Kuru (also known as laughing sickness due to the outbursts of laughter that mark its second phase) was first noted in New Guinea in the early 1900s. By the 1950s, anthropologists and Australian government officials reported that kuru ("trembling" in the language of the Fore) was rampant among the South Fore, a single census division of approximately 8,000 individuals within the Okapa subdistrict. This particular group partook in ritual acts of mortuary cannibalism, which behaviour was later determined to be responsible for the epidemic transmission of the disease. The following codes are used with International Statistical Classification of Diseases and Related Health Problems. ... The following is a list of codes for International Statistical Classification of Diseases and Related Health Problems. ... Laughter is the biological reaction of humans to moments or occasions of humor: an outward expression of amusement. ... // Events and Trends Technology First flight by the Wright brothers, December 17, 1903. ... // Events and trends This map shows two essential global spheres during the Cold War in 1959. ... Anthropology (from the Greek word άνθρωπος, human or person) consists of the study of humanity (see genus Homo). ... The Fore are a highland people of Papua New Guinea. ... A ritual is a set of actions, performed mainly for their symbolic value, which is prescribed by a religion or by the traditions of a community. ... Cannibalism in Brazil in 1557 as described by Hans Staden. ... In epidemiology, an epidemic (from Greek epi- upon + demos people) is a disease that appears as new cases in a given human population, during a given period, at a rate that substantially exceeds what is expected, based on recent experience (the number of new cases in the population during a... The microorganisms (bacteria and viruses) that cause disease may be transmitted from one person to another by one or more of the following means: droplet contact - coughing or sneezing on another person direct physical contact - touching an infected person indirect contact - usually by touching a contaminated surface airborne transmission - if...

Kuru is now known to be a prion disease, one of several known transmissible spongiform encephalopathies. Understanding the structure and replication of the prion is crucial to interpreting the dynamics of kuru and the several other prion diseases which exist today. A prion (pronounced pree-on) — short for proteinaceous infectious particle — is a unique type of infectious agent, as it is made only of protein. ... Transmissible spongiform encephalopathies (TSEs) are fatal degenerative diseases of the brain transmitted by prions with no cure. ...

Knowledge of the dynamics of the disease has continued to grow, even though the disease all but disappeared with the termination of cannibalism in New Guinea. The onset of kuru led to a five-decade study of an unfamiliar disease. This particular disease serves as an example of the procedures scientists undergo in order to understand and appreciate all of the aspects of a disease and how potential therapies and solutions can be found.

Kuru among the South Fore

Upon the death of an individual, the maternal kin were responsible for the dismemberment of the corpse. The women would remove the arms and feet, strip the limbs of muscle, remove the brains and cut open the chest in order to remove internal organs. Shirley Lindenbaum, one of the early kuru researchers, states that kuru victims were highly regarded as sources of food, because the layer of fat on victims who died resembled pork. Women also were known to feed morsels, such as human brains and various parts of organs, to their children and the elderly (Lindenbaum, 1979). It is currently believed that kuru was transmitted among the South Fore through participation in such cannibalism, although opportunistic infection through wounds when removing infectious tissue from the corpse can be assumed to be another cause, as not all cases can be explained by ingestion of infectious tissue. With regard to living things, a body is the integral physical material of an individual, and contrasts with soul, personality and behavior. ... A top-down view of skeletal muscle Muscle is the contractile tissue of the body and is derived from the mesodermal layer of embryonic germ cells. ... Comparative brain sizes In animals, the brain, or encephalon (Greek for in the head), is the control center of the central nervous system. ... This article or section is in need of attention from an expert on the subject. ... This page refers to the year 1979. ...

The kuru epidemic reached its height in the 1960s. Between 1957 and 1968, over 1,100 of the South Fore died from kuru. The vast majority of victims among the South Fore were women. In fact, eight times more women than men contracted the disease. It later affected small children and the elderly at a high rate as well. The 1960s decade refers to the years from 1960 to 1969, inclusive. ... 1957 (MCMLVII) was a common year starting on Tuesday of the Gregorian calendar. ... 1968 (MCMLXVIII) was a leap year starting on Monday (the link is to a full 1968 calendar). ...

