Colorado State University Extension
SafeFood Rapid Response Network


SAFEFOOD NEWS - Winter 1998 - Vol 2 / No. 2

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Chronic Wasting Disease

Several studies are currently taking place to research this disease. It is of particular interest to Coloradans as cases of chronic wasting disease have been confirmed among deer and elk since 1981. The current research in Colorado is looking at the possibility of chronic wasting disease being transferable to cattle.

What is it?

A "chronic wasting disease" has been diagnosed sporadically in wild mule deer, white-tailed deer, and elk in north-central Colorado since 1981. This disease causes damage to portions of the brain of deer and elk.

Affected animals show progressive loss of body condition, behavioral changes, excessive salivation, increased drinking and urination, depression and eventual death. Chronic wasting disease is fatal. The pathogen that causes this disease has not been identified.

Where is it found?

The distribution of chronic wasting disease in wild deer and elk in Colorado appears to be restricted to an area along the northern Front Range from the Wyoming border south to Lyons and east to Ft. Morgan. Most cases documented by the Division of Wildlife have come from the Estes Park vicinity or the foothills between Ft. Collins and Loveland.

Two cases have been documented along the South Platte River just southeast of Larimer County. Cases have also been documented in southeastern Wyoming. The disease seems to primarily affect deer, although several elk have been diagnosed with chronic wasting disease.

How often does it occur?

Chronic wasting disease is relatively rare. Less than 100 cases, mostly in mule deer, have been documented since 1981. Although the disease doesn't appear to be common, the number of cases detected has increased in recent years. This trend may be explained by increased vigilance by Division of Wildlife personnel and the public in reporting cases, but it may also reflect increased disease occurrence. The Division of Wildlife is currently conducting surveys in select Game Management Units (GMU's) to obtain better estimates of disease prevalence.

How is it transmitted?

Neither the agent causing chronic wasting disease nor its mode of transmission have been identified. Experimental and circumstantial evidence suggests infected deer and elk probably transmit the disease through animal-to-animal contact and/or contamination of feed or water sources with saliva, urine, and/or feces. Chronic wasting disease seems more likely to occur in areas where deer or elk are crowded or where they congregate at man-made feed and water stations. Artificial feeding of deer and elk may compound the problem--in recent years the disease has been most prevalent in areas in the Estes Valley where residents put out feeders to attract deer and elk. Although that practice has been specifically prohibited by regulations approved by the Colorado Wildlife Commission in 1992, many well-meaning individuals continue to ignore the law and may be exacerbating this problem.

Is it transmissible to humans?

According to experts and public health officials, there's no evidence that chronic wasting disease can be naturally transmitted to humans, or to animals other than deer and elk. As a general precaution, however, it's a good idea for people to avoid contact with any wild animal that appears sick.

Is the disease transmissible to domestic livestock?

According to experts, there's no evidence that chronic wasting disease can be naturally transmitted to domestic livestock. Chronic wasting disease is similar in some respects to two livestock diseases: 1) scrapie, which affects domestic sheep and goats world-wide and has been recognized for over 200 years, and 2) bovine spongiform encephalopathy (BSE), which is a more recent disease of cattle in the United Kingdom and other European countries. Though there are similarities, there is no evidence suggesting either scrapie or BSE are caused by contact with wild deer or elk.

What should a person do if (s)he sees a deer or elk that looks sick, emaciated or lethargic?

Call the Division of Wildlife at 970-484-2836 (Fort Collins) or 303-291-7227 (Denver); they will send someone to investigate. If the animal appears to have chronic wasting disease, field personnel will probably euthanize it in order to help prevent the spread of infection.

What precautions should hunters take when handling the carcass of a deer or elk?

There is no evidence that chronic wasting disease affects humans. However, the Division of Wildlife advises hunters to take simple precautions when handling the carcass of any deer or elk harvested in the units where CWD occurs. Wear rubber gloves when field dressing carcasses, minimize handling brain or spinal tissues and wash hands afterwards. Hunters should bone out carcasses or at least avoid consuming brain, spinal cord, eyes, spleen, and lymph nodes of harvested animals. Hunters should not handle or consume wild animals that appear sick, regardless of the cause.

Source: Adapted from Chronic Wasting Disease Facts, Colorado Division of Wildlife, November 17, 1997.

Updated Tuesday, March 26, 2013