There's a non-zero chance that we're about to experience another huge population bottleneck due to misfolded proteins. Prions bioaccumulating in the environment for untold years is the terrifying part.
I read this book years ago. Fascinating and scary subject. At the time I read this book, I was wondering about plants - now I have the answer - yes - it is transmissible via plants.
In this brilliant and gripping medical detective story. Richard Rhodes follows virus hunters on three continents as they track the emergence of a deadly new brain disease that first kills cannibals in New Guinea, then cattle and young people in Britain and France -- and that has already been traced to food animals in the United States. In a new Afterword for the paperback, Rhodes reports the latest U.S. and worldwide developments of a burgeoning global threat.
Honestly the fact that prions can just hang out on grass and leaves is beyond horrifying. For me the Chronic Wasting Disease was the most unsettling part of my research, that the environment itself was a reservoir of infectious proteins.
Very strange that these misfolded proteins do not degrade into single proteins once outside the organism in which tbey were created. Also, when eaten, one would expect stomach acid to denatute them as is usually the case for ingested proteins. A few years back when frau Merkel was the pm of Germany there were some theories about her suffering from kuru, as there were multiple videos in which she showed symptoms similar to those of kuru.
Stone Age Herbalist, a few aspects of your summary don't seem to fit with the explanation for kuru. First, was the rate of kuru in the 1950s-70s an increase over what occurred in prior eras? The way you described it makes it sound as if the incidence in the postwar period was an abrupt increase over prior times. If that's so, what would account for it? Had the Fore given up cannibalism before the war, but then returned to it after the war? And why would they have restarted cannibalism then? Second, the rate of fatal disease (>10%) is extremely high, even for a homozygous condition. By your description, it had a major impact on social behavior (e.g., marriage patterns), which implies that this rate of kuru was very unusual for the Fore. The rate might be so high as to threaten extinction. In contrast, the prevalence of homozygous sickle cell disease (not trait) seems to be about 1-3% in west Africa. That seems like a much more evolutionary stable proportion.
I think Kathleen Lowrey's comment about the second-hand nature of reports of cannibalism also deserves discussion.
Thanks Devon! To answer some of those questions - the annual death rate for kuru approached around 2% of the population at its peak and almost certainly represents an event of spontaneous CJD-like prion disease entering the Fore speaking population. Given that prion incubation rates can be as long as 20+ years (median is 12 iirc) then it stands to reason that around 1890-1900 was the initial kuru death. Nobody really knows when the Fore began endocannibalism, but their neighbours practice exocannibalism, which is consistent with anthropological behaviour for 'rival' or 'differentiated peoples'. Spontaneous CJD is rare, and to get a situation where people are eating one another in quantities to pass along a prion is rarer still, but it does happen - prion diseases from animals to humans and between animals follows a similar pattern.
Ultimately I think given that we have Fore brain tissue with vacuoles, that Fore brains have been used to infect other animals, that the kuru prion has been sequenced and matches other prion diseases, that the Fore have a distinctive heterozygous generation of females for codon 129 and that kuru behaves in the same way as other prion diseases - it seems all but certain that kuru is a prion disease spread through eating human flesh. The nail in the coffin is that only this sequence of events could account for the sex disparity in the death rates. Female protein availability is well known in the anthropological literature to be limited in many parts of the world, and they will eat just about any source of protein they can find. There are interviews with older Fore women who describe the mortuary feasts and the taste of human meat.
On whether cannibalism is implicated, whatever causes kuru, I'd recommend
Review: Kuru and Cannibalism?
Reviewed Work(s): Kuru: Early Letters and Field-Notes from the Collection of D.
Carleton Gajdusek by Judith Farquhar and D. Carleton Gajdusek
Review by: Lyle B. Steadman and Charles F. Merbs
Source:
American Anthropologist , Sep., 1982, New Series, Vol. 84, No. 3 (Sep., 1982), pp.
611-627
It cites Arens, whom I consider unreliable (Arens thought cannibalism has basically never been practiced anywhere, my own view is that he was totally wrong about this -- there are lots of examples in the whole human record). But leaving that aside, the review makes a very good and specifically documented case that all of the accounts of cannibalistic practices of the sort that would explain the pattern of kuru (mortuary cannibalism by women) are second-hand anecdotes.
Finally, if Gadjusek had been an all-round stand up guy, it would be easier to suppose he never played fast and loose with evidence. That's just not the case with Gadjusek... at all. Maybe mentioning this part of Gadjusek's history didn't seem relevant? But it is relevant to assessing whether we should take challenges to his work seriously. Was he generally a person of high integrity? Nope.
