Actually, there is some good news. Many types of prions diseases do not spread from animals to humans (so far). There have been some studies around this with CWD, but also Scapie has been around for hundreds or even thousands of years and never made the jump. Even in areas with CWD, we see that herd numbers do typically rebound. It's believed that there is some genetic factor that prevents the onset of the symptoms, like the body's proteins are less likely to fold in that way, so you only accumulate what you eat, or that the body can clean up the misfolded proteins. So it's not like it would wipe out everyone. I think I remember reading that some people are also researching prion treatments with some limited sucess. I would imagine they would come up with something even more quickly if there was a epidemic type of situation, similar to how medical researchers around the world focused on covid.