Understanding CWD in Montana

By Angie
Wetherell
Earlier this year Mon-tana FWP announced that Chronic Wasting Disease (CWD) had been con-firmed in Montana. Alt-hough no cases have been identified in northwest Montana to date, FWP is taking the treat very seri-ously throughout the state.
Most of Montanans have heard of Chronic Wasting Disease but, do you know the in depth analysis of what causes it? How it affects the wildlife herds? How it could af-fect you?
Chronic wasting dis-ease is a progressive dis-ease affecting the central nervous system of deer, elk and moose. It is caused by an infectious prion protein. Prion is an abbreviated term that stands for “proteinaceous infectious particle.” Pri-ons are normal proteins found in the brain and nervous system that go rogue. In order for pro-teins to function properly they must be folded a cer-tain way. When a prion takes over a normal pro-tein, it destroys the fold but, not the biological structure. The slow de-generation that occurs in the brain takes years and leads to neurological dis-ease and death. Although scientists have yet to de-termine the actual func-tion of prions, most mam-mals, birds and reptiles have them.
Chronic wasting dis-ease was first discovered in the late sixties in mule deer in Colorado in re-search facilities. The first case discovered in the wild wasn’t until 1981, though researchers be-lieve it may have existed long before then. Con-tamination is spread in several ways, 1. Deer to deer contact. 2. Saliva, feces and perhaps urine. 3. Contaminated soil from saliva, feces, etc.
Studies have shown that contaminated soil from infected carcasses still held the active prion two years later. CWD is now recognized in 23 states.
Clinical symptoms of CWD may take up to a year or more to manifest after exposure. In the ear-ly stages it is impossible without lab work to de-termine if an animal is infected. Late stage symp-toms include drastic weight loss, lack of coor-dination, listlessness, ex-cessive thirst or urination, aggression, and/or a lack of fear of people. These symptoms are often diffi-cult to identify in the wild and because of the slow progress of the disease, infection rates may be higher than anticipated. Most states that show active results for CWD have seen at least a 20% – 30% decline in their deer populations.
A study that began in Canada in 2009 recently announced the cross con-tamination of the patho-gen after feeding primates the infected meat of a deer. Two out of five mon-keys developed symp-toms of CWD and a third died after ingesting parts of an infected deer’s brain. The brain and spi-nal cord was observed to have lesions. It is the first known occurrence of the pathogen crossing the species barrier.
There is no evidence, currently that CWD is transmissible to humans. However, the Centers for Disease Control and the World Health Organiza-tion have recommended to never ingest meat from animals that appear to be sick or are known to be from a CWD positive area. The Centers for Dis-ease Control and Preven-tion recommends hunters who have harvested a deer, elk, or moose from a known CWD-infected area have the animal tested prior to consuming it. If hunters harvest an animal that appears to be sick, the best thing to do is con-tact FWP and have the animal inspected.
Some simple precau-tions should be taken when field dressing deer, elk or moose. Wear rub-ber gloves and eye protec-tion when field dressing. Minimize the handling of brain and spinal tissues. Wash hands and instru-ments thoroughly after field dressing is complet-ed and avoid consuming brain, spinal cord, eyes, spleen, tonsils and lymph nodes of harvested ani-mals.
Last month, Sen. Jon Tester introduced legisla-tion to allocate $60 mil-lion nationally to help state and tribal wildlife management agencies fight the spread of Chron-ic Wasting Disease, and Montana FWP is conduct-ing a special hunt in Car-bon County, to gather da-ta on CWD. For more information please visit fwp.mt.gov or contact your local office.