kuru

n.
A fatal progressive, degenerative neurological disease caused by a slow-acting virus, found in certain peoples of New Guinea and transmitted by cannibalism.

[Fore (language of eastern Papua New Guinea).]

Definition

Kuru is the name of a progressively disabling and ultimately fatal brain infection caused by a unique protein particle called a prion.

Description

Kuru was first described in a specific tribal group in Papua, New Guinea. The word "kuru" means "to shake or tremble" in this tribal group's language. Individuals in New Guinea are believed to have acquired the infection through a cannibalistic ritual involving the blood and brains of deceased tribal members.

Because infection with kuru may occur years or decades before the advent of actual symptoms of the disease, it belongs to a group of diseases originally known as slow virus infections. Currently, slow virus infections are classed together as transmissible spongiform encephalopathies (TSE). TSEs include kuru, Creutzfeldt-Jakob disease, Gerstmann-Sträussler-Scheinker syndrome, and fatal familial insomnia. The TSE new variant called Creutzfeldt-Jakob disease (also known colloquially as "Mad Cow Disease") has received a great deal of public attention. The TSEs, including kuru, involve abnormal clumps of protein that accumulate throughout the brain, destroying brain tissue and leaving spongy holes.

Demographics

Kuru reached epidemic proportions among tribal members in the 1950s. Since the practice of cannibalism was halted, the disease has essentially disappeared. Some sources suggest that as few as zero to 10 cases of kuru are diagnosed each year.

Causes and symptoms

Kuru is caused by an infectious protein particle called a prion, which stands for proteinaceous infectious particle. A prion is similar to a virus, except that it lacks any nucleic acid, which prevents it from reproducing. Prions are abnormal versions of proteins that are found in the membranes of normal cells. These abnormal proteins can be passed directly to individuals through the ingestion of prion-infected tissue or when open sores on the recipient's skin are exposed to prion-infected tissue. In addition to being transmissible (as are other infectious agents like viruses or bacteria), prions are unique because they can also be acquired through genetic inheritance.

Symptoms of kuru tend to begin in later middle age, years or decades after the prion was actually acquired. Early symptoms include lack of energy, intense fatigue, headache, weight loss, joint pain, difficulty walking, twitchy muscles, personality changes, mood swings, memory problems, and bizarre behavior. As the disease progresses, the individual experiences stiff muscles, involuntary movements, problems talking, hallucinations, increased confusion, blindness, and sometimes dementia. Death often occurs within three months to two years of the initial symptoms.

Diagnosis

Diagnosis is arrived at through characteristic abnormalities found on the electroencephalogram (EEG), a test of brain waves and electricity. Seventy-five percent of individuals with kuru will display these specific abnormalities on EEG. MRI studies and biopsies (tissue samples) from the brain may also show changes that are characteristic of slow virus infection.

Treatment team

Diagnosis of slow virus infection is usually made by a neurologist.

Treatment

There are no available treatments for kuru. It is relentlessly progressive, incurable, and fatal. Supportive care for the patient and his or her family is the only treatment.

Prognosis

Kuru is always fatal.

Resources

BOOKS

Berger, Joseph R., and Avindra Nath. "Slow virus infections." Cecil Textbook of Medicine, edited by Thomas E. Andreoli, et al. Philadelphia: W.B. Saunders Company, 2000.

Murray, T. Jock, and William Pryse-Phillips. "Infectious diseases of the nervous system." Noble: Textbook of Primary Care Medicine, edited by John Noble, et al. St. Louis: W.B. Saunders Company, 2001.

PERIODICALS

Sy, Man-Sun, Pierluigi Gambetti, and Wong Boon-Seng. "Human Prion Diseases" Medical Clinics of North America 86 (May 2002) 551–571.

WEBSITES

National Institute of Neurological Disorders and Stroke (NINDS). Kuru Fact Sheet. Bethesda, MD: NINDS, 2003.

Rosalyn Carson-DeWitt, MD

Or trembling disease; progressive degeneration of brain cells, associated with cannibalism in Papua-New Guinea, and believed to be caused by a prion. More or less eradicated since ritual cannibalism was abolished.

from Fore
This word originated in Papua New Guinea

Some of the remotest civilizations on earth live in the hilly rain forests of eastern New Guinea--hundreds of separate cultures and tribes, speaking hundreds of separate languages. Although "Coca-colonization" by Western popular culture is beginning to have an effect even there, for the most part these New Guinea villagers and their languages have remained out of touch with the rest of the world. How, then, did a word from the Fore language of Papua New Guinea leave its remote mountain hideout and travel round the world, earning a Nobel Prize for the man who explained it?

The world's attention was drawn by a terrifying disease suffered by the Fore people, a disease they called kuru. Over a period of fifteen years or so, kuru can turn the brain to mush. Victims gradually lose the ability to walk, talk, or eat. In an autopsy, the brain looks something like a sponge or Swiss cheese, hence the term "spongiform encephalopathy."

There was no known cure, and for a long time there was no known cause. The Fore thought the disease might be caused by sorcery. Outside researchers thought it might be genetic, since it resembled the inherited Creutzfeld-Jacob Disease. What stopped the kuru epidemic was the discovery by Carleton Gajdusek of the U.S. National Institutes of Health that kuru is infectious. Chimpanzees can be given the disease by injection of kuru-infected brain tissue.

That discovery ended the Fore custom of showing respect for their ancestors by eating them after they died. The widow had the honor of preparing the brain for her children to eat, and only women and children who had participated in such feasts suffered from the disease. Once they learned of the connection with kuru, the Fore quickly stopped this practice. And for his work with kuru, Gajdusek shared the Nobel Prize for Medicine in 1976.

What has made kuru more than a historical footnote is its association with Creutzfeld-Jacob Disease and with scapies or "mad cow disease," more formally known as Bovine Spongiform Encephalopathy. Kuru was the first known human version of spongiform encephalopathy, but there have been others since. When another infection of humans was found in what is now Slovakia, it was given the name Oravske Kuru.

The Fore language is spoken by some 17,000 residents of 170 villages in the Eastern Highlands Province of Papua New Guinea. It is among more than 500 little-known languages of the Trans-New Guinea group, none with more than 100,000 speakers and most with just a few thousand. English has no other words from Fore.

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A chronic, progressive, uniformly fatal central nervous system prion disease of humans probably resembling the scrapie agent of sheep, and transmissible to nonhuman primates; seen only in the Fore and neighboring peoples of New Guinea. Believed to be transmitted by cannibalism.