With 1,000 Student Infections, U. of South Carolina Urges Vigilance

Mr. Berlusconi, 83, is working from his mansion near Milan, where he will spend the isolation period, according to a prepared statement. He will continue his political activities, including daily interviews on television and social media to support his party’s candidates in the coming regional elections.

His physician, Dr. Alberto Zangrillo, told the Italian news agency ANSA that Mr. Berlusconi was asymptomatic.

Mr. Berlusconi, who is a media mogul, recently returned from a vacation at his villa in Sardinia, where he met political allies and friends, including Flavio Briatore, a businessman whose upscale nightclub gave rise to one of the island’s largest clusters of coronavirus infections. Mr. Briatore also tested positive last week.

Some regions of the country set up tents for rapid testing at ports, airports and train stations after many recent cases emerged among tourists returning from Sardinia. The island’s beaches and clubs were very busy this year, as Italians chose to spend their holidays nearer to home.

As the news spread that Mr. Berlusconi had the virus, politicians across the spectrum flooded social media with comments and good wishes.

“I want to send my best wishes to Silvio Berlusconi for a rapid recovery by all the Democrats’ community,” Nicola Zingaretti, the leader of the Democratic Party and one of the first political leaders to have the virus last March, wrote on Twitter. “He will strongly fight this battle, too.”

Matteo Salvini, leader of the right-wing League party, sent a “hug” to his “friend” via social media, while Giorgia Meloni of the extremist party Fratelli d’Italia, Brothers of Italy, called Mr. Berlusconi a “lion” on Twitter and wrote that he will “brilliantly overcome this, too.”