Thanks, its an interesting review and Gajdusek was obvs a disagreeable personality regardless of his integrity. I'm not convinced by the counter-arguments against the cannibalism-prion hypothesis though: firstly Arens is just wrong and his work is considered incorrect even amongst today's anthropologists, but the sentiment that cannibalism was a colonial fantasy was strong between the 50's and the 70's, and researchers working with the Fore at the time were both squeamish and sensitive about the subject, hence a lot of back and forth in the field notes and later on about it. Secondly, the review was written before definitive knowledge of the prion protein and folding disorders. We have both the brains of kuru victims and their genetics, which show that fibril plaques and vacuoles formed in the cerebral tissue, along with the SNP polymorphisms at codon 129 on the PRNP gene. Kuru has been transferred into multiple animals and the exact protein sequence and isomers are known. Fore people have been carefully studied by age and sex and there is distinctive and reproducible loss of the Hardy–Weinberg equilibrium at codon 129 amongst females born prior to the end of the cannibalistic mortuary feasts, and weaker disequilibriums for males who would have been children at the time. Add to this that kuru behaves in the same way as other prion diseases, it seems a watertight case imo.
Sorry that is not an honest summation of the article. This is not about PC squeamishness this is about whether anyone actually observed a practice Gajdusek makes central. If it is prions (IF), that women are tasked with handling corpses and heads of corpses specifically is widely attested by direct observation and thus a more plausible transmission source. Less titillating than cannibal ladies but life bees that way sometimes.
I now also wonder… when I say Gajdusek’s lack of personal integrity are you aware of what I mean? It is not “oh he was kind of a jerk”.
You can make a perfectly valid case for both the vector of transmission and the existence of prions without Gajdusek's work - Shirley Lindenbaum and Robert Glasse were the anthropologists who conducted the field work on Fore kinship and mortuary traditions, and it was they who demonstrated that Fore endocannibalism matched the spread of kuru. Ignoring Gajdusek's work on transmission, kuru brains and the discovery of prions and subsequent work on prion protein genetics is enough on its own to prove how kuru began and spread. Otherwise we have a massive coincidence that some other unknown cause of death was also operating on people who separately happened to have a degenerative prion disease.
Not to be too pedantic, but it's not beneficial to my offspring for me (and later them) to die. It's beneficial to the wider society, potentially, to nip the problem in the bud. But in this case me and my offspring are the problem being nipped, which is definitely not helpful.
I don't quite understand how being heterozygote could act as selection for future generations since heterozygote individuals could presumably have homozygote descendants by chance (e. g. ab mating with ab can produce ab, aa or bb).
People with rarer versions of gene will breed more than people with more common versions or gene, keeping all versions roughly as common (if they otherwise are equally good).
That said, since it only offers protection against a thing you will not get unless you eat diseases meat, this strategy is dumb.
Thank you for your detailed response. However, the main questions I posed remain. If kuru didn't arise until the late 1800s, then presumably cannibalism didn't occur in meaningful frequency until then -- very recently in evolutionary time. What happened in the Highlands to cause such a shift in behavior? In addition, a 2% annual death rate, producing a 12.5% (2,500/20,000) decline in population within a generation, is not sustainable demographically for very long. Sickle cell disease produces orders of magnitude less mortality. If what you describe is accurate, the Australian prohibition of cannibalism saved the Fore from extinction. Furthermore, the integrity of researchers and their research is extremely important. If Gajdusek's scientific character is questionable, then the case here might begin to crumble. As Kathleen Lowrey has noted, it's tough to make a "watertight" case if there are no credible direct and detailed observations of the behavior responsible for transmission by multiple independent observers. Off the top of my head, I can't think of another infectious condition that lacks such critical evidence.
A lot of things happened in the Highlands - WW2, Australian administration, the introduction of canned foods, the loss of forest territory and more. The comparisons between prion disease deaths and sickle cell are not valid, they are not the same biological agent - prions are not a species of living creature, they are not a parasite or a virus.
Gajdusek is not a lynchpin in this case, his integrity regarding Fore endocannibalism is not especially important in building the case. We have Australian patrol reports, a legal ban on cannibalism in the Highlands, the work of anthropologists like Lindenbaum and Glasse, oral testimony from Fore themselves.
Besides this, we know that cannibalism is involved in the transmission of prion diseases, look at the epidemic of bovine spongiform encephalopathy - cows being fed ground bovine meat and bone meal led to the spread of the BSE prion in the population. You can ignore Gajdusek and still have a tight case for the origin and spread of kuru: we have kuru brains, we have the prion proteins, we have the genetics of the protein, we have the genetic tests of the Fore, we have multiple other prion diseases to compare it to.
I asked what happened in the Highlands in the late 1800s that would have caused the onset of kuru. WW2, the Australian administration, canned foods, and forest loss came many decades later. You are trying to make an evolutionary argument for events that seemingly came about very recently in evolutionary time. If the Fore were cannibals for centuries or millennia, wouldn't have kuru began long before the late 1800s? And if so, the high death rate from kuru would have eliminated the Fore from existence. Sickle cell disease is not an infection -- it's a homozygous condition, so it is parallel with the scenario you paint for kuru (with homozygous individuals susceptible to disease when exposed to an environmental factor). It's also relevant as a condition that seemingly has been around a long time and developed into an evolutionarily stable pattern -- something that the mortality from kuru that you describe would seem to be impossible on demographic grounds alone.
