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Season 1 · Episode 4

One Flew Over The Kuru Nest

29:03Updated November 10, 2026

How does Monticello span to Kuru and the cannibalistic Fore people of Papua New Guinea? Traverse from Thomas Jefferson and his plan for maple sugar, ending slavery, and the Louisiana Purchase, westward expansion along the Oregon Trail, the fate of the Donner Party, cannibalism, Fore people, Daniel Carleton Gajdusek, and the Kuru prion disease.

0:0029:03
Transcript

In this episode

Jump to
  1. Kicked Out of Mount Vernon
  2. Jefferson’s Maple Scheme
  3. The Oregon Trail
  4. The Donner Party
  5. Kinds of Cannibalism
  6. Kuru, the Trembling Death
  7. A Protein That Folds You
  8. One Flew Over the Kuru Nest
  9. Corrections to the audio
Snow-covered pine trees and a partially frozen Truckee River in winter

Truckee River

© Bruce Cooper, CC BY-SA 3.0
Two cross-sectioned lobes of a Kuru-infected cerebellum

Cerebellum with Kuru

© D.C. Gajdusek, CC BY 3.0

Kicked Out of Mount Vernon#

This one opens with a confession: one of us nearly got thrown out of George Washington’s house. The crime was chewing gum. A guard at Mount Vernon spotted it, delivered the firm reminder that this is a museum, sir, and set off a quiet panic in which a whole tour group of fellow gum-chewers discreetly tucked their wads into their cheeks before anyone else could be singled out. It is a small and very human story, and it is also, improbably, the first step on a path that ends at the strangest infectious agent biology has ever found, one that carries no genes at all. The road there runs through a founding father’s sugar idealism, a doomed wagon train, and a funeral ritual on the far side of the world. The thread holding it together, the whole way, is what people choose to eat.

Jefferson’s Maple Scheme#

From Washington’s Mount Vernon it is a short hop to Thomas Jefferson’s Monticello, and to one of Jefferson’s lesser-known enthusiasms: maple sugar. Jefferson was close with Dr. Benjamin Rush, the Philadelphia physician, signer of the Declaration, and one of the more outspoken abolitionists among the founders. In the early 1790s Rush threw himself into an unusual campaign to get Americans to sweeten their tea with sugar tapped from maple trees instead of cane. The appeal was practical and moral at once. Maple was cheap and homegrown. Cane sugar was grown by enslaved people in the West Indies; maple sugar could be made by free farm families in a New England spring. Rush’s stated aim was to cut the demand for slave-grown sugar and, by doing so, to help strangle slavery itself. To prove the product, he staged a kind of scientific tea party, pouring cups sweetened with equal measures of cane and maple sugar for guests including Alexander Hamilton, who agreed the maple was every bit as sweet.

Jefferson signed on with gusto. He urged farmers to keep a stand of sugar maples the way they kept an apple orchard, and he put his own land to the test, buying sixty saplings from a Long Island nursery and having them planted in a grove at Monticello. Virginia, it turned out, is too warm for good sugaring, and the trees died, nearly all of them within a few years. The grand scheme to make the young United States a sugar power never materialized. But maple sugar caught on enough in the North to become a real provision, the kind of thing a family would pack for a long trip. And in the 1840s, a great many families were about to take the longest trip of their lives.

The Oregon Trail#

They packed it onto the Oregon Trail, the roughly two-thousand-mile overland route from the Missouri River to the valleys of Oregon, beaten in by fur traders and trappers and considered passable for wagons by about 1840. The provisioning lists were enormous: hundreds of pounds of flour and bacon per adult, beans, a keg of rendered fat, sometimes live cattle driven alongside, and yes, sugar, including maple sugar carried west from the world Jefferson and Rush had been promoting. Canned food existed but was new and expensive, so most families ate what they could carry and what they could forage, picking berries along the way.

