WINCHESTER — Two people have been diagnosed with the coronavirus in the northern Shenandoah Valley as of Sunday evening.

The first diagnosis occurred Friday night and involved a man in his 60s who was visiting the area, according to Dr. Colin Greene, Lord Fairfax Health District director. Greene wouldn’t say where the man was hospitalized. Greene was uncertain of the man’s condition, “but he certainly has got the attention of every expert that’s available,” he said.

The second person is a woman in her 30s who lives in the Lord Fairfax Health District, which encompasses Winchester and Clarke, Frederick, Page, Shenandoah and Warren counties. Her positive test came back this weekend, according to Greene. He said she has displayed mild symptoms and has been asked to self-quarantine.

Citing medical privacy laws, Greene wouldn’t identify either of the patients. People who came in contact with them who are believed to be at risk will be asked to self-quarantine. Greene said the woman may have come in contact with people from four local communities.

The virus, for which there is no vaccine, was first discovered in China in January and declared a global pandemic on March 11. Through Sunday afternoon, it had killed 14,376 worldwide and infected 329,300, according to the John Hopkins University of Medicine Coronavirus Resource Center website. In the U.S., there were 322 deaths as of Sunday morning, according to the New York Times. In Virginia, three people have died and 219 have been diagnosed, according to the Virginia Department of Health (VDH).

Due to a shortage of test kits — the Centers for Disease Control and Prevention said on its website on Sunday said 66,371 people have been tested in the U.S. — there are far more people infected than diagnosed. In Virginia, a state of 8.5 million people, just 3,317 have been tested, according to the VDH.

Greene said there are almost certainly many more infected people locally who haven’t been diagnosed. “They’ll continue to turn up as the days go by,” he said.

To decrease the risk, Greene said people should stay inside other than for essential trips or exercise. When outside, people should maintain a six-foot distance from other people when feasible. The goal is to avoid breathing in respiratory droplets.

Greene emphasized people can be contaminated without being coughed on. Breathing the air of someone nearby for more than a brief time or touching a surface of someone who has recently touched it and is infected and then touching your face can cause infection. Frequent washing with soap and hot water or hand sanitizer is recommended.

Greene said hospitals have to be careful about treating COVID-19 patients to avoid it spreading to medical personnel. With no federal plan on how to deal with hospitals being overwhelmed with patients as the pandemic grows, some communities are using athletic fields or gyms as field hospitals. In New Haven, Connecticut, the Payne Whitney Gymnasium at Yale University has been converted into a makeshift hospital for virus patients. In King County, Washington, a state where at least 94 people have died, a 200-bed hospital has been created on a soccer field.

Locally, Greene said here has been discussion of using empty buildings to shelter homeless people who have mild symptoms and have nowhere to self-quarantine. Any homeless person with serious symptoms would be hospitalized.

Greene, a 30-year Army veteran who served in the Iraq War, said if local hospitals are overwhelmed, military-style field hospitals with tents could be created.

“None of that’s being actively discussed, to my knowledge, right now,” he said. “But nothing would be off the table. We’re Americans. We can be innovative.”