If there’s one thing to take away from the Rosenmeier Forum Tuesday, Jan. 28, is that chronic wasting disease poses a formidable threat to the time-honored traditions of deer hunting and wildlife conservation.
And, according to Michelle Carstensen, a wildlife group leader with the Minnesota Department of Natural Resources, 60 years of evidence from ravaged areas like south Wisconsin and Wyoming serve to show nature can’t be allowed to go its own way, or the state of Minnesota risks a pandemic of generational proportions.
“They’ve done nothing,” Carstensen said of Wyoming, one of two early states afflicted with CWD, along with the more proactive Colorado. “You can see what has happened with the disease there compared to Colorado, the studies have documented the population level effects — they’re dying. I think the end game is the disease continues to increase in prevalence and spread overtime, and there is no silver lining or light at the end.”
Carstensen said the state of Wisconsin is looking at an infected rate of more than 55% among bucks and 35% among does in counties most affected by CWD, predominantly situated in the south-central portions of Minnesota’s next door neighbor.
She also noted southeastern areas of Minnesota are seeing escalating rates of CWD, but that central Minnesota — including Crow Wing and Aitkin counties, which have separately documented cases of both farm and wild infected deer since 2002 — does not have a visible epidemic yet, a clean record so far from 12,000 tissue samples harvested by hunters and taxidermists in recent years.
The general mindset people need to have is “prevention, prevention, prevention,” said Carstensen, who emphasized hunters have typically shown strong compliance in terms of mandatory carcass testing, restrictions on moving animal remains across state lines, bans on feeding and mineral salt blocks, using preapproved drop sites and other measures.
During a lengthy and comprehensive presentation on CWD, Carstensen was joined on stage by three other experts in Marc Schwabenlander, the chronic wasting disease research program and outreach manager at the Minnesota Center for Prion Research and Outreach; Linda Glaser. an assistant director of the Minnesota Board of Animal Health; as well as Joni Scheftel, who is currently serving as state public health veterinarian and supervisor of the Zoonotic Diseases Unit at the Minnesota Department of Health.
These experts spent more than two hours in an informative series of presentations to roughly 150 attendees of the forum, who engaged in a robust question and answer session afterward that addressed ways, or if, CWD can be prevented, as well as questions on how long it remains contagious or whether it can be transmitted to humans.
Fears of a local outbreak ignited after a CWD-infected deer was discovered near Merrifield Jan. 23 and confirmed Feb. 14 in 2019. The dead yearling doe was the first documented wild animal with chronic wasting disease in central Minnesota. In Aitkin County, an infected animal was discovered on a game preserve in 2002, while CWD-infected deer were first confirmed in Crow Wing County in 2016 on the 112-acre deer farm, Trophy Woods Ranch, less than a half-mile from the infected wild carcass discovered in 2019.
In response to the presence of CWD in central Minnesota, the DNR implemented a containment plan to eradicate and track CWD. Shortly after the discovery in the wild doe, 66 deer were killed by federal sharpshooters and hundreds more were killed and tagged by archers and firearms hunters in the fall across management zone 604, which encompasses part of the Brainerd lakes area.
Crow Wing County also established a carcass dropoff site at the county landfill in hopes of preventing further spread of the disease. None of the deer harvested in management zone 604 centered around Crow Wing County tested positive for CWD.
Efforts to contain CWD going back to its discovery in the mid-'60s are largely unsuccessful beyond eradicating enough deer to squelch little pockets of the outbreak before it can mature into a full-blown epidemic, Schwabenlander said. Unlike viruses, bacteria or fungi, CWD manifests in malformed proteins, or prions, which cannot be treated by virtually any traditional anti-pathogenic method and have been proven to be contagious years after the host animal died.
As it typically takes roughly two years for an infected animal to succumb to CWD and current technology can’t determine a positive diagnosis in living animals, detecting the condition in the local deer herd can be difficult, Scheftel said.
While there’s some reasons for optimism that new technologies to detect or combat CWD are around the corner — and being actively pursued by researchers at the University of Minnesota — the proven and time-tested solutions remain the best option, Schwabenlander said. This means hunters have to utilize caution when transporting any spinal or cerebral tissue, where CWD prions primarily reside and find their way back into the food chain upon decomposition.
Hand in hand with that, Glaser said management of game farms — where the disease was first documented in Minnesota, and attributed by DNR officials as the source of CWD in the wild in Crow Wing County — follows that vein. Captive deer are the most closely regulated animal in the state of Minnesota, Glaser said, while the interstate transport of deer is banned and animals currently housed are closely monitored, tested and subject to severe measures if CWD is detected.
On that note, Glaser said game farms are subject to federal buyouts and the Minnesota Legislature recently made it law that all animals on these farms must be eliminated, whether there’s an indemnity plan or not. While farms are already required to construct their fencing in a way that deters contact between animals, they are also required to properly seal the facility from outside animals for five years after the infected herd is euthanized.
As cases of CWD continue to mount across 26 U.S. states and three Canadian provinces, so do fears of CWD being transmitted to humans, noted Scheftel, who pointed to the advent of another prion-based neurological degenerative disease in mad cow disease in the mid-1980s.
While there are no documented cases of CWD infecting a human host, this prion disease is particularly hardy and adaptable — even compared to similar prion conditions like scabies in sheep, mad cow disease, or others.
With that in mind, Scheftel advised hunters to thoroughly avoid eating CWD-infected meat, just as it’s always practical to avoid eating unhealthy and sickly animals.
“This is going to take everybody’s working together,” Scheftel said. “This is not one person’s problem, or another person’s problem — this is all of our problem for everybody in the state of Minnesota.”