As the traffic grew, so did a small industry of guidebooks promising the fastest way west. A guidebook is a wonderful thing until it is selling you a shortcut. That is the hinge this whole story turns on, because one such promoter talked one such party into one such shortcut, and the result is the most infamous tragedy of the westward migration.

The Donner Party#

In the spring of 1846, a group that would swell to about eighty-seven people, several families plus stragglers met along the way, set out from Springfield, Illinois, bound for California in a column of ox-drawn wagons. Near Fort Bridger they chose to leave the established trail for a new route called the Hastings Cutoff, named for a self-promoting guide named Lansford Hastings who had publicized it as a faster way to California before ever traveling it himself. It was not faster. It dragged them across the Wasatch Range and the punishing salt flats west of the Great Salt Lake and added something like a hundred and twenty-five miles, costing them weeks they did not have. By the time they reached the Sierra Nevada in late autumn, an early and ferocious snowfall had sealed the passes, and the party became trapped near Truckee Lake, now called Donner Lake, for the winter of 1846 to 1847.

What followed is the part everyone half-remembers. Supplies and livestock gave out. A small group strapped on snowshoes in mid-December and set off to find help; the first relief party did not reach the camps until the middle of February, more than three months after they were trapped. People later photographed the tree stumps the survivors left behind and found them tall, not because anyone climbed the trees but because that was the depth of the snow when the trees were cut. Of the roughly eighty-seven in the party, about forty-eight survived, most of them women and children. Some survived, in the end, by eating the bodies of those who had already died. The Truckee River and the lake that bears the party’s name are the quiet backdrop to that fact.

Kinds of Cannibalism#

Cannibalism, it turns out, comes in categories. Exocannibalism is eating someone from outside your own group, the stuff of warfare and, in the modern imagination, of serial killers. Endocannibalism is eating someone from within your community or family, and one form of it is ritual or funerary cannibalism, eating the dead not to survive but as a rite, a way of honoring or mourning them. The Donner Party is survival cannibalism, a horror born of circumstance. But the case that turns this episode from history into microbiology is funerary, and it belongs to the Fore people of the eastern highlands of Papua New Guinea.

The Fore practiced a funerary cannibalism in which deceased relatives were mourned by being consumed, a way of returning the dead person to the community and helping free the spirit rather than leaving the body to rot in the ground. The work of preparing and eating the dead fell largely to the women and the children, who handled the corpses and ate the organs, including the brain. That detail, who ate the brain, is the whole story, though no one knew it yet. Through the middle of the twentieth century, Fore women and children began dying by the thousands of a mysterious affliction no outsider could explain.

Kuru, the Trembling Death#

They called it kuru, from a Fore word meaning to shake or tremble, because that is how it began: a creeping loss of coordination, an unsteady stance, a gait that wobbled and failed. The medical term is cerebellar ataxia, the breakdown of the brain’s coordination center, and footage of afflicted Fore shows people unable to stand without support or to bring their own fingertips together. It had a crueler nickname too, the laughing sickness, because in its course patients’ faces would contort into something between a smile and a grimace, bursts that looked like laughter wrung out of failing muscles. The disease moved through three stages, from the still-walking phase, to the inability to walk unaided, to a final stage of helplessness, difficulty swallowing, and wasting, with death usually following within roughly three months to two years of the first symptoms. It was, without exception, fatal, and there was no treatment then and none now.

The most unnerving feature was the delay. Kuru’s incubation period averaged around a dozen years and could stretch to fifty or more, so a meal eaten in childhood could kill someone in middle age. The generally accepted explanation is that the epidemic grew from a single seed: sometime around 1900, one person on the edge of the kuru region likely developed a spontaneous case of something like Creutzfeldt-Jakob disease, a rare brain disorder that arises on its own in roughly one or two people per million each year. That person died, was eaten according to custom, and the agent began to spread, concentrated in the brain and passed on most efficiently to the women and children who consumed it. The men, who largely abstained from the brain, were mostly spared.

