I'm thinking kuru.
That would make sense. One of the major methods of contraction is through cannibalism.
“I’m thinking kuru.”
“Kuru is a very rare disease. It is caused by an infectious protein (prion) found in contaminated human brain tissue. Kuru is found among people from New Guinea who practiced a form of cannibalism in which they ate the brains of dead people as part of a funeral ritual.”
Now that would explain a lot of things!