Fear and Trembling: Prion diseases on Twitter

Even if you don't immediately recognize the words "prion" or "Kuru", the history has seeped into popular culture, like a horrifying fairy tale that just happens to be true. Once, there was a tribe in New Guinea that ate the dead. It wasn't the kind of fakey cannibalism you see in the movies, with hunters rushing out to spear people for sustenance. Instead, it was about respecting your elders. When a member of your family died, you ate them—you took a part of them into yourself. And that included the brain.

But over time, these people found themselves plagued with a terrible illness. Children and perfectly healthy adults, usually women, would suddenly begin to lose control of their limbs. They would jerk and shudder. Within weeks, they wouldn't be able to stand up at all. And then they died. Everybody who had those symptoms died.

Eventually, Western scientists would learn the awful truth. When the people from New Guinea ate their ancestors they were also eating a disease. It attacked their brains—riddling the tissue with holes. The New Guineans, the Fore people, called the disease kuru. In their language it meant "trembling" or "fear".

Today, we know a little bit more about the disease, kuru. We know it's not caused by a virus or a bacterium or a fungus. We know it's related to other brain-damaging diseases, including Creutzfeldt-Jakob disease, which turns healthy adults senile and kills them within a year of the onset of symptoms; scrapie, which affects sheep; and the dreaded bovine spongiform encephalopathy -- mad cow disease.

Tying all these diseases together is a scary little something called a prion. On August 16th, I attended a lecture by Jay Ingram, a Canadian journalist who has written a book about prion diseases, called Fatal Flaws. The lecture taught me a lot about prions, but it also taught me about some of the flaws inherent in trying to live-tweet a lecture as I'm listening to it. When the subject is so scary—and so confusing—even well-intentioned live tweets can go awry.

Fear and Trembling: Prion diseases on Twitter

A public lecture introduced me to the terrifying world of mad cow disease and kuru. But to really understand what there was to fear, I had to dig deeper.

Storified by Maggie Koerth-Baker · Tue, Sep 11 2012 08:22:17

Drugline

You have probably heard this story before. Even if you don't immediately recognize the words "prion" or "Kuru", the history has seeped into popular culture, like a horrifying fairy tale, or an urban legend that just happens to be true. Once, there was a tribe in New Guinea that ate the dead. It wasn't the kind of fakey cannibalism you see in the movies, with hunters rushing out to spear people for sustenance. Instead, it was about respecting your elders. When a member of your family died, you ate them -- you took a part of them into yourself. And that included the brain. 

But over time, these people found themselves plagued with a terrible illness. Children and perfectly healthy adults, usually women, would suddenly begin to lose control of their limbs. They would jerk and shudder. Within weeks, they wouldn't be able to stand up at all. And then they died. 

Everybody who had those symptoms died. 

Eventually, Western scientists would learn the awful truth. When the people from New Guinea ate their ancestors they were also eating a disease. It attacked their brains --riddling the tissue with holes. The New Guineans, the Fore people, called the disease Kuru. In their language it meant "trembling" or "fear". 

Prions show up as little brown specks on desktop microscope images of infected brain tissue. #banffscienceMaggie Koerth-Baker

Frontalcortex

That story is true. Mostly. It happened in the 1950s and 1960s. Today, we know a little bit more about the disease, kuru. We know it's not caused by a virus or a bacterium or a fungus. We know it's related to other brain-damaging diseases, including Creutzfeldt-Jakob disease, which turns healthy adults senile and kills them within a year of the onset of symptoms; scrapie, which affects sheep; and the dreaded bovine spongiform encephalopathy -- mad cow disease. 

I'm at a @jayingram talk about his new book on prion diseases. #banffscienceMaggie Koerth-Baker

Tying all these diseases together is a scary little something called a prion. On August 16th, I attended a lecture by Jay Ingram, a Canadian journalist who has written a book about prion diseases, called Fatal Flaws. The lecture taught me a lot about prions, but it also taught me about some of the flaws inherent in trying to live-tweet a lecture as I'm listening to it. 

Public lectures are fascinating introductions to a subject. Twitter is a great way to share information with people who can't be in the live audience. But they are both, by necessity, short summaries of much deeper stories. When you combine the two, it's easy to end up with a collection of snappy ideas, rather than a deep, context-laden narrative. And that can be the difference between education and sensationalism.
The tweets I wrote during Jay Ingram's lecture got a lot of attention. But as I looked at the questions and criticisms some of my readers had -- and as I started to read Ingram's actual book -- I realized that the missing context of Twitter might be leading people to conclusions that weren't correct. That's why I'm writing this up as a Storify. I want to take the disconnected ideas and fit them into a bigger whole. I also want to give you some things to think about the next time that I (or anybody else) live tweet a lecture.

Prions represent a revolution in the study of biology - starts in 1950s with kuru. - @jayingram #banffscienceMaggie Koerth-Baker

I tried to make it clear that I was quoting Ingram here. And, in general, most tweets from a lecture are quotes. But this is one of the places where it becomes difficult to understand the context. Am I, as the tweeter, telling you what I think? Am I simply relaying what was said by someone else? I can tell you what a speaker says, or I can tell you whether what that speaker is saying matches up with the bigger picture of evidence and opinion. The problem is that a live tweet of a public lecture can be a mixture of both. And knowing which perspective you're reading matters. Sometimes, it helps to ask before you re-tweet. 

That's not to say that Ingram is incorrect in this quote. Prions do represent a revolution in how we think about biology. That's because prions are simply misfolded proteins. 

Proteins are everywhere. Your body is built out of them. There are proteins in your cells that make the cells function. There are proteins in your hair, your skin, your muscles. Proteins control your metabolism, allowing you to turn a sandwich into energy. There are proteins in your brain. 

Every protein is made up of amino acids, the little molecular building blocks of biochemistry. In his talk, Jay Ingram had a really nice model that will help you visualize this stuff. Imagine a pearl necklace. 

