The number of people infected with the coronavirus in Italy rose 40pc to 1,576 in only 24 hours, authorities said yesterday, adding that five more infected people had died.
It came as new US government advice urged Americans not to travel to the two Italian regions hardest hit by the virus.
The latest fatalities bring the number of deaths in Italy to 34 since the virus hit the country on February 21.
Health author- ities said the increase was expected since it takes as long as two weeks for containment measures to take effect and because Italy has a large number of elderly people.
The US travel advice cited quarantines set up in 10 towns in Lombardy and one in Veneto, with a combined population of 50,000 people, as well as "the level of community transmission of the virus".
It followed an earlier warning for Americans to avoid non-essential travel to all of Italy.
Tourism officials said the warning covering the whole country was potentially calamitous to the industry, which represents 13pc of GDP.
More than 5.6 million Americans visit Italy every year, representing 9pc of foreign tourists and the second-largest national group behind Germans.
Lombardy, which includes Italy's financial capital, Milan, accounts for more than half of cases while Veneto and Emilia-Romagna have 18pc and 20pc respectively. All three regions have closed schools.
In Veneto and Lombardy, closures have also hit masses, museums, theatres, cinemas and public offices, emptying cities such as Milan, where many office staff are working from home.
Meanwhile, tourists and art lovers were unable to visit the Louvre in Paris yesterday as workers staged a walkout after a staff meeting about the coronavirus outbreak.
Long lines of tourists snaked outside the museum as management held a staff meeting about the outbreak to reassure workers the risk was contained.
However, the home of Leonardo da Vinci's Mona Lisa and the Venus de Milo sculpture remained closed afterwards.
Workers refused to return to work after the meeting failed to reassure them.
"Despite talks with management and the staff doctor, the Louvre Museum was unable to open in the absence of sufficient personnel," a spokeswoman said.
In England, 12 new coronavirus cases were confirmed as the number of people infected across the UK leapt to 35.
Health Secretary Matt Hancock admitted it was "inevitable" the deadly virus would continue to spread, and did not rule out following China's lead in shutting down cities if the outbreak escalates.