A proper epidemiologic investigation would involve comprehensive assessment of all possible factors for the symptoms and deaths, including exposure to modern medical care among many other factors. And such an investigation would also involve gathering direct, observable evidence of the factors associated with disease. Such investigations seem to be absent for kuru.
I'm a little mystified about the strident defense of the kuru hypothesis. Science is about taking doubts and questions to challenge hypotheses. I didn't question kuru before I read your piece. But now that I see the obvious anomalies and defects in the research (all of the other evidence you mention notwithstanding), I have serious doubts.
1. One would have to search through the German colonial literature to understand the history of the Highlands during the 19th century, but there were plantations, missionaries, new diseases and other disruptive factors that could account for a change of mortuary practice, but we don't know. Spontaneous CJD is rare, and total endocannibalism i.e eating every part of a human body, is also rare, so we have no baseline of kuru-like epidemics since the conditions to create a prion epidemic are unusual.
2. You seem to want to rule out either the mortality rate or kuru altogether as the agent on evolutionary grounds, which is using theory to attack the empirical data. The evolution of prion diseases is still under research, and the positive feedback loop created by the Fore cannibalism practice is arguably an unnatural phenomenon. One can always disrupt some posited evolutionary equilibrium.
3. The epidemiology for kuru is one of the longest running data collection projects in the world. UCL's Prion Unit only finished their fieldwork in 2012. There has been consistent monitoring of the Fore and surrounding peoples for the last half century, identifying the last victims of kuru between 2005-2009. I don't know what more you would expect to be done given that not many in the medical profession have any doubts over whether kuru is a prion disease - if somebody wants to analyse the data or collect more to create a counter-hypothesis then they are free to do so. But since all the foundational principles of kuru were repeated during the BSE outbreak, there's no question that infectious proteins can be transmitted between organisms by endocannibalism.
4. If kuru had never occurred and Gajdusek never worked on prions, the BSE crisis would have led researchers to the same conclusions - prions can be passed within species and between species through consumption of infectious tissue. BSE was passed between cattle, mice, cats and so on. Likewise Chronic Wasting Disease can be passed between species. One can breed mice to express variant PrP proteins and they will develop all the symptoms of neurodegenerative prion diseases.
5. If the counter-hypothesis is that kuru was not caused by a prion, then one has to accept that it is a pure coincidence Fore women of a particular generation show a disequilibrium in the 129 codon, which also coincidently happens to be one the most important sites for SNPs in all other prion diseases.
I appreciate your additional comments, but your responses don't address the fundamental questions I raised and you don't seem troubled by the significant gaps in evidence. As I said, I didn't question kuru until I read your piece and saw the huge holes.
2. I'm not using theory to attack data, but data to challenge theory. The data are the very high mortality rates, and the theory (that you describe) is that kuru and cannibalism in the Fore are not new in evolutionary terms and are related to each other. I'm also noting the wholesale lack of epidemiologic and experimental data to justify the interpretation of kuru among the Fore (which is an hypothesis). As Kathleen Lowrey noted, nothing is indisputable in science, and all knowledge is provisional.
3. I have stated in multiple comments the kinds of epidemiologic evidence that are absent for the kuru hypothesis.
4. Even if this genetic association is genuine, and not marked by serious methodological and design flaws as in the kuru research, it is secondary evidence. Without sound basic epidemiologic and experimental evidence, the kuru hypothesis is deficient at a primary level in empirical terms.
If these reviews of kuru research (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6466359/; https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2577135/) are accurate, it seems that the experimental transmission studies did not involve controls (such as brain tissue from non-kuru human corpses) and they involved transmission routes very different from cannibalism exposures (intracerebellar injection [https://www.jstor.org/stable/1721151] vs. oral consumption). Also, it's not clear that any of the epidemiologic studies among the Fore involved comparisons with persons unaffected by kuru, or if they did, involved comprehensive assessment of diverse potential factors. The evidentiary gaps for the kuru hypothesis are massive.
I wrote somewhat inaccurately about one of the parallels between kuru, as Stone Age Herbalist describes it, and sickle cell disease. Disease occurs in homozygous individuals in both cases, but only the hypothesized kuru requires an environmental exposure to develop. However, apparently those with sickle cell disease are more vulnerable to malaria than those heterozygous individuals with sickle cell trait. Another parallel is that heterozygous individuals in both cases have some protection against disease when exposed to a particular environmental factor (malarial parasites in the case of sickle cell disease).
Very interesting, but I do not fully understand how a population can remain heterozygotic. Surely mixing between fully heterozygotic individuals will lead to a 50:50 hetero-homo split in the next generation. At least if men and women are both heterozygotic, order of pairs doesn't matter, and my very rudimentary GCSE level understanding of this holds up.
