The man who linked kuru to cannibalism
A hike in the New Guinea highlands helps solve a medical mystery, protect Britons from mad cow disease, and reveal an uncomfortable truth about the past. Jo Chandler chats to intrepid biologist Michael Alpers.
The afflicted had contorted, anguished faces and tremors. As their illness progressed, they lost the ability to speak or move, but would laugh uncontrollably. Their devastating disease became known as “the laughing death”.
It had nearly wiped out the Fore people of the Purosa Valley in the remote highlands of what was then the Australian colony of New Guinea.
The Fore believed it was a curse, and blamed sorcery for the condition, which they called “kuru”. Intrigued, medical scientists postulated a genetic cause, or maybe an environmental factor.
When medical student Michael Alpers came across a report of this mysterious disease in the Adelaide Advertiser in 1957, he was drawn by a sense of adventure and the opportunity to “do health in a different kind of way”. So, after graduating in 1961, he secured a post as a medical officer for the Australian administration, and soon found himself deep in New Guinea’s kuru heartland.
Alpers, now the Professor of International Health at Curtin University in Western Australia, now sits in his kitchen in Fremantle and tells me the story of what he found as a young doctor visiting the New Guinea highlands more than 50 years ago.
When he first arrived, he spent “a couple of months walking around, talking to people”.
A particularly warm welcome was extended by a village called Waisa, a solid hour’s trek from the nearest road but smack in the heart of the epidemic. “People said ‘come, you’re very welcome,’ and I settled.”
The Fore people, who lived in the village, built Alpers a hut, replacing it in time with a house supplied with water and a generator. It would become his home — and later that of his young family — for long months over many years.
While kuru was the young medical officer’s focus, Alpers was soon aware of the community’s other urgent medical needs. “We set up a medical clinic. People came from valleys miles away. Everyone at that time had tropical ulcers … fortunately they respond excellently to penicillin. Word got around.”
Over the decades that saw New Guinea become part of independent Papua New Guinea or PNG, that spirit of collaboration was to pay off. The Fore people themselves became critical to solving the kuru mystery, says Alpers. They acted as translators and cultural advisors, nurses and autopsy assistants, data collectors, cooks, security guards, drivers and custodians of precious brain tissue destined for research laboratories overseas.
“We had to climb mountains and cross fast-flowing rivers,” one of the original assistants, Taka Gomea, recalled at a Royal Society gathering on kuru in London in 2008. “When we approached some villages they tried to chase us away, threatening us with their bows and arrows.
We would placate them by giving them salt and other small presents.”It was in the field, in early 1962, Alpers first met American scientist Carleton Gajdusek, who had by then been studying kuru for several years.
A dynamic but controversial figure, Gajdusek, later won the Nobel Prize for his kuru-related work. Later still he was convicted and jailed for child molestation. Alpers did not share the Nobel Prize. Some considered this unjust, but Alpers has said that he did not mind at all.
Gajdusek wanted to test the idea that kuru was a transmissible disease, rather than caused by environmental or genetic factors, “and I did too” says Alpers. Together they planned an experiment: to collect autopsy samples from kuru victims, injected them into chimpanzees and monitor them for 10 years.
Collecting the tissue from afflicted brains was the first challenge. The local kiap, the powerful Australian field officer, vetoed autopsies, telling Alpers “absolutely not, people are fed up”. But Alpers determined that much of the local people’s distress was due to the bodies being examined in hospitals and not promptly returned.
His solution was to conduct limited autopsies in the villages, assisted by local people, and by the families of the dead. This assuaged some of the local anxiety about the process, and secured fresh tissue soon after death.
“So, having established the fact I had permission to do an autopsy I then would go to the kiap and he would provide a coroner’s certificate – in advance – authorising it,” says Alpers. As death approached, Alpers would move into the patient’s village, and wait.
Her end was lingering and awful. Her father despaired and ran away until it was over.
“You couldn’t do anything else but hang around, a bit like a ghoul. And it normally took a long time even after the patient was moribund, [almost] paralysed, but subsisting on sips of sugar water,” Alpers says. He would prepare a hut and his instruments for the autopsy, setting out sterile vials for the tissue.
In his Fremantle kitchen, Alpers picks up an old photo of a little girl leaning on a stick in front of some village huts, looking shyly into the camera. “That’s Kigea,” he says. “She was from my own village, Waisa. A wonderful little 11-year-old girl.”
Her end was lingering and awful. Her father despaired and ran away until it was over; her mother had already been claimed by kuru.
“The extraordinary thing was that I could still make contact. I remember asking Kigea the day before she died to put her tongue out. She was in this locked-in state, but she wasn’t paralysed, and she understood me. It was a terrible situation for everybody.”
