One day, we'll get sick from eating infected deer meat.
An irony about prion diseases is that our bodies continually make and destroy prions of many different kinds. Only in rare instances are prions created that are both defective and invulnerable.
Their “reproduction” of sorts is like other proteins, except they are able to persuade normal proteins kind of like them to also go active using the same defective process. It is so close to the natural process it is very hard to correct or fight.