A Protein That Folds You#

In 1957, an American researcher named Daniel Carleton Gajdusek, working with the physician Vincent Zigas, brought kuru to the world’s attention, and Gajdusek went to live among the Fore to study it. Back in the United States he did the experiment that cracked it open: he inoculated chimpanzees with brain tissue from people who had died of kuru, and after a long wait, one of the chimps, named Daisy, developed the disease. That proved kuru was transmissible, an infection rather than a purely inherited or environmental condition, even though no one could find any virus, any bacterium, any DNA or RNA at all in the infectious material. For that work Gajdusek shared the Nobel Prize in 1976. A veterinarian named William Hadlow had already noticed, in 1959, that kuru looked uncannily like scrapie, a fatal brain-rotting disease of sheep that leaves the animals scraping themselves raw against fences.

The agent with no genes turned out to be a prion, a word coined by the neurologist Stanley Prusiner, who won his own Nobel in 1997 for the idea. A prion is simply a protein gone wrong. The normal protein, called PrP, sits on the surface of nerve cells in a tidy, coiled, alpha-helical shape. The dangerous version is the same protein folded into a flat, sheet-like form (the abbreviation for that misfolded form borrows from scrapie, the first such disease recognized). What makes it infectious is templating: the misfolded protein, on contact, coaxes a normal copy to refold into the bad shape, which then converts the next one, and the next. Picture a circle that touches a square and becomes a square. In many cases of kuru the misfolded proteins pile up into dense clumps called amyloid plaques, and the disease punches the brain full of microscopic holes until it looks like a sponge, which is why this whole family of illnesses is called transmissible spongiform encephalopathy.

If that sounds like an exotic problem confined to a remote highland, the modern world got its own lesson in the 1980s. British cattle began staggering and collapsing with a new prion disease, bovine spongiform encephalopathy, better known as mad cow disease. The cause was a kind of industrial cannibalism: cattle were being fed protein supplement rendered from the remains of other animals, including other cattle, recycling the misfolded protein through the herd. It then crossed into people who ate contaminated beef, surfacing in the mid-1990s as variant Creutzfeldt-Jakob disease and killing 178 people in the United Kingdom. One scholar called it the first man-made epidemic, since it took a human decision, feeding ground-up animals to herbivores, to move the pathogen into our food. The Fore had stumbled into the same trap with their funerals, just by hand.

One Flew Over the Kuru Nest#

From a gum-chewing scolding in George Washington’s house, through Jefferson’s maple scheme, the Hastings Cutoff, and a Fore funeral, the chain ends at a protein that copies a bad fold. The connective tissue is food and the customs built around it. Looking at the Fore as uniquely self-inflicted misses the point the show lands on: every culture has practices that quietly harm it, the oversized soda and the cigarette as much as the funeral feast.

When the Fore gave up cannibalism around 1960, the disease stopped finding new victims, and the last known death was in 2005. In the survivors, researchers found a protective variant of the prion gene that had spread under the pressure of the epidemic, natural selection caught in living memory. A prion is not alive. It does not breathe, eat, or carry a single gene. It is a shape, copying itself one fold at a time. One flew over the kuru nest, and infection had to stretch to cover a protein with no genome.

Corrections to the audio#

The episode audio states seven things that are wrong. The corrections:

  • At 12:54, the audio says rescuers took about two months to reach the party. The emigrants were trapped in early November 1846 and rescuers reached the camps in February 1847, more than three months later (National Park Service).
  • At 18:29, the audio calls prion plaques areas of cell death. They are deposits of amyloid fibrils made of misfolded prion protein (Liberski et al., Viruses (2019)).
  • At 19:27, the audio says cerebral ataxia. Kuru is a progressive cerebellar disease, and its ataxia is cerebellar ataxia (Alpers, Philosophical Transactions of the Royal Society B (2008)).
  • At 20:27, the audio says the incubation period could be as short as five years. It may often have been as short as two years (Alpers, Philosophical Transactions of the Royal Society B (2008)).
  • At 22:16, the audio says death came three months to two years after the terminal symptoms began. That range, about 3 to 23 months, runs from the first symptoms to death (Liberski, Pathogens (2013)).
  • At 23:40 and 24:25, the audio calls the chimpanzees monkeys. Chimpanzees are apes (Liberski, Pathogens (2013)).
  • At 25:04, the audio says a 44-ounce Coca-Cola has about 380 calories and several grams of sugar. A 12-ounce can has 140 calories and 39 grams of sugar, so 44 ounces has about 510 calories and 140 grams of sugar (Coca-Cola).