Can you link what work this is - I've been reading Duesberg's thoughts on kuru, and while he attack Gajdusek's insistence that kuru is a 'slow virus', I can't find a single reference to prions or Duesberg's response to prion diseases. All I can see is that Duesberg is using Gajdusek's methods to discredit the approach taken to identifying a virus - but as we now know, kuru is not a virus.
Yes this was earlier, but if you come away from it thinking “Gajdusek sounds like a researcher from whom I should believe startling new claims”, well. The first several chapters of - Inventing the AIDS virus- are a tour de force history of virology even if you think Duesberg is wrong about AIDS.
OK, I'll give it a read, but I don't see what this has to do with prions? Is your argument that prions don't exist, or that they do exist but not for kuru? That kuru is caused by something else? Clearly you don't think much of Gajdusek, but I don't see what the argument is about kuru - it's clearly a prion disease, or is it a coincidence that kuru infected brains happen to suffer from plaque-vacuoles which account for how kuru patients died?
My argument is that both sides of your cannibalism kuru case are flawed. The cannibalism side fatally by lack of direct evidence, the kuru side by doubts about Gajdusek, the science of prions, and also whether kuru was epidemiologically among humans what Gajdusek said it was: an infectious disease most specific to women.
I disagree - cannibalism amongst the Fore has been documented by multiple anthropologists, by Australian adminstrators and law enforcement officers, and by the Fore themselves. Gajdusek is irrelevant to this question.
The science of prions is indisputable, they are amongst the most studied proteins in the world, and prion disease prevention is a major part of every developed country's public health system. To call it 'my' cannibalism case is ridiculous, I'm not advancing some obscure theory, it is one of the most studied medical events of the last 100 years, and the genetics continues to be advanced to the point where we can infer CJD amongst Neanderthals.
I don't know what point you're making, but there are plenty of papers of kuru victims who participated in mortuary feasts as children - eg this paper of a 16 year old male brain who died in 1967:
and this paper of a 60 year old male brain, a man born in 1943 who was confirmed by his community as having eaten human tissue as a child, whose mother died of kuru in the 1960's:
Thank you, Kathleen. I think it's reasonable to wonder how his behavior might have affected his research. Clearly, many people around him knew what he was doing for many years, and that could have left him open to manipulation (e.g., blackmail) by others who wanted him push (or suppress) a particular point of view. Also relevant were his former employers, who might have had interest in kuru for bioweapons/biodefense or just creating fear about another condition that supposedly threatens the world.
I don't think it has to be an elaborate conspiracy! I just think he was a person of low integrity and being a research star let him get away with more of what he wanted to get away with. Coming up with a very dramatic account of his groundbreaking research and how it was also lurid and exotic helped make him a kind of darling: ooh, he's a maverick! Get out of the way and let him do his boundary-breaking thing!
I also think pedophiles are not so much attracted to children as they are attracted to violation, lying, corruption of innocence, duper's delight.... there are many kindred pleasures to be had as a crooked research superstar. Quite a few red flags about the plausibility of Gajdusek's research have been raised along the way but the response is "oh you are SHOCKED by cannibalism or oh you are SMALL MINDED about this totally novel epidemiological claim". It has an overlap with "oh you don't understand he really LOVES those boys, why are you suspicious you conventionally minded little nobody" I think Gajdusek was perfectly aware of how these things could conveniently resonate in his life and enjoyed both to the hilt.
I'm just mentioning possibilities, along with the ones you mentioned. It is strange, however, that he got a Nobel for what seems to be weak work, even by the standards of the times. That implies he had very powerful supporters working behind the scenes, if only to overlook/cover up what he did and was doing to those children. And his work fits in the broader context of research funded by the US military, NIH, and CDC leading to sensational claims about the next scary infectious condition poised to wipe out humanity. It's now an old game, whatever the motivation. I've been through several cycles of this myself professionally, and it took multiple cycles for me to realize what was going on (and has continued at an ever more feverish pace recently).
There's a non-zero chance that we're about to experience another huge population bottleneck due to misfolded proteins. Prions bioaccumulating in the environment for untold years is the terrifying part.
Agreed, far and away the most unnerving part
I read this book years ago. Fascinating and scary subject. At the time I read this book, I was wondering about plants - now I have the answer - yes - it is transmissible via plants.
DEADLY FEAST, Richard Rhodes.
https://www.amazon.com/Deadly-Feasts-Controversy-Publics-Health/dp/0684844257/ref=sr_1_1?crid=2I8QM68IAH6II&keywords=deadly+feasts+richard+rhodes&qid=1707807734&sprefix=deadly+feast%2Caps%2C157&sr=8-1
Amazon's description
In this brilliant and gripping medical detective story. Richard Rhodes follows virus hunters on three continents as they track the emergence of a deadly new brain disease that first kills cannibals in New Guinea, then cattle and young people in Britain and France -- and that has already been traced to food animals in the United States. In a new Afterword for the paperback, Rhodes reports the latest U.S. and worldwide developments of a burgeoning global threat.