Lindenbaum and Vincent Zigas worked among the South Fore in New Guinea trying to identify and catalog the symptoms and possible behavior causing the disease. Daniel Carleton Gajdusek also traveled there in 1957, to study disease patterns in primitive and isolated populations (Gajdusek, 1996). Lindenbaum, Zigas, and Gajdusek were all crucial to explaining the specifics of kuru to the rest of the world. Daniel Carleton Gajdusek (born September 9, 1923, Yonkers, New York, U.S.A.) is an American physician and medical researcher, who was the corecipient (along with Baruch S. Blumberg) of the Nobel Prize in Physiology or Medicine in 1976. ... 1996 (MCMXCVI) was a leap year starting on Monday of the Gregorian calendar, and was designated the International Year for the Eradication of Poverty. ...

Symptoms of kuru

In Daniel Gajdusek's studies of kuru, he found the condition of kuru victims to be an upsetting sight. "To see them, however, regularly progress to neurological degeneration in three to six months (usually three) and to death is another matter and cannot be shrugged off." (Gajdusek, 1996:10) Gajdusek reported three main stages in the progression of symptoms: Neurology is a branch of medicine dealing with disorders of the nervous system. ... This article deals with the social-philosophical meaning of degeneration. ...

1. The ambulant stage, with unsteadiness of stance, gait, voice, hands, and eyes; deterioration of speech; tremor; shivering; loss of coordination in lower extremities that moves slowly upward; and dysarthria (slurring of speech).
2. The sedentary stage: patient can no longer walk without support, more severe tremors and ataxia (loss of coordination of the muscles), shock-like muscle jerks, emotional lability, outbursts of laughter, depression, and mental slowing. It is important to note that muscle degeneration has not occurred in this stage, and tendon reflexes are usually still normal.
3. The terminal stage, which is marked by inability to sit up without support; more severe ataxia, tremor and dysarthria (slurring of speech); urinary and fecal incontinence; difficulty swallowing (dysphagia); and deep ulcerations appear. Cerebellar dysfunction is the cause of these conditions.

These symptoms are common among prion diseases, such as Creutzfeldt-Jakob disease (CJD). A human hand typically has four fingers and a thumb. ... This article or section does not cite its references or sources. ... Dysarthria (from new latin dys-, prefix meaning mis-, dis-, accidental + greek -arthro, joint) is an injury or symptom describing minor speech impediments, often slurred speech. ... Ataxia (from Greek ataxiā, meaning failure to put in order) is unsteady and clumsy motion of the limbs or trunk due to a failure of the gross coordination of muscle movements. ... Lability is constantly undergoing change or something that is likely to undergo change. ... In everyday language depression refers to any downturn in mood, which may be relatively transitory and perhaps due to something as trivial as your team losing. ... A reflex action or reflex is a biological control system linking stimulus to response and mediated by a reflex arc. ... Ataxia (from Greek ataxiā, meaning failure to put in order) is unsteady and clumsy motion of the limbs or trunk due to a failure of the gross coordination of muscle movements. ... The word incontinence has several distinct meanings: urinary incontinence is the inability to control urination fecal incontinence is the inability to control defecation the word incontinence can also be used to mean a lack of self-control governing morality. ... Dysphagia is the technical term for the symptom of the sensation of difficulty in swallowing. ... Endoscopic images of a duodenal ulcer. ... Figure 1a: A human brain, with the cerebellum in purple. ... Creutzfeldt-Jakob Disease (CJD) is a very rare and incurable degenerative neurological disorder (brain disease) that is ultimately fatal. ...

Misinterpretations of kuru

Scholars who first studied the disease had two major misconceptions concerning its nature. They first incorrectly postulated that it was a genetic disorder, as it had a tendency to occur among family members. This possibility was eventually ruled out because kuru was too common and too fatal (Lindenbaum, 1979) — such a lethal genetic disorder would drastically reduce the fitness of a population and soon die out of the gene pool. A genetic disorder, or genetic disease is a disease caused by abnormal expression of one or more genes in a person causing a clinical phenotype. ... This page refers to the year 1979. ... The gene pool of a species or a population is the complete set of unique alleles that would be found by inspecting the genetic material of every living member of that species or population. ...

