Until the 1960s, the Fore tribe practiced ritualistic cannibalism and many contracted kuru, a disease caused by misfolded prion proteins in the brain. Creutzfeldt-Jakob disease occurs when people consume brain tissue from cows infected with mad cow disease, and works in much the same way.
In the study, authors recorded the age of death and genetic makeup of 11 members of the Fore tribe who died of kuru between 1996 and 2004. All eleven members were born prior to the 1950s when the Australian government outlawed the tribe's practice of honoring their dead by eating them at mortuary feasts.
Researchers noted that some infected members of the tribe were able to live for years without any symptoms of kuru, and found that the disease can incubate for up to 56 years before causing a rapid descent into dementia and death. The study authors theorize that some people infected with mad cow disease may also be able to live long lives before succumbing to the disease.
However, many experts disagree with this assumption. As a human disease, kuru is more likely to infect people than mad cow disease. Also, cannibals in the Fore tribe had direct contact with infected brain tissue, while most people who eat beef do not consume brain matter.