CWD is not spread by baiting. That being said,if it is legal to bait and you feel good about it go for it. Its illegal to bait in Iowa so I have never hunted over bait but I do leave a mineral lick year round about 60 yards from my stand on a travel route from a food plot to a bedding ground.
Well I looked into the spreading of CWD and right now it can go either way. Heres just one of the sites I found.
http://www.bowhunter.com/conservation/bn_knowhuntingdec2003/#cont
Pretty much, they believe that anything that brings deer together may spread the disease. Baiting, which brings deer together, causes them to leave urine, feces, and saliva in the area which is a potential for the spread of CWD.
I am not "bashing" anyone for baiting deer. I could care less how any of yall get your tags filled. I have used salt and mineral licks in the past and I just don't fool w/ them anymore. Was I spreading CWD? Possibly, but thats before I knew what CWD even was.