The uncertainty and worry that has permeated the region for days turned to reality Friday when officials announced the first positive cases of coronavirus in Pennsylvania and South Jersey, and separate concerns about potential exposure in Bucks County prompted a school district there to close five schools.

Two adults in Delaware and Wayne Counties were quarantined at their homes and were “in good physical condition” after testing positive for the virus Friday morning, said Pennsylvania’s secretary of health, Rachel Levine. Both patients had recently traveled, one out of state and one overseas.

In Cherry Hill, a man in his 60s has been hospitalized with the illness since Tuesday and was stable, Camden County officials disclosed.

Gov. Tom Wolf issued an emergency disaster declaration as Pennsylvania became at least the 20th state to report cases of the fast-spreading illness, based on tracking by the U.S. Centers for Disease Control and Prevention. The number of confirmed cases on Friday surpassed 250 nationwide and 100,000 globally.

Through Friday night, no one in Philadelphia had tested positive for the virus, city health officials said.

The Central Bucks School District became the first around Philadelphia to cancel classes, shutting five schools after determining that “a person from out of state, who is now known to have coronavirus, attended a recent private gathering at a residence” with students and staff from the five schools. It was unclear how long the schools would remain closed, although test results Friday evening showed none of the people who came in contact with the infected patient had contracted the virus, county spokesperson Larry King said.

Officials across the region on Friday sought to encourage calm among residents, yet declined to release details about where the patients live, how old they are, or how they had contracted the illness, citing patient confidentiality. Pressed by reporters, Delaware County officials said state officials instructed them not to release more information.

“They have their reasons for holding back that information. I don’t know exactly what they are, but again, rest assured that if they feel a certain individual or group is at risk, they will reach out to them and make them aware,” said George Avetian, senior medical adviser for the county.

Still, details emerged.

Following an afternoon phone call with county officials, State Rep. Greg Vitali (D., Delaware-Montgomery) said they told him the Delaware County patient was a woman who had recently returned from Boston, where a handful of coronavirus cases have been linked to a recent conference. His account was confirmed by another person on the call.

The patient was treated at Crozer-Chester Medical Center in Upland, and her physician was also under quarantine, emergency services officials said on the call, according to Vitali.

“The person moved throughout Delaware County,” county emergency services head Timothy Boyce told reporters. “It’s fair to say they moved about Delaware County to seek medical treatment and returned home.”

But sources said only state officials know exactly where the woman lives or had traveled within Delaware County, and that county officials planned to press Harrisburg to disclose that information. Vitali said his office is also working to learn more.

In Camden County, officials were also unable or unwilling to provide details about the local patient with the virus, who is at Jefferson Cherry Hill Hospital. “Whenever we get more information we will share it,” County Health Officer Paschal Nwako said at a late afternoon news conference. “What I shared is what we know.”

In states including Virginia and Florida and Texas, governors or state officials have also cited confidentiality in declining to release the details about the infected patients, including where they live or may have contracted the illness. But in some states, including Washington, which has the most cases, details about patient location have seeped out, and New York has been forthcoming, down to identifying the law firm where one patient works, his hometown, and the hospital where he is being treated.

The announcement of Pennsylvania’s first coronavirus cases came several weeks into emergency preparations for a potential outbreak of the illness, which is characterized by fever, cough, and shortness of breath. The worst outbreaks in the United States to date are on the West Coast, but this week, cases emerged in New York, New Jersey, and Pennsylvania.

On Friday afternoon, New Jersey was advising its public schools to plan for closures. The University of Washington canceled in-person classes in the Seattle area. New York state confirmed 22 more cases. President Donald Trump arrived in Atlanta to visit the CDC.

Wolf’s emergency disaster declaration directed up to $20 million in unused appropriated funds to combat the virus in Pennsylvania. State officials are having multiple daily briefings with federal officials, working with every level of government in the commonwealth, and running a command center in Harrisburg, he said.

“Right now, the emphasis of the plan is mitigation — tactics to keep the virus from spreading widely,” he said. "I want to emphasize we all should remain calm here.”

Delaware County officials said they learned of their local case at 9:30 a.m. Friday, when Wolf made his public announcement. The county does not have a health department, but officials said this week that they had “a very strong plan in place” to respond to any cases or an outbreak.

The county has distributed masks to first responders, and janitorial staff have been directed to increase sanitation inside county buildings, officials said Friday. The Department of Intercommunity Health, Department of Emergency Services, the County Council, and a medical countermeasure team are coordinating the response, and the county set up a page on its website where information on coronavirus can be found.

Wolf told Pennsylvanians to wash their hands, cover their coughs, stay home if sick, and get information from the state website. He urged employers to provide sick time and telecommuting opportunities for workers.

“We expect more cases to be confirmed in the upcoming days and weeks,” said Levine, Wolf’s Health Department secretary. “And we want everyone to take action to help prevent the spread.”

Staff writers Ellie Rushing, Anna Orso, Ellie Silverman, Michaelle Bond, Frank Kummer, and Oona Goodin-Smith contributed to this article.