Final answer:
The Kuru epidemic was caused by a prion, an infectious protein variant, spread through ritualistic cannibalism in Papua New Guinea. It was controlled by ending the practice of cannibalism.
Step-by-step explanation:
The root cause of the Kuru epidemic was discovered to be linked to a type of infectious protein known as a prion. The specific prion responsible for kuru is an abnormally folded structural variant of the normal cellular protein PrP, which becomes infectious in its misfolded form, known as PrPSC.
This disease, primarily found among the Fore tribe in Papua New Guinea, was transmitted through ritualistic cannibalism, wherein consumption of the brain tissue of deceased individuals spread the prions to those partaking in the rituals. Most affected were women and children, as they were more likely to ingest the highly infective brain material during these practices. The epidemic was eventually controlled by ceasing the practice of cannibalism.