About 1 in 5 deer tested in the Devil’s Lake area, tested positive for CWD or Chronic Wasting Disease according to the most recent numbers. That’s a lot. So with deer gun season nearly upon us, it’s a good time to look a little deeper into CWD, what it means and what the numbers for our area are looking like.
Call this a “dummies” guide to CWD and Sauk County by the numbers, sort of post. The CDC describes Chronic wasting disease (CWD) as a prion disease that affects deer, elk, reindeer, sika deer and moose. CWD has been killing animals in the wild and on game farms. It was first discovered in captive mule deer in Colorado in 1967. Since then CWD has spread to 23 states and 2 provinces in Canada.
How does CWD kill? Well, Dr. Nick Haley wrote for the North Deer Farmer’s Association that CWD’s effects (Which is a brain-damaging disease similar to Mad Cow or Creutzfeldt-Jakob disease (CJD) in humans, are “…very similar to Alzheimer’s disease and other causes of dementia in people.” Infected deer will lose weight and show “obvious neurologic problems like aggression, inability to stand, or difficulty swallowing – symptoms mirrored by aging Alzheimer’s patients.” They will eventually die.
In researching for this article, one big surprise for me was what we are learning about how the disease is spread. I had heard CWD was thought to spread through feces, urine or saliva, animal contacts such as touching noses and maternal contact (mother to fetus). However, the CWD Alliance points out that It is not known exactly how CWD is transmitted. The surprise to me was that plants and even dirt could help spread the disease!
Dirt? It’s the prions… According to the CDC, “The term “prions” refers to abnormal, pathogenic agents that are transmissible and are able to induce abnormal folding of specific normal cellular proteins called prion proteins that are found most abundantly in the brain.” Well, that’s a mouthful, but the important bit is that a recent study showed that these infectious prion proteins could bind with plants and even dirt;
“Scientists already knew that these CWD prions are good at binding to soil, especially clay-based soils, and that they can persist there. Soto (Claudio Soto, Ph.D.,) said that when some of the soil where an infected dead animal had been buried was injected into research animals several years after it had been buried, the injected animals came down with prion disease.” – Food Saftey News
This bit really stuck out to me having found a “gut pile” (Discarded organs of deer left by hunters.) along the road at the Sauk Prairie Recreation area yesterday (Nov 7th) and another along the road here in Baraboo just this morning! Not only will this help to spread CWD, but it’s just gross as well. As you can imagine the Wisconsin DNR suggests other disposal methods!
Of course, the big question is; Can CWD pass through the meat to humans who eat it? The answer isn’t as simple as you might think. What we do know is that every conceivable test done so far seems to suggest that CWD won’t pass to humans, but there is one big caveat when looking at test results, the incubation period. Prion diseases have such long incubation periods that all the tests done to date may not be the final word. Claudio Soto, Ph.D., (Mentioned Above) a UTHealth researcher and lead author of an article about the topic published May 26, 2015, in Cell Reports is quoted in an article by Food Saftey News as saying, “…Even though there have been no confirmed cases of infections in humans from CWD, the public should know that “it’s a possibility that needs to be explored.” and “…these (CWD) prions are accumulating, and prions have a long incubation period — sometimes as long as 30 to 40 years in humans.” Certainly, it’s reasonable why some folks don’t want to eat CWD infected deer.
This, of course, is all background to my research into how prevalent CWD is the Devil’s Lake State Park region, especially with the annual Deer Gun hunt just a couple weeks away. The key is understanding the numbers. A popular way to present the numbers recently has been to combine total test results since testing began in 2002. Done this way, The report for Sauk County would read something like; Out of 15,883 tested, only 402 tested positive for CWD. Only about 2.5% positive. Sounds good. Still, look at the chart above from the Wisconsin DNR. You’ll see that since testing started in 2002, the number of samples taken has nose-dived while the number of positive results has climbed. So in 2016 when only 442 samples were taken, 90 tested positive! That is 20.36% or basically, 1 out 5 deer tested had CWD. So far in 2017, (Based on WDNR test results by county*) 10 out of 52 deer analyzed here in Sauk County showed positive for CWD. Again, about 20%.
Of course, everyone has to make their own choices about what is safe to eat and whether CWD is a health concern. The science isn’t clear yet and certainly, Wisconsin’s sample sizes are no longer adequate. It does seem that our part of the state is showing much higher numbers than elsewhere and the percentages are going up, but with so few samples and those from random, voluntary locations, anything could be argued or true for that matter.
One last thought. I was also looking into what happens when wildlife managers lose the “battle” with CWD. From what I could find, there seems to be a leveling off point around 40% out west. One report says that, In “Wyoming, where CWD has been endemic for decades, 40% of some herds are infected while white-tailed deer populations are declining by 10% per year.**” Even if you don’t care about deer as a food source and just enjoy seeing them in your backyard, those are some hard numbers to swallow.
Deer Gun hunting in Sauk County (Devil’s Lake Area) runs from Nov. 18 – 26th with another antler-less-only Holiday Hunt from Dec. 7 – 10.
I’ve provided a bunch of links below if you’d like to learn more.
- Cronic Wasting Disease – Wisconsin DNR
- *CWD Deer Testing Results by County, Sauk Co.
- Interactive CWD Positive Map – WDNR
- How Chronic Wasting Disease Kills Deer and Elk – NADeFA
- Cronic Wasting Disease Alliance
- ‘Surprising’ Discovery Made About Chronic Wasting Disease – FSN
- Cronic Wasting Disease – CWC
- People Who Eat Deer And Elk With Chronic Wasting Disease May Avoid Infection Because Of Species Barrier, Study in Monkeys Suggests – Science Daily
- ** Chronic Wasting Disease – Amidst the Gloom and Doom, There Are Things We Can Do – Minnesota Deer Hunters Association
- The First Five (or More) Decades of Chronic Wasting Disease: Lessons for the Five Decades to Come by M. W. Miller & J. R. Fischer
- Chronic Wasting Disease and Potential Transmission to Humans – (2004)
- Prions in Plants? New concern for chronic wasting disease
**Just a reminder, DevilsLakeStatePark.com is owned by Skillet Creek Media and is not associated with the Wisconsin DNR in any way. My opinions do not represent those of the park or the Wisconsin Department of Natural Resources.