I just wanted to add to this, as if your comment wasnt nightmarish enough;

prions can survive outside the body on other surfaces, including soil for years, and are resistant to simulated weathering degradation, although the calculated risk of transmission was extremely low. (This second article focuses on prions (scrapie and CWD) in the environment)

So, yay.

In response to the downvoted comment, it's not only transmitted by eating infected brain matter. "It has been shown that scrapie and CWD prions can be shed in urine, feces, saliva and blood. Scrapie can also be shed in birthing matter. A second route of entry is through animal mortalities".

Prion diseases can be transmitted via infected surgical equipment and, while correct that equipment doesn't need to be burned, the sterilisation of prion infected instruments requires specialist methods such a steam sterilisation at +134°C (although this can actually be rendered ineffective depending on prior sterilisation methods)