Stunning views of Mountain View Pond and Moosehead Lake from the ski trials of Big Squaw Mountain in Greenville. As of Monday, Piscataquis County was the only one without a confirmed case of the fast-spreading infection that has caused a pandemic and shut down much of daily life. Credit: Linda Coan O'Kresik

Click here for the latest coronavirus news, which the BDN has made free for the public. You can support our critical reporting on the coronavirus by purchasing a digital subscription or donating directly to the newsroom.

More than three weeks after Maine confirmed its first case of the new coronavirus, the state has recorded cases in all but one of its 16 counties.

As of Monday, Piscataquis County was the only one without a confirmed case of the fast-spreading infection that has caused a pandemic and shut down much of daily life. Two other counties, Aroostook and Washington, both recorded their first cases last week.

[Our COVID-19 tracker contains the most recent information on Maine cases by county]

The lack of confirmed cases is likely the result of the county’s low population density and the limited testing for the virus that has obscured the full extent of the coronavirus outbreak. But there’s a good chance the virus is in the county even if testing hasn’t confirmed it.

“You have to assume it’s there, and I would,” said Dora Mills, chief health improvement officer for the MaineHealth hospital system and a former director of the Maine Center for Disease Control and Prevention. “What we know from other places, the virus likely circulated for several weeks before they knew it was circulating.”

Piscataquis County has a lot in common with the hundreds of other U.S. counties that have yet to record a coronavirus case. Some 85 percent of them are rural, according to an Associated Press analysis published late last month. They also tend to have older populations, lower household incomes and higher poverty rates — factors that put more residents at greater risk from the virus because they correlate with poorer health.

At a time when people are told to keep their distance from each other to slow the virus’ spread, Piscataquis County’s low population density — the lowest of any county in the state, at 4.4 people per square mile in 2010 — offers an advantage, said Mills.

“It could be protecting them for a while,” she said. “When we talk about social distancing, it’s obviously easier in Piscataquis County than it is in New York City that has 70,000 [people] per square mile.”

With no local cases recorded, Mills said, county residents could be lulled into a false sense of security.

“There’s no reasons to think Piscataquis County is somehow isolated from the rest of the state,” she said. “The virus doesn’t see the border, and there’s still traffic going up and down the roads there.”

And the healthy people among whom the virus first typically circulates aren’t prioritized for a limited number of COVID-19 tests. Those tests have recently been reserved for people who are already hospitalized, have underlying health problems and live in congregate care settings such as nursing homes.

Northern Light Health, the hospital system that owns Piscataquis County’s two hospitals, has set up drive-up testing sites in Dover-Foxcroft and Greenville. However, because of the testing criteria, “it’s rare that someone would be tested at the assessment site,” said Northern Light spokesperson Chris Facchini.

While low population density offers some protection, the county’s rural nature could also put it at risk for an event that infects a large portion of the population at a single time, Mills said. Rural areas are more susceptible to those so-called super-spreading events — such as a single funeral in late February that is responsible for a coronavirus outbreak in Dougherty County, Georgia.

“Because you have a gathering of 30 people or 50 people in a rural town for a funeral, proportionately it’s much bigger than a 50-person gathering in a city,” she said. “You could have the most of the town infected within a couple weeks.”

The hospitals, Northern Light C.A. Dean in Greenville and Northern Light Mayo in Dover-Foxcroft, are working to increase their capacity in case of a coronavirus outbreak, Facchini said. Those preparations include training staff to work in the hospital departments that would likely see the greatest demand during an outbreak and at the testing sites.

Watch: How does COVID-19 spread?

[bdnvideo id=”2958926″]