Natural Grey Freshwater Pearl Necklace ~ Accented with Rhodolite Garnets ~ Pearl Drop NecklaceNaomi King

Now, imagine that necklace twisted and turned, folded back on itself in a complex pattern. 

Natural Grey Freshwater Pearl Necklace ~ Accented with Rhodolite Garnets ~ Pearl Drop NecklaceNaomi King

Protein folding is an incredibly complex process that happens in fraction of a second. And must be done perfectly. #banffscienceMaggie Koerth-Baker

That's what you should be thinking of when you think about proteins. At its most basic, a protein is just a chain of amino acids. But it gets its power -- an individual protein gains specific skills and tools -- because of how that chain is folded. In some ways, that's a great system. It allows you to do more things with the same set of tools, as if your screwdriver could suddenly become a hammer.

The catch: The same protein can act in very different ways, depending on how it's folded. 

Healthy human brains have "prion proteins" on surface of neurons. Nobody is sure what they do yet. #banffscienceMaggie Koerth-Baker

Healthy prion protein has a tendency to misfold. When it does, it can touch off infectious process and spread misfolding. #banffscienceMaggie Koerth-Baker

To demonstrate this, @jayingram throws a sprung mousetrap into a batch of set ones ... so they all spring too. #banffscienceMaggie Koerth-Baker

So there's a nice, healthy protein that sits on the surface of the neuron cells in your brain. Nobody knows what, exactly, it does. But prions seem to be this same protein, folded up all wrong. And that's the revelatory part. 

All that stuff I told you about proteins is basic biology. Nobody questions that. But as they studied kuru, scientists began to see evidence of something a lot more controversial -- the idea that misfolded proteins could cause deadly disease, and that the disease could be spread by the misfolded proteins, themselves. Somehow, they think, misfolded proteins trigger healthy proteins to also misfold. This idea is way out in left field compared to everything we thought we knew about how disease works. It's still not 100% proven. In fact, there are researchers who think misfolded proteins are only a mere symptom of mad cow and other prion diseases -- not their cause. There's a lot we don't know. But it does seem like, the more scientists study this, the more evidence appears supporting the theory that prions -- misfolded proteins -- can make more of themselves and can, together, make people and animals sick. 

Wow. @jayingram showing 1950s era video of kuru victims. Only affected motor neurons. Still alert. But couldn't move. #banffscienceMaggie Koerth-Baker

When I say that there's a lot we don't know, I mean A LOT. For instance, we have microscopes that can see healthy proteins, but we can't get a good look at a prion. That's because, when proteins misfold, they seem to immediately start clumping together, like one of those magnetic desk toys. We can't see any of the individual units that make up that mess. Which means that when we talk about prions we are talking about something we have not yet directly observed. 

Here's another example of how little we know when it comes to prions: As I mentioned in the tweet above, the effects of kuru are centered around the control of limbs. Victims jerk and writhe. Slowly, they lose the ability to walk. But they're lucid and cognitively normal right up until the end. Victims of mad cow disease, on the other hand, have severe problems with memory. They experience hallucinations. 

Video of cow with mad cow, terrified of hallucinated threats is heartbreaking. #banffscienceMaggie Koerth-Baker

Jay Ingram wasn't able to get in touch with the researchers who own this video, so I can't share it with you here. But here's what I saw: A cow running aimlessly around its paddock, stopping short in fear of non-existent terrors and hopping over obstacles that weren't actually there. I've never seen an animal behave this way, and it looks nothing like the video of kuru. But the theory is that both these diseases involve the same protein from the surface of neurons. 

Why would the same misfolded protein cause such very different symptoms?  That's a question we don't have an answer for. When I interviewed him after the lecture, Jay Ingram told me that the best guess that the difference has to do with the structure we can't see. 

"They’re all misfolded, but in different ways. That’s the assumption," he said. "Supposedly that also accounts for the so-called species barrier when it happens. People eat sheep meat infected with scrapie all the time and never get ill. Structural differences probably account for that, and also probably account for where in the brain the damage happens. It’s not a great explanation though, because you can't get details yet on the structure, on how they misfold." 

Early #FF to @maggiekb1, because she's scaring the crap out of me with her live tweets right now.Alex Knapp

Fair enough. I'm scaring myself, too. Now, on to the cannibalism. 

Australian miners and laborers guessed kuru was related to cannibalism before scientists did.#banffscienceMaggie Koerth-Baker

Of course, those miners weren't prescient or anything. They just got lucky in this prediction. Their prejudices against the Fore happened to overlap with the actual mode of transmission. Or, anyway, with what scientists are pretty sure was the actual mode of transmission. 

Because here's another thing you need to remember about public lectures: They're edited for time and they're edited to tell a compelling story. There are always details that get left out. And you can see this in the difference between Jay Ingram's lecture and his book. In the lecture, he went with the general consensus: Kuru spread among the Fore because they were eating the brains of kuru victims and ingesting prions. But in the book, he explains why this story can't be said to be the unquestionable truth. 

Lots of Western doctors and anthropologists wrote about the Fore eating their dead. But none of those people actually saw them do it. In fact, there's very little direct evidence for cannibalism among the Fore. Scientists believe it happened, though, for two reasons. First, the Fore say it happened. And there's not really an obvious benefit to lying about eating your dead grandmother. Second, it just makes sense. Most prion diseases are not very easy to transmit. Directly eating infected tissue is one of the few ways to do it. Plus, the Fore say they began eating their dead in the early 20th century and that kuru only started killing people after that. And we know that cases of kuru tapered off to almost nothing as soon as the Fore say they stopped eating their dead in the 1950s. But we don't know for sure. It's a story that's never been independently verified. 