Gajdusek conducted studies on chimpanzees injected with brain material from a victim. These studies led scientists to hypothesise that the agent was a slow virus, because the chimps developed a very similar condition after a long incubation period. Gadjusek defined a slow virus as a viral disease with an abnormally long incubation period. In humans, kuru had an incubation period with a minimum of two years and maximum of twenty-three (Gajdusek et al., 1966). Later studies showed the slow virus hypothesis to be a misinterpretation as well. Gajdusek’s results, however, confirmed the infectious, transmissible nature of the prion. The human immunodeficiency virus (HIV) A bacteriophage virus A virus is a submicroscopic parasitic particle that infects cells in biological organisms. ... 1966 (MCMLXVI) was a common year starting on Saturday (the link is to a full 1966 calendar). ...

The prion protein

Main article: Prion

All known prion diseases are fatal. Such diseases are often called spongiform encephalopathies, because they frequently cause the brain to become spongy, that is, riddled with holes (Prusiner, 1995). Well known prion diseases include scrapie, bovine spongiform encephalopathy (BSE or mad cow disease) and Creutzfeldt-Jakob disease (CJD). Less well-known prion diseases include the transmissible mink encephalopathy, chronic wasting disease, feline spongiform encephalopathy, exotic ungulate encephalopathy, Gerstmann-Sträussler-Scheinker syndrome (GSS) and fatal familial insomnia (Krakauer et al., 1997). Four of these affect humans: Creutzfeldt-Jakob disease, Gerstmann-Strässler-Scheinker syndrome, fatal familial insomnia and kuru. The most common form of prion disease is scrapie, expressed in sheep and goats (Prusiner, 1995). According to Cohen et al. (1994), prions cause a variety of degenerative neurologic diseases that can be infectious, inherited or sporadic in origin. The cause of the sporadic forms is unknown; inherited forms are caused by up to twenty different mutations of the human PrP gene; and the infectious forms are transmitted through contact with or consumption of previously infected tissues (Prusiner, 1997). A prion (pronounced pree-on) — short for proteinaceous infectious particle — is a unique type of infectious agent, as it is made only of protein. ... A prion (pronounced pree-on) — short for proteinaceous infectious particle — is a unique type of infectious agent, as it is made only of protein. ... 1995 (MCMXCV) was a common year starting on Sunday of the Gregorian calendar. ... Scrapie is a fatal, degenerative disease that affects the nervous systems of sheep and goats. ... Look up Bovine spongiform encephalopathy in Wiktionary, the free dictionary. ... COW is an acronym for a number of things: Can of worms The COW programming language, an esoteric programming language. ... Creutzfeldt-Jakob Disease (CJD) is a very rare and incurable degenerative neurological disorder (brain disease) that is ultimately fatal. ... Transmissible mink encephalopathy is caused by proteins called prions ... Chronic wasting disease (CWD) is a transmissible spongiform encephalopathy (TSE) of deer and American elk (wapiti). ... Feline spongiform encephalopathy is caused by protiens called prions ... Gerstmann-Sträussler-Scheinker syndrome (GSS) is a very rare, usually familial, neurodegenerative disease that affects patients in the third to seventh decades of life. ... Fatal familial insomnia (FFI) is a very rare autosomal dominant inherited disease of the brain. ... 1997 (MCMXCVII in Roman) is a common year starting on Wednesday of the Gregorian calendar. ... It has been suggested that Primary insomnia be merged into this article or section. ... Species See text. ... Species See Species and subspecies The goat is a mammal in the genus Capra, which consists of nine species: the Ibex, the West Caucasian Tur, the East Caucasian Tur, the Markhor, and the Wild Goat. ... 1994 (MCMXCIV) was a common year starting on Saturday of the Gregorian calendar, and was designated the International year of the Family. ... Neurology is a branch of medicine dealing with disorders of the nervous system. ... Infection is also the title of an episode of the television series Babylon 5, and the English title of the Japanese film Kansen. ... To inherit something is to get it from ones ancestors. ... In biology, mutations are changes to the genetic material (usually DNA or RNA). ... 1997 (MCMXCVII in Roman) is a common year starting on Wednesday of the Gregorian calendar. ...

