The only solution that I can see is to use autonomous small vehicles to steam the soil and sanitize it .. literally 1000s of them running all day.
Apparently mountain lion digestive system destroys most of prions!! They need more mountain lions
That’s what need. Lots of machines cleaning up the landscape. That’s nature at work!
The contaminated soil passes the prions. There is not too many things that can do much other that heat and some acids. Heat is viable by it requires massive amount of energy. Maybe small area or few miles as parameter combined with fences.