After each death, he says, “I would go and talk to the family again, and say, ‘OK?’ They had cut up bodies in the past, so that was not an unusual activity for them …
“The father, or a close relative, would hold the head, and I would take the top of the skull off with a bone handsaw. It would take maybe 20 minutes … like cutting an avocado. I would go to particular parts of the brain … take out small cubes …
“Then I’d take the whole brain out and put it in a bucket full of formalin and cotton wool so it wouldn’t be deformed. All our samples would go into an insulated box. Then I put the skull cap back on, and sewed up. Then we said goodbye … gave everyone a hug, and took off. I did this five times.
It was enough.”
The next morning a chartered aircraft would fly the insulated box to Lae. From there, the box was flown first to Melbourne, and then on to a primate facility at the National Institutes of Health in Bethesda near Washington DC, where Gajdusek had assembled some chimpanzees.
In early 1964, Alpers followed the samples to Washington. There, he and Gajdusek would spend the next four years exploring the pattern of how kuru spread through the New Guinea population.
By now the tissue Alpers had taken from Kigea and another sample from a boy called Eiru had been inoculated into a pair of chimps – Daisey and Georgette. Alpers would visit them twice a week, growing fond of the animals and their personality quirks. “Chimps are so close to humans it made them difficult to use in lots of ways, but we felt we had to do it.”
Two years into the experiment, Daisey and Georgette started behaving strangely. Their gait changed, they had difficulty walking and lost co-ordination. When they couldn’t pick up pieces of apple and put them to their mouths they improvised, using their lips to scoop the apple from the ground. Alpers had seen it all before.
“It was just striking. The tremors, the gait …” By this time Gajdusek was back in PNG. Alpers alerted him by telegram. By the time he arrived a week later, “Daisey was falling all over the place … it was awful. But at the same time there was this elation that our experiment was going to be successful.”
Final proof came several months later, when samples taken from the dead Georgette’s brain were examined by a neuropathologist in London.
A telegram arrived in Washington advising that the chimp’s brain pathology was “indistinguishable” from human kuru.
“We wrote our paper in a day,” says Alpers.Unusually, the paper identified the victims Kigea and Eiru – as well as Daisey and Georgette – by name. Scientific convention generally scrubs documents clean of personal elements such as identity. But in this case the scientists in their haste gave credit where it was painfully due.
Two weeks later, the paper appeared in the journal Nature. It identified kuru as a new category of infectious disease that caused degeneration of the brain and nervous system, and was capable of crossing the species barrier.
The transmissible agent would later be identified as an infectious, self-propagating protein. It broke all previously assumed rules, because it lacked its own genes. The protein was called a prion. It was the first new pathogen identified in more than a century.
The 1966 breakthrough was momentous, but the mechanism that caused kuru to spread remained elusive.
By then Alpers had spent several years reviewing the epidemiology of the disease, trawling through data collected by patrol officers, scientists and missionaries. Their work had been ably assisted by the Fore’s formidable collective memory — “cause of death is always known, even going back three generations”, says Alpers.
He combined the charts with work done by anthropologists in the field, including husband-and-wife team, Robert and Shirley Glasse (who later became Shirley Lindenbaum). They had been looking for clues to kuru in cultural practices and diet, including the Fore’s tradition of mortuary feasting, which the kiaps had outlawed by the time Alpers arrived in 1961.
By eating their dead, they were able to show their love and express their grief.
According to the Fore’s complex belief system, each individual has five souls. After death they travel the country on a farewell tour and ultimately – assuming various rituals are honoured – they are reunited in the land of the ancestors. The most efficient path to the hereafter is for the body to be eaten.
As Alpers, with Jerome Whitfield and other colleagues wrote in a 2008 paper in Philosophical Transactions of the Royal Society B: “If the body was buried it was eaten by worms; if it was placed on a platform it was eaten by maggots; the Fore believed it was much better that the body was eaten by people who loved the deceased. By eating their dead, they were able to show their love and express their grief.”
It was the women’s responsibility to eat the dead, grinding the bones and cooking the flesh, feeding their children the tastiest bits. Although small boys joined in, they were generally excluded after about age 10.
By 1964, Alpers had solid figures on kuru deaths over seven years. “I compared the data for 1957, ’58 and ’59 with ’61, ’62 and ’63,” he says. “If you looked at the young kids, the disease had essentially disappeared – even in that short time.”
“The argument for cannibalism – and I don’t use that term any more, but it was used then – was compelling. Everything fitted,” says Alpers.
“Why did women and children get the disease? Because they were the ones that carried out the practice – the men didn’t. It explained why it was dying out in young children – because the kiaps had proscribed cannibalism. You could also conclude that the disease was not being transmitted vertically from mother to child.”
Unhappy with the language used to discuss his finding – “you don’t like to call your friends cannibals” – Alpers invented a new term for the Fore ritual: “transumption”. It borrowed from the Catholic lexicon concerning the transubstantiation of bread and wine into the body and blood of Christ.
