Kuru is an incurable degenerative neurological disorder endemic to tribal regions of Papua
New Guinea. It is a type of transmissible spongiform encephalopathy, caused by a prion
found in humans. The term "kuru" derives from the Fore word
"kuria/guria", a reference to the body tremors that are a classic symptom of the disease;
it is also known among the Fore as the laughing sickness due to the pathologic bursts of laughter
people would display when afflicted with the disease. It is now widely accepted that Kuru
was transmitted among members of the Fore tribe of Papua New Guinea via cannibalism.
History Kuru was first noted in the Fore tribes of
Eastern Highlands and lowlands Provinces of Papua New Guinea as Australian administrators
explored the area in 1953–1959. Kuru was reported by W. T. Brown in Kainantu Patrol
Report No 8 of 1953/54 .. "The first sign of impending death is a general debility which
is followed by general weakness and inability to stand. The victim retires to her house.
She is able to take a little nourishment but suffers from violent shivering. The next stage
is that the victim lies down in the house and cannot take nourishment, and death eventually
ensues." The same reports described the cannibalism practiced by the Fore people. It was in the
late 1950s that the full extent of the disease was realized, after it had reached large infection
rates in the South Fore of the Okapa Subdistrict, though the agent was unknown.
Awande Hospital was built in 1961 in the Eastern Highlands to accommodate kuru patients and
research. Kuru was first noted in 1952-1953 by anthropologists Ronald Berndt and Catherine
Berndt among the Fore, Yate, and Usanufa people. Charles O. Pfarr, Lutheran Medical Services,
was brought to the area by tribal persons and reported the disease to Australian authorities.
Dr. Vincent Zigas, District Medical Officer, began observation. Blood specimens and brain
tissue were sent to Melbourne. In 1957, Dr. Daniel Carleton Gajdusek of the
National Institute of Health joined Dr. Zigas at the research center. Sister Eva Hasselbusch
of Germany joined the hospital in 1959 to take care of the patients. Sister Maria Horn
of Germany was the first trained sister to work with the doctors to study the disease.
By 1968, the hospital ceased to function as a kuru hospital and was closed.
The disease was researched by Daniel Carleton Gajdusek as part of an international collaboration
with Australian doctor Michael Alpers. In the mid-1960s, Alpers collected post-mortem
brain tissue samples from an 11-year-old Fore girl, Kigea, who had died of kuru. He took
these samples to Gajdusek in the USA, who then injected two chimpanzees with the infected
material. Within two years, one of the chimps, Daisy, had developed kuru, demonstrating that
the unknown disease factor was transmitted through infected biomaterial and that it was
capable of crossing the species barrier to other primates.
Subsequently, E. J. Field spent large parts of the late 1960s and early 1970s in New Guinea
investigating the disease, connecting it to scrapie and multiple sclerosis. He noted similarities
in the diseases interactions with glial cells, including the critical observation that the
infectious process may depend on structural re-arrangement of the host's molecules. This
was an early observation of what was to later become the prion hypothesis.
In 1976, Gajdusek, along with Baruch S. Blumberg, was awarded the Nobel Prize in Physiology
or Medicine, in part for showing that kuru was transmissible to chimpanzees. This was
the first time that this group of encephalopathies had been demonstrated to be infectious and
therefore a major step forward in their investigation. As kuru is the only epidemic of human prion
disease in known human history, it has provided important insights into Creutzfeldt–Jakob
Disease in humans and Bovine Spongiform Encephalopathy in cattle.
Causes The victims are usually those people who follow
the practice of family mortuary cannibalism. In some parts of Papua New Guinea, bodies
of those who died from kuru were dismembered in order to feast on the internal organs.
"Often they would feed morsels of brain to young children and elderly relatives."
Kuru is believed to be caused by prions and is related to Creutzfeldt–Jakob disease.
It is best known for the epidemic that occurred in Papua New Guinea in the middle of the twentieth
century, and earlier. Although it is considered a transmissible prion disease, there is some
evidence that the origin of the outbreak was due to eating a human with sporadic CJD, thus
implying a common pathophysiology. Presentation
Kuru causes physiological as well as neurological effects that ultimately lead to death. It
was endemic among the Fore tribe of Papua New Guinea and was confined to the Fore population
and those nearby populations with whom they intermarried. It is characterized by truncal
ataxia, preceded by headaches, joint pains and shaking of the limbs. Trembling is present
in almost all patients with transmissible spongiform encephalopathy; Kuru is also known
as "shiver". The preclinical or asymptomatic phase, also
called the incubation period, lasts between possibly 5 to 20 years following initial exposure.