Square Cowadrian fu

British govt suppressed connection between mad cow and scrapie when first noticed. Hid data for four years. #banffscienceMaggie Koerth-Baker

.@maggiekb1 UK minister at time notoriously fed his young daughter a burger on TV to show editing beef was 'safe'. Not his proudest momentAnsonMackay

That's true. British scientists noticed that there were similarities between the brains of victims of mad cow disease, the brains of sheep infected with scrapie, and the brains of kuru victims. But the government worried that publishing that information could decimate the beef industry. Because the scientists worked for the government, the government was able to prevent them from publishing their work. You can read all about this in several volumes of The BSE Inquiry Report, published in 2000. 

[ARCHIVED CONTENT] The BSE Inquiry Report: HomeThis site is an archive of the BSE Inquiry. It is no longer being updated and some links from the site may no longer work. This site co...

At the peak, in 1993, 45,000 British cows were dying per year. #madcow #banffscienceMaggie Koerth-Baker

Somewhat reasonable that they didn't suspect risk to humans at first; scrapie has never infected ppl. #madcow #banffscienceMaggie Koerth-Baker

Cow disease peaked in 1993. Human disease peaked 2001. But incubation period was a decade. #banffscienceMaggie Koerth-Baker

One woman who died of mad cow had been a vegetarian for 8 years. #banffscienceMaggie Koerth-Baker

“@maggiekb1: One woman who died of mad cow had been a vegetarian for 8 years. #banffscience”'Splain THAT one!Diana McIntosh

@dianamcintosh that shows you how long the incubation period is.Maggie Koerth-Baker

The incubation period for prion diseases is another thing we don't understand very well. I mentioned that kuru cases dropped off to "almost nothing" after the Fore say they stopped practicing cannibalism. I worded it that way for a reason. No Fore born after 1960 has ever developed kuru. But people who were alive during the time when cannibalism happened do still occasionally die from the disease. In his book, Ingram notes that 11 people died from kuru between 1996 and 2004. Assuming they were infected before 1960, that gives them a good 40-odd years of living, symptom-free with an incubating prion disease. 

But why would some people, including children, die within a few years of exposure, while others lived to a ripe old age? I asked Jay Ingram about this. He told me there are two factors that likely account for the wide variety of incubation periods we see in prion diseases.

First, it might have to do with how well-adapted the prions are to their host species. Some prion diseases -- like mad cow -- seem to be able to jump from one species to another. Mad cow can infect cows, and humans ... and cats. In fact, Ingram told me that it was the death of a housecat named Max in 1990 that really got people seriously considering the idea that mad cow wasn't limited to cows. 

But it does seem like prions can get better at infecting a specific species over time. You can infect a mouse with mad cow disease from a cow, Ingram told me. And if you take the brain of that mouse and use it to infect more mice, something weird starts to happen. 

"If you continue in the lab and infect mice, and then infect more mice, eventually the incubation period seems to start to shrink," he said. Nobody understands why that happens. But it could be a form of adaptation as the prions "figure out" how to better infect a new species. Basically, it could be a form of natural selection. Remember, we can't see the prion, itself. There's a possibility that every prion disease actually represents a variety of specific types of protein misfoldings. In a new a host, a previously small-potatoes type of misfold could turn out to be a better match for the host's proteins. Over several generations of infection, that type could come to dominate the mix, allowing the infection operate more efficiently. 

Genetics might also affect how long it takes an individual person to develop symptoms of a prion disease. Remember that healthy prion proteins -- the ones we all have on the surface of our neurons -- are long chains of amino acids. It seems to be very important to have specific amino acids at a specific place in the chain. 

The place is called position 129. There are two amino acids at this spot and what pairing you get is determined by who your parents are. You can have two methionine amino acids, two valine amino acids, or one of each. 

"That seems to determine resistance to prion diseases," Ingram said. "We know that people who are heterozygous, with a methionine-valine pair, were most resistant for kuru. For instance, a lady who was incubating it for 50 years was methionine-valine."

Again, we don't know for certain what's going on here, but there seems to be evidence that some people are more susceptible to prion diseases than others. And that has implications for mad cow disease. The peak of human deaths has long since passed. But there's a possibility that that was only the first peak -- as the most susceptible people died. Others could still be carrying the disease.

 "We don’t know whether it will someday pop up again," Ingram said. "And we don't know, if people are carrying it, whether the incubation period will turn out to be long enough that they all die of something else first."

Today, though, mad cow is no longer the most critical prion disease to pay attention to. 

Elk SculptureInAweofGod'sCreation

What is the most important prion disease today? @jayingram say chronic wasting disease in deer and moose. #banffscienceMaggie Koerth-Baker

CWD is different than mad cow. Terrifyingly so. Not just brain is infectious. Saliva, flesh, bones, the soil a deer dies on. #banffscienceMaggie Koerth-Baker

Normally, it's not easy to get a prion disease. We're talking about something that infects the brain, and passing it on usually requires direct contact. Kuru was probably spread when people ate the infected brains of other people. Mad cow passed from cow to cow via "protein meal" -- a cattle feed made from scrap meat like brain and nervous system tissue. Humans most likely picked up mad cow from nervous system tissue in ground hamburger meat. Creutzfeldt-Jakob disease, which appears spontaneously in humans, is probably linked to unlucky genetics. But it has been spread from person-to-person in the past by surgical transplants of brain dura matter.  

Chronic wasting disease (CWD) is different. It's spreading among wild deer, but they aren't getting invasive brain surgery. They aren't eating each other's brains. And they're dying anyway. It's not exactly clear how this is happening, but researchers have found prions in deer saliva. It's present in urine and feces. And deer have become infected simply by having contact with the bones of a deer that died from CWD, or the ground the bones were lying on. Meanwhile, scrapie, the sheep disease, has been known to hide out in the soil, too. Sheep have been infected by grazing on land that played host to a scrapie outbreak two years before. 

Which, of course, brings up an interesting question: Is CWD transmissible to humans? 

