Kuru is a prion disease that now occurs rarely if ever. It causes rapid deterioration of mental function and loss of coordination. This disease was once common among the Fore natives of the Papua New Guinea highlands and was transmitted by cannibalism that was part of the native burial ritual.
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. Many of these rituals have been abandoned, and kuru has been virtually eliminated. Few, if any, people develop kuru anymore.
The first symptoms include loss of coordination (ataxia), difficulty walking, and shaking (tremors) that resembles shivering (kuru means to shake). The limbs become stiff, and muscles jerk (called myoclonus).
Later, abnormal involuntary movements, such as repetitive, slow writhing or rapid jerking of the limbs and body (called choreoathetosis), may develop. 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.
Most people die within 24 months after symptoms appear, usually as a result of pneumonia or infection due to bedsores (pressure sores).