I read an interesting report regarding specific risks that are indicators of the likelihood of contracting prion diseases such as mad cow disease, BSE, or CWD(chronic wasting disease), all 100% fatal.  Researchers have determined that eating venison from deer killed in 3 states in the USA (Colorado, Nebraska, and Wyoming), hunting practices and related hygiene, which parts of the carcass you eat, and whether you are a regular visitor to certain parts of Europe where mad cow is endemic.  I believe the authors understated the risk of eating animal brains and cuts of meat near the spinal cord   For example,  t-bone steaks, which are near the spinal cord, increase your risk.  The report is a nice concise read for consumers who like to remain knowledgeable about their food.

Survey participants were asked about behaviors that could be associated with exposure to the agents causing BSE and CWD, including travel to the nine countries considered to be BSE-endemic (United Kingdom, Republic of Ireland, France, Portugal, Switzerland, Italy, the Netherlands, Germany, Spain) and the cumulative length of stay in each of those countries. Respondents were asked if they ever had hunted for deer or elk, and if that hunting had taken place in areas considered to be CWD-endemic (northeastern Colorado, southeastern Wyoming or southwestern Nebraska). They were also asked if they had ever consumed venison, the frequency of consumption, and whether the meat came from the wild.  Eurekalert Link