Annnnnd, there goes my love of summer sausage. #banffscienceMaggie Koerth-Baker

Firefighters in rural New York accidentally served CWD infected deer to 80 ppl. Five yrs gone by. So far, so good. #banffscienceMaggie Koerth-Baker

.@maggiekb1 eek! 80 people with potentially infectious saliva?Adam Kent

Another problem with live-tweeting public lectures: Not everything from the lecture makes it to the tweets. I type quickly. But I don't type that quickly. Sometimes, what gets left out ends up being important. This is one of those times. 

On March 13, 2005, more than 200 people attended the Sportsman's Feast, hosted by a fire company in Oneida County, New York. By that point, CWD had already been detected in local deer populations so any deer harvested from a domestic deer farm -- like the ones eaten at the Sportsman's Feast -- had to be tested. Unfortunately, there were no laws preventing the meat from being fed to anyone before the test results came back. People only found out that one of the deer had CWD after the feast was already over. 

Since then, 81 of the people who went to the feast have agreed to participate in long-term monitoring. In 2008, researchers published a study documenting various risk factors: Who ate the deer meat and what parts did they eat; who was involved in cooking; did they wear gloves; that kind of thing. The study also documents any risk factors that happened outside the 2005 feast. For instance, whether or not any of the participants are regular hunters. If, someday, any of these people do start dying of prion diseases, researchers will be able to look back at this data and learn a lot more about whether the prion disease in question is likely to be CWD and, if so, which activities are risky and which aren't. 

Environmental Health | Full text | Risk behaviors in a rural ...... one and can be found online at: http://www.ehjournal.net/content/7/1/31 ... (http: //creativecommons.org/licenses/by/2.0), which per...

The really important information is at the end of that paper. Turns out, there's good reason to think that CWD is not transmissible to humans at all. 

The Sportsman's Feast research is an ongoing, observational study. Researchers are watching these people to see what happens to them. But there are other ways you can study something like this. In 2001 and 2006, other scientists published papers that looked backwards in time, to see if they could spot any evidence that CWD is already affecting humans. 

Creutzfeldt-Jakob disease in unusually young patients who consumedArch Neurol. 2001 Oct;58(10):1673-8. Creutzfeldt-Jakob disease in unusually young patients who consumed venison. Belay ED, Gambetti P, ...

The first of these two studies looked at three people who died of Creutzfeldt-Jakob disease while extraordinarily young -- all before the age of 31. Dying that young of Creutzfeldt-Jakob can be a sign that the victims acquired their prion disease from another source. (That was the case with mad cow disease.) But it doesn't necessarily mean that. It could just be that these people were extraordinarily unlucky. Their healthy prion proteins just shifted into prions spontaneously. 

In fact, that's what researchers think happened. Even though all three had regularly eaten deer meat during their lives (two were hunters and one was the daughter of a hunter) their illnesses looked more like classic, spontaneous Creutzfeldt-Jakob than any acquired prion disease. For instance, we already talked about how people who die quickly from acquired prion diseases tend to share a particular pairing of amino acids at Position 129 in their prion protein. None of these people had that. 

Human prion disease and relative risk associated with chronic wastingEmerg Infect Dis. 2006 Oct;12(10):1527-35. Human prion disease and relative risk associated with chronic wasting disease. Mawhinney S, ...

The second study evaluated 22 years' worth of death certificates from counties in Colorado where CWD is endemic. Looking at hunting licenses, the researchers knew that people who hunted in those counties also tended to live in those counties. So, if people who lived there were more likely to die from from Creutzfeldt-Jakob disease than people who lived in other counties in the state, that might be a sign that hunters and their families were quietly acquiring CWD from the deer they killed and ate. 

But the researchers saw no difference between the people who lived in counties with lots of CWD and those who didn't. What's more, rates of Creutzfeldt-Jakob disease in CWD-infected counties haven't gone up over time. Together, these results suggest that humans can't be infected with CWD. It's not absolute proof. Personally, I'm still feeling a little squeamish about eating venison. But it tells us that there's a pretty good chance all those people in New York (and whoever they've been kissing for the past seven years) are going to be okay. 

That's not to say there's no reason to worry about the effects of CWD. We're still talking about a disease that could drive deer and elk in North America to extinction. If that happens, it'll have big impacts on the food chain, human culture, and economic activity -- especially in parts of Canada where people rely on these animals for food. But those are different concerns than a killer disease that can be spread by saliva. 

ποντίκι / μυς, mouse (Mus musculus) by George Shuklindullhunk

Finally, we need to talk about mice. Lab mice, specifically. 

In Jay Ingram's lecture, I learned that scientists have been using mice to study some interesting connections between exotic prion diseases and far more common illnesses, including Alzheimer's disease. This is a good example of why tweeting a public lecture can be really tricky. The ideas I'm talking about here aren't crazy. They aren't conclusions promoted by fringe scientists who don't know what they're doing. But it's also really, really easy to blow these particular ideas out of proportion. In a space like Twitter, the act of discussing interesting early findings can very quickly turn into accidental fear-mongering. Especially when the tweeter (in this case, me) hasn't heard about the research before. 

ALS, parkinsons, alzheimers are all also related to misfolded proteins, though not prions. Could still be infectious ... #banffscienceMaggie Koerth-Baker

Brain material from human alzheimer patient injected into healthy mice equals mice with same kind of misfolded proteins #banffscienceMaggie Koerth-Baker

There is a lot we don't know. But medical world is starting to look at connections between prion disease and alzheimers. #banffscienceMaggie Koerth-Baker

So, is alzheimers infectious? Researchers say "welll probably not. But might not have done right epidemiology" @jayingram #banffscienceMaggie Koerth-Baker

@Lewis_Lab @maggiekb1 Suggesting AD is infectious is incredibly dangerous and possibly damaging to patient care. Grammy WILL NOT give you ADDarren Boehning

Darren Boehning is right. But, at the same time, my tweets (and Jay Ingram's speech) aren't incorrect. 