Honestly the fact that prions can just hang out on grass and leaves is beyond horrifying. For me the Chronic Wasting Disease was the most unsettling part of my research, that the environment itself was a reservoir of infectious proteins.
Very strange that these misfolded proteins do not degrade into single proteins once outside the organism in which tbey were created. Also, when eaten, one would expect stomach acid to denatute them as is usually the case for ingested proteins. A few years back when frau Merkel was the pm of Germany there were some theories about her suffering from kuru, as there were multiple videos in which she showed symptoms similar to those of kuru.
Stone Age Herbalist, a few aspects of your summary don't seem to fit with the explanation for kuru. First, was the rate of kuru in the 1950s-70s an increase over what occurred in prior eras? The way you described it makes it sound as if the incidence in the postwar period was an abrupt increase over prior times. If that's so, what would account for it? Had the Fore given up cannibalism before the war, but then returned to it after the war? And why would they have restarted cannibalism then? Second, the rate of fatal disease (>10%) is extremely high, even for a homozygous condition. By your description, it had a major impact on social behavior (e.g., marriage patterns), which implies that this rate of kuru was very unusual for the Fore. The rate might be so high as to threaten extinction. In contrast, the prevalence of homozygous sickle cell disease (not trait) seems to be about 1-3% in west Africa. That seems like a much more evolutionary stable proportion.
I think Kathleen Lowrey's comment about the second-hand nature of reports of cannibalism also deserves discussion.
Thank you for thought-provoking Substack!
Thanks Devon! To answer some of those questions - the annual death rate for kuru approached around 2% of the population at its peak and almost certainly represents an event of spontaneous CJD-like prion disease entering the Fore speaking population. Given that prion incubation rates can be as long as 20+ years (median is 12 iirc) then it stands to reason that around 1890-1900 was the initial kuru death. Nobody really knows when the Fore began endocannibalism, but their neighbours practice exocannibalism, which is consistent with anthropological behaviour for 'rival' or 'differentiated peoples'. Spontaneous CJD is rare, and to get a situation where people are eating one another in quantities to pass along a prion is rarer still, but it does happen - prion diseases from animals to humans and between animals follows a similar pattern.
Ultimately I think given that we have Fore brain tissue with vacuoles, that Fore brains have been used to infect other animals, that the kuru prion has been sequenced and matches other prion diseases, that the Fore have a distinctive heterozygous generation of females for codon 129 and that kuru behaves in the same way as other prion diseases - it seems all but certain that kuru is a prion disease spread through eating human flesh. The nail in the coffin is that only this sequence of events could account for the sex disparity in the death rates. Female protein availability is well known in the anthropological literature to be limited in many parts of the world, and they will eat just about any source of protein they can find. There are interviews with older Fore women who describe the mortuary feasts and the taste of human meat.
I'd be down with being eaten. They're already inheriting all my stuff, might as well take the body, too!
Fascinating and horrifying piece of history. Thank you for sharing it.
You're welcome, hope it wasn't too grisly
Not at all, it was a fascinating insight into a different culture.
On whether cannibalism is implicated, whatever causes kuru, I'd recommend
Review: Kuru and Cannibalism?
Reviewed Work(s): Kuru: Early Letters and Field-Notes from the Collection of D.
Carleton Gajdusek by Judith Farquhar and D. Carleton Gajdusek
Review by: Lyle B. Steadman and Charles F. Merbs
Source:
American Anthropologist , Sep., 1982, New Series, Vol. 84, No. 3 (Sep., 1982), pp.
611-627
It cites Arens, whom I consider unreliable (Arens thought cannibalism has basically never been practiced anywhere, my own view is that he was totally wrong about this -- there are lots of examples in the whole human record). But leaving that aside, the review makes a very good and specifically documented case that all of the accounts of cannibalistic practices of the sort that would explain the pattern of kuru (mortuary cannibalism by women) are second-hand anecdotes.
Finally, if Gadjusek had been an all-round stand up guy, it would be easier to suppose he never played fast and loose with evidence. That's just not the case with Gadjusek... at all. Maybe mentioning this part of Gadjusek's history didn't seem relevant? But it is relevant to assessing whether we should take challenges to his work seriously. Was he generally a person of high integrity? Nope.
Thanks, its an interesting review and Gajdusek was obvs a disagreeable personality regardless of his integrity. I'm not convinced by the counter-arguments against the cannibalism-prion hypothesis though: firstly Arens is just wrong and his work is considered incorrect even amongst today's anthropologists, but the sentiment that cannibalism was a colonial fantasy was strong between the 50's and the 70's, and researchers working with the Fore at the time were both squeamish and sensitive about the subject, hence a lot of back and forth in the field notes and later on about it. Secondly, the review was written before definitive knowledge of the prion protein and folding disorders. We have both the brains of kuru victims and their genetics, which show that fibril plaques and vacuoles formed in the cerebral tissue, along with the SNP polymorphisms at codon 129 on the PRNP gene. Kuru has been transferred into multiple animals and the exact protein sequence and isomers are known. Fore people have been carefully studied by age and sex and there is distinctive and reproducible loss of the Hardy–Weinberg equilibrium at codon 129 amongst females born prior to the end of the cannibalistic mortuary feasts, and weaker disequilibriums for males who would have been children at the time. Add to this that kuru behaves in the same way as other prion diseases, it seems a watertight case imo.
