More concerning is that some of these diseases are transmissible. Imagine how many people you could infect in 7 years when symptoms only appear after 5-10 years.
I read about some of the most common prion diseases and as far as I can tell, all the transmissible ones require the ingestion of infected material. While a transmissible prion epidemic that spreads through the air would be really scary, it doesn't seem especially likely as an existential threat in our lifetimes.
These prions sound horrible, less defensible against than viruses, and at the same time much simpler in form than viruses so much more common (easier to appear).
What is the reason that we can thank for prion diseases not being much more common?
Not all proteins can exist as prions. (In fact, it's amazing that some can even exist: think about it: a protein that exist in two stable shapes where the shape that does not normally exist in the body can cause the other shape to make the switch!)
The outer layer of your skin is mostly made of dead cells. It's cold, dry, exposed to the elements, constantly discarded, and has the wrong pH for most biochemical processes that are optimized for the inside of your body. It takes a fairly invasive pathogen to break that barrier.
Anything expressed by DNA is a protein, but not all proteins are the same. Prion infections are caused by proteins that change the same proteins in the same way, like how crystals replicate.
A human analogy might be a disgruntled but charismatic worker who starts spreading a disruptive attitude until morale and productivity plummet in their department. As long as one of that team remains, the issue can still spread. Coincidentally, both the potted plants and highly compensated leadership are unaffected.
I’m far from knowledgeable in this area, but the model in my head is: the $foo_protein can be folded in at two important ways, $foo_v1 is what you want, $foo_v2 is a catalyst for refolding $foo_v1 into $foo_v2 but doesn’t refold much (or anything?) else.
I think it largely comes down to there being no benefit to the prion. It’s more of a lightly continuous sort-of-poison than an actual actor looking for its own reproduction. Viruses and bacterias existence depends on reproduction. Prions just kinda appear naturally from folding errors.
They don’t “want” to exist, even to the minimal extent of a virus, they just happen.
I like to tell people that early humans lived in close contact with animals for hundreds of thousands of years, and until a few generations ago, when most people were still farming for a living. If prions had the potential to end the human race, they would already have.
The slight problem there is, prions probably did end a bunch of tribes which were sufficiently local - and then left the area alone long enough that the prion contamination in the environment broke down.
Today we have international animal shipping and trade, and global distribution. Prions are able to spread from exposure to shared pastures. A couple years of contamination used to be no big deal - today, if missed, it can spread all through the food supply.
It is hypothesised that Kuru (and vCJD) in some individuals (due to genetics) might take 40-50 years to develop if introduced through intestine. Well after the individual had a chance to reproduce.
The advent of agriculture and animal husbandry is generally thought to be much more recent than your comment makes it sound. More like ten thousand years ago.
I think prions are a bigger problem in crowded single-species environment than in comparatively sparse mixed-species pre-industrial world.
In particular when you feed cows proteins made from dead cows it's making it more likely to create prion problems than when wild animals live in small herds in forests (and the ones that are sick are killed by predators or starvation before they can infect others more than likely).
Feeding the output back into the input definitely makes it a bigger problem, however Chronic Wasting Disease in Elk and Dear in North America is becoming a huge problem and is a prion disease, and they’re living wild.
So it doesn’t require it, it just increases the odds (and they don’t eat each other to spread it - it’s highly infectious and demonstratively infects if they share browsing/grazing land).
It doesn’t appear to spread between them and humans, but it definitely makes me nervous.
We're actually having a worse situation re/ animals than our ancestors. We nowadays cram farm animals in stables so tightly that without antibiotics and medical treatment the animals would almost immediately perish. Our farms and our animal "care" practices have been the breeding ground for all recent global pandemics (swine flu, bird flu, SARS/MERS/SARS2). Not to mention the conditions that farm and slaughterhouse workers have to work and live in (as evidenced by massive COVID outbreaks).
The chance of any infectious agent "jumping the species" due to cramped conditions or because of exposure of workers to contaminated animal parts in unclean slaughterhouses is immense - the current SARS-CoV-2 pandemic in my opinion is a warning signal of something much worse to come, and no matter what kind of agent it will be, we're pretty much screwed. Half the population or more of the world doesn't believe in vaccination, a quarter or more don't have access to vaccines or any kind of modern medicine at all, we are already running out on reserve antibiotics...
