In Spain, the streets emptied on Sunday, a day after Prime Minister Pedro Sánchez ordered all citizens to stay indoors, with exemptions only for exceptional circumstances.

“The majority of the Spanish population wants to overcome this virus as soon as possible,” Mr. Sánchez said, “so I’m convinced the majority will comply.”

Globally, there are almost 150,000 confirmed cases of infection, according to the World Health Organization. More than 5,000 people have died.

Europe, the W.H.O. said, is the new epicenter of an epidemic that began in China. On Sunday, Italian officials reported that the number of deaths there had risen to 1,809, a 25 percent increase over the day before and the largest one-day rise yet seen in any country.

Throughout Europe, the squares and stadiums were empty, the churches unpopulated. Even the Vatican was forced to abandon a long and venerated tradition, announcing that its services during the week before Easter, which usually draw tens of thousands of people, would not be open to the public next month.