 |
The Spread of Chronic Wasting Disease in American Deer and Elk: 1969-2002 |
Chronic Wasting Disease (CWD) is one of the transmissible spongiform encephalopathies (TSEs), a group of chronic, degenerative diseases that affect the central nervous system and erode brain tissue. Like "Mad Cow Disease" (bovine spongiform encephalopathy - BSE), CWD is most likely caused by the activity of a deviate protein molecule called a prion. However, unlike the cattle and sheep forms of the disease, BSE and scrapie, there are no statistics that would link CWD to animal feed contaminated by insufficiently treated material from other animals. And, unlike BSE and despite much concern, there is as yet no firm evidence that consumption of meat from CWD infected animals can lead to new forms of human infection. The recent discovery by Dr. Stanley Prusiner of prions in the muscle tissue of laboratory-infected mice, even though his findings have not been corroborated by tests on naturally infected livestock, will undoubtedly lead to more focused research into the possibility.
CWD is widely known as a disease of North American elk (wapiti) and deer, even though it has been observed in Norse reindeer. From the late 1960s, CWD has been known to infect captive deer and elk found on game farms. Since 1996, it has also been diagnosed in wild cervids, both elk and deer. The wildlife findings, however, evidence a wider interest in prion disease more than they demonstrate any spread of the disease from domestic herds into wild populations, or from one state to another. Indeed, the picture that is emerging in the United States suggests that CWD has existed for some time in a variety of locations.
| 1969 - 1996 |
|
Wyoming and Colorado |
| 1997 - 1999 |
|
Montana and Oklahoma |
| 2000 - 2001 |
|
Nebraska, Kansas |
| 2002 |
|
Wisconsin, South Dakota, New Mexico |
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