There really is evidence that Alzheimer's disease (along with a host of other disorders, including, believe it or not, Type 2 diabetes) might be related to protein misfolding, and that these misfolded proteins can create more misfolded proteins and spread through a brain -- just like prions do. In these cases, the proteins being misfolded aren't the same ones as in prion diseases. But the misfolded proteins do seem to be able to spread from one part of a person's brain to another. For instance, in people with Parkinson's disease who received grafts of healthy brain tissue, the misfolded proteins involved in Parkinson's appeared in the donor tissue ten years later. Nobody knows how that could happen, unless the misfolded proteins spread on their own by converting healthy proteins, the same way that prions spread.  

And there have been several animal studies that suggest it might be possible to transmit Alzheimer's from one individual to another by injecting infected brain material into a second animal. These aren't perfect studies. For instance, this research has mostly been done in mice, which aren't the ideal models of human disease. And only one study -- conducted by Claudio Soto at the University of Texas -- has been done in mice that weren't already genetically engineered to be more susceptible to Alzheimer's. 

We need more information. But we have enough information to know that this isn't something we can just brush off. In May 2012, the New England Journal of Medicine published an article that will give you a good overview of this research. 

The Spread of Neurodegenerative Disease — NEJMMay 31, 2012 ... Clinicians who care for patients with neurodegenerative disease often believe that their patients' diseases are sp...

Alzheimer's and mad cow might operate in similar ways, but they are two very different things. And, as far as anybody can tell, Alzheimer's disease is not being spread from person to person.

Jay Ingram said the researchers he spoke with didn't think Alzheimer's was contagious, but they also thought the right kinds of epidemiological studies hadn't been done to really know for sure. That matters, because "as far as anybody can tell" only covers what we can see. If we haven't done the right kinds of studies, we could easily be missing evidence. 

When Ingram that, one of the researchers he had in mind was Neil Cashman, a neurologist and neuroscientist at the University of British Columbia. I spoke with Cashman for this story and asked him what the "right kind" of study would look like. 

For one thing, he said, it would take a long time to do. His ideal scenario would be to look at blood donors and recipients. Researchers could find older donors, who later turned out to have Alzheimer's, and then follow what happened to the people who received that donated blood. You'd have to follow the recipients for 20 years or so, he said, but in the end you'd have the information you need to get an idea of whether receiving blood from an Alzheimer's victim increased your risk of getting it. Without a study like that, we really don't know whether Alzheimer's can spread from person to person or not. 

But what does that mean for caregivers now? We're swimming in a sea of scary studies, none of which are yet telling us enough to know much about real-world risks. It's completely possible that all these little clues could end up not being clues to anything, at all. Sometimes things happen in the lab that don't happen in reality. Sometimes we see patterns where patterns don't actually exist. 

Cashman says it puts researchers, doctors, and (yes) journalists in a difficult position. "We’re trained not to alarm people with unproven possibilities," he said. "One side of me says it’s not a good idea to publish or even discuss the possibility that Alzheimer's is transmissible. But another part of me says there’s a legitimate public health concern here. Where’s the balance between not panicking people, but giving them enough information to know that this is something that really needs to be investigated? Right now, there's not enough evidence to worry about it. But there's not enough evidence to not worry about it, either." 

On the plus side, he said, if Alzheimer's is actually infectious, it's probably nowhere near as infectious as prion diseases like mad cow. You can see that just by looking at the epidemiological data we do have, Cashman said. "You didn't need a lab to tell you that Chronic Wasting Disease and kuru were incredibly contagious. That was clear from the patterns of infection," he said. "With Alzheimer's, if it is contagious it must be much less contagious. Otherwise, we’d see much larger outbreaks of Alzheimer's happening, and it would be clear from day one."

 Basically: Alzheimer's is not like Chronic Wasting Disease. Unfortunately, from reading my twitter posts, it was easy to get the impression that it might be. The information about the two topics just came too close to each other. Implications happened: Whether I meant them to or not. 

Even the best-intentioned live tweets can be misleading. 

I'm not exactly sure what I'm going to do with this realization, myself. I enjoy live-tweeting at conferences and lectures. From my perspective, it seems like the people who read my Twitter stream enjoy it, too. But, clearly, there are downsides I had not previously considered. I'll be thinking about it. But, when you read Twitter, you should think about it, too. 

Read Jay Ingram's book: 

Fatal Flaws: Amazon.ca: Jay Ingram: BooksMost people have never heard of prions. Indeed, most are only barely aware of the diseases caused by them, except, perhaps, for mad cow...

Another good story to check out: 

Infectious proteins on the brain: Alzheimer's and prions | SmartPlanetFeb 21, 2012 ... Scientists seeking to understand the fundamental pathology of Alzheimer's disease have long debated the merits of ...

• [Stephen Schenck]

  That mousetrap example doesn’t sound like a very good demonstration of misfolding. Of a chain reaction, sure, but the specific form of the sprung mousetrap isn’t what’s causing other mousetraps to turn to the same state.

• [michael heap]

  surprised no mention of Amyloid Plaques or post-mortem diagnosis via Congo Red

• [Stephen Gordon]

  This was a fascinating article, and I am now going to fully compartmentalize this knowledge away and ignore it so I don’t turn into a shutin.

  Also, needed more weird penises.

• [Ron Georg]

  Without an autopsy, it’s very easy to mistake BSE or other prion diseases for Alzheimer’s.  Epidemiological studies show that Alzheimer’s was rare in western cultures until the advent of refrigeration, which is also when meat became the center of our diets, as opposed to a special treat. Studies also show that Alzheimer’s remains relatively rare in cultures with low rates of meat consumption. 

  I know there’s a danger of confusing correlation and causation here, so I hope it’s not specious logic, but it’s entirely possible that consuming animal protein (the source of prions, after all) is the root of our otherwise inexplicably high rates of dementia. 

  Thanks for the story, it’s further confirmation that I’m not just putting on a tinfoil hat by giving up meat.

  • [Maggie Koerth-Baker]

    I spoke briefly with Neil Cashman about some of these “meat eating causes Alzheimer’s” theories. He says the evidence supporting that idea is actually pretty poor. I don’t know a lot of detail on it, but, suffice to say, an expert in prion diseases thinks you don’t have as much worry about as you think you do.