Virus does not "want" to exist either - they just happen. There is no success criteria or will, just a structure that happens to cause self-replication, with variants that cause more aggressive replication being more present and common.
Prions are in that sense no different - they are just less successful.
I think it’s debatable as to the meaning of “want” of non-thinking/non-living things. Viruses continued existence depends on reproduction however, which they’ve been doing for billions of years. That’s a “want” in my book as far as something seemingly inanimate can want.
Viruses that don’t “want” reproduction fail to do so and disappear.
Still not sure I get the distinction with prions that you're making.
The essential idea is roughly "we end up with more of the things that replicate more". Despite the redundancy, there is a crucial idea in here. If we allow the use of the word "want" metaphorically then anything that replicates "wants" to reproduce including memes, crystals, prions and computer viruses.
Maybe you're just saying that a prion isn't as good at replicating as a virus? It seems like a difference of degree rather than kind.
> Maybe you're just saying that a prion isn't as good at replicating as a virus? It seems like a difference of degree rather than kind.
They are qualitatively different.
A virus infects a cell, and critically, can quickly adapt (through random mutations) in an unthinking war between the various forces of the immune system and transmission mode efficacy; A prion does not evolve, it's a misfold of a single type of protein. If you want to compare it to a virus, it's like a virus that is incapable of replicating anything other than an exact copy - and can also only replicate itself using a particular cell (one type of protein).
Why the human body cannot effectively defend itself against particular propagating misfolded proteins is a mystery to me though... perhaps it's too low level to be identified by the immune system as something to attack, much like a poison.
A protein can misfold in countless ways, and there are countless of proteins to misfold.
That a virus can be a big and complicated structure does not mean that smaller and simpler structure is fundamentally different.
Viruses themselves also have many different modes of operation, with things like virophages, satellite virus and giant virus showing just how unclear the term "virus" is.
> A protein can misfold in countless ways, and there are countless of proteins to misfold.
They are countable, but yes there are many ways, but that alone doesn't mean it's capable of meaningfully evolving. It's a search space multiple orders of magnitude smaller than a piece of DNA, so it's easy to see how a different successfully propagating misfold will be significantly less likely when starting from an existing propagating misfold.
If you are suggesting one propagating misfolded protein can, by chance, misfold into another propagating misfolded protein at a rate fast enough to become adaptive... then it's qualitatively the same as a virus, but I don't see this as likely given the significantly smaller search space.
The largest protein we produce is about 27k amino acids, more complicated than most virophages. That is merely the biggest we produce. I know of no upper limit on protein complexity, and that is before even taking folding options into consideration.
The space of possible proteins - and thus prions - is not at all limited, neither figuratively nor literally. It is most certainly not "countable" without some Nobel-prize inducing discovery.
I definitely see where you're coming from, but viruses do have modes of transmission that evolve over time to counter immune defenses. Unless I'm mistaken, with prions, you either have to ingest infected tissue or apparently prick yourself with a needle with infective material on it.
I don't believe they reproduce in any but the broadest sense either. Don't they just cause other proteins of the same type to misfold as well? It's not really a transfer of genetic material, it's a change in the emergent structure of the protein.
It is all a matter of definition. They are both merely a physical structure, they both have to interact with very specific tissues in very specific ways to do anything, they both make our own matter replicate into additional copies of itself, they both have "preferred" areas of attack which are simply areas that they are more successful in, they both tend to "accidentally" cause behaviors that make us assist in spread (e.g. biting), and they both cause various bad things to happen as a side effect of their means of operation.
The prion's mode of operation isn't just "bump into stuff". It reaches the brain, causes other materials (DNA aptamers) to clump together, and causes other prions to be created.
That one happens to have a part that looks like genetic material and the other looks like a misfolded protein is merely a small implementation detail to me.
(Disclaimer: I, like everyone else I'm this thread, is not a qualified source of medical information.)
There's a lot we don't know about prions and a heck of a lot I don't know, but I would be surprised if prions turned out to be something substantially different from a misfolded protein.
I've never heard of prions targeting certain tissues. I need to do some reading, as it's been a while since my last bio course. Do you have an article that explains how that works? In order to have that ability, they would have to be more complicated than I understand them to be.
