Kuru is an extremely rare prion disease. It is almost exclusively found among people from New Guinea, who practiced a form of cannibalism in which the brains of dead relatives were eaten as part of a funeral ritual. Kuru causes neurodegenerative changes similar to another prion disease, Creutzfeldt-Jakob disease, which occurs sporadically around the world and for which risk factors are unknown.

In addition, similar prion diseases appear in sheep as scrapie, mink as encephalopathy, and in cows as bovine spongiform encephalopathy (BSE) ("mad cow disease"). The main risk factor for the development of kuru is eating human brain tissue, which can contain the infectious particles.

Kuru may begin with difficulty walking and increasing incoordination, which eventually become severe. Tremors and muscle jerks are often seen in the later stages of the disease. Difficulty swallowing and inability to feed oneself lead to malnutrition or starvation.

The incubation period (the time it takes until symptoms develop) for this disease can be up to 30 years or longer. Death, however, usually occurs within a year after the onset of symptoms.

• Difficulty walking (cerebellar ataxia)
• Incoordination
• Swallowing difficulty