Chronic Waste Disease is a fatal neurological found in cervids (Deer and Elk). It is also known as transmissible spongiform encephalophathies (TSEs) or prion diseases. It shares certain features of other THEs, like bovine spongiform encephalopathy (Mad Cow Disease) or scrapie in sheep. CWD has been diagnosed in captive and wild free-ranging deer and elk. The known natural hosts of CWD are mule deer, whitetail deer, elk, and moose. CWD was identified in Colorado in the late 1960s and in the wild in 1981.
CWD occurs more in Colorado, Wyoming, Montana, Utah, New Mexico, Texas, North Dakota, South Dakota, Nebraska, Iowa, Oklahoma, Minnesota, Missouri, Wisconsin, Illinois, Michigan, West Virginia, Pennsylvania, New York, Maine, Alberta, and Saskatchewan. Surveillance shows studies of hunter-harvested animals indicate the overall prevalence of the disease on northeastern Colorado and southeastern Wyoming from 1996 to 1999 was estimated to be approximately 5% in mule deer, 2% in white-tail deer, and <1% in elk. Iowa has tested that over 42 thousand wild deer and over4 thousand captive deer and elk as part of the surveillance efforts since 2002. In Iowa all 99 counties were tested for the disease and the samples showed that nearest to areas where CWD has been detected in other states.
CWD is highly transmitted within deer and elk populations. The way that this disease is transferred is not fully understood. Research has shown that CWD may be transmitted by various means. Evidence supports the possibility that the disease is spread through direct animal-to-animal (contaminated feed and water sources). Or through contact with or ingestion of infected bodily fluids (saliva, blood, and urine). Prion from decomposing infected carcasses and bodily waste may remain in certain soils for many years and CA eradicated easily by environmental factors, heat or disinfection. Transmission by environmental contamination can be possible. This disease hasn’t been transmitted to humans yet.
To minimize the risk of exposure to CWD, hunters/trappers should consult their state wildlife agencies to identify the areas this disease is located. Hunters and others should avoid eating the meat of the infected animal, such as deer and elk that look sick. Hunters that harvest the deer in the infected locations may wish to consider getting the animal for CWD for consuming the meat (information on that are at your wildlife agencies). If you are involved in field dressing carcasses, you should wear gloves. You should also bone out the meat from the animal, and minimize handling the brain and spinal cord tissues.
Clinical features are adults 17 months to >15 years, mostly 3-5 years old. It’s both in male and female (elk & deer). There is not strict season for this disease; it goes mostly all year round spreading. The most obvious sign is weight loss over time, and gradual loss of body condition. In majority of cases behavior changes, like decreased interactions with other animals, listlessness. Lowering of head, blank facial expression and repetitive walking in set patterns. Excessive drinking and urination are common in the terminal stages. There is also excessive salivation, drooling and grinding of teeth. In elk there are behavioral changes, including hyper-excitability and nervousness.