Sorry that is not an honest summation of the article. This is not about PC squeamishness this is about whether anyone actually observed a practice Gajdusek makes central. If it is prions (IF), that women are tasked with handling corpses and heads of corpses specifically is widely attested by direct observation and thus a more plausible transmission source. Less titillating than cannibal ladies but life bees that way sometimes.
I now also wonder… when I say Gajdusek’s lack of personal integrity are you aware of what I mean? It is not “oh he was kind of a jerk”.
You can make a perfectly valid case for both the vector of transmission and the existence of prions without Gajdusek's work - Shirley Lindenbaum and Robert Glasse were the anthropologists who conducted the field work on Fore kinship and mortuary traditions, and it was they who demonstrated that Fore endocannibalism matched the spread of kuru. Ignoring Gajdusek's work on transmission, kuru brains and the discovery of prions and subsequent work on prion protein genetics is enough on its own to prove how kuru began and spread. Otherwise we have a massive coincidence that some other unknown cause of death was also operating on people who separately happened to have a degenerative prion disease.
Not to be too pedantic, but it's not beneficial to my offspring for me (and later them) to die. It's beneficial to the wider society, potentially, to nip the problem in the bud. But in this case me and my offspring are the problem being nipped, which is definitely not helpful.
He's controversial, but it's worth at least reading what Peter Duesberg has to say about kuru if this is a topic in which you are very interested.
Short version: he thinks the case for kuru being a disease transmitted by a virus-like agent is very weak.
I don't quite understand how being heterozygote could act as selection for future generations since heterozygote individuals could presumably have homozygote descendants by chance (e. g. ab mating with ab can produce ab, aa or bb).
People with rarer versions of gene will breed more than people with more common versions or gene, keeping all versions roughly as common (if they otherwise are equally good).
That said, since it only offers protection against a thing you will not get unless you eat diseases meat, this strategy is dumb.
Thank you for your detailed response. However, the main questions I posed remain. If kuru didn't arise until the late 1800s, then presumably cannibalism didn't occur in meaningful frequency until then -- very recently in evolutionary time. What happened in the Highlands to cause such a shift in behavior? In addition, a 2% annual death rate, producing a 12.5% (2,500/20,000) decline in population within a generation, is not sustainable demographically for very long. Sickle cell disease produces orders of magnitude less mortality. If what you describe is accurate, the Australian prohibition of cannibalism saved the Fore from extinction. Furthermore, the integrity of researchers and their research is extremely important. If Gajdusek's scientific character is questionable, then the case here might begin to crumble. As Kathleen Lowrey has noted, it's tough to make a "watertight" case if there are no credible direct and detailed observations of the behavior responsible for transmission by multiple independent observers. Off the top of my head, I can't think of another infectious condition that lacks such critical evidence.
A lot of things happened in the Highlands - WW2, Australian administration, the introduction of canned foods, the loss of forest territory and more. The comparisons between prion disease deaths and sickle cell are not valid, they are not the same biological agent - prions are not a species of living creature, they are not a parasite or a virus.
Gajdusek is not a lynchpin in this case, his integrity regarding Fore endocannibalism is not especially important in building the case. We have Australian patrol reports, a legal ban on cannibalism in the Highlands, the work of anthropologists like Lindenbaum and Glasse, oral testimony from Fore themselves.
Besides this, we know that cannibalism is involved in the transmission of prion diseases, look at the epidemic of bovine spongiform encephalopathy - cows being fed ground bovine meat and bone meal led to the spread of the BSE prion in the population. You can ignore Gajdusek and still have a tight case for the origin and spread of kuru: we have kuru brains, we have the prion proteins, we have the genetics of the protein, we have the genetic tests of the Fore, we have multiple other prion diseases to compare it to.
I asked what happened in the Highlands in the late 1800s that would have caused the onset of kuru. WW2, the Australian administration, canned foods, and forest loss came many decades later. You are trying to make an evolutionary argument for events that seemingly came about very recently in evolutionary time. If the Fore were cannibals for centuries or millennia, wouldn't have kuru began long before the late 1800s? And if so, the high death rate from kuru would have eliminated the Fore from existence. Sickle cell disease is not an infection -- it's a homozygous condition, so it is parallel with the scenario you paint for kuru (with homozygous individuals susceptible to disease when exposed to an environmental factor). It's also relevant as a condition that seemingly has been around a long time and developed into an evolutionarily stable pattern -- something that the mortality from kuru that you describe would seem to be impossible on demographic grounds alone.