But there is a difference between e.g. crystals and viruses. Both "want" to exist under some conditions. Crystals will even "evolve" to a small extent that more stable/lower-solubility polymorphs will dominate, and there have been cases of polymorph "infection" (ritonivir) between production facilities. Prions are like crystals in this aspect.
The difference is that viruses have many more tools available in order to evolve and adapt. Prions, like crystal polymorphs, merely have the configuration space of the molecule. Viruses have the configuration space of dozens of proteins, and complexity can increase, so in theory there is no upper bound.
So I guess yes, they are all replicators that differ in extent by the amount of phase space available to their lifecycle. But the complexity jump between prions and viruses is huge, and prions are inherently bounded.
Comparing a crystal to a prion or virus is a fun exercise, especially as they all appear in the body and causes health issues. Kidney stones, sugar crystalization around nerves, etc.
One main "behavior" difference between crystals, prions and viruses is that a crystal only forms by recruiting its equals when in high concentration - growth, but no replication.
Most virus is way more complicated than prions as you say, but a blue whale is also more complicated than a single-celled myxozoa and yet they are both animals. I do not think a comparison of complexity is meaningful in this debate.
One should also consider that there are countless proteins to misfold in any number of ways, so the prion space is not necessarily that limited. Virus do have the upper hand by using our well-oiled evolutionary machinery though.
By that metric, everything just happens though. Humans just happened, we didn’t will ourselves into existence. Human free will cannot be proved and may very well just be an illusion in our perceiving of a cosmic causal chain. Are our “desires” for reproduction any different? Or are they artifacts of our internal calculations of the future? When we are optimistic, we reproduce. When we are pessimistic, we don’t. That seems more like opportunism than free will to me. And that seems very much like what a pathogen would encounter: favorable or unfavorable conditions.
I guess what I am saying is that either you are right and that can be extrapolated all the way up the chain to humanity. Or that you are wrong and you can apply free will all the way down the chain.
I think another way to state this without getting into philosophy or semantics is that viruses are capable of evolving methods of being more successful at infection. Prions are not, because their method of operation involves remaining single molecules.
Prions can't self replicate from raw resources: they depend on inducing conformational change in other proteins. The host has to produce, and use, the specific protein they can target in an accessible location.
The upshot of this for prions is that lacking genetic code, or a need for replication machinery, and being a variant of the protein they target, they are perfectly adapted for their environment and host and currently impossible to destroy without also damaging the normal correct protein form.
Another aspect is that a prion disease requires a much more specific confluence of circumstances. It requires a protein, which can be misfolded, and a misfolding that, when in contact with other proteins of that same type, causes the same misfolding to occur.
> less defensible against than viruses, and at the same time [...] so much more common (easier to appear).
Not really on both parts. It's only transferred by eating meat so the defence is as soon as prion infection is detected all possibly infested livestock is culled and severe bans on trading are placed. Cannibalism in animal feed is also disallowed which makes transmission rare. Being vegetarian is also a complete defence.
They're also rare to appear, otherwise eating livestock would have regularly wiped out humans already. They're basically non-existent if you don't eat humans and livestock isn't fed to livestock.
Lady in the story could have been a Vegetarian yet still died from a Prion. As others have pointed out swimming in bodies of water is possible vector for prions.
Second part is incorrect, first part is a nitpick. She got it from working in a lab. If I say abstinence make you immune from HIV are you going to "counter" that by saying you could get it from being transfused or pricking with infected blood?...
As I understand it, prions are just an ever-present rare tiny probability of a cascading malfunction of your physical composition. They are rare because they need to be, in order for a biological system to survive. (any biological system that had a high probability of prions would die off) They can never fully be eliminated because your body is built on probability, not mathematical certainty. Most organisms live less than 100 years, so the probability is good enough not to affect species survival. As long as young organisms don't eat old organisms, the chances remain low.
Another way to look at it is that the combined lifespans of the organisms of a food chain are shorter than the time it would take for one mis-folded protein to be likely to occur and then also cascade to a degree that would affect the health of the top organism. Prion diseases only show up when you introduce a loop in the food chain.
I suspect the issue is that, prions require a fairly large series of coincidences to be viable, so the biological niche is a pretty small one. I think they're much more specific conditions than that required of viruses.
In addition, your body probably has evolved to use proteins that aren't particularly susceptible to misfolding AND accumulation. (Perhaps a long time ago, it WAS quite common?)
