On January 12, 1967, Chronic Wasting Disease was first identified in Colorado in a captive deer herd. It was later detected in free-ranging deer in 1981. The disease subsequently spread to surrounding areas of northern Colorado and southern Wyoming by the 1990s. It has continued to spread and is one of the most concerning and challenging natural resource issues facing wildlife professionals today.
What is Chronic Wasting Disease?
Chronic Wasting Disease (CWD) is a neurological disease of deer, elk, and moose caused by infectious, misfolded proteins called prions. Because of the abnormal shape, they aren’t recognized and destroyed by the body when needed so they stack up in clumps in brain and nervous system tissue and kill the surrounding cells. Microscopically, this gives the brain a spongy appearance which is why it’s categorized as a transmissible spongiform encephalopathy (TSE). Other, more familiar diseases such as bovine spongiform encephalopathy (or “mad cow disease”) and scrapie, which is found in domestic sheep and goats, are also TSEs. TSEs are progressive neurodegenerative fatal disorders.
What are the symptoms?
After an individual deer contracts the disease, it can take over a year before symptoms begin to develop. Symptoms will include dramatic weight loss (wasting), poor body condition, subtle head tremors may occur, head and ears may be droopy, and, in the last stages, it is not uncommon for the animal to have excessive drooling. These symptoms alone cannot be used to diagnose the disease. In order to confirm infection, the brain must be examined microscopically forspongiform lesions.
How does it spread?
The disease is transmitted through direct contact with body fluids (blood, saliva, feces, urine) infected with prions. It can also be passed indirectly in the environment through contaminated soil, food, or water. CWD prions are very contagious and once established, the disease is practically impossible to get rid of. The prions or disease agents can persist in the environment for long periods of time, so even after an infected animal has died, other animals can still contract the disease from the contaminated area for years.
Is there a cure?
There are no treatments at this time and the disease will always result in the death of the infected animal. There are also no preventative vaccines to protect healthy individuals.
Is it transferable to humans?
Currently, there is no evidence to suggest that humans are at risk of contracting the disease. However, as the potential health risk is continuing to be evaluated by public health officials, it is strongly recommended that exposure to infectious materials be avoided. The Center for Disease Control advises not to consume the meat of a known positive animal. Also, when field dressing or processing deer, elk, or moose in areas where CWD is known to exist, precautions should be taken. Hunters are recommended to wear latex gloves when field dressing. It is also recommended to bone out the meat and not to saw through bones. Also, avoid cutting through the brain or spinal cord and handling of these tissues. It is advisable to not consume the brain, spinal cord, eyes, spleen, tonsils, and lymph nodes of any harvested animal. Hunters should thoroughly wash their hands and instruments after cleaning their harvest. Another suggestion is to have your animal tested if it was harvested in a CWD known area. If you choose to have the meat processed professionally, it is recommended that the meat be processed separately without the addition of meat from other individual animals to yours.
Where does it currently exist?
As of August 1, 2018, the CDC reports that based on the best available information from multiple sources, 226+ counties across 26 states (including TN) are reported to have CWD in free-ranging deer, elk, and moose herds. For a more complete list of the infected areas, please visit https://www.usgs.gov/media/images/distribution-chronic-wasting-disease-north-america-0. The disease has also been confirmed in many captive herds, two Canadian provinces, Norway, Finland, and a few imported cases in South Korea. Because the disease is extremely difficult to detect when first introduced and at low prevalence, there is a possibility that the disease has already spread to additional areas, especially where monitoring and testing efforts are limited. Once established, however, the disease agent may remain in the environment for many years and continued expansion of infection to other areas is likely.
How can it be prevented from coming to Georgia?
The movement of live animals is one of the greatest risk factors for introducing CWD. Because there is no live test available to check for CWD in deer, deer movements pose a high risk for moving animals that may be shedding prions but not yet showing symptoms of the disease. As such, the live importation of all deer species from other states has been prohibited. Additionally, Georgia hunters hunting in CWD positive states may only bring home boned out meat, hides, cleaned skull plate with antlers attached, elk ivories, and finished taxidermy mounts. All other carcass parts must be left behind. While the requirement applies only to CWD positive states, this is a good practice to follow no matter what state you’re hunting. Actions that increase the transfer of saliva among deer, such as supplemental feeding, should also be discouraged or minimized. Although we have not detected the disease in Georgia, it is possible that it could exist and has not been found yet. Feeding deer increases the possibility of direct contact with an infected individual or the body fluids of that animal, particularly saliva. Feeders that spread feed, such as spin feeders pose less risk of saliva transfer than trough style or gravitational feeders. Although CWD prions can be found in the urine of infected animals there has been no documented spread of the disease through use of natural deer urine attractants. However, to minimize the potential risk of spreading the disease in this manner, only natural urine products bearing the Archery Trade Association Deer Protection Program Checkmark or synthetic urine products may be used.
What should I do if I suspect an animal has CWD?
If you believe an animal to be infected with CWD or another wildlife disease, please report all cases to 800-241-4113.
CWD is a fatal neurological disease found in deer and elk. It is caused by infectious proteins, called prions. Georgia hunters and DNR need to do everything possible to keep this disease out of Georgia.