In a troubling sign of COVID-19's resurgence, the Minnesota National Guard has been called in to provide emergency staffing support at two nursing homes struggling to contain large and deadly outbreaks of the respiratory disease.

Over the past 10 days, the National Guard has dispatched small teams of medical professionals to facilities at opposite ends of the state where dozens of residents and staff have been sickened, and where staffing levels became so depleted that they turned to the state for help. Both facilities — one in the southern Minnesota city of Austin and the other on the Iron Range in Hibbing — have active outbreaks and are isolating infected residents in separate COVID-19 units.

The rare deployments come amid an alarming resurgence of COVID-19 across the region and amid mounting evidence that the virus is infiltrating Minnesota's 2,100 long-term care facilities after declining over the summer. They also reflect how the virus is shifting toward smaller facilities in rural areas where staffing shortages are more severe.

With cases rising statewide, public health experts fear a repeat of the chaotic scenes this spring, when some senior homes became so overwhelmed they had to move residents to hospitals and get support staff to fill in as caregivers because so many employees were infected and had to be quarantined.

The use of rapid testing and stricter isolation techniques have reduced coronavirus-related fatalities in Minnesota's senior homes since their peak in May. Even so, the list of such facilities with at least one confirmed infection in a resident or worker in the past 28 days has grown from 239 on Sept. 1 to more than 340, the state Health Department reported last week. Slightly more than 70% of Minnesota's 2,151 coronavirus deaths have occurred in nursing homes and assisted-living facilities.

"There's just a lot more disease out there than we've seen in the past," State Health Commissioner Jan Malcolm said Monday.

Even before the pandemic, long-term care facilities struggled to recruit and retain caregivers. But the two nursing homes that sought emergency help are in areas of the state where staffing shortages have been particularly severe, leaving them more vulnerable when the virus struck and employees became sick. Both facilities, Sacred Heart Care Center of Austin and Guardian Angels Health and Rehabilitation Center in Hibbing, have received above-average scores for overall care from federal health regulators.

The Minnesota National Guard has a cadre of Army and Air National Guard personnel who are trained doctors, physician assistants, nurses and emergency medical technicians who can be deployed to facilities facing a staffing crisis, according to the Health Department.

"If you have to call out the National Guard, that is an extreme step — and it should be a call out to all of us that we need to invest in staffing and retention in nursing homes," said Joseph Gaugler, a professor who specializes in long-term care and aging at the University of Minnesota School of Public Health.

Late last week, Sacred Heart Care Center, a 59-bed nursing home, requested assistance from the National Guard to help contain a COVID-19 outbreak that has sickened nearly a third of its staff and about 60% of its residents, county officials said. The nursing home last month reported two dozen positive cases of the virus among its residents and staff as well as two resident deaths, according to Minnesota Department of Health records.

On Saturday, a nurse and four medical technicians with the National Guard arrived at the nursing home in medical scrubs to provide help with resident care for up to two weeks. Mower County officials also are helping with weekly testing and monitoring staff to ensure they are following proper infection-control protocols, such as washing hands and wearing personal protective equipment properly.

The county also plans to bring in counselors to help staff who are suffering from "compassion fatigue and burnout" from caring for residents during the outbreak, which began in late August, said Pam Kellogg, division manager at Mower County's health and human services department.

"This is a very good facility, but it's unfortunate that this virus is so contagious that it's really difficult to contain once it gets in," Kellogg said. "You have staff who had no symptoms and end up coming up positive [for COVID-19] when you do serial testing."

Nearly 300 miles north in Hibbing, an even larger outbreak has unfolded at the 90-bed Guardian Angels Health and Rehabilitation Center, where 65 residents and staff have tested positive since the pandemic began, and at least nine residents have died of the virus, according to an update on its website. On Oct. 3, the National Guard sent a team of five medical professionals to help with resident care. A Department of Health spokesman said "the situation has stabilized" and the National Guard has since left.

The deployments reflect the toll the pandemic has taken on thinly staffed facilities. In April, about 40 residents of an assisted-living facility in Wayzata were evacuated after COVID-19 swept through the home, infecting a majority of its residents and staff members and killing two residents. At the Good Samaritan Society nursing home in Brainerd, so many staff got infected in May that the facility brought in nine nurses from the Federal Emergency Management Agency (FEMA) to stay open.

An August survey by Care Providers of Minnesota, a long-term care industry group, found that nearly 15% of caregiver positions in nursing homes and assisted-living facilities were unfilled statewide.