system
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human
Why does cannibalism cause prions but eating other animals’ meat does not?

I keep seeing that cannibalism cause prions like during the mad cow disease epidemic and the jack kreuz something disease that killed a lot of tribesmen in the mid 19th century. However, i havent seen any explanation as to why cannibalism spreads prions but eating other species’ meat does not.
gpt
So this is an interesting one and largely based on theory. Prion disease is an umbrella term for lots of different conditions including Creutzfeldt Jakob, Mad cow, chronic wasting disease. 

The issue is with a misfolded protein. This protein then causes nearby proteins to misfold and become non-functional, they then do the same to other nearby proteins. This gives you an accumulation of non-functional proteins (amyloid) which causes the symptoms. This happens (very rare) spontaneously in humans causing Creutzfeldt Jakob.

It’s thought that Kuru (cannibalism origin) occurred because one of the tribe members developed this prior to their death and passed it to tribe members due to their feeding habits. It then can take 30-50y to show symptoms so once those infected members died other tribes people became infected and it was a neverending cycle. 

For some reason brain is the most likely tissue to pass it on but any tissue can. This is why all cows with mad cow (bovine version of CJD) are slaughtered and their meat not eaten. It’s not that eating a brain gives you prion disease it’s just more likely than other tissues to give you prion disease if the animal had it.