Hosts

Sources and Credits
  1. CreditWritten and performed by Dr. Dustin Edwards and Dr. Faith Cox (another site)
  2. MusicCrinoline Dreams by Kevin MacLeod (another site)incompetech.comCC BY 4.0
  3. ImageCerebellum from a Kuru-infected Fore patient (another site)Daniel Carleton GajdusekCC BY 3.0
  4. ImageTruckee River (another site)Bruce CooperCC BY-SA 3.0
  5. referenceSugar Maple (Thomas Jefferson Encyclopedia) (another site)Monticello.orgBenjamin Rush's maple-sugar campaign and 'scientific tea party' with Alexander Hamilton; Jefferson bought sixty sugar maples from the William Prince Nursery for Monticello; the aim was to undercut slave-grown West Indian cane sugar.
  6. referenceThomas Jefferson and the Maple Sugar Scheme (another site)Colonial Williamsburg JournalOf the sixty saplings planted at Monticello, nearly all died within a few years; Virginia proved too warm for commercial sugaring.
  7. referenceDonner Party (another site)Wikipedia~87 members took the Hastings Cutoff and were trapped near Truckee Lake (now Donner Lake) in winter 1846-47; the snowshoe 'Forlorn Hope' left Dec 16 1846; first relief arrived mid-February 1847; only 48 survived.
  8. referenceDonner party (History, Route, Facts, Survivors) (another site)Encyclopaedia Britannica87 people (29 men, 15 women, 43 children) in 23 ox-drawn wagons; Hastings claimed his cutoff would shave more than 300 miles from the journey.
  9. referenceHastings Cutoff (another site)U.S. National Park Service, California National Historic TrailHastings proposed the cutoff in his 1845 guide though he had never been that way; in spring 1846 he crossed it eastbound with a party of horsemen; it begins at Fort Bridger and turned out to be over 100 miles longer than the original California Trail.
  10. referenceDonner and Reed Wagon Train Incident (another site)U.S. National Park Service, California National Historic TrailThe Donner-Reed party consisted of 87 men, women and children and left Illinois on April 12, 1846; of the 87, 40 died that winter.
  11. referenceChristmas on the Emigrant Trails: Christmas 1846 at Donner Lake, California (another site)U.S. National Park ServiceThe party tried to cross the central Sierra Nevada in early November 1846 and was trapped by blizzards near present-day Truckee; rescuers reached the camps in February 1847.
  12. referenceTraveling the Emigrant Trails (another site)U.S. National Park ServiceThe 2,000-mile trip took 4 to 6 months; Joseph Ware's 1849 guide suggested, for three people, 1,080 lbs of flour, 600 lbs of bacon, 150 lbs of sugar, 50 lbs of lard and beans, with canned foods listed among the luxuries.
  13. referenceRobert Newell and Joseph Meek reach Fort Walla Walla with the first wagons driven overland to the Columbia River in September 1840 (another site)HistoryLink.org (Essay 5235)Newell and Meek's wagons were the first to reach the Columbia River over land, opening the final leg of what became the Oregon Trail to wagon traffic.
  14. referenceOregon Trail Education Resource Guide (2016 edition) (another site)Bureau of Land Management, National Historic Oregon Trail Interpretive CenterWild berries, roots, greens and fish might supplement the diet; Benjamin Bonney, who traveled the trail at age 7 in 1845, recalled that his father made over a hundred pounds of maple sugar that the family took along instead of loaf sugar.
  15. referenceA Novel Protective Prion Protein Variant that Colocalizes with Kuru Exposure (another site)New England Journal of Medicine 361:2056-2065 (Mead et al., 2009)A protective prion protein variant, G127V, was found only in the region where kuru was prevalent and was selected during the epidemic.
