Updated: 8:35 a.m.
The state agency responsible for wildlife management in Minnesota is ramping up efforts to contain a disease outbreak that threatens the state's white-tailed deer population.
In response to what Commissioner Sarah Strommen called a concerning outbreak of chronic wasting disease in the northern part of the state, the Minnesota Department of Natural Resources imposed a statewide ban on the movement of farmed white-tailed deer, beginning Tuesday and continuing through the end of July.
The ban is meant to curtail the spread of the highly infectious and always fatal disease, which can spread when captive deer from infected herds are transferred to other parts of the state, as part of regular herd management, and pass it on to the wild deer they encounter.
"We want to make sure that we can protect the wild herd by locating all infected farmed deer in the state,” Strommen said. “And that's much more difficult to do if they're still moving around."
A total of 13 deer in a farmed herd in Beltrami County tested positive for chronic wasting disease. It's spread by prions, or proteins, in the animals' bodily fluids. Prions can also remain viable for several years in the ground, long after an infected animal has died and its carcass decomposed, continuing the cycle of contagion.
During a check of the Beltrami County farm, investigators found that carcasses of infected deer had been dumped on nearby public land, beyond the farm’s fences, increasing the risk to wild deer in the area.
Compounding the concern: Investigators believe the Beltrami County herd was infected by animals that came from a herd in Winona County, an area in far southeastern Minnesota where CWD is considered endemic. In Minnesota, the disease was first detected in wild deer in 2010 — and since then, most cases of CWD in the state have been found in the southeast.
But the already worrisome situation has become far more urgent, Strommen said, now that an outbreak has been detected in Minnesota’s north woods.
"You've got now something several hundred miles away from where we have been managing the core of this disease, in a place that is really the heart of Minnesota's deer country," said Strommen.
It’s that urgency, she said, that prompted the temporary emergency halt, set to take effect Tuesday. An official with the Minnesota Deer Farmers Association said he won't comment, because, he said, farmers have not been officially notified of the emergency ban.
Strommen issued a shorter, 30-day emergency ban on farmed deer movement two years ago.
It’s the Minnesota Board of Animal Health — not the DNR — that regulates the state’s 259 captive elk and deer herds. The agency says currently 174 farms have white-tailed deer. But the board does not have the authority to issue emergency rules — and the DNR is responsible for maintaining the health of the state’s wildlife populations.
In addition to its presence in southeastern Minnesota, CWD has been found in wild deer in two other locations: One in Dakota County in the spring of 2020 and another in Crow Wing County in February 2019.
While no disease has been detected in wild deer populations in Beltrami County, the farm outbreak there significantly raises the level of concern, said DNR Fish and Wildlife Division director Dave Olfelt.
"One of the things that it highlights is that the disease can move at 55 miles an hour down the road, that the animals on this farm came from hundreds of miles away, and brought the disease with them," he said.
Farmed deer are bought and sold, and moved between farms for breeding purposes or to manage herd size.
Olfelt lives in Grand Rapids.
"We've not had to think about chronic wasting disease in this part of the world. [But] now we do. It's a real eye-opener for Minnesotans," he said.
If the disease spreads widely in wild deer, it has the potential to have a significant effect on hunting and natural resource management. According to the DNR, white-tailed deer hunting has an annual $500 million economic impact, much of it in rural areas. Olfelt points to Wisconsin as a cautionary tale: In some areas of the state, half the deer population is infected.
Management is key to containment
Chronic wasting disease is a degenerative brain disease that causes significant weight loss, changes in behavior, loss of bodily function and death in infected deer.
Olfelt said Minnesota's management strategy has been effective in southeastern Minnesota, where testing of wild deer indicates that the rate of infection is less than one percent of the population.
But as the disease spreads to more areas of the state, the management strategy becomes more difficult, time-consuming and more costly. The DNR spent $2.8 million on CWD surveillance last year.
In Beltrami County, the agency is working with the county to build a fence around the 10-acre site where the dead deer were dumped, in an effort to keep wild deer from coming into contact with prions that might remain in the soil.
"We are asking, if people see sick or dead deer in this area, we would like to get them tested as soon as possible," said the DNR’s big game program supervisor, Barbara Keller. "So we could get a few samples prior to this fall deer season. But our best way to get a large number of samples is through hunter harvest."
