As the deadly coronavirus continues its rampage through Minnesota nursing homes, public health officials are facing a fresh dilemma: Where to care for surging numbers of sickened patients without spreading the virus.

Over the past 10 days, authorities have scrambled to evacuate dozens of residents from three long-term care facilities in separate parts of the state, from Winona to Duluth, after they became overwhelmed by large and particularly lethal outbreaks of the novel coronavirus. In each case, staff members became so ill that they couldn't care for patients, and local authorities and hospital systems had to move swiftly to prevent a wider catastrophe. The rescue efforts were mostly orchestrated on the fly at the local level by facility administrators and county agencies.

But as the number and severity of outbreaks intensify in senior care facilities, alarmed public health experts have raised questions about whether the state has enough safe places to isolate and treat the hundreds of elderly residents sickened by the virus.

In addition, there are growing calls on public health authorities to shift their focus from screening measures, which have largely failed to stop the rapid spread of outbreaks, to containing the virus' spread by quickly identifying and moving people to safer facilities.

In recent weeks, the long-term care industry has been working intensely with the state Department of Health to identify special sites for treating infected patients from nursing homes and assisted-living facilities. Known as "COVID support sites," these would be special units or wings within existing facilities staffed with health care professionals who are trained to treat people infected with the virus.

Unlike in crowded nursing homes, where patients are often doubled up in rooms, patients in these wings would be isolated in private rooms until they recover. Thus far, officials are reviewing specially designed support sites that could care for more than 90 infected people, according to LeadingAge Minnesota, a long-term care industry group.

Other states, including Connecticut and Massachusetts, have explored the possibility of opening entire facilities for nursing home patients infected with the coronavirus.

"It is likely that preventive strategies alone will not be enough to mitigate the increased risk of COVID transmission for people living in residential long-term care," said Joseph Gaugler, a professor who focuses on long-term care and aging at the University of Minnesota's School of Public Health. "Creative strategies are needed to establish COVID-specific residential care settings."

Nursing homes and assisted-living facilities, which are home to more than 80,000 Minnesota seniors, have become the deadliest battleground in the state's fight against the pandemic. Together, these facilities account for 102 of the 143 deaths across the state, and dangerous clusters of cases have become more common. There are more than 130 long-term care facilities statewide with at least one positive case of COVID-19, the respiratory disease caused by the virus, and at least eight facilities with more than 20 cases, according to the Minnesota Department of Health.

Over the weekend, a bus and van transferred 14 healthy patients, one at a time, from Sauer Health Care, a 71-bed nursing home, to an alternative senior facility, Lake Winona Manor, about 4 miles away in Winona. The transfers are meant to insulate people who have not been infected with the coronavirus, which has already claimed eight lives at Sauer Health and infected 21 other residents and staff. To prevent the virus from spreading, all the people were moved to a segregated wing of Lake Winona Manor with its own entrance and dedicated staff, officials said.

Rachelle Schultz, president and chief executive of Winona Health, a nonprofit hospital that operates Lake Winona Manor, said the residents who have been moved, as well as the staff caring for them, will be monitored and tested for the virus regularly.

"We've all understood that wherever [the virus] shows up first is where it shows up first," she said. "The risk is not over." She added, "Once the virus takes hold, it's really difficult to eliminate."

The quarantine effort in Winona marked the second time in the past few days that residents of long-term care facilities in Minnesota have been temporarily relocated amid extreme coronavirus outbreaks. Nearly four dozen residents of the Meridian Manor assisted-living facility in Wayzata were moved Saturday to hospitals, to other long-term care facilities or to family housing. The evacuations were necessary because a majority of staff and administrators had fallen ill with COVID-19.

At both facilities, many of the people who tested positive for the virus did not show symptoms, such as coughing, breathing problems or a high temperature, officials said. Data from recent studies in the United States show that as many as half of people with COVID-19 infections in care homes had no signs of the illness when they were tested.

The tendency of the virus to spread rapidly among people who do not know they are infected underscores the urgent need for people to stay home, said Karen Sanness, director of health and human services in Winona County. "What is really scary about this whole situation is that people who have [the virus] often don't even know that they have it, and just by making trips to the grocery store could potentially be infecting people," she said. "So please, please, please, everyone stay home, because you are the ones that control the spread of this disease."