i will post more as i find them. and keep in mind some of these articles are a little dated. cwd research is on going and new info is out all the time.
here is a link talking about thefirst cwd case being found in canada's elk herd due to the selling of infected animals from the usa
http://www.cdc.gov/ncidod/EID/vol10no6/03-1082.htm
here is a link talking about cwd in soil types
http://www.sciencedaily.com/releases/2006/04/060414013751.htm