Chronic Wasting Disease - CWD

Chronic wasting disease is also known as CWD. It is a transmissible disease also called a TSE, or transmissible spongiform encephalopathy. CWD occurs in deer, elk, and moose. Found mostly in adult animals, it is a progressive disease and is always fatal. The disease was first found in northern Colorado in 1967. In 1978, it was identified as a TSE. The disease continues to spread, and is now known to exist in 12 states and 2 Canadian provinces. CWD is chronic weight loss, and is always followed by death.

Chronic wasting disease (CWD) has many signs and symptoms. The most common and noticeable sign is weight loss. Behavioral changes are another sign. The majority of behavioral changes include decreased interactions with other animals, listlessness, head lowering, a blank facial expression, and walking in a set pattern continuously. Behavioral changes in elk are notices as hyperexcitability and nervousness. The animals that are infected do not eat as much hay, but will continue eating grain. Other signs include increased urination and liquid consumption, grinding their teeth and salivating more than normal. During necropsy, or postmortem examination and testing, gross lesions are found as signs of CWD. The actual cause of death can be aspiration pneumonia. Lesions caused by CWD in the central nervous system (CNS) look like those of other TSE's and are found under a microscope. Immunohistochemistry is another type of test that is ran on brain tissue, used to find abnormal prion protein, which is another sign of CWD.

A prion is an abnormal form of a normal protein, also called a PrP, or prion protein, which is located in the CNS. It can spread to the peripheral nervous system (PNS). This causes the muscle or meat in the deer and elk to become infected. The bad prion protein infects the animal by changing the normal protein to an abnormal form. CWD is transferred between animals. It can also be spread from feed and water that has been contaminated by an infected animal.

Elk, mule deer, white-tailed deer, black-tailed deer, and moose are animals that are affected by the disease. Hunters should take precautions with animals taken from the affected areas. The animals harvested from these areas should be taken in to be tested before being used for consumption. Hunters should always wear rubber gloves when field dressing any animal, taking special precaution with hoofed animals. If your harvested animal does test positive for CWD, avoid eating any of the meat. Taking these precautions can lessen your chances of exposure to the disease.