He defined the Fore custom as “incorporation of the body of the dead person into the bodies of living relatives, thus helping to free the spirit of the dead”. It was a final act of love. Yes, as anthropologists insisted, there was a gastronomic element: people testified that humans were delicious, especially their brains.
With the means of transmission identified, the next task was to work out how the outbreak began. According to oral testimonies of the Fore, kuru appeared in the 1910s. In a 1970 paper Alpers proposed kuru had spread from a single spontaneous case of Creutzfeldt-Jakob Disease (CJD) – a rare but well-documented occurrence in any human population.
Spontaneous CJD shares the hallmarks of kuru, but ordinarily the disease is not transmissible. However, if the brain of the afflicted person was eaten, that single episode could multiply over a generation or two, and start an epidemic.
However some people were less susceptible to the effects of kuru than others.
A gene providing elderly survivors of Fore mortuary feasts resistance to kuru was also found to occur across thousands of people from other cultures. This suggested that eating human flesh – and outbreaks of a kuru-like disease – had occurred widely in the human past, Alpers proposed in 2003, in a sensational paper in the journal Science. Cannibalism, it appeared, was one of humanity’s darker secrets.
With kuru having all but vanished, and the mechanism for its spread eradicated, the episode might have disappeared into the annals of curiosity. But then, in the mid-1980s, came “mad cow” disease.
More correctly known as bovine spongiform encephalopathy, or BSE, mad cow disease was a consequence of cows eating meal derived from the recycled offal of other cows. Britons feared that eating diseased beef would see BSE spread to humans.
That fear was realised in 1996when the infection turned up in people as variant Creutzfeldt-Jakob Disease (vCJD). With 177 deaths confirmed to date in the UK, and another 52 elsewhere, it has thankfully not reached the epidemic proportions anticipated – partly because its similarities to kuru were recognised early.
“I spoke to Michael before vCJD appeared, on the basis that we thought it might transmit to humans,” says John Collinge, director of the UK Medical Research Council Prion Unit in London.
“It seemed to me that kuru was the major experience we had of one of these diseases. And we had better get to know as much about it as we can.”
When Collinge landed in PNG, his first question was whether prion disease could really incubate in a human for more than 50 years. Cases from the kuru archive showed that it could. “This was quite extraordinary,” he says.
“We also wanted to see what strain or strains of prions caused kuru,” he says.
“But we couldn’t turn up as westerners and say ‘we’re only interested in kuru — you’re dying of malaria, but that is not our interest’. It was ethically essential that we work with the community, contribute … tend to patients with common infectious diseases that might be lethal without treatment, in the same way they were helping us with our medical problem.”
The result was an enduring funding and co-operation agreement between London and PNG – and a slew of critical clinical data gathered from the Fore.
For instance, inheritance patterns of the genes that shape the body’s defences against kuru and vCJD — and hence survival times— are similar, enabling scientists to predict that further delayed cases of vCJD will emerge in the UK in the next few decades.
Another alarm raised by kuru, says Collinge, is how the use of human tissue in the UK — albeit in medical, not cultural, practice — might contribute to the spread of prion disease.
vCJD prions cross the gut wall after infected meat is eaten, replicating in lymphoid tissue in the gut, before spreading to the brain and other lymphoid tissue such as the appendix. In July 2012, the UK Health Protection Agency published findings from a survey of appendix tissue removed routinely from Britons: it identified abnormal vCJD prions in 16 of 32,441 cases.
“That is quite a worrying figure,” Collinge said at the time, “suggesting that one in 2,000 people in the UK population are infected. Now these individuals are healthy. Will they ever develop CJD? Are they individuals with very long incubation periods like we see in kuru? Some of them, possibly. But I suspect a majority of them will be genuine carriers – infected, but they will never develop the disease themselves. They do, though, represent a risk to others if they are blood donors or donate organs. This is an ongoing public health issue in the UK … and kuru still has things to say about that.”
The most recent insights to be drawn from the PNG kuru archive were published by Collinge and his team in Nature in June 2015, identifying another variation in the prion resistance gene that in mice, rather than simply delay the onset of kuru, provides total protection against it and other forms of CJD.It's been six years since the kuru pathogen last claimed a victim in PNG, a 61-year-old woman from a far-flung hamlet. She could have been only a tiny girl when she ate the morsel that would eventually kill her.
The decades-long surveillance program Alpers set up was finally closed down in 2012.
Kuru may be gone, but it is not forgotten. Although Alpers retired from his long-held post as chief of the PNG Institute of Medical Research in 2000, he trekked into the highlands after being summoned to a rumoured kuru case that turned out to be Parkinson’s disease only about five years ago.
“Kuru is still the first thing people think of if anyone gets a bit shaky,” he says. “It’s an extremely powerful disease, horrible to live with, and horrible to see someone die of. People are still very much afraid of it.”
This is an edited and updated version of an article originally published in The Global Mail.