WASHINGTON (AP) — A public health and economic maelstrom brought on by the coronavirus swirled around President Donald Trump and drew closer to him personally Monday as several of his congressional confidants placed themselves in quarantine, including one who traveled with him on Air Force One.

While intent on projecting calm, Trump lashed out about the plunging stock market and convened a meeting of his top economic advisers to address what to do about it. Meanwhile the number of Republican lawmakers who announced they were isolating themselves because of possible exposure to the virus grew to five.

As Trump grappled with an epidemic whose consequences he has repeatedly played down, the White House asserted it was conducting "business as usual." But the day's business was anything but normal. Lawmakers pressed for details on how the Capitol could be made secure, a Pentagon meeting was broken into sub-groups to minimize the number of people in the same room and the Army commander in Europe placed himself in a precautionary quarantine.

Trump was set to hold a press briefing Monday at 6 p.m.

The president dove into handshakes with supporters Monday morning when arriving to headline a fundraiser in Longwood, Florida, that raised approximately $4 million for his reelection campaign and the Republican Party. He ignored shouted questions about the sinking stock market as he boarded Air Force One for the flight back to Washington.

On that flight: Florida Rep. Matt Gaetz, who later went into a voluntary quarantine. He was one of several GOP lawmakers who were exposed to a person at last month's Conservative Political Action Conference who tested positive for the virus.

In Monday morning tweets, Trump vented about the market drop and news that large public gatherings were being called off because of the virus.

"At this moment there are 546 confirmed cases of CoronaVirus, with 22 deaths," Trump tweeted, comparing it to seasonal influenza and the thousands of deaths that causes. "Think about that!"

Scientists at this stage don't know what the death rate of the new coronavirus actually is and whether it will wind up being about the same as flu or worse.

At the same time, administration officials were insistent that they weren't trying to dismiss public concerns. "This is a very serious health problem," Health and Human Services Secretary Alex Azar told Fox News.

At the Pentagon, officials have begun "social distancing" measures.

On Monday, Defense Secretary Mark Esper's regular meeting with senior staff, which normally would be held face-to-face in a single room with 40 to 50 participants, was broken up into three rooms, with video-teleconferencing among the rooms, according to the Pentagon's chief spokesman, Jonathan Hoffman. He said Esper and the 15 to 20 people in his room, including Gen. Mark Milley, chairman of the Joint Chiefs of Staff, sat at least six feet apart, in line with health guidance.

Trump was delegating much of the virus response to Vice President Mike Pence, who convened a video teleconference to give an update on the federal government's virus response Monday afternoon with the nation's governors.

On Capitol Hill, where many lawmakers are older and have frequent constant contact with the public, leaders were fielding questions from members and staff about how the complex will be secured. Leaders have so far shown little willingness to close the Capitol, but meetings were scheduled throughout the day to discuss preparations.

On Monday, Rep. Doug Collins, R-Ga., and Gaetz put themselves in voluntary quarantine because of their contacts with someone at the Conservative Political Action Conference.

Both said they did not have any symptoms but would wait out the remainder of the 14 days since the contact at home. Gaetz last week wore a gas mask to the House vote on the emergency funding bill for the virus response and said he wanted to highlight how Congress could become "petri dish" for the virus.

Collins met Trump on Tuesday night at the White House and shook hands with him Friday when the president visited the Centers for Disease Control and Prevention's Atlanta headquarters.

Sen. Ted Cruz, R-Texas, and Rep. Paul Gosar, R-Ariz., also placed themselves in quarantine after coming in contact with the same person at the conservative conference.

"The president of the United States, as we all know, is quite a hand washer," press secretary Stephanie Grisham told Fox News earlier Monday. "He uses hand sanitizer all the time. So he's not concerned about this at all."

The White House didn't immediately respond to a request for comment on the new cases.

As well, Rep. Julia Brownley, D-Calif., said she met last week with a person who has since been diagnosed with the virus. She closed her office and said she and her staff are "self-monitoring and maintaining social distancing practices."

Vast numbers of visitors come to the Hill, especially at this time of year when advocacy groups arrange "fly-in" trips to lobby and speak to lawmakers, and school groups descend for tours.

In one manifestation of lawmaking in the age of the coronavirus, Rep. Richard Neal, D-Mass., approached a Republican colleague on the House floor Monday for a routine congratulatory handshake after the chamber approved a bill expanding a visa program. "Shake or bump?" Neal asked Rep. Kelly Armstrong, R-N.D.

The two men bumped elbows.

Trump met Monday afternoon Treasury Secretary Steven Mnuchin, Larry Kudlow and other aides when he returned to the White House about a range of economic actions he could take, officials said. He also invited Wall Street executives to the White House on Wednesday to discuss the economic fallout of the epidemic.

Kudlow, director of the president's National Economic Council, told reporters Friday that the administration is not looking at a "massive" federal relief plan. Rather, any federal aid package would be "timely and targeted and micro."

Lawmakers on Capitol Hill had barely started to contemplate the economic implications of the spread of the virus and what might be needed to stimulate the economy as people cancel vacations and business trips and stay away from stores. Senate Finance Committee Chairman Chuck Grassley is "exploring the possibility of targeted tax relief measures that could provide a timely and effective response to the coronavirus," spokesman Michael Zona said Monday.

"Everything's on the table," Grassley told reporters.

Democrats indicated they preferred other responses, like passing legislation requiring employers to give their workers paid sick leave — a longtime policy priority of Democrats — and additional help for those with lower incomes.

"The best way to ensure economic security for the American people right now is to deal with the coronavirus itself, competent and full on," said Senate Democratic Leader Chuck Schumer. "Something we haven't yet seen. Getting a handle on the crisis and containing the spread of the virus is by far the best way to address any effects on the economy."

A day after saying it was "proceeding as normal," Trump's campaign canceled a three-day Women for Trump bus tour across Michigan that included Mercedes Schlapp, the former White House aide who is married to the American Conservative Union chairman, Matt Schlapp.

Schlapp is under self-quarantine after after he, too, was exposed to the infected person at CPAC. He introduced Trump and greeted him with a handshake on stage before the president's spoke on Feb. 29.

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Associated Press writers Lauran Neergaard, Andy Taylor, Kevin Freking, Jill Colvin, Bob Burns, Lisa Mascaro and Mary Clare Jalonick contributed to this report.

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