After clocking out of her shift at a clinic in Northern Virginia, Taniqua James changed out of her scrubs in her car and drove the 45 minutes to pick up her 2-year-old daughter, wondering whether it would be the toddler’s last day at the child-care center — and, maybe, her last day at work.

The toddler’s private day care in Largo, Md., had stayed open even as the number of people testing positive for the novel coronavirus was multiplying. James, a 28-year-old single mother, was still able to continue working full time as an ambulatory technician. But on Monday, Maryland’s governor announced the closure of all nonessential businesses, and James had no idea whether that might include her daughter’s child care.

“Am I going to have to leave work?” James asked. “If I leave work because I don’t have child care, then who is paying our bills?”

Across the country, single parents have seen their support systems crumble at a time when they need them most.

Schools and day-care centers have closed for weeks or even months to come. Families have had to scramble to rearrange schedules, juggle teleworking with home schooling and feed their children three times a day. In two-parent households, the adults can swap shifts to care for children and keep working. But single parents have to manage this unexpected chaos almost entirely on their own, 24 hours a day, while praying they don’t contract the virus. With no other parent to fall back on, many are terrified to think what would happen to their kids if they fell ill.

About 1 in 4 children across the country lives in a single-parent household, a share that has more than doubled since 1970, according to the U.S. Census Bureau. More than 80 percent of those children, nearly 16 million, live in a household headed by a woman.

Even in the best of times, single mothers face significant barriers to employment because of a lack of universal child care, paid leave and flexible work schedules. For low-wage workers, the coronavirus crisis has upended their lives. Many relied on day-care workers, babysitters, family members and friends to help care for their children while they work. But social distancing has isolated households into discrete bubbles and broken apart these networks.

“The web of support that families have is being ripped away by this pandemic,” said Gina Adams, a senior fellow at the Urban Institute who studies low-income working families and who is also a single mother of a teenager.

A significant portion of nurses, home-health aides and other providers who must continue to go to work are single mothers who risk exposure to the coronavirus, said C. Nicole Mason, president and chief executive of the Institute for Women’s Policy Research and a single mother of 10-year-old twins.

“We know they are working around the clock,” she said. “What’s happening to the children, especially the children who are left at home?”

Equally concerning, Mason said, are the single parents who are now unemployed because of the pandemic. The closures of restaurants, stores, day-care centers and schools also meant the loss of jobs.

Passion Ferrell is a single mother of three children — ages 3, 7, and 9 — whose father is incarcerated. For the past two years, the 30-year-old Southeast Washington resident has waited tables four days a week at a sushi restaurant, relying on babysitters to take care of the children when they’re not in school and when she’s at work.

But the restaurant couldn’t keep paying its employees after customers started staying home, and Ferrell hasn’t been able to work for about two weeks. Without an income, she worries she won’t be able to pay her electric bill. And with schools closed, she must budget for more food for her children. Even with the government SNAP benefits she already receives, she expects she’ll have to start looking for nearby charities offering free meals. Their public elementary school is offering free lunches, but Ferrell and her children would need to take two buses to get there, potentially exposing them to the virus.

And the last thing Ferrell needs right now is to get sick. Last week, she fell ill with a fever, which a doctor said was the flu.

“No one stepped up to say, ‘I will help you out with your children because you’re sick,’” she said. At times when she struggled to get out of bed, her oldest daughter, 9-year-old Promise, helped her younger siblings make peanut butter and jelly sandwiches.

Rahima Rice, a 40-year-old single mother in Washington, spent the past few years building her career as a screenwriter and a playwright. She had lined up performances at festivals and conferences for the spring and summer that have now been postponed or canceled. With schools closed, she’s no longer able to work as a substitute teacher, which brought in the bulk of her income. Now she’s working for food-delivery services such as DoorDash and Postmates, but that requires finding a babysitter or a relative to watch her 5-year-old daughter, who can no longer go to kindergarten.

She would normally ask her parents for help since they live nearby. But because they are 73 and 63, she doesn’t want to put them at risk of contracting the virus.

“There is no one to take on the burden of responsibility when I need a moment, you know?” Rice said.

Being stuck at home and worrying about the virus has been stressful not just for Lyndsey Medsker, a 44-year-old single mother on Capitol Hill, but also for her two sons, who are 9 and 10. “There have been questions of, ‘Mom, what happens if you get sick?’ My 9-year-old just asked me that today. I said, ‘I’m trying really hard not to, and if I do I’ll be okay because I’m healthy.’”

She does not have family in the area to help, and over the years she has relied on a network of friends she has created.

“I lean on my village a lot, whether it is for education, child care, a cooked meal, a positive male role model or just a mental break from the 24 hours a day, every day, of parenting,” Medsker said. But because of social distancing, she said, “My village has become a ghost town.”

In the midst of it all, Medsker, who is self-employed, must keep working. Since school closed, she works from 5 to 9 a.m. and again late at night, making calls during the day.

The situation has upended her idea of herself. “I usually have the answer for everything. I’m usually a planner — ‘I’ve got this, I have everything handled.’ In my normal life, I’m a plate-spinner and everything’s balanced. But if one plate falls, everything comes crashing down.”

Jane Mattes, a psychotherapist and founder and director of the organization Single Mothers by Choice, said the biggest fear among members is about falling ill. “What if I get really sick and I’m the single parent of a 2- or a 4- or an 8-year-old. … In these scary times, will people be willing to take them?”

Single fathers with no other adults in the house also grapple with that question. Jon Kimball, 49, of Coeur d’Alene, Idaho, has full custody of his children, who are 10, 13, and 15. Since their schools closed March 16, he has been working from home so the family could socially isolate. His job is secure for now. He makes stealth radio antennas popular among survivalists, and business is booming. But one day when he went out to grab something at his office, he came home to see the garage door open and the kids gone. He found them riding their bikes at a nearby golf course.

He was horrified. “Where the heck have they been, have they gone into someone’s house, have they eaten food that someone gave them?” he said. “Now I’ve got a laptop and I’m setting myself up at the kitchen table so I can keep an eye on them.”

Kimball has no one who could take the children if he gets sick. His 82-year-old mother lives six hours away and is in isolation, too. “It’s a freaky question. I don’t have a backup plan,” he said. For now, he has stocked up on vitamin C and Indian tonics. “I don’t know what I’d do. I’m still [focused] on the housework and the pattern of the kids’ days.”

James, the ambulatory technician, also worries that she might contract the virus and bring it home to her daughter. But social distancing isn’t an option for her. Her main concern this week was making sure she could still get to work.

Minutes after she picked up her daughter from day care on Thursday night, her twin sister called her, asking her whether she had seen the news: Maryland’s governor had announced that all child-care programs in the state would have to close by Friday evening.

“You’re joking,” James said.

“What are you going to do?” her sister asked.

“I have no idea,” James said.

She thought about possible backup options: Her twin recently gave birth to a baby, so she wouldn’t be able to take her daughter in. Her other sister lives almost two hours away in Woodbridge, Va., meaning more money spent on gas. And would that sister be willing to take care of a toddler full time while working from home?

After getting off the phone, James called her boss to tell her what happened.

“There’s a possibility that I will not be there on Monday,” she said.