Chronic Wasting Disease (CWD) was confirmed in White-tailed Deer in Wisconsin in 2002. The disease is caused by an unusual infectious agent called a prion. A prion is a protein that all vertebrates have but can exist in different structural forms (sort of like the transformer toys). The ‘bad’ form’ of prions can convert ‘normal’ prion proteins into more ‘bad ‘ form and thus makes fibrils that can clog neurons and cause nervous systems signs and symptoms such as instability. The disease is not caused by a true infectious agent because the protein itself is not replicated. Therefore, we say that the disease is caused by a transmissible agent rather than an infectious agent. Other transmissible prion diseases includes Bovine Spongiform Encephalopathy (Mad Cow Disease) and a number of other animal and human diseases. Much remains to be learned about this agent and how it causes disease.
A big question on some peoples’ minds is whether one can get a prion disease from eating venison. No conclusive evidence exists, that CWD can be readily transmitted to humans, although some scientists think that many of the prion diseases are in fact somehow related through transmission over from one animal to another. Some of these transmission mechanisms have been artificial such as feeding animal by-products to other animals. Recent studies have focused on the transmissibility and stability of this agent in the deer environment. We have recently learned that prions can be released in urine, saliva, blood, and feces of affected deer. It can be associated with water and feed troughs at feeding stations. Prions can be found in gut piles and carcasses of killed deer. All of these examples provide modes of transmission from deer to deer in the contaminated environment. It obviously can be isolated from nervous tissue such as brain but also has been detected in muscle seemingly normal freshly killed deer.
Prions are quite stable in the soil for 3 years or more. And because deer consume grams of soil for nutrients, normal grazing provides another way for them to acquire the agent. CWD has been shown to bind quite strongly to some minerals in the soil that may also provide protection for prion as it passes through the digestive tract of the deer.
A big question on some peoples’ minds is whether one can get a prion disease from eating venison. No conclusive evidence exists, that CWD can be readily transmitted to humans, although some scientists think that many of the prion diseases are in fact somehow related through transmission over from one animal to another. Some of these transmission mechanisms have been artificial such as feeding animal by-products to other animals. Recent studies have focused on the transmissibility and stability of this agent in the deer environment. We have recently learned that prions can be released in urine, saliva, blood, and feces of affected deer. It can be associated with water and feed troughs at feeding stations. Prions can be found in gut piles and carcasses of killed deer. All of these examples provide modes of transmission from deer to deer in the contaminated environment. It obviously can be isolated from nervous tissue such as brain but also has been detected in muscle seemingly normal freshly killed deer.
Prions are quite stable in the soil for 3 years or more. And because deer consume grams of soil for nutrients, normal grazing provides another way for them to acquire the agent. CWD has been shown to bind quite strongly to some minerals in the soil that may also provide protection for prion as it passes through the digestive tract of the deer.
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