The clinical stage lasts an average of 12 months.
The symptoms of kuru are broken down into three specific stages. The first, ambulant
stage, exhibits unsteady stance and gait, decreased muscle control, tremors, deterioration
of speech and dysarthria. In the second, sedentary stage, the patient is incapable of walking
without support, suffers ataxia and severe tremors. Furthermore, the victim is emotionally
unstable, depressed, yet having uncontrolled sporadic laughter. Interestingly, the tendon
reflexes are still normal at this point. In the final, terminal stage, the patient
is incapable of sitting without support, suffers severe ataxia, is unable to speak, is incontinent,
has dysphagia, is unresponsive to his or her surroundings, and acquires ulcerations. An
infected person usually dies within 3 months to 2 years after the first symptoms, often
because of pneumonia or pressure sores infection. Transmission
In 1961, Australian Michael Alpers conducted extensive field studies among the Fore accompanied
by anthropologist Shirley Lindenbaum. Their historical research suggested that the epidemic
may have originated around 1900 from a single individual who lived on the edge of Fore territory
and who is thought to have spontaneously developed some form of Creutzfeldt-Jakob Disease. Alpers
and Lindenbaum's research conclusively demonstrated that kuru spread easily and rapidly in the
Fore people due to their endocannibalistic funeral practices, in which relatives consumed
the bodies of the deceased to return the "life force" of the deceased to the hamlet, a Fore
societal subunit. The dysmorphism evident in the infection rates
— kuru was 8 to 9 times more prevalent in women and children than in men at its peak
— is because, while the men of the village took the choice cuts, the women and children
would eat the rest of the body, including the brain, where the prion particles were
particularly concentrated. There is also the strong possibility that it was passed on to
women and children more easily because they took on the task of cleaning relatives after
death and may have had open sores and cuts on their hands.
Although ingestion itself of the prion particles can lead to the disease, there was a high
degree of transmission if the prion particles could reach the subcutaneous tissue. With
elimination of cannibalism because of Australian colonial law enforcement and the local Christian
missionaries' efforts, Alpers' research showed that Kuru was already declining among the
Fore by the mid‑1960s, although cases continued to appear for several more decades and the
last sufferer died in 2005. However, the mean incubation period of the disease is 14 years,
and cases were reported with latencies of 40 years or more for those who were most
genetically resilient. Immunity
Simon Mead of University College London, and others, showed in their genetic and clinical
assessment that people who survived the epidemic in Papua New Guinea were carriers of a prion-resistant
factor. The Immunity is a genetic condition that is transcribed at birth. Mead's group
has shown the source of immunity to be the inheritance of a genetic variant of prion
protein G127V. This work remains breaking news as of November 22, 2009, and further
implications of the discovery, including evidence for rapid natural selection of populations,
are being discussed. Kuru in popular culture
The history and epidemiology of kuru has been the subject of both fictional and non-fictional
portrayals. The 2010 documentary Kuru: The Science and the Sorcery recounts the work
of Alpers, Gajdusek and their colleagues in uncovering the link between kuru and endocannibalism
in the Fore and the discovery of prions as the cause of the disease.
The connection between kuru and cannibalism has been drawn in popular entertainment, where
characteristic "shaking" or other kuru-like symptoms are an indicator of cannibalism.
For example, in the 2010 post-apocalyptic film The Book of Eli, people are asked to
show their hands before doing business as trembling hands are considered a sign of cannibalism.
Similarly, in the video games Fallout 3 and Fallout: New Vegas, the player encounters
townsfolk who display kuru-like symptoms after unwittingly consuming human flesh. In the
2013 movie We Are What We Are the elders of a cannibalistic family show symptoms of kuru.
A 1995 episode of the American science fiction television series The X-Files titled "Our
Town" revolved around the residents of a fictional Arkansas town who display kuru-like symptoms,
which apparently result from cannibalistic practices brought back from the South Pacific.
The episode "Theef" also dealt with a victim seemingly suffering from the disease.
The zombie outbreak in the 2011 video game Dead Island, which takes place at a holiday
resort in Papua New Guinea, is described in the game as being a mutated form of kuru.
A season three episode of the cable television series Perception, titled "Shiver", featured
a suspect who had spent time in New Guinea and believed he had kuru.
References Notes