Not usually, but in this magical setting I can believe cannibalism is slightly more common and you don't know how many humans the meat ate before you.
Well, no, that's not how that works. You catch a prion disease from eating someone that has a prion disease. The disease is extremely rare. And fatal. If you have a prion disease, you have, at best, a few years to live. Even the mad cow disease epidemic in Europe a few decades ago only reported a handful of cases of humans contracting the disease.
The likelihood of actually eating someone that has it are astronomically low. Hell, the gang is probably more likely to contract something from eating monster meat.
