5 Reasons to Get Your Deer Tested for CWD

December 4, 2023 By: Dr. Jenn Ballard

Should you test your deer if you hunt in a chronic wasting disease (CWD) management zone? Do you test it even if you don’t hunt in a CWD zone? Will your fellow club members be mad at you if you get a positive result? Is it better to know, or is ignorance bliss? As a wildlife veterinarian, I talk to a lot of hunters about CWD, and I try to answer their questions. Inevitably, the conversation comes around to the question of CWD testing. 

As a deer hunter myself, I know the biggest problem with CWD testing is it requires us to do more. It adds extra steps to our well-formed traditions, and we’re all creatures of habit. The temptation to keep doing things the way we’ve always done them is real, but when it comes to CWD, it’s time to decide if we’re going to be part of the problem or part of the solution. 

Deer hunters around the country hold the power for both management and surveillance of this disease and, as a result, hold the future health of our deer herds in their hands. If you’re still not convinced, let me give you five reasons I believe every hunter should be testing their harvested deer for CWD.

1. Early and Ongoing Detection of CWD Is Critical

Based on surveys in my home state of Arkansas, hunters report the most common reason they participate in voluntary CWD surveillance is a desire to contribute to wildlife management and conservation, and that fact alone fills me with hope. Testing your harvested deer for CWD is citizen science in action. It’s the only way to efficiently gain the information necessary to direct science-based management. 

CWD is a slow-moving disease with a patchy distribution across herds. This makes it very difficult to detect while the prevalence is low. As prevalence climbs, the negative impacts of the disease on a deer population begin to set in. Changing harvest strategies is one of the few tools we currently have to suppress disease prevalence and stave off damage. 

The caveat is that these strategies are most effective when they are implemented early. That’s where hunter surveillance comes into play. Conservation agencies can’t hope to accomplish the kind of robust surveillance necessary for early detection and management without help from the folks who have their hands on the most deer. Even after CWD management is implemented, continued surveillance is necessary to measure its effectiveness.

State wildlife agencies fighting CWD, like the Arkansas Game & Fish Commission, provide numerous ways for you to get your deer tested in and outside of CWD zones, including no-cost self-service drop-boxes like this one. Hunters can leave deer heads or lymph nodes in these freezers. Photo: Mike Wintroath, AGFC.

2. Knowing Your Local CWD Status Helps You Fight It Where You Hunt

Another important benefit of CWD testing is to help you manage the lands you hunt and the deer on them in ways that reduce the risk of this disease to the population. Testing animals harvested where you hunt is the best way to know your local CWD status and to inform your management approach.

CWD is a prion disease caused by an abnormally folded but highly stable protein. It accumulates in the tissues of infected animals and is shed through urine, feces, and saliva. CWD prions can be deposited in the environment from these excretions or in the tissues of dead deer. Once in the environment, CWD prions remain infectious to other deer for many years, potentially even decades. 

You can reduce the risk of CWD being introduced to lands you hunt by avoiding high risk activities, such as releasing live deer from other locations, depositing body fluids from unknown animals as attractants, and discarding waste from deer harvested outside of the immediate area

If the disease is already present, artificially congregating deer can be a recipe for increased disease transmission. Supplemental food or mineral sources cause deer family groups to intermingle and congregate in potentially contaminated environments. Sick deer may also be attracted to these easy food sources. 

Unfortunately, extra nutrients won’t help animals recover from CWD nor is there evidence that supplementation can prevent new infections. If CWD is detected where you hunt, your best bet is to avoid encouraging unnatural congregation. Cover old feeding and mineral sites with fresh soil, and focus your management efforts on developing habitats that provide high-quality forage and encourage natural behavior – consider thinning timber, prescribed burning and planting forage. 

3. Most CWD-Positive Deer Look Healthy

CWD has a long incubation period, referring to the length of time between initial infection and obvious disease. For deer, this can stretch out 12-18 months, followed by a relatively short period of illness and then death. This means that the majority of animals with CWD on the landscape at any given time look perfectly normal

There are also other diseases of deer that can mimic the signs of CWD. Testing sick and abnormal animals may help with general surveillance, but it is never recommended to eat obviously sick animals even if they test negative for one particular disease.

It is true that older age class bucks tend to have a higher prevalence of CWD than other segments of the population. For this reason, conservation agencies sometimes focus their surveillance efforts on old bucks to be efficient. However, there is still value in testing other deer. Not every population follows this trend in disease distribution, and even when prevalence is higher in bucks, the difference between bucks and does may be as small as a few percentage points. Regardless of age, sex, or apparent health, the only way to know if an animal has CWD is to test it with a valid diagnostic test.

In Arkansas, deer hunters usually get CWD test results back in two to three weeks during the peak of deer harvest, faster at other times. Here, a lab technician scans samples of lymph nodes submitted for CWD testing at an Arkansas Game & Fish Commission laboratory. Photo: Mike Wintroath, AGFC.

4. Minimize Your Own Risk 

While I don’t work for a public health agency, I think it’s important that hunters know the facts about CWD and human health so they can make informed decisions when handling their harvest. To date, no cases of CWD infecting a human have been detected, and after decades of potential exposure, that’s a very good thing. Nonetheless, the public health and prion research communities widely acknowledge that there is still uncertainty about this issue. Much of that uncertainly comes from experience with other prion diseases. 

First, there was scrapie, a prion disease of sheep and goats that has been recognized since the 1700s and has never been detected in humans. Then Bovine Spongiform Encephalopathy, the so-called “Mad Cow Disease,” emerged, and a small proportion of people exposed to that prion pathogen developed a fatal disease known as variant Creutzfeldt-Jakob disease. 

So why do some prion diseases spillover from animals to humans while others do not? The answer is most likely a combination of prion strain characteristics, human genetics, and routes of exposure. While the risk of CWD infecting a person is considered very low, experts generally agree that it is wise to minimize human exposure to animals with prion diseases. The CDC recommends testing all deer harvested in known CWD affected areas and not consuming those that test positive.

5. Protect Our Conservation Legacy

Deer are not likely to go extinct from CWD, but it is increasingly clear that this disease has and will continue to change the way we manage our deer resources. More herds are going to be affected by CWD, and those with a high prevalence will become more common. These populations will change whether we want them to or not. 

The temptation to keep doing things the way we’ve always done them is real, but when it comes to CWD, it’s time to decide if we’re going to be part of the problem or part of the solution. 

Without active intervention, deer population dynamics will shift, populations will become less resilient, and sick deer will become increasingly visible on the landscape. Sick deer in grocery store parking lots and news reports about zombie deer diseases will do nothing but undermine public perceptions of deer and deer hunting. 

By avoiding the issue of CWD management or kicking it down the road for future generations, we do a disservice to the resource we claim to love. If we hope for a better outcome, now is the time for hunters, researchers, and wildlife managers to work together to slow the spread of this disease, control it where we can, and support the development of new management tools. 

Participating in CWD surveillance is the first critical step hunters can take to lay the groundwork for a better future. It’s time to ask ourselves what our conservation legacy is going to be and if we’re willing to make the changes necessary to protect it.

About the Author: Dr. Jenn Ballard is the State Wildlife Veterinarian and Assistant Chief of Research for the Arkansas Game and Fish Commission. Jenn is a certified wildlife biologist and licensed veterinarian who specializes in applying health and disease concepts to free-ranging wildlife management. She is a native Arkansan and avid hunter living a field-to-table lifestyle with her family in the Ozark foothills.