The prospect of the 30-day ban is already sowing chaos across the Continent and hammering the airline industry.

European leaders, whose own cohesion is under strain, said it had been issued “unilaterally and without consultation.”

And in the U.S., our White House correspondents write, a president who presents himself as the nation’s commanding figure has failed to offer clear guidance to the local officials who are busy shutting down much of American life.

Here are the latest updates on the virus and the markets, maps of where the pandemic has spread and a primer on the travel ban.

In other news:

The U.S. House of Representatives is expected to vote today on a sweeping economic rescue package to offset the pandemic’s colossal effects. It includes free virus testing and enhanced unemployment benefits, among other measures. If approved, it will then advance to the Senate.

Prime Minister Justin Trudeau of Canada will address the nation today, after the government confirmed that his wife, Sophie Grégoire Trudeau, has tested positive for the coronavirus after returning from a trip to Britain. Mr. Trudeau will remain in isolation for the next two weeks.

Prime Minister Boris Johnson of Britain stuck to a notably restrained set of measures on Thursday, while President Emmanuel Macron of France announced that his country’s schools and universities would close starting next week.

The White House said that President Trump and Vice President Mike Pence would not be tested for the virus, even after they posed for a photo at Mr. Trump’s oceanfront resort in Florida with a Brazilian official who later tested positive. Two Republican senators who also had contact with the official said that they would self-quarantine.

The mayor of New York City, which had 95 confirmed coronavirus cases as of Thursday, declared a state of emergency and warned of the potential for job losses, food shortages and large-scale evictions of renters. Broadway will go dark for at least a month.

The Champions League, the grandest tournament in club soccer, faces the prospect of being suspended after Real Madrid became the latest team to go into quarantine.

China’s effort to restart its economy after draconian coronavirus countermeasures is proving to be more difficult than shutting it down.

What to know: The Times is providing free access to our most important updates and guidance on the outbreak. And our Coronavirus Briefing, like all our newsletters, remains free.