The DNR will ask hunters to provide samples so wild deer can be tested for CWD during the fall deer hunting season in Beltrami County. The state will coordinate the testing with the Red Lake, Leech Lake and White Earth bands of Ojibwe, because the infected site is on tribal treaty lands.
Officials say testing is a critical component of understanding the spread of the disease. It’s also key for public health: Officials caution people against eating infected deer. The Centers for Disease Control and Prevention says there is "no strong evidence for the occurrence of CWD in people," but adds that "experimental studies raise the concern that CWD may pose a risk to people and suggest that it is important to prevent human exposures to CWD".
The state Board of Animal Health, which regulates farmed cervids like elk and deer, is also concerned about CWD’s movement into northern Minnesota.
Under the regulatory body’s current rules, farms in areas where the disease is endemic in wild deer have restrictions on the movement of animals. But farms can be exempt from the rule if they take steps, such as installing double fences, to prevent nose-to-nose contact between captive deer and wild deer.
Assistant Director Linda Glaser said the agency recently tried to expedite a a rule change that would restrict movement of farmed deer from areas where the disease is considered endemic to areas where it is not, but an administrative law judge denied the request last month, saying the board did not prove that the rule was needed to “address a serious and immediate threat to the public health, safety, or welfare.”
The board instead will now proceed with implementing the rule through its standard rulemaking process, and is expected to approve a draft rule change at a special meeting in June, Glaser said.
"What we want to stop is that movement to other locations in Minnesota, outside of where CWD is found in the wild,” she said. “That's a really critical part."
As research improves our understanding about how the disease is transmitted, Glaser said, it will lead to a clearer understanding of which preventive measures are most effective. The Beltrami County infection is a case in point, she said, because infected animals came from a Winona County farm that had double fencing to prevent disease transmission.
“We just think that it's not prudent [to allow the movement exemption] at this time,” she said, “because we're learning more and more about CWD all the time, and we believe that somehow it's getting inside the fence, even though they may be preventing this nose-to-nose contact.”
She said the prions that cause the disease can also be spread by scavengers who feed on infected carcasses — and, of course, prions can move along with soil particles, after a sick animal has moved on or its body decomposed.
"All that information, you know, is coming out now to show us that there's just a lot more potential for it to move around than we previously considered," Glaser said.
And the disease is spreading faster.
“[Cases are] increasing in frequency, and we're seeing more infected animals in the herd,” she said. “I'm seeing an increase in speed and prevalence in CWD in Minnesota farmed cervid herds. I don't necessarily know the reason for that. I just know that we keep finding it more frequently. And that's certainly concerning.”
While the Board of Animal Health regulates farmed deer, the Department of Natural resources manages the disease in wild deer. There's long been tension between the agencies over how farms are managed.
A 2018 report by the state’s Office of the Legislative Auditor said Minnesota's chronic wasting disease regulations were among the most rigorous in the country, but it identified problems with the state’s disease monitoring.
The report found that, between 2014 and 2017, "about one-third of producers that reported dead deer or elk failed to submit tissues from at least one of those animals for CWD testing," as regulations require, and the Board of Animal Health staff did not systematically check whether farm operators followed the rule.
State officials say the farmer operating the Beltrami County farm where the disease was discovered clearly violated regulations by dumping dead, infected animals on public land.
As a result of tracing the movement of animals in the Beltrami County herd, Board of Animal Health investigators have identified potential spread related to captive herds in five counties and four states, and their investigation is ongoing.
"As a state, we need to move to a management strategy that is less reactive and more proactive and preventative," said DNR commissioner Strommen. "We've been reacting to specific sites. And I think it's clear as they continue to pop up, that we need a more preventative approach."
Strommen put no timeline on a revised regulatory approach, but said discussions are ongoing, and there are legislative proposals to change the management of farmed deer.
Strommen said a proactive approach needs to focus on oversight, inspection, and movement of farmed deer and proper disposal of dead deer. “Really making sure that we are on top of those things before we see CWD in farmed herds, and before it has an opportunity to potentially pass into wild deer,” she said. "I think we still have some work to do on getting a plan around that, but I think it's very clear that we need to do that quite quickly."
This is a developing story. Check back for more updates.
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