“Don’t touch me!” Senator Pat Roberts, an 83-year-old Republican from Kansas, ordered when he was approached by a reporter off the Senate floor.

Many college-age interns in the House were recalled home by their universities this week, leaving offices stranded during appropriations season, a time when they are normally dispatched to visit hundreds of offices to collect lawmakers’ signatures on official funding requests. In the case of one House office, instead of interns, lower-level aides wearing masks and gloves were sent to collect the signatures.

Lawmakers up for re-election privately discussed how they would handle campaigning. Senator Chris Coons, Democrat of Delaware, said he had planned to knock on doors on Saturday, but canceled the outing after consulting with his campaign staff.

“We were debating, do people want me knocking on their door?” Mr. Coons said.

Ms. Pelosi discouraged reporters from bumping elbows as a greeting.

“Forget any physical contact,” she said.

That is easier said than done in the Capitol, where the coronavirus has created something of a perfect storm. Congress is home to dozens of elderly lawmakers whose sheer age puts them at higher risk, not to mention the fact that they routinely work long hours; crisscross the country by plane; meet with a constantly rotating cast of constituents, lobbyists, donors and experts from around the world; and are by nature eager to shake every hand they see.

Then there are their aides, who work on their committees and in their offices and meet with even more people than their bosses do, running reports and memos back and forth to other aides in other offices. It is an entire network of thousands of Type A personalities guided by a belief that they can reason, spin, flatter or glad-hand their way out of any and all problems. And it is all best done face to face, not at a distance.

On Thursday, Senate pages could be seen wiping down desks and chairs on the floor, and behind the scenes, enterprising aides bartered their offices’ snacks for hand sanitizer. House administrators have ordered 1,500 new laptops before what could be a crush of demands for technology products as congressional offices begin urging staff members to work from home, according to one Democratic aide familiar with the order.