  16. referenceKuru (StatPearls) (another site)NCBI Bookshelf / NIHPrototype human prion disease, first reported by D. Carleton Gajdusek and Vincent Zigas in 1957; cerebellar signs; death within one to two years of symptom onset.
  17. referenceThe epidemiology of kuru: monitoring the epidemic from its peak to its end (another site)Michael P. AlpersPhilosophical Transactions of the Royal Society B (2008)The last death from kuru was in 2005, with no known current case; the epidemic is generally accepted to have arisen in a single individual from a spontaneous change.
  18. referenceKuru: Genes, Cannibals and Neuropathology (another site)Journal of Neuropathology and Experimental Neurology 71(2):92-103 (Liberski et al., 2012)First human neurodegenerative disease proven transmissible; led to Nobel Prizes for Gajdusek (1976) and Prusiner; kuru imposed balancing selection on the Fore at PRNP codon 129; Hadlow linked kuru to scrapie in 1959.
  19. referencePrions (Learn.Genetics) (another site)University of Utah, Genetic Science Learning CenterNormal prion protein (PrP-sen) misfolds into PrP-res; misfolded prions kill neurons leaving the brain full of holes; the Fore cooked and ate their dead (women and children), explaining the sex/age pattern; cannibalism's end halted spread.
  20. referenceKuru: A Journey Back in Time from Papua New Guinea to the Neanderthals' Extinction (another site)Pathogens 2(3):472-505 (Liberski, 2013)Kuru won Gajdusek the 1976 Nobel Prize and contributed to Prusiner's 1997 Nobel Prize; transmission to children stopped in the 1950s when cannibalism ceased among the Fore, though incubation periods of more than 50 years meant cases continued; the Fore practiced ritual endocannibalism, eating relatives as part of mourning; a gold prospector first witnessed kuru in 1936; patients came to need support to stand, and dysmetria was usually the first sign of upper-limb ataxia; kuru lasted about 12 months (3 to 23 months) from the first signs to death.
  21. referenceKuru, the First Human Prion Disease (another site)Viruses 11(3):232 (Liberski et al., 2019)Electron microscopy of kuru brains showed typical plaques composed of amyloid fibrils; misfolded PrPSc was present as kuru plaques and in synaptic and perineuronal sites.
  22. referencePrions (Nobel lecture) (another site)Stanley B. PrusinerProceedings of the National Academy of Sciences 95(23):13363-13383 (1998)PrPC sits on the cell surface and is about 40% alpha-helix with little beta-sheet; PrPSc is about 45% beta-sheet and acts as a template for converting PrPC; prions are devoid of nucleic acid.
  23. referenceCreutzfeldt-Jakob Disease in the UK (By Calendar Year), monthly statistics as at 6 January 2025 (another site)National CJD Research and Surveillance Unit, University of Edinburgh178 definite or probable variant CJD deaths in the UK (123 definite, 55 probable); none of the cases still alive as of January 2025.
  24. referenceAbout Variant Creutzfeldt-Jakob Disease (vCJD) (another site)U.S. CDCvCJD is caused by eating meat from BSE-infected cows; feeding cattle meat-and-bone meal from dead cows fueled the UK outbreak; first vCJD cases reported 1996, ~10 years after exposure.
  25. referenceVariant Creutzfeldt-Jakob disease (another site)WikipediaDescribed as the first 'man-made epidemic': feeding meat-and-bone meal to herbivorous cattle moved an animal prion into the human food chain.
  26. referenceCoca-Cola Original (another site)The Coca-Cola CompanyA 12-ounce can of Coke contains 140 calories and 39 grams of sugar.
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