BEMIDJI, Minn. -- Earlier this year, Beltrami County detected its first confirmed case of chronic wasting disease in a farmed deer herd.
Despite efforts to contain this rare yet highly contagious disease through quarantine and herd depopulation, the illegal disposal of infected carcasses on county land spurred additional concerns and assertive responses by local, state and federal agencies.
Last week, officials from the Minnesota DNR’s wildlife health and big game programs, along with partner representatives from the Minnesota Board of Animal Health and the University of Minnesota’s Center for Prion Research and Outreach, gathered to lead two public information sessions about Beltrami County’s current CWD status.
This included measures being taken to mitigate the disease, research being conducted to better understand it, and the steps deer hunters will need to take if hunting in Beltrami County once opening weekend kicks off Nov. 6-7.
What is CWD?
CWD is a neurological disease of the deer and elk family caused by misfolded proteins called prions and is always fatal. The disease, which was first identified in Colorado in the 1960s, can be spread by both direct (animal-to-animal) and indirect (environmental) contact with infected Cervidae.
“It’s important that we notice that (CWD) is caused by prions,” said Dr. Marc Schwabenlander, associate director of the University of Minnesota Center for Prion Research and Outreach. “It’s not caused by a virus or bacteria, which makes it very unique to wildlife disease.”
Prions can be shed through saliva, urine, blood, feces and antler velvet and are known to persist in the environment for up to 20 years. Carcass remains from a dead infected deer can serve as a source of further infection to other Cervidae and can also be spread by scavengers, water movement and people.
“There have been no confirmed cases of a person contracting a prion disease after ingesting a positive deer -- but there’s a huge ‘but’ after that. One thing that we can understand from a research aspect is that the species barrier is not solid."
-Dr. Marc Schwabenlander
“When that animal dies, that carcass is full of prions,” Schwabenlander said. “That misfolded prion is quite indestructible. . . . Our bodies and deers’ bodies cannot break down these misfolded prions and they keep building up, which causes progression of the disease. They’re hard to destroy in the body, but outside the body, they’re also hard to destroy.”
It may take over a year before an infected animal develops symptoms of CWD, which can include drastic weight loss (wasting), stumbling, listlessness and other neurologic symptoms. CWD can affect animals of all ages and some infected animals may die without ever developing the disease.
Additionally, consuming meat from CWD-infected animals is not advised, Schwabenlander said.
“There have been no confirmed cases of a person contracting a prion disease after ingesting a positive deer -- but there’s a huge ‘but’ after that,” Schwabenlander said. “One thing that we can understand from a research aspect is that the species barrier is not solid.
There’s some lab evidence -- at the level of a petri dish so to say -- that a deer prion can cause a human prion to misfold…but at this point, we don't know for sure if it can cause disease in humans.”
Beltrami County deer farm investigation
Dr. Linda Glaser, the assistant director of the Board of Animal Health, oversees the state’s Farmed Cervid Program and said Beltrami County’s first confirmed case of CWD was detected in a 3-year-old white-tailed doe at a Beltrami County farm in early April.
The herd was initially quarantined in October 2020 due to receiving 11 animals from a Winona County source herd that was linked to a Houston County CWD detection. These animals were considered CWD-exposed, leading to the quarantine. Among the deer received by the Beltrami County herd was the doe which tested positive for CWD, about 1-1.5 years after moving out of the source herd.
In May, 12 additional white-tailed deer tested positive for CWD in the infected Beltrami County farmed deer herd, five adult does and seven fawns. Earlier that month, the remaining 54 animals in the herd were depopulated by the USDA, and samples from each animal were collected and then tested.
However, during an inspection of the Beltrami County premises following the quarantine of the herd, a board agent discovered several adult deer and fawn carcasses had been moved by the owner to nearby county-managed tax-forfeited land.
Glaser said the herd owner violated quarantine by moving the carcasses off site without board permission. The board is now pursuing a court order for the herd owner to remedy conditions of dumping carcasses on county land.
Keeping deer out, not in
The illegal dumping prompted an investigation by the board, leading to collaboration with the Department of Natural Resources, Pollution Control Agency, tribal and local officials, among other agencies, to mitigate any potential spread of CWD from these carcasses.
Schwabenlander said in May his MNPRO team secured dumpsite carcass remains, soil, insects and plants for CWD testing. Through RT-QuIC testing, they identified CWD-positive bones.
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At least 19 CWD-positive deer remains have been confirmed in the area.
“We can learn a lot from this dumpsite. It’s an unfortunate situation, but from a research aspect, we can really learn a lot about CWD prions in the environment,” Schwabenlander said. “When we look at the ecological aspect of this environmental contamination, some of those initial soil samples that we tested were also CWD positive.”
Because test results indicated CWD-causing prions are on the site, the Minnesota DNR began constructing a 10-foot-high, 120-foot-wide deer exclusionary fence in June that would prevent wild deer access to the site and reduce the risk of prion exposure.
Infected deer carcasses had been spread across multiple acres by scavengers, so the fence was to encompass approximately 12 acres of land. Blane Klemek, the assistant regional wildlife manager of the Minnesota DNR northwest division, said the fence was constructed to last 20 years with the DNR absorbing the cost of construction -- about $194,000 -- and maintenance.
