The Lowdown on the Latest Deer Diseases

by Steve Sorensen (Originally published in the Warren Times Observer, June 8, 2013.)

HIV. COPD. EHD. CWD. Every day you’re bombarded by a blizzard of acronyms, many of them medical terms. We have too many to remember, and assigning them an alphabet soup of letters can make them scary. Like IRS. The four I named are all scary. The first two kill people. The last two kill deer – and hunters should know something about them.

You might be sick of acronyms, but every deer hunter 
should educate himself about deer diseases, especially CWD.

EHD

EHD is an acronym that stands for the tongue-twister Epizootic Hemorrhagic Disease, sometimes called Blue Tongue Virus (though Blue Tongue is a similar but slightly different affliction). EHD is carried by flying insects that bite – gnats, midges, and no-see-ums. Once bitten, it takes only a week for the deer to develop symptoms, which include internal hemorrhage, weakness, high fever, bruising, and shortness of breath. The animal dies within 8 to 36 hours. EHD affects ruminants (animals that chew their cud) – mainly sheep, cattle, goats, buffalo, deer, and antelope.

The fact that EHD is transmitted by flying, biting insects holds the key to the reason why it’s a localized disease. It’s seasonal, and less persistent in cold weather. It kills individual deer, but deer populations recover.

CWD

CWD is an acronym for Chronic Wasting Disease. It belongs to a class of diseases that include mad cow disease (big news in cattle herds in England a few years ago), and scrapie in sheep. These are diseases of the nervous system, and are caused by something you may not have heard of – prions. The word “prion” is a combination of the words “protein” and “infection.” In laymen’s terms we can refer to a prion as an infectious, mutated protein.

Simpler than viruses, prions don’t even qualify as living things, so it’s impossible to kill them. CWD affects cervids – whitetails, mule deer, elk and moose – by creating a network of lesions in neural tissue (brain, spinal chord, etc.) Ultimately the brain develops a sponge-like texture. It may take months or years for CWD to develop, and it can’t be diagnosed in a living animal. CWD is also untreatable and universally fatal.

Chronic Wasting Disease might be much more devastating than EHD, and its effects are likely to last much, much longer. Those two statements rest on the fact that the prion that causes CWD lasts almost indefinitely. It infects the soil where deer feed, and may even enter the plants they feed on. There’s even evidence that the prions can pass through an animal’s digestive tract and still remain infectious. And it doesn’t subside in cold weather.

Today, 21 states and two Canadian provinces have confirmed cases of CWD. At least 19 have confirmed cases in wild cervid populations, including Pennsylvania.  

Biologists have found no evidence that CWD is transmissible to humans. That’s the good news. We don’t know if CWD will reach epidemic proportions, but it’s serious enough that every hunter should know what it is and what he can do to help keep it from spreading.

Fortunately, we live in a day when information is readily available through the Internet, and most hunters can easily research the rules for the areas they hunt. Virtually all state game agencies publish what you need to know in their game regulations booklets, and on their websites. Two other websites with up-to-date information are www.knowcwd.com, and www.cwd-info.org.

You might be sick of acronyms, but every hunter should educate himself about deer diseases, especially CWD, and be an intelligent participant in the battle against it.