April 2018
From the State Vet's Office

What You Should Know About Chronic Wasting Disease

 

New testing equipment for CWD diagnosis has been received at the Alabama Department of Agriculture and Industries diagnostic lab.

A recent case of Chronic Wasting Disease in a free-ranging white-tailed deer in west Mississippi prompted me to write this article.

CWD is a malady found in cervids (deer, elk, moose) that is caused by a prion. We don’t write about prion diseases a lot because there are a limited number of those diseases. However, when a prion disease does infect an animal, that animal needs to get its affairs in order. It is most likely going to die. There is no vaccine or treatment for these diseases. Most infectious diseases are caused by bacteria, viruses or parasites. A few diseases caused by prions are bovine spongiform encephalopathy, scrapie in sheep, Creutzfeldt-Jakob disease in humans and CWD in deer.

A prion is a misfolded protein that usually affects the brain. Most prion diseases are spread by other animals consuming tissues or fluids from an infected animal, but the diseases can occur spontaneously when the offending protein gets folded wrong (whatever that means). The good news is that these prion diseases are usually pretty species specific (they do not usually jump from one species to another) and they do not spread quickly like fire on a dry sage grass field.

Since I have been employed by the Alabama Department of Agriculture and Industries, we have been involved in surveillance programs for BSE, scrapie and CWD. We have been working with the Alabama Department of Conservation and Natural Resources to conduct CWD testing on deer since 2002. This ongoing surveillance program has tested hunter-harvested deer, captive deer and suspect animals.

For a lot of years, the samples were tested at our diagnostic lab. However, the equipment became outdated, inoperable and just too expensive to replace. When we were no longer able to do in-house testing at our laboratory, we sent samples to an approved out-of-state lab.

Recently, through our partnership with ADCNR, we have worked to get new testing equipment. We now have that new equipment and dedicated personnel for CWD testing. We are waiting for the equipment to be validated by the U.S. Department of Agriculture, National Veterinary Services Laboratory. These tests are performed on brain tissue and lymph nodes. There is no test for CWD that can be done on a live animal.

CWD affects the nervous system of deer, elk, moose and other cervids. Because it affects the brain, there are neurological signs such as incoordination. The deer are often emaciated or excessively thin. And, although we have never had a deer test positive for CWD in Alabama, we recommend hunters not harvest deer exhibiting abnormal behavior or that do not appear to be in good health. We request you contact a local game warden if, while hunting or any other time of the year, you see a deer acting strangely. Also, we recommend you contact them if you harvest a deer that appears normal, but you find the internal organs do not look exactly right when you dress the deer.

There is an old saying that goes, "If you don’t want to find something, don’t look for it." There may be some truth to that, but eventually it will come back to bite you. Diseases have a funny way of flying under the radar if you aren’t looking for them. Then, when the disease gets picked up on the radar, it is much more difficult to deal with than if it were detected close to its introduction.

Closing out 2017, there were 186 counties in 22 states that had reported CWD in free-ranging deer. During February, a positive case was reported in extreme west-central Mississippi, now making the count 187 counties in 23 states. A 4½-year-old buck died and tested positive, being the first positive case in Mississippi. Before then, northern Arkansas was the closest cases of CWD to Alabama. We always felt like we had a pretty good buffer, but, with a positive case in Mississippi, it makes us slightly less comfortable.

Prion diseases do not drift on the wind or attach to people’s shoes or truck tires. If Alabama gets a case of CWD, it will be because it came from an infected deer or infected tissue from a cervid. ADCNR has tightened regulations now to prevent hunters from bringing back whole carcasses or anything containing brain or spinal cord from out of state. The meat must be deboned. There are some regulations applying to the cape and antlers. These regulations apply to whitetails, mule deer, elk and moose.

If you are going hunting out of state, go to ADCNR’s website or call their wildlife division to get the actual regulation. If you get in trouble, don’t go telling them Dr. Frazier said this would be OK.

After the Mississippi deer was reported positive, there were some not-exactly correct news reports. I believe reporters do their best, but they are incorrect when they indicate our cattle may be in danger because of CWD. In fact, it is completely incorrect. There are no cases confirming CWD affecting humans or cattle. There are some studies indicating some subhuman primates – monkeys and such – could be susceptible to CWD. And, again, that is not proven, just a suggested possibility. So, I guess, if I had a subhuman primate, I probably wouldn’t feed it deer, elk or moose meat. But on second thought, I won’t own a subhuman primate in the first place.

Finally, I want to re-emphasize that we are testing for CWD and our ability to test continues to get better and faster. We just want you to be educated about the disease. If I had my druthers, I would druther we just keep our surveillance program going and continue to report all results as negative. However, if that is not the case, I feel very comfortable our colleagues at ADCNR have a response plan to minimize damage to our deer population and the hunting industry.

 

If you have questions, don’t hesitate to call me.

 

Dr. Tony Frazier is the State Veterinarian for Alabama. You can contact him at 334-240-7253.