    • [Ron Georg]

      Fortunately, I’m not a big worrier, or else that incubation period would weigh heavily–I ate meat for decades. But there are much more scientifically justifiable reasons for giving it up, especially for vascular health. 
      Still, until the experts better understand the mechanisms of various forms of dementia, and can explain the apparent link suggested by the epidemiology, I’m going to hope that my dietary choices may protect my brain as well as my heart.And, off-topic, I recently finished Before the Lights Go Out. While I was aware when I put solar panels on my roof that I was becoming an active participant in the grid, rather than getting off of it, I was fascinated by the complexity of what it means to be part of the grid. I hope that was just the first in a long line of great science books.

      • [Maggie Koerth-Baker]

        Thanks so much!

    • [Joshua Bardwell]

      I always assumed that increased rates of Alzheimer’s were probably because of increased life span due to better medical care. We simply started living long enough that our brains had time to give out. Is there any truth to that, or not?

  • [Reg Robson]

     I’m thinking just correlation not causation. The advent of refrigeration also led to longer lifespans due to generally better kept food. It could simply be that many people didn’t get old enough before refrigeration to get Alzheimer’s in the numbers we’ve seen over the last 70 years or so.

    • [Ron Georg]

      That could account for the historic comparison, but it doesn’t explain the geographic discrepancy. Life expectancy in Japan, a culture fond of rice and veggies, is about five years longer than in the U.S., but Alzheimer’s rates are ten times higher in the States, where there’s a cheeseburger on every corner.

      • [TheMadLibrarian]

         Let’s compare lifespans in both Japan and the US for people on comparable diets.  There are too many variables otherwise.

        • [Ron Georg]

          Absolutely. That’s the problem with epidemiological studies–there are too many variables. It may turn out not to be dietary at all.  Although, when Japanese families move to the United States and adopt a standard American diet, their health patterns quickly start to resemble those of other Americans. 

      • [Reg Robson]

        Sounds like time to set up a study.

• [Freakpipe]

  Also, Jay Ingram, while correctly identified as a Canadian journalist, should perhaps be referred to as one of Canada’s pre-eminent science journalists (along with David Suzuki and Bob MacDonald).  

  His work on the weekly science radio show Quirks and Quarks from 1979-1992, followed by his Daily Planet science news show on Discovery from 1995-2011 have educated a generation on the relevance and value of Science!

  Glad to know he’s still rocking it.

• [Matt Popke]

  Why did I read any of that, let alone all of it? Something new to fear: twisted molecules. The bit about the incubation period is especially cringeworthy. Every night now, I will lie awake, staring at the ceiling, wondering if there are prions in my brain waiting to put an end to me. I could live to 100 and still lie there, staring at the ceiling, wondering.

  This is worse than stories about parasites. We need a new NSFW-like warning. NSFH: Not Safe For Hypochondriacs. I must go meditate on the possibility of dying from a brain-wasting disease now so that I can go on living my life without fear.

  • [xzzy]

    Your brain began wasting away on its own sometime in your mid 20′s anyways, due to the process of aging.

    Alzheimer’s is effectively senility with the pedal mashed to the floor.

• [Boundegar]

  I’ve read the kuru story before, and there was an amusing or horrifying bit of trivia attached.  Apparently, the disease might have been understood sooner, except that Western anthropologists stubbornly held to a doctrine that cannibalism is a myth – despite the knowledge that the Fore term for funeral literally translates, “Cut’em up, cook’em and eat’em.”

  Also, that was one of the most confusing articles I’ve ever tried to read, being in two media at once and tiny grey letters.

  • [James Agenbroad]

     Epidemiologicaly speaking the weird thing about Kuru was that it tended to affect more women than men, and it seemed to run in the families that they married into rather than the ones that they were  born into.

    • [Anony Mouse]

      I heard that one reason for this is that their beliefs held that vaginas were dangerous juju, so men consumed genitals during funeral rites to show how tough they were. They reduced their exposure to bad prions via this pattern of consumption, and women bore the brunt of it.

      • [James Agenbroad]

         Sounds like an excuse for men to get the tasty bits and for the women t0o get left with what is essentially  human scrapple…

• [Edwin Lyons]

  My cousin died for vCJD a few years ago – he went from being an incredibly fit guy in his late 20s to being bed-ridden and seemingly unaware of his surroundings in a matter of months. One of the scariest things I’ve ever seen.

• [Christina Ward]

  First:  I ate lunch while reading that.

  Second:  In 2008 two women that I knew (that did not know each other, nor were socially connected in any way) died of Creutzfeld-Jacobs.  Neither had the traditional genetic risk associated with CJ.

  I live in Wisconsin. We have CWD.  I always wondered why this connection isn’t studied more. And then I wonder how many people have died of CJ…I personally knew of those two in a 9 month period. What is that connection between CJ/CWD or is it truly a case of coincidence.

  Third:  For a time, ‘living in the UK’ during the ’90′s was on the list of reasons you could not donate blood; a precaution because of BSE.

  • [Maggie Koerth-Baker]

    On your third point: I think it still is on that list. Jay Ingram mentioned that he can’t donate blood in Canada for that very reason. 

• [JohnQPublic]

  This is like a Vonnegut book about Ice-9.   How about this:  I read that even if you incinerate the body of an infected cow, the prions causing mad cow will be present in the ashes of the remains and can infect anyone ingesting those prions.

  • [jandrese]

    Seems to me that if there are prions left in the cow you didn’t incinerate it enough.  This is understandable given the difficulty in doing it properly though.  Simply cooking the cow isn’t enough, you need to reduce it to ash, even the bones. 

    Something like a Crematorium could do it if their oven is large enough I think, but a guy out in a field with some logs and a can of gasoline isn’t going to get the job done properly. 