“When we found out these carcasses were dumped on Beltrami County land illegally, we had a discussion, as DNR employees, because this is something we had never faced before,” Klemek said. “We had an idea that maybe it would be a carcass pile and we could just scoop them up and take some soil with it… but it was forested so taking and removing soil where these bone fragments were wasn’t going to be a possibility whatsoever.
So the fence became a reality. We were going to have to build a fence around this to keep deer out, not keep deer in.”
The fence was finished in August, and Klemek said about $9,000 was reimbursed to Beltrami County for lost revenue of timber, as the site was an “income-producing forest” for the county. He said nothing -- not even trees -- can be removed from the area because it creates a risk for spreading prions.
In the coming years, the Bemidji and Park Rapids DNR staff will have to monitor vegetation growth around the fence and most likely do a chemical application to keep woody vegetation from growing close to it, Klemek said.
The area will also play host to an ongoing CWD study that Schwabenlander and his associates are conducting.
“We’re looking at multi-year research in the area,” Schwabenlander said. “We want to understand the extent of this contamination inside the fence, around the fence, outside of the fence and the fate of those CWD prions in the environment.”
Hunting in Beltrami County
This fall, the DNR is following its CWD response plan and is planning to test hunter-harvested deer to understand whether CWD is in wild deer in the Beltrami County area.
CWD surveillance is occurring in six areas of the state this season. Parts of Beltrami County fall into a DNR-designated CWD surveillance zone, meaning hunters will be required over opening weekend, Nov. 6-7, to provide sampling for any deer they kill -- except fawns.
After opening weekend, appointments will be available for hunters to get their deer tested at any one of the DNR’s 21 CWD stations. Hunters should visit the DNR’s webpage or regulations booklet for locations. Tribes will also be coordinating with tribal hunters for sampling.
“The clock has now just started for a three-year precautionary testing phase,” said Michelle Carstensen, wildlife health program supervisor for the DNR.
Carstensen said hunters should know and expect the following for CWD testing of their deer:
Where test stations are. They should decide if they want to do drop-box or in-person testing.
The location of their hunting area and what day it occurred. They will be asked to provide their contact information as well.
DNR staff will take two lymph nodes from the neck of the deer. It is helpful if the deer’s head is facing the back of the vehicle for easy access, or with the head towards the truck tailgate.
There is a taxidermist network in place working with the DNR to take samples, with a list available on the DNR website. Carstensen said the DNR wants hunters to still have their trophies and will not damage a hide that will be mounted.
Along with getting deer tested, Carstensen recommends that hunters consider disposing of carcasses in a disposal stream destined for a landfill. Carcasses should not be moved out of an area and discarded on the landscape in a different area. However, carcasses not detected for CWD can safely be deposited on the landscape. She said Polk County Landfill is accepting deer carcasses.
To help reduce the CWD risk to the wild deer population, she also recommends not feeding deer and encourages residents to report observations of sick wild deer to their local wildlife office by calling (218) 732-8452.
“It would be good not to throw your carcass remains on your back 40 until your results come in,” Carstensen said. “Because, if for example, you end up with a positive carcass we would like to collect that from you.”
According to Barb Keller, big game program leader for the DNR, there will likely be an expansion of a deer feeding ban in Beltrami County and surrounding areas this winter.
“Feed is especially problematic because we have deer coming into a very small point source on the landscape depositing saliva, feces and urine -- all things we know that transmit prions so that can be particularly problematic for disease spread,” Keller said.
If no wild CWD-positive deer are detected during the surveillance period (and sampling is adequate) the response will conclude. But if CWD is detected, the DNR resets the surveillance clock and various new guidelines are put in place, such as:
A new management zone is likely determined.
Deer attractant bans added to the feeding ban.
A late CWD hunt in December depending on the timing of infection discovery.
Targeted culling in January through March (scope depending on a number of positives).
Increased bag limits, hunting opportunities and carcass movement restrictions in fall 2022.
For more information about CWD hunting regulations in Beltrami County and the state, visit the DNR website at www.dnr.state.mn.us/hunting/deer/index.html.
CWD remains a rare disease in Minnesota with prevalence relatively low (under 1%) and confined mostly to the southern part of the state. More than 90,000 deer in Minnesota have been sampled since 2002, with 115 positive cases.
Keller said the infection appears to be persisting in the Preston-Lanesboro area and spreading outward in the state. She said CWD prevalence in 2020 was only slightly higher than in 2019, but there has been no significant increase over the past four years.
“One of the most important things with this disease is to find it where it exists as early as possible in the infection process,” Keller said. “Wisconsin has had this disease for quite a long time. In the core area of Wisconsin, they have prevalence rates of over 50% adult bucks that test positive for the disease. So we are nowhere near that in southeastern Minnesota, and we will keep it that way. It points to the management we've been doing on the ground to keep that prevalence low.”
In Beltrami County, the DNR hopes their response plan has been initiated in time to prevent a wild CWD infection. But they say they can’t effectively respond to the risk of the disease without help from hunters and landowners.
“It’s unfortunate that this disease arrived in this area, but we’re working hard to try to mitigate that,” Carstensen said. “We hope we’re making steps that prevent a wild infection from happening -- and that it hasn't already happened. We want to effectively respond to this, and we can't do it without cooperation from our hunters and landowners. So we’re all in this together to keep a healthy deer herd.”