This dual nature of prions-inducing other proteins to become prions, while also being the basis of inherited disease-is otherwise unknown to medical science.
In addition, prions underlie both inherited (i.e., familial forms) and communicable forms of diseases. The controversy continues today, although additional evidence has accumulated to support the hypothesis that spongiform encephalopathies are caused by prions rather than viruses.Īccording to current theory, prion proteins multiply by inducing benign protein molecules to convert themselves into the dangerous form of the molecule simply by changing their shape. Prusiner as an acronym for "proteinaceous infectious particles," was originally met with great skepticism by most scientists when Prusiner and his co-workers proposed the existence of these proteins 15 years ago. The concept of prions, a term coined by Stanley B. Finally, the victim succumbs to severe skin ulcers caused by lying in one position for extended periods of time or to pneumonia caused by stagnation of the blood in the lungs.Īmong the other human spongiform encephalopathies caused by prions are Creutzfeldt-Jakob disease (millions of cases worldwide characterized by dementia and loss of coordination) Gerstmann-Straussler-Scheinker disease (found in 50 extended families by 1995) and fatal familial insomnia (trouble sleeping, followed by dementia found in nine extended families by 1995). Toward the end of the disease, the person with kuru is very calm and quiet and unresponsive to stimulation. Often, the victim bursts out in wild laughter for no obvious reason. Among the major signs of kuru are cerebellar abnormalities such as rigidity of the limbs and clonus (rapid contractions and relaxations of muscles). The course of the illness runs from three months to one year. About 2,600 cases were identified before the Fore highlanders ended this custom. When the Fore highlanders were persuaded to cease consuming human brains, kuru disappeared from Papua New Guinea. This disease affects the brain, and it was probably spread by the Fore practice of honoring the dead by eating their brains. The disease caused its victims to lose coordination and often to develop dementia.
It was first noted by Vincent Zigas of the Australian Public Health Service and D. Kuru occurred among the Fore highlanders of Papua New Guinea, who called it the "laughing death".
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