Not a biologist, so this is just a guess, but I imagine their simplicity is their weakness.
Viruses rely on the machinery of nucleic acids to replicate. That machinery is complex and robust and the result of some long period of continuous evolution, which means viruses exists in a fairly smooth fitness space where mutation and recombination are effective means of improving fitness.
Prions by contrast seem more like isolated spikes in a much sparser fitness space. Presumably the equivalents of mutation and recombination for prions lead to molecules that almost never retain the capacity to replicate, so they have limited potential to become fitter over time.
That they don't spread through the same mechanisms that viruses and bacteria use. You'd have to have much more direct contact between the organisms to transfer prions from the one to the other, they are internal and don't self-replicate in the way that bacteria and viruses do. The lack of selection pressure on prions is what keeps them in their lane.
But: consuming bush meat, brains, feeding dead animals to other animals, being careless with sharps and so on are all excellent ways to contract them.
> What is the reason that we can thank for prion diseases not being much more common?
We kinda take this for granted, but it may be the case that our deeply-rooted psychological disgust and aversion to eating human flesh is a product of prion disease killing populations of ancestors who did. Or perhaps, even our tendencies to ceremonies of death helped us: those that feared the bodies of the dead, or were more likely to create rituals of destruction and avoidance, were more likely to persist and pass on their genes :)
> Cattle are believed to have been infected from being fed meat and bone meal (MBM) that contained the remains of other cattle who spontaneously developed the disease or scrapie-infected sheep products. The outbreak increased throughout the United Kingdom due to the practice of feeding meat-and-bone meal to young calves of dairy cows
It is estimated around 400 000 infected cows entered human foodchain in the UK in the 1980s. Less than 200 people died. Samples from appendectomy imply many more are infected, but didn't develop symptoms (yet).
Heat isn't kind to proteins (denaturing, and specifically unfolding them), so cooking that meat - as most people likely did - should have made it safer.
Ye a silent pandemic of "mad cow" would be terrifying, like those people who now carry it asymptomatic would spread it or something. I think there is a "mystery" brain disease in an area in the US somewhere, but I can't remember enough details to find it.
I know it’s obviously not that simple in a medical research environment, but I do wonder if the basic idea of a sewing thimble could be adapted into a contoured, finger-shaped thin metal layer that’s mounted inside special gloves for the researchers to wear. It would have to be done in such a way as to not hinder their dexterity, but I’d think that’s quite doable if said “thimble” was confined to the first segment of each finger.
I think that tragedies like these should absolutely cast a spotlight on the institutional and procedural weaknesses that may have contributed. With this in mind I still I have to say - it blows my mind that someone could be working with prions and not be wearing the correct hand protection. Why? How often did they work so unsafely? How many others aren't? Did nobody notice and speak up?
Even the article itself doesn't seem to ask these questions.
From articles I've read (and my father's experience in construction work), the biggest challenge in workplace safety is getting the workers to wear the damn equipment that's specifically made to save their life.
It's especially dangerous with unscrupulous bosses, who will just shrug and not have a fight with their own employees over making them follow the regulations.
I had never thought about kevlar being a brand name before and your comment made me curious. Apparently the generic name for that material is "para-aramid".
Upon reading the comments on this post, I realised that many people are terrified of prions, as am I.
But why much more than a virus or bacteria? I am terrified of rabies, sure, but not in the same way. Something about prions rubs me in the weirdest of ways.
Maybe it has to do with them not being an "external" assailant (even if originally acquired externally), but an inherent defect of some part of myself?
While entirely incurable today (like many other diseases), I suspect that reality is not nearly as terrifying as the story that as painted. A virus is after all your own cells used against you, so its modus operandi of having your body fail yiu is not really that unique.
Articles make it sound like our entire being unwinds in their presence, while the real outcome is likely much less exciting: clumps slowly forming that fail to get cleared and end up causing problems as they accumulate. Fatal and no available cure once there are symptoms, but... Less scary.
(Disclaimer: I, like everyone else in this thread, is not a qualified source of medical information.)
I agree that it seems at least plausible that a cure will be found in the future. The cell already has a number of quality control mechanisms for detecting misfolded proteins. It seems not unusual that we'd be able to piggyback onto this system do develop something that can detect specific prions and neutralize or destroy them, possibly delivered an an RNA shot.
