Here is some authoritative information on CWD in deer and elk.

http://www.cwd-info.org/index.php/fuseaction/recommendations.precautions

Fortunately the desease is rare in most areas. It might pay to have a short conversation with your commercial processor before the season to gauge their level of knowledge in processing deer to avoid not only possible CWD infected tissue, but eliminating lead particles from fragmented bullets as well.

The most persistant advice I have seen is to avoid harvesting a deer that looks sick, and even then to avoid contact with certain parts of the deer when field dressing.