    • [JohnQPublic]

      The text I read involved a crematorium setup, not a guy in a field with a can of gasoline and some sticks:
      from:  http://petergeekie.hubpages.com/hub/BSE-infected-Tallow-and-a-power-station-near-you

      The problem of what to do with potentially BSE infected tallow has been examined by various august bodies, who have rejected land-fill or chemical destruction and have agreed that the only satisfactory and safe method is incineration at high temperature (1000° C). Even at these temperatures the Environment Agency’s own tests confirm that the prion protein responsible for BSE/NvCJD is not necessarily completely destroyed but only the risk of infection is significantly reduced.

      The published results stated “At present, no specific analytical technique exists to test for the presence of the BSE prion in any matter. There is no direct method, therefore, of detecting the prion in either emissions or ash.” It goes on to say “…on the advice of SEAC( Spongiform Encephalopathy Advisory Committee) the agency has made the cautious assumption in its risk calculation that the presence of amino acids, albeit in incomplete sequences, might indicate the presence of some infectivity in the final ash”

      • [jandrese]

        That reads to me like “we don’t have a good test for this stuff, so we are going to err on the side of caution and say it might still be unsafe.”

  • [smut clyde]

     the prions causing mad cow will be present in the ashes of the remains and can infect anyone ingesting those prions.

    Isn’t that how “Return of the Living Dead” ends?

• [Reed Roberts]

  Also highly recommended is Deadly Feasts by Richard Rhodes. Really nice look at the science and scientists surrounding the early days of prion (or was that slow virus?) research.

• [Graham Steel]

  Good post/Storify.

  Made contact with Jay a while back when I was Information Resource Manager for the CJD International Support Alliance.

  Whilst my slide-deck needs an update it is still relevant:- http://www.slideshare.net/steelgraham/2007-cjdf-presentation-graham11-presentation

  (I lost my brother to vCJD in 1999 so that it how I became involved in the patient support group side of things. I also became very interested in Prion research).

  The second time I went to Washington DC to give a talk at the annual CJD Foundation Conference, prior to leaving the UK, I had already prepared my slides which were science based. I was then asked to give a talk about the patient support group side of things. I decided to combine the two since a lot of work had gone into the science.

  I was quizzed over dinner after giving my talk by the President of the CJD Foundation as to why I didn’t tell her that my talk was not exactly what I was asked to do. I responded with “Did anyone complain?” Since no-one did, she didn’t respond ;-)

  • [JohnQPublic]

     It was a good story but I do think all references to the tweets could be removed from this storify.  The text of the story is a great and interesting account of the disease.  The explanation of how the tweets were sent in the context of a lecture kind of interferes needlessly with the compelling story that it is meant to convey – I’d edit those out to bring the focus closer to the subject matter.

    • [oneswellfoop]

      I agree.  It’s an interesting story, with a side story talking about how you purposefully used a communications medium that is inefficient and ineffective to potentially spread misinformation.  Obvious result is obvious.  Anyone with half a brain could have told you twitter isn’t particularly great for conveying complex and lengthy subject matter.

    • [cjporkchop]

      Disagree. I think it’s useful and interesting to do a ‘post-mortem’ of how a series of communications won/failed in conveying accurate info to the reader.

      • [oneswellfoop]

        Well, my last comment was apparently deleted, so: If you find it useful, good for you.  While the tweets get an A for brevity, they get an F for clarity.  It should have been apparent from the nature, length, and complexity of the material that 148 characters at a time would be insufficient to communicate it.  If you need a post-mortem to tell you that, then….good luck or something.

        • [James Agenbroad]

          But the lack of clarity is kind of the point…This is as much a post about how misleading tweets are as it is about the history of kuru.

• [Jellodyne]

  Maybe once we grok prion disease more fully the Fore people can return to their more enlightened funerary practices.

• [Anony Mouse]

  “But it does seem like prions can get better at infecting a specific species over time. You can infect a mouse with mad cow disease from a cow”

  A minor point, but I don’t think mice can actually contract prion diseases as you present it here, because they don’t have a prion protein at all. Some people also don’t have a prion gene, and because whatever it does isn’t very important (facilitates copper uptake, maybe?) they get on fine and can’t suffer these diseases. I would be very interested to know if I’ve misunderstood this.
  In order to create mouse models for variant CJD and similar diseases, a human prion protein gene has to be inserted into the mouse genome.

  • [jandrese]

    I’ve always thought of prion diseases as a whole class of diseases.  Basically misfolded proteins that can catalyze other proteins to refold in the same shape that cause your body to slowly disintegrate.  The high lethality and poor inter-species communicability (it only works on one specific protein that may or may not exist) has always been the limiting factor in their spread. 

    I wouldn’t be surprised if there are countless numbers of prion type diseases out there that we have never detected because they only affect one person or animal at a time and don’t spread, and also because we don’t have a good way to test for them. 

    Since I read about them, it also suggests an evolutionary reason for the predisposition against cannibalism. 

• [Jim Jones]

  I’m actually fascinated by this because of the restrictions that the national blood supply puts on people who were stationed (or family members living with a person stationed) in some European countries during the 1980s during the Mad Cow outbreak. We lived in Germany, one of the countries listed.

  I’ve grown up in a military household that saw giving blood as part of your civic duty. My father has a rare blood type and would receive calls whenever there was a blood drive in his unit or on the post where we were stationed. MANY people, at least at that time, in the military donate blood.

  So, when I graduated high school and moved back to the US, I would give blood  whenever I heard about blood drives in my community. Skip forward a few years, and one of the screening questions asked if potential donors had lived in Europe in the late 1980s. I didn’t think anything of it until, the person running the drive pulled me aside and said that that question disqualified and would continue to disqualify me for the foreseeable future. That was in the mid 1990s and I (nor my father, nor MANY active duty and retired military) have been able to give blood since.

  I’ve brought this up to a number of doctors and some of them weren’t even aware of the restriction.