The exact nature of kuru perplexed scholars for decades after the discovery of the ailment, until Stanley B. Prusiner identified and defined prion diseases in 1982 (Prusiner, 1995). Prusiner (1991) classified a prion as an infectious particle composed of a protein that causes neurodegenerative disorders. According to Cashman (1997), prions are infectious agents by biological and medical criteria. However, they are also fairly unique, and properties of prions differ from those of conventional microbes. Stanley B. Prusiner, M.D. (born May 28, 1942) is a Professor of Neurology and Biochemistry at the University of California, San Francisco. ... 1982 (MCMLXXXII) was a common year starting on Friday of the Gregorian calendar. ... 1995 (MCMXCV) was a common year starting on Sunday of the Gregorian calendar. ... 1991 (MCMXCI) was a common year starting on Tuesday of the Gregorian calendar. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... Neurodegenerative disease is a condition which affects the brain function. ... A microorganism or microbe is an organism that is so small that it is microscopic (invisible to the naked eye). ...

Scientists have worked on the prion puzzle since the 1950s, with microbiologists and epidemiologists having been confused by them. Advancements have been made, particularly in the 1990s, as evidenced by Prusiner receiving the Nobel Prize for Physiology or Medicine in 1997. However, it is still difficult to detect prion infection, track its transmission and type the different strains (Cashman, 1997). The Fore's long struggle with kuru serves as a poignant example. // Events and trends This map shows two essential global spheres during the Cold War in 1959. ... Microbiology is the study of microorganisms, which are unicellular or cell-cluster microscopic organisms. ... Epidemiologic studies are generally categorized as descriptive, analytic (aiming to examine associations, commonly hypothesized causal relationships), and experimental (a term often equated with clinical or community trials of treatments and other interventions). ... The 1990s decade refers to the years from 1990 to 1999, inclusive. ... List of Nobel Prize laureates in Physiology or Medicine from 1901 to the present day. ... 1997 (MCMXCVII in Roman) is a common year starting on Wednesday of the Gregorian calendar. ...

References

• NR Cashman (1997), "A prion primer". Canadian Medical Journal Association, 157(10):1381–1386.
• FE Cohen, K Pan, Z Huang, M Baldwin, RJ Fletterick and SB Prusiner (1994), "Structural clues to prion replication". Science, 264:530–531.
• DC Gajdusek (1996), "Kuru: From the New Guinea field journals 1957–1962". Grand Street, 15:6–33.
• DC Gajdusek (1973), "Kuru in the New Guinea Highlands". In Spillane JD (ed): Tropical Neurology. New York, Oxford University Press.
• DC Gajdusek, CJ Gibbs and M Alpers (1966), "Experimental transmission of a kuru-like syndrome to chimpanzees". Nature, 209:794.
• DC Gajdusek, PM de Zanotto and M Pagel (1998), "Prion's progress: Patterns and rates of molecular evolution in relation to spongiform disease". Journal of Molecular Evolution, 47:133–145.
• S Lindenbaum (1979), Kuru Sorcery. Mountain View, Ca, Mayfield Publishing Company.
• SB Prusiner (1991), "Molecular biology of prion diseases". Science, 252:1515–1521.
• SB Prusiner (1995), "Prion diseases". Scientific American, 272(1):48–56.
• SB Prusiner (1997), "Prion diseases and the BSE crisis". Science, 278:245–251.
• Stacy McGrath, Kuru: The dynamics of a prion disease.

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External links

• NIH Kuru
• The Straight Dope Notes supporting routine cannibalism as myth

Acknowledgements

• This article was adapted with permission from a report "Kuru: The dynamics of a prion disease", authored by Stacy McGrath.