The major differences between these diseases relate to their targets rather than their pathological features, which are all similar.

Chronic Wasting Disease mainly targets elk and deer. To date, there is no evidence that this disease can infect humans who consume CWD–infected meat, but more data are needed to establish this definitively.

Mad Cow Disease targets cattle. The leading theory of BSE infection attributes the spread of the disease to cows that have been given feed contaminated with animal tissue, especially from scrapie–infected sheep. However, several recent reports show that Mad Cow can also have other causes.

Creutzfeldt-Jacob Disease targets people. Those who eat BSE–contaminated meat are at an extremely high risk to develop CJD, also known in its variant form as vCJD.

The cause of the TSE family of diseases is neither a bacterium or a virus. It is believed to be a prion—an abnormal form of cellular prion proteins that exist in the brain—that leads to brain damage and the characteristic symptoms of the disease. Prion diseases are transmissible by eating the meat of an affected animal. They are usually rapidly progressive and always fatal, but CJD can have an incubation period of up to 30 years.

NIH/National Institute of Allergy and Infectious Diseases
http://www.niaid.nih.gov/factsheets/priondis.htm

Wikipedia
http://en.wikipedia.org/wiki/Transmissible_spongiform_encephalopathy

American Veterinary Medical Association
http://www.avma.org/communications/brochures/cwd/cwd_brochure.asp

State of Michigan
http://www.michigan.gov/emergingdiseases/0,1607-186-25806---,00.html

Medical News Today (RSS feed)
feed://www.medicalnewstoday.com/rss/cjd-vcjd-mad_cow_disease.xml

The New York Times
http://topics.nytimes.com/top/news/health/diseasesconditionsandhealthtopics/
chronic_wasting_disease/index.html