A proper epidemiologic investigation would involve comprehensive assessment of all possible factors for the symptoms and deaths, including exposure to modern medical care among many other factors. And such an investigation would also involve gathering direct, observable evidence of the factors associated with disease. Such investigations seem to be absent for kuru.
I'm a little mystified about the strident defense of the kuru hypothesis. Science is about taking doubts and questions to challenge hypotheses. I didn't question kuru before I read your piece. But now that I see the obvious anomalies and defects in the research (all of the other evidence you mention notwithstanding), I have serious doubts.
1. One would have to search through the German colonial literature to understand the history of the Highlands during the 19th century, but there were plantations, missionaries, new diseases and other disruptive factors that could account for a change of mortuary practice, but we don't know. Spontaneous CJD is rare, and total endocannibalism i.e eating every part of a human body, is also rare, so we have no baseline of kuru-like epidemics since the conditions to create a prion epidemic are unusual.
2. You seem to want to rule out either the mortality rate or kuru altogether as the agent on evolutionary grounds, which is using theory to attack the empirical data. The evolution of prion diseases is still under research, and the positive feedback loop created by the Fore cannibalism practice is arguably an unnatural phenomenon. One can always disrupt some posited evolutionary equilibrium.
3. The epidemiology for kuru is one of the longest running data collection projects in the world. UCL's Prion Unit only finished their fieldwork in 2012. There has been consistent monitoring of the Fore and surrounding peoples for the last half century, identifying the last victims of kuru between 2005-2009. I don't know what more you would expect to be done given that not many in the medical profession have any doubts over whether kuru is a prion disease - if somebody wants to analyse the data or collect more to create a counter-hypothesis then they are free to do so. But since all the foundational principles of kuru were repeated during the BSE outbreak, there's no question that infectious proteins can be transmitted between organisms by endocannibalism.
4. If kuru had never occurred and Gajdusek never worked on prions, the BSE crisis would have led researchers to the same conclusions - prions can be passed within species and between species through consumption of infectious tissue. BSE was passed between cattle, mice, cats and so on. Likewise Chronic Wasting Disease can be passed between species. One can breed mice to express variant PrP proteins and they will develop all the symptoms of neurodegenerative prion diseases.
5. If the counter-hypothesis is that kuru was not caused by a prion, then one has to accept that it is a pure coincidence Fore women of a particular generation show a disequilibrium in the 129 codon, which also coincidently happens to be one the most important sites for SNPs in all other prion diseases.
I appreciate your additional comments, but your responses don't address the fundamental questions I raised and you don't seem troubled by the significant gaps in evidence. As I said, I didn't question kuru until I read your piece and saw the huge holes.
In response to your most recent points:
1. According to Wikipedia and other sources, the Highlands had no European contact until the 1920s and 1930s, beginning with Leahy's expeditions: https://en.wikipedia.org/wiki/Fore_people; https://en.wikipedia.org/wiki/New_Guinea_Highlands#History
2. I'm not using theory to attack data, but data to challenge theory. The data are the very high mortality rates, and the theory (that you describe) is that kuru and cannibalism in the Fore are not new in evolutionary terms and are related to each other. I'm also noting the wholesale lack of epidemiologic and experimental data to justify the interpretation of kuru among the Fore (which is an hypothesis). As Kathleen Lowrey noted, nothing is indisputable in science, and all knowledge is provisional.
3. I have stated in multiple comments the kinds of epidemiologic evidence that are absent for the kuru hypothesis.
4. Even if this genetic association is genuine, and not marked by serious methodological and design flaws as in the kuru research, it is secondary evidence. Without sound basic epidemiologic and experimental evidence, the kuru hypothesis is deficient at a primary level in empirical terms.
If these reviews of kuru research (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6466359/; https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2577135/) are accurate, it seems that the experimental transmission studies did not involve controls (such as brain tissue from non-kuru human corpses) and they involved transmission routes very different from cannibalism exposures (intracerebellar injection [https://www.jstor.org/stable/1721151] vs. oral consumption). Also, it's not clear that any of the epidemiologic studies among the Fore involved comparisons with persons unaffected by kuru, or if they did, involved comprehensive assessment of diverse potential factors. The evidentiary gaps for the kuru hypothesis are massive.
I wrote somewhat inaccurately about one of the parallels between kuru, as Stone Age Herbalist describes it, and sickle cell disease. Disease occurs in homozygous individuals in both cases, but only the hypothesized kuru requires an environmental exposure to develop. However, apparently those with sickle cell disease are more vulnerable to malaria than those heterozygous individuals with sickle cell trait. Another parallel is that heterozygous individuals in both cases have some protection against disease when exposed to a particular environmental factor (malarial parasites in the case of sickle cell disease).
Very interesting, but I do not fully understand how a population can remain heterozygotic. Surely mixing between fully heterozygotic individuals will lead to a 50:50 hetero-homo split in the next generation. At least if men and women are both heterozygotic, order of pairs doesn't matter, and my very rudimentary GCSE level understanding of this holds up.