The problem is that there are a minuscule number of prion deaths in the developed world, so I don't see it getting a huge amount of attention.
On the other hand, the Covid RNA vaccines were basically invented by a handful of people looking at a string of nucleotides over the course of five days. (It took large companies to actually develop the vaccine itself, of course.) This could end up being something that's solved by more accurate protein-folding simulations (perhaps Google's AlphaFold) and a couple of grad students.
Our bodies at least have a chance of defending themselves against almost all viruses. Prions? No chance. It’s a death sentence with a slow and terrible decline.
It's the distance between cause and effect. What were you doing 5 years ago today? In 2 years, maybe you develop a 100% fatal disease and die because of it - and there's no way to verify until you actually do or do not die of it, so you don't know it's coming.
The only reliable prion disease diagnostic is brain tissue biopsy.
I think it's just that the usual protections do nothing against them. Boiling, freezing, disinfecting do nothing. There is no cure, no treatment, just a slow and inevitable decline.
I think my own fear of rabies is actually somewhat similar, but yours may be different.
There is no cure, yes. But I just learned from Wikipedia that the Fore (the people from Papua New Guinea) developed a gene mutation, so that the Kuru disease does not break out. And it even protects against all other TSEs!
I agree it's scary, but at the same time I realize fearing it is completely irrational for me. I would assume in a first world country you are much more likely to die of, say, slipping in a shower than of a prion disease.
If I'm bitten by an animal which I suspect is rabid, I can simply take some doses of anti-rabic serum and be done with it. Actually I've done that more than once.
If I suspect I've had contact with a meat or blood of a prion-infected animal, what could I do about it?
For me it’s because they have a component of “natural destructor” mixed with “indestructible evil”. A virus, a bacteria, an amoeba feel like mosquitoes, even if deadly ones. Poisons and radiation feel like dangerous substances. They are all external and countable. Prions are your own bad design, a trivial key to a malfunction at the very core level, like an instant crystallization catalyst for your tissues, which you cannot undo. It’s not even your death that is terrific about prions, but the fact of the whole possibility of their existence - they feel just alien/enemy to our entire nature. I have similar feelings about SCP-009 (red water) and false vacuum.
I had researched on prions and the Kuru disease for a class while looking at the impacts of animal testing (the Kuru disease is a prion found in New Guinea and is considered to be the first prion disease). Prions are scarily dangerous - near-fatal if exposed to it, and stable at much higher temperatures that regular non-misfolded proteins.
However, your chances of getting prions is very low. As long as you avoid "exotic" meat like monkey brains and stay in countries with strong regulatory bodies (like the US/EU etc) the risk of exposure is extremely limited. Bonus points if you avoid swimming in random bodies of water to not get contaminated water with brain-eating amoeba traveling up your nose.
My great love is travelling (mostly outside the EU/US) and this often involves countries where swimming in random bodies of water is part of the standard itinerary.
I'm sure I'm not particularly unusual in this respect. Most of friends have similar preferences.
Yeah my girls loved swimming in my in-laws pond behind their house. This ruined that. Statistically almost zero chance it will happen, but the ghost of the idea is there.
This really is a poor example. The vast majority of children who grew up doing "dangerous" activities are still alive and well. Survivorship bias is more often used when the chance of surviving is statistically lower than most people realize.
It's still survivorship bias. They're only happy about it because nothing bad occurred to them, while there really are kids that got sick and I bet they're much less positive about these dangerous things they got to do.
I'm genuinely confused by this. Most of my friends (pre-covid) would holiday fairly regularly outside of Eurpope. We're not especially wealthy or unusual as far as I know. I can't think of many people I know who only holiday in the EU.
South-East Asia is a hugely popular destination. Do we know different demographics?
The Amoeba is most problematic in warm fresh water bodies. However, a couple of years ago a woman got infected from a neti pot- scared the crap out of me[1]. I now always boil the water.
I do not doubt that. Meanwhile, I didn't. At issue is how common your experience is. We know it is not universal, p=1. We know it is not nil, p=0. So, is it close to 0.5? 0.1? 0.01? My guess is it is between 0.1 and 0.01.
"Strange women lyin' in ponds distributin' swords is no basis for a system of government!"
I'll grant the freshwater bit pushes the probability down a fair bit.
