Prions are considered infectious, although when they were first proposed it was essentially heresy that something could be infectious without containing any nuc

Prions are considered infectious, although when they were first proposed it was essentially heresy that something could be infectious without containing any nucleic acid (DNA/RNA). Whether they self-replicate or not is sort of a semantic issue. They replicate in the same way "fallen-down dominos" replicate. Prior to being a prion, they are an already complex protein, but by folding a particular way, they become a prion, which causes other proteins of the same type to fold similarly.