authorities, they’re scaring everybody, and since every part has been happening since June, they begin scaring folks for September,” he added.

He additionally cited a remark made by his physician, Alberto Zangrillo, who has mentioned, “Covid clinically not exists; somebody is terrorizing the nation.” (Dr. Zangrillo later mentioned that he had been talking loosely and that he believes the virus is actual.)

Dr. Zangrillo can be the private physician of Mr. Berlusconi, who’s in a Milan hospital the place his situation is claimed to be bettering.

Mr. Briatore visited Mr. Berlusconi at his Villa Certosa on Aug. 11.

“Go to to a particular pal,” Mr. Briatore titled an Instagram post documenting the splendid seaside property. Within the publish, Mr. Briatore pays tribute, saying he discovered Mr. Berlusconi in “nice type.”

“A heartfelt thanks,” Mr. Berlusconi replied.

After making a political profession out of victimization, Mr. Berlusconi this week appeared to have discovered a once-in-a-lifetime enemy: his coronavirus an infection.

In a name on Tuesday to members of his occasion, Forza Italia, he mentioned that hoped to return to political battle and that, out of all of the hundreds of checks carried out on the Milan hospital for the reason that begin of the epidemic, “I’ve come out within the prime 5 when it comes to the energy of the virus.”

“I’m combating to beat this infernal illness,” Mr. Berlusconi added, “It’s very ugly.”