A rare but deadly human illness spread by cannibalism has an incubation period in some individuals of about 4 decades, researchers in New Guinea have discovered. The finding implies that a related human illness caused by eating beef from cattle with mad cow disease could also lie dormant for many years.
Scientists have identified a handful of diseases caused by misfolded proteins called prions, including mad cow disease, scrapie in sheep, and chronic wasting disease in deer and elk. In people, eating contaminated beef can cause Creutzfeldt-Jakob disease. Like the other prion diseases, Creutzfeldt-Jakob disease kills brain cells and is fatal.