A D.C. church leader who oversaw services for hundreds of worshipers was identified Sunday as the first confirmed coronavirus patient in the District, while authorities in Maryland and Virginia announced three new cases but said the risks for public exposure were low.

The number of known coronavirus cases in the Washington region reached nine as local public health authorities moved to increase their testing capabilities and contain the spread of the illness. A D.C. high school will be closed Monday after a staff member came into contact with someone who has tested positive for the virus.

Maryland Gov. Larry Hogan (R) announced two new confirmed cases Sunday evening, bringing the state’s total to five. They include a Harford County woman in her 80s and a Montgomery County man in his 60s, both of whom contracted the virus while traveling overseas, according to the governor.

Maryland health officials do not believe there is a major risk of community exposure or any connection to three cases in Montgomery County announced Thursday, meaning the state has no evidence of community transmission. Hogan is scheduled to release more details at a Monday afternoon news conference.

The University of Maryland Medical System said Sunday that a person with covid-19 was being treated at one of its hospitals. The patient is being treated in isolation “until such time that clinical guidelines indicate that they are able to be released from our care,” the hospital system said in a statement.

Virginia officials said Sunday that a Fairfax City resident in his 80s tested positive for the coronavirus. They believed there was a low risk of exposure to the public because he had limited interactions with the community.

And in the District, Christ Church Georgetown said the Rev. Timothy Cole, its top-ranking clergy member as rector, tested positive for the virus on Saturday. District officials confirmed he was the same man in his 50s with no recent international travel whom they identified Saturday as the first presumptive case.

The historic Episcopal church canceled Sunday services — the first cancellation since a fire in the 19th century — and has been calling and emailing parishioners. D.C. health officials said they have launched an “intensive investigation to identify any exposures” at the church.

Cole fell ill shortly after attending an Episcopal conference in Louisville on Feb. 22, church spokesman Rob Volmer said. His health improved before he attended church events last weekend, including four services attended by 550 people March 1.

Cole provided Communion to parishioners during the 11:15 a.m. service, Volmer said, and washed his hands before doing so.

Cole, who did not appear to show symptoms then, had been vigilant about using hand sanitizer available throughout the church and washing his hands, and had spent part of his services reminding parishioners about good hygiene practices, Volmer said.

But Cole’s health deteriorated after Sunday, and he was diagnosed with the flu on Tuesday, Volmer said. He was admitted to a hospital Thursday, and a coronavirus test came back positive Saturday.

His wife and son are self-quarantined at their home, while Cole is hospitalized in stable condition.

Cole told parishioners there was “no need to panic” in a message Sunday.

“First, I want to assure you that I will be okay,” Cole wrote. “I am receiving excellent care and am in good spirits under the circumstances. I will remain quarantined for the next 14 days as will the rest of my family.”

D.C. officials did not respond to questions Sunday about the risk of exposure to those who attended Christ Church Georgetown. The health department said it would reach out to “potentially impacted” congregants and visitors.

Since the coronavirus outbreak began in the Wuhan province of China, the virus has infected more than 109,000 people globally and has killed more than 3,700. Italy launched a plan Sunday to restrict the movement of 16 million people across northern regions of the country after a surge in cases.

Confirmed cases in the United States topped 500 Sunday, with fatalities rising to 21 after the deaths of two more residents of an infection-stricken nursing home in Washington state.

To curb the spread of the virus, authorities are urging people to regularly wash their hands, avoid close contact with people who are sick and stay home when ill. According to the Centers for Disease Control and Prevention, patients are thought to be the most contagious when they are the most symptomatic, but some spread may be possible before people are visibly sick.

In an interview Friday, Dr. Jinlene Chan, Maryland’s assistant health secretary, said there is a lot unknown about the virus and its transmission, including when asymptomatic people could shed infectious virus. That certainly can happen when covid-19 patients are showing symptoms, she said, but it was not as clear when — if at all — during the 14-day incubation period patients who are not showing symptoms could potentially transmit it.

Meanwhile, many have questions about who should be tested and when.

D.C. resident Maggie McDow, 46, who traveled through the Seoul airport after a trip to Thailand late last month, said she was alarmed when the D.C. Health Department overruled an emergency room doctor treating her Friday at George Washington University Hospital, preventing her from being tested for the virus. She wrote about the experience in a Facebook post shared widely on Saturday.

