Inb4inv3-
Viruses aren't alive because they require a host cell to reproduce.
Awwwww...
Edit: It sounds like these prions are just going through rapid microevolution (adaptation, which, from a Creationist view, is a built-in-feature). Bacteria and viruses can do the same thing to gain immunities to antibiotics and to survive in radical climates. However, what I see missing is the claim that these proteins can change into other species, or even if they are a species themselves, seeing as they aren't classified as "living".