  Check out the “In-Depth Discussion of Variant Creutzfeld-Jacob Disease and Blood Donation” section of the Red Cross Blood Donation Eligibility requirements page: http://www.redcrossblood.org/donating-blood/eligibility-requirements/eligibility-criteria-alphabetical-listing#arc5 The few that were aware of it thought that is was odd that the ban was still in effect, but, as Maggie pointed out, there is no test for the disease and there as so many unknowns about incubation times that the Red Cross (and other blood banks) can’t take the risk.

  As a result, I’ve followed lots of the general news, watched a few documentaries, and paid attention to popular science coverage of the topic.  When I started hearing reports of CWD, it freaked me out.Anyway, I thought you all might be interested in how the US blood supply, at least, is already addressing prion diseases (or the potential for them) in its policies.

  • [Ghostfucker]

    I lived in Germany as a child in the late 80′s as well, and was always taken out of line during school blood drives when I moved back to the US. Understanding the long incubation period of Mad Cow makes the restriction seem more sensible, when at the time it always seemed like a ridiculous piece of red tape. Of course knowing about the long incubation period isn’t terribly comforting for me!

• [Øyvind]

  Articles like this was, and still is, the reason why I read BB every day. Also, only tangentially related; I think kuru was either mentioned or used as basis for an episode of X-files once upon a time.

  • [Marc Mielke]

    “Our Town” It actually tried really hard to use every cannibalism meme available at the time.
    http://en.wikipedia.org/wiki/Our_Town_(The_X-Files) 

    • [James Agenbroad]

       And it was mentioned in an episode of Scrubs.

• [efergus3]

  Lived in Ely, England, ’87 to ’90. So far so good.

  • [smut clyde]

     I was in the UK, living largely on a diet of meat pies and hamburgers, in the late 1980s, and so far so  erkwnsvcsetcnnz ,,sw

    • [efergus3]

      Soooooooo funny.

• [carolin shining]

  The wonderful Canadian show “Regensis” had a plot line surrounding prion disease in Season 1, episode 4.  
  http://en.wikipedia.org/wiki/List_of_ReGenesis_episodes
  The characters are all employees of “NORBAC”, a fictional entity that investigates all kinds of biological epidemiological threats to North America.  Awesome show.

• [Evan G.]

  Thanks for this. If I can add my own thoughts about people live-tweeting conferences…I hate it. It can easily become too much clogging up my feed, so I either mute the conference hashtag or unfollow the tweeter for a period of time. And I do this even when I’m interested in the topic–I’d rather read something longer and thought out about the topic than a bunch of rapid fire nibbles of information with no bigger context mixed in with everything else I’m reading. 

• [tortoiseparade]

  I’m surprised that after 40 odd comments to this piece not one person has brought up William Arens and the considerable controversy surrounding the cannibalism theory of the kuru epidemic, in both the medical and anthropological communities. According to Arens, there were defects in the research methodology of Daniel Gajdusek who won the Nobel Prize for his research into Kuru. For example, correspondence written by Gajdusek indicates that he had concluded that the highlanders of New Guinea were cannibals, before conducting any research or field interviews.  Furthermore, he misrepresented photos of people eating pork as pictures of people eating human flesh. A lot of people would say that Gajdusek’s conclusion has been debunked, but I’d probably just say it’s been harshly questioned. 

  There was a fascinating debate – one of the biggest debates in late-20th century anthropology — over whether south seas cannibalism actually existed, or was merely the product of European racist fantasy, primarily carried on (if I recall from correctly) between Marshall Sahlins on one side, and Arens and Gananath Obeyesekere, on the other.

  It’s worth checking out!

• [pjcamp]

  Civilized people don’t eat their parents.

  They eat their god.

  Who, by the way, could do with a little cheese or salsa or something. Would some salt diminish the holiness?

• [fredfraudster]

  You know the major players in the prion field have all recently been accused of scientific fraud, right? Read it at http://www.science-fraud.org. All the evidence right there for everyone to see for themselves, copying and pasting of western blot images, re-use of microscopy images, faking of data, the whole lot! Click the prion tag down the bottom right of the page for the articles on Claudio Soto, Stan Prusiner and others. It’s all a sham (not to mention thermodynamically impossible!)

  • [Antinous / Moderator]

    Your proof is a link to an anonymous blog written by you. Forgive me if I don’t take you seriously.

    • [michael.kovari]

      If you look at the evidence on science-fraud. org, you would not write this.Anonymous bloggers have very good reasons to remain anonymous. Anonynity does not equal invalidity

      • [Antinous / Moderator]

        It looks like sniping from the sidelines to me. And when linking to your own blog, you generally identify yourself as the blog author. Failing to do so makes it look like astroturf.

• [Michele]

  Interestingly several people in the Southern US also suffer from a similar disease, from eating squirrel brains. 
  We concentrate a bit too much on kuru and its exoticism I think (it fits comfortably with the Western barbarian/headhunter narrative we have about South Sea islands), and not enough with similar disease manifestation in the Western world. As you pointed out, it’s not just about cannibals or industrial farming. 

• [scientist]

  Dear Dr. Koerth-Baker,
  It might be work repeating that there is reason, first brought forward by the anonymous author of the blog http://www.science-fraud.org, to believe that one of the tenets of the prion idea,that the altered conformation can propagate in vitro, rests at least in part on manipulated image data.  While I understand that as a new media journalist, one might find this anonymity to be problematic, the blogger self identifies as a working scientist who had reviewed numerous grant applications for public funds.  For what it is worth I find this implicit argument for anonymity to be compelling.  I understand that new-journalistic etiquette here hasn’t gelled yet, but I believe that the work alerting readers to issues with the published work constitutes a public service.  In any case it has already served to cast into doubt one of the pillars of the currently accepted view of prion-caused disease, at least among some members of the scientific community.

• [I_of_Horus]

  Here’s a clip of a Kuru sufferer
  http://www.youtube.com/watch?v=C8tmgpOiWRw