Read Duesberg on that airtight case, not summaries of his work written by detractors. You might come away with doubts.
Can you link what work this is - I've been reading Duesberg's thoughts on kuru, and while he attack Gajdusek's insistence that kuru is a 'slow virus', I can't find a single reference to prions or Duesberg's response to prion diseases. All I can see is that Duesberg is using Gajdusek's methods to discredit the approach taken to identifying a virus - but as we now know, kuru is not a virus.
Yes this was earlier, but if you come away from it thinking “Gajdusek sounds like a researcher from whom I should believe startling new claims”, well. The first several chapters of - Inventing the AIDS virus- are a tour de force history of virology even if you think Duesberg is wrong about AIDS.
OK, I'll give it a read, but I don't see what this has to do with prions? Is your argument that prions don't exist, or that they do exist but not for kuru? That kuru is caused by something else? Clearly you don't think much of Gajdusek, but I don't see what the argument is about kuru - it's clearly a prion disease, or is it a coincidence that kuru infected brains happen to suffer from plaque-vacuoles which account for how kuru patients died?
My argument is that both sides of your cannibalism kuru case are flawed. The cannibalism side fatally by lack of direct evidence, the kuru side by doubts about Gajdusek, the science of prions, and also whether kuru was epidemiologically among humans what Gajdusek said it was: an infectious disease most specific to women.
I disagree - cannibalism amongst the Fore has been documented by multiple anthropologists, by Australian adminstrators and law enforcement officers, and by the Fore themselves. Gajdusek is irrelevant to this question.
The science of prions is indisputable, they are amongst the most studied proteins in the world, and prion disease prevention is a major part of every developed country's public health system. To call it 'my' cannibalism case is ridiculous, I'm not advancing some obscure theory, it is one of the most studied medical events of the last 100 years, and the genetics continues to be advanced to the point where we can infer CJD amongst Neanderthals.
(1) Just sticking your fingers in your ears then.
(2) There is nothing in science that is "indisputable".
Which PNG human kuru patients had these autopsies done in the period in question (1950s to 1970s)?
I don't know what point you're making, but there are plenty of papers of kuru victims who participated in mortuary feasts as children - eg this paper of a 16 year old male brain who died in 1967:
https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1750-3639.1997.tb01072.x
and this paper of a 60 year old male brain, a man born in 1943 who was confirmed by his community as having eaten human tissue as a child, whose mother died of kuru in the 1960's:
https://royalsocietypublishing.org/doi/pdf/10.1098/rstb.2008.0091
I think you can see how a skeptic might not find those evidentiary chains airtight.
Response appeared out of order tant pis
Could you please elaborate on this part of Gadjusek's history or give a link that has more information? Thank you!
https://www.nytimes.com/1997/02/19/us/nobel-scientist-pleads-guilty-to-abusing-boy.html
He brought boys to his home from PNG and sexually abused them while posing as their benefactor
Thank you, Kathleen. I think it's reasonable to wonder how his behavior might have affected his research. Clearly, many people around him knew what he was doing for many years, and that could have left him open to manipulation (e.g., blackmail) by others who wanted him push (or suppress) a particular point of view. Also relevant were his former employers, who might have had interest in kuru for bioweapons/biodefense or just creating fear about another condition that supposedly threatens the world.
I don't think it has to be an elaborate conspiracy! I just think he was a person of low integrity and being a research star let him get away with more of what he wanted to get away with. Coming up with a very dramatic account of his groundbreaking research and how it was also lurid and exotic helped make him a kind of darling: ooh, he's a maverick! Get out of the way and let him do his boundary-breaking thing!
I also think pedophiles are not so much attracted to children as they are attracted to violation, lying, corruption of innocence, duper's delight.... there are many kindred pleasures to be had as a crooked research superstar. Quite a few red flags about the plausibility of Gajdusek's research have been raised along the way but the response is "oh you are SHOCKED by cannibalism or oh you are SMALL MINDED about this totally novel epidemiological claim". It has an overlap with "oh you don't understand he really LOVES those boys, why are you suspicious you conventionally minded little nobody" I think Gajdusek was perfectly aware of how these things could conveniently resonate in his life and enjoyed both to the hilt.
I'm just mentioning possibilities, along with the ones you mentioned. It is strange, however, that he got a Nobel for what seems to be weak work, even by the standards of the times. That implies he had very powerful supporters working behind the scenes, if only to overlook/cover up what he did and was doing to those children. And his work fits in the broader context of research funded by the US military, NIH, and CDC leading to sensational claims about the next scary infectious condition poised to wipe out humanity. It's now an old game, whatever the motivation. I've been through several cycles of this myself professionally, and it took multiple cycles for me to realize what was going on (and has continued at an ever more feverish pace recently).
The history of virology in the first chapters of Duesberg’s book will be of serious interest to you!