Chronic Wasting Disease
Understanding the landscape of Chronic Wasting Disease in Michigan’s deer population
What is Chronic Wasting Disease
Map of CWD surveillance in Michigan
Chronic Wasting Disease or CWD is a prion disease that affects deer, elk, and moose. Prion diseases, like CWD, cause damage to the brain and central nervous system and lead to deterioration of body condition, behavioral changes, excessive salivation, and eventually death. As of right now CWD has only been shown to affect deer population, and does not seem to infect humans (CDC 2021), but there are other prion diseases like bovine spongiform encephalopathy (Mad cow disease) or Creutzfeldt-Jakob disease which do infect humans. Prion diseases like these have never been cured, and anyone infected eventually died as a result of their disease. Since 2015, 253 deer in Michigan have tested positive for CWD. Most of these cases are focused around the mid-lower Michigan.
How CWD affects people physically and with regulations
Photo taken at a deer sanctuary in the Upper Peninsula
- Like said previously, CWD has not been found to be infectious to humans, but that does not mean that the issue should be ignored or be not of importance. While prion diseases are inherently different from other diseases like bacterial or viral, there are many examples of diseases crossing from one species to another. Maybe the most famous example being rabies.
Warning: The paragraph below has a photo attached that shows two deer that have been harvested.
How CWD affects people physically and with regulations Cont.
- Regulation related to CWD has been a decisive issue. Since the discovery of CWD in Michigan deer populations, the DNR has enacted regulations that make the lives of hunters more difficult. The two main regulations enacted because of CWD are related to transportation of deer carcasses and baiting. (DNR 2024) For counties that have had previous cases of CWD, transportation of deer carcasses is tightly controlled when leaving that county. Essentially, to transport a harvested deer across county borders, all meat must be deboned and not be attached to any part of the head or spinal column. There are exceptions if you are taking the harvested deer to a processor or taxidermist. The other main issue being baiting. Baiting is entirely illegal in the lower peninsula, with no exception.
Two deer that were harvested last year with tags on their antlers
The potential of an outbreak of CWD
- A paper recently published on the ecological modeling of CWD has brought some potential good news related to an outbreak of CWD. In short, the ecological model found that more often than not, infectious deer were dead before they were able to transmit CWD to other deer in the population (Hanley 2022). Meaning, that most of the time, when there was no interference, CWD would not be able to infect deer after deer leading to an outbreak. When combined with the fact that deer infected with CWD often act differently from healthy deer, it is relatively safe to say that in untouched deer populations, CWD is unlikely to spread.
Distributions of all CWD cases reported in North America
What people can do to limit the spread of CWD in deer
- The most important thing people can do to limit the spread of CWD is follow regulations set in place by the State and DNR. These are explicitly in place to prevent the spread of CWD in the deer population, and prevent CWD from being spread to places that it was not previously. This is what the transportation or baiting regulations are for. Baiting is especially important, as it confines deer to a specific location. It can cause deer, that otherwise would not, to be in close contact with each other. As said in the slide before, because of the nature of the prion disease CWD, in natural untouched habitats CWD really can’t spread aggressively and lead to an outbreak. An increase in CWD cases would almost certainly be caused by human interference. These regulations are there to help prevent people from making that interference.
A photo of the sun rising while hunting last November
References
New York State DOH. Chronic Wasting Disease (CWD), Nov. 2011, www.health.ny.gov/diseases/communicable/zoonoses/cwd.htm#:~:text=CWD%20is%20a%20disease%20found,changes%2C%20excessive%20salivation%20and%20death.
DNR. “CWD Hunting Regulations.” SOM - State of Michigan, 2024, www.michigan.gov/dnr/managing-resources/wildlife/wildlife-disease/disease-monitoring/cwd/cwd-hunting-regulations.
Hanley, Brenda. Carstensen, Michelle. Et. al. “Informing Surveillance through the Characterization of Outbreak Potential of Chronic Wasting Disease in White-Tailed Deer.” Https://Www.Sciencedirect.Com/, Elsevier, 24 June 2022, www.sciencedirect.com/science/article/pii/S0304380022001648#sec0003.
CDC. “Chronic Wasting Disease (CWD).” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 10 Sept. 2021, www.cdc.gov/prions/cwd/index.html.