Yeah, it was a version of Mad Cow Disease, Creutzfeldt-Jakob. It is caused by a bizarre, rogue protein that causes other proteins to become distorted merely by contact. It causes literal holes to develop in the victim's brain. The trouble is, because it is a protein and not technically alive, it cannot be cooked to death. In other words, because I like a well-done steak, I'll never, ever get e-coli. However, if that cow had mad-cow disease, you could char that sucker until it was ashes and still get the disease. Also because of that, it is not curable. There is neither a defense against getting it (other than not eating certain foods) nor is there a cure or treatment once you have it.
It is also known to occur in cannibalistic societies.
Ash