(See also Overview of Prion Diseases.)
Scientists have been interested in kuru mainly because it shows how prion diseases can be transmitted from person to person.
Until the early 1960s, kuru was fairly common in Papua New Guinea. Prions were probably acquired during a burial ritual, which involved eating tissues of a dead relative as a sign of respect (called ritual cannibalism). Kuru probably started when prion-contaminated tissues from a person with Creutzfeldt-Jakob disease were eaten. Kuru was more common among women and children because they were given the brains, which were more infectious. These rituals have been prohibited since the 1950s, and kuru has been virtually eliminated. Few, if any, people develop kuru anymore. However, 11 cases of kuru were reported between 1996 and 2004. These cases suggest that after a person is infected, symptoms may not develop until more than 50 years later.
Later, abnormal involuntary movements, such as repetitive, slow writhing or rapid jerking of the limbs and body (called choreoathetosis), may develop. The limbs become stiff, and muscles jerk (called myoclonus). Emotions may switch suddenly from sadness to happiness with sudden outbursts of laughter. People with kuru become demented and eventually placid, unable to speak, and unresponsive to their surroundings.
No effective treatment is available. Treatment of kuru focuses on relieving symptoms.