Jack, if you had read the early papertrail on CWD there is no other answer to find other than CSU and the research at the Foothills Wildlife Research S`tation in the early/mid 60s resulted in the stage being set for transmission of scrappie from infected sheep to healthy mule deer at the station. Beth Williams, one of the grad students in the research and later Doctor who discovered it was a TSE disease said as much. She would know.
I don't believe there is any other conclusion to reach than that they, the researchers, made CWD come about. They didn't believe that scrappie would jump the species barrier when putting healthy deer into a pen that had help infected sheep. Remember, this is BEFORE the whole Mad Cow outbreak.