“It’s really worrisome to me when a doctor feels you should have a test and someone’s overruling them,” McDow said in a phone interview Saturday while self-quarantined with achiness and chills. “To me that’s just wrong.”

A top health department official said McDow did not qualify for testing because airport exposure, even in a country like Korea with community spread of the disease, does not warrant testing.

“We bring a different perspective to that single clinical encounter,” Anjali Talwalkar, senior deputy director for the community health administration at the D.C. Health Department, said at a Saturday evening news conference. “An airport is not considered by CDC to be that kind of exposure.”

Still, the situation left McDow frustrated about halfway through a period of self-isolation that meant she hadn’t seen her 13- and 14-year-old daughters in more than two weeks.

She said after a week in Thailand, she began to feel sick on her flight home to Dulles International Airport, and in the next few days she twice contacted the D.C. Health Department for guidance.

She said she was told she was low risk, but finally went to the emergency room at GWU Hospital. There, she said, a doctor ruled out the flu and other illnesses and wanted to test her for coronavirus, but District health officials refused.

“I didn’t know I should have stayed in Thailand to get better medical care,” McDow said. “We’re supposed to be the best in the world at this. There’s just a false sense of security.”

All the confirmed cases in Maryland and Virginia so far involve people who authorities believe contracted the virus overseas.

The Fairfax City resident “traveled on a similar Nile cruise” as other patients who have tested positive in Maryland, the Virginia Health Department said. The resident showed signs of a respiratory illness Feb. 28 and was hospitalized Thursday. The person is in stable condition.

The resident had “very little exposure” to the community after returning home and had no interaction with school-age children before being hospitalized, Benjamin Schwartz, Fairfax County’s lead epidemiologist, said at a Sunday afternoon news conference. The resident’s spouse is not showing symptoms of covid-19 but is being tested.

The announcement about the Fairfax City resident came less than a day after Virginia announced its first presumptive positive patient — a U.S. Marine assigned to Fort Belvoir. The Marine had recently returned from “official business” overseas, tweeted Jonathan Rath Hoffman, assistant to the secretary of defense for public affairs.

The Defense Department is leading the effort to trace his contacts, local authorities said. It is not immediately clear whether he interacted with school-age children or the elderly before being hospitalized. Officials said he is being treated at Fort Belvoir Community Hospital.

Additionally, Loudoun County Combined Fire and Rescue System said Sunday that an employee has been self-quarantined since learning Saturday about exposure to a person outside the county who tested positive for the coronavirus. Officials declined to say which patient the employee had been exposed to.

In the District, School Without Walls High School, a selective public high school in the Foggy Bottom neighborhood serving about 600 students, will be closed Monday after city officials determined that a staff member had close contact with a person who tested positive for the coronavirus, the school system announced Sunday evening. The closure was expected to last a day at the campus, which is the first public school in the city to close as a result of the virus.

The employee has displayed no symptoms and tested negative for the virus, city officials said.

Still, D.C. Public Schools Chancellor Lewis D. Ferebee said the school would be closed Monday so crews could thoroughly clean the campus. The closure will also give school leaders time to communicate with staff and families. D.C. International School, a charter school in the Takoma neighborhood, announced early Monday it would close for deep cleaning.

School Without Walls @ Francis-Stevens — an elementary and middle school that shares some administrative staff with the high school but is in a separate facility — will remain open Monday.

In Maryland, Hogan urged residents not to panic over the new cases announced Sunday.

“We continue to hope for the best, and actively plan for the worst,” Hogan said in a statement. “I encourage all Marylanders to remain calm, but to take this seriously and continue to stay informed.”

Agencies across the Washington region have been ramping up efforts to test for coronavirus cases.

Jenifer Smith, director of the D.C. Department of Forensic Sciences, said the city’s public lab can test 50 people a day. Testing capabilities in the District will increase when private labs receive test kits.

As of Sunday, Virginia has two test kits with the capacity to test up to 400 people — an adequate number given the existing cases, said Denise Toney, the state’s director of lab services. More test kits are on their way, she added.

Maryland’s public lab can test about 1,000 people, and officials are working with the CDC to double that capacity, officials said.

Perry Stein and Martin Weil contributed to this report.