Although the deer diseases Chronic Wasting Disease (CWD) was first identified in the 1960s and Epizootic Hemorrhagic Disease (EHD) has been around since the 1890s, it seems as though concern over the two has increased in the past decade. And in recent years, the push to track potentially sick deer has continued.
Some organizations say one or both diseases are the greatest threat to hunting deer, elk and moose that exist. Others question whether the issue has been irrationally overhyped. How much of a threat are CWD and EHD, really? What should hunters know? Let’s find out.
What is CWD?
CWD is a transmissible spongiform encephalopathy, also referred to as a prion disease. On the whole, prion diseases are rare. CWD specifically is contagious, fatal, and it causes a recognizable set of symptoms. Deer and other cervids with CWD don’t just lose mass and waste away, they exhibit other symptoms. These include drooling, staggering/ataxia, trouble swallowing and an extreme degree of thirst. That aspect tends to be accompanied by the expected excessive urination. Of course, it’s the weight-wasting feature of CWD that hunters tend to notice first.
What is EHD?
EHD is a hemorrhagic virus. Unlike the broader cervid spread of CWD, it’s usually found in Whitetail deer, although mule deer and antelope are sometimes diagnosed with it as well. It’s sometimes confused with BTV, blue tongue virus. The diseases are similar but not the same. EHD generally progresses a lot faster than CWD; in EHD, death can occur within 36 hours of the onset of symptoms.
EHD symptoms include a loss of natural fear of humans, overall weakness, drooling, and swelling of the head, neck, and tongue. Fever and increased respiration rate are also present. Fever is likely why many deer with EHD can be found attempting to cool off by lying in water. Deer with EHD usually die, but they don’t always. It is possible for deer to become infected and symptomatic, then recover and develop immunity.
Can Hunters Catch Them?
At this writing, there have been no cases of people catching CWD from infected deer. Similarly, there haven’t been any cases of people catching EHD from animals. That includes the midges Culicoides, bugs whose bites spread EHD in deer. They are not considered to be zoonoses (diseases that transmit from animals to humans).
You might still be wondering about eating meat from a potentially infected animal. That circles right back to the fact that there have been no recorded cases of CWD or EHD being transmitted from a cervid to a human.
Even so, the World Health Organization recommends against eating meat from an animal you know or strongly suspect is infected. Unlike some things that can be cooked out of meat, prions aren’t living and can’t simply be cooked to death. So, while there haven’t been any known cases of people getting these diseases from infected meat, the various health organizations fall on the side of being cautious.
Side note: If you’re also worried about your dogs or cats getting into infected deer meat, there have also been no reported cases of that happening. This is because the disease is specific to ruminants.
disease. PHOTO CREDIT: CORNELL WILDLIFE HEALTH LAB
How Common Are They?
Odds are that you’ve seen the websites and articles proclaiming CWD and EHD to be widespread emergencies that threaten the very face of hunting. In reality, the prevalence of diseases tends to be a regional issue. Major disease organizations agree that this is not truly a nationwide issue. That doesn’t mean you shouldn’t be aware of the appearance and symptoms in animals. As a deer hunter, it’s your responsibility to be aware of such potential issues so you can recognize them and report them as needed. Even though these diseases aren’t national problems today, that condition could certainly change.
So, which regions have the biggest issues? According to the Centers for Disease Control, the states with the heaviest occurrences of CWD, as of March 2023, include Kansas, Wisconsin, Nebraska, Montana, Missouri, Colorado, Wyoming and Illinois (among others). Yes, CWD incidents are heavily centered in certain western and midwestern/upper midwestern states. Other states, such as Texas, had seven reported cases; Washington State had none.
As for EHD, that disease is also found more commonly in midwestern states, though it has occurred in some other states as well (usually southeastern ones). Reports of EHD didn’t really ramp up until around 2018. They have been reported in many states including Pennsylvania, Kentucky, Delaware, New York, Connecticut, New Jersey and Ohio.
If you look at a map showing cases of diseased deer, you’ll notice the sites are centralized around specific areas. That doesn’t mean cases don’t exist elsewhere; it’s only that they’re far more unusual.
Are CWD and EHD Still Serious?
Whether or not CWD or EHD remains a big issue depends on whom you ask. Based on what several organizations say, neither disease is quite as severe an issue as they seem made to appear. That doesn’t mean the diseases shouldn’t be taken seriously or that they can’t have a devastating impact on wild deer.
No matter where you live, you should be able to recognize a sick deer, and if you live in an area with known outbreaks, you should certainly be paying close attention. That doesn’t mean you need to panic or worry that deer hunting as we know it is doomed. It’s not.
Where Did CWD Start?
It’s believed that CWD began to spread among captive deer on breeding farms (typically high-fence properties). The infected deer either break loose or are let out for hunts, and then spread it to the local wild deer population. Of course, it’s also possible for wild deer to get close enough to captive deer to catch a disease without the captive ones ever leaving their enclosure.
It’s possible CWD’s actual origins were elsewhere, but they were first recognized and diagnosed in captive herds of mule deer. (It’s worth noting that the first diagnosis in the 1960s was at a wildlife research center). Some believe the source within that facility was sheep scrapies, and that’s certainly possible.
Now, does that mean deer farms are to blame? No. Actually, wild deer with CWD have been found in states without any deer farms anywhere nearby. So, while cases of CWD have been seen on deer farms and many theories center around deer farms, no one will ever be able to pinpoint its source. Laser focusing on deer farms isn’t the answer.
What all this comes down to is that while hunters should be aware of the potential risks of CWD and EHD among wild deer, they needn’t have to obsess over it. Don’t let worries over CWD or EHD stop you from going hunting and filling your freezer with venison (which we think is pretty much the best meat in existence).
CWD and EHD are unlikely to ever disappear, but that doesn’t mean the diseases will cause the end of wild deer everywhere (or anywhere, for that matter). Despite wildlife biologists’ attempts to quantify the effects of those diseases, they haven’t been that successful in deducing whether the diseases have a noticeable impact on deer herds overall. Many assumptions are made, though.
Enjoy your hunt. If you see a sick deer, report it to your local wildlife agency. And if you end up taking a deer that you discover seems to have been ill, do the same and report it. But don’t let worry over these diseases ruin your hunts.