But the comment that I was responding to was "Doing that sort of travel is, for most citizens of the industrialized west, pretty unusual." which seems to be more about "outside of Europe" than it was "and swimming in freshwater. That was the part I found strange. I think there's a couple of countries with much lower than average travel (the US already mentioned and I seem to recall that the French tend to stay within their own borders more than the average)
It's safe to say we know different demographics. I think this is more of an EU thing than a US thing. Also, likely an upper middle class or greater thing. I'm from the US and even pre-covid, most Americans in the bottom 80% of incomes are not "holidaying" anywhere, domestic or overseas on a regular basis. A large percentage of the remainder stick to the US for the majority of their vacations. Pretty much everyone I know(mostly top 20% earners) who travels overseas more than once a decade or so is foreign born, or at least 2nd generation, and traveling to visit family.
Apparently 42% of Americans have passports now, but it was about half that just a decade ago, and I'd attribute most of the growth to immigration, not vacations. Anecdotal, I'd say in SEAsia the "foreigners" I encountered were like 80% European. In Central America, the cheapest/shortest flight from the US, it was still like 50% Europeans. Whenever we're finally able to visit my wife's family again, she's goin to have to get special permission to take unpaid vacation time or else change jobs in order to be get enough time to make the trip to Asia worthwhile. That's pretty typical here.
If a lower class person in the US goes to Europe or Asia, or really anywhere except other than the US, Canada, or sometimes Mexico at most, a lot of us of us will probably think of them as the particularly adventurous sort.
We do have a fair amount of people who go to Mexico, but even then, It's extremely common to not go.... anywhere, unless you have money, and especially not go anywhere regularly, mostly because it's expensive and nobody can afford time off work even if they could afford plane tickets.
It's semi-possible, but as far as I can tell lot of people don't really save up and make it a priority.
I doubt it, because I do the same type of travel and many (or often most) of the other people at those locations are also from the “industrialized west”
Yeah they really are scary dangerous. The risk of exposure is low. There are some other important transmission channels to consider. As you noted on their temperature stability, prions aren't sterilized by normal medical sterilization procedures including autoclaving. So transmission of prions by surgical instruments can occur and is well documented. The conventional advice is that surgical instruments contaminated with prions need to be thrown out. It can also occur with organ transplants. Advice: don't read about this if you're scheduled for surgery. It's probably the smallest risk you'll encounter but it might really capture your imagination.
As noted in the article, prions are also responsible for 'mad cow disease', Bovine Spongiform Encephalopathy (BSE) as well as Creutzfeldt–Jakob disease. If you really want to get into prions you can start with the wikipedia entries for those. They're pretty incredible from a physics / biology standpoint.
The thing the article doesn't point out that is important to keep in mind is that CJD is a really awful neurological wasting disease and it's likely that in those seven years Émilie Jaumain and her family suffered terribly.
"prions are also responsible for 'mad cow disease', Bovine Spongiform Encephalopathy (BSE) as well as Creutzfeldt–Jakob disease" ...
and scrapie in sheep, and Chronic Wasting Disease in deer and other wild Cervidae in North America. The latter is increasingly common in the US, although its wide spread is recent enough that little is known as to whether it is being transmitted back to humans through hunting and processing of deer.
This sounds like a twist on the plot of World War Z but kicked off by a newly discovered, highly contagious rapid onset form of human prion disease spreading across the population and turning people into the living dead with Mad Human Disease (i.e. becoming homicidal and deranged while their brains rapidly deteriorate), the difference from zombies in this plot however is that even if you kill them to save your life, you risk exposing yourself to the mutated prions even after their death and nothing can limit your exposure, they are essentially radioactive to be around and their human form prions persist long after their body is gone, leeching into the ground, water, air when physically disturbed, etc.
Re: the medical instrument - why isn't bleach used in such a case then, or even as a standard procedure before autoclaving? (Or does that just damage the metal instead?)
Idk about bleach, but if you look at some of the studies, 600deg treatment for over a day and similar protocols were being evaluated, and even those scales of energy weren't clearly enough.
Looks like bleach (sodium hypochlorite) plus autoclaving is a method recommended by the World Health Organization (WHO), for whatever that's worth.
https://en.wikipedia.org/wiki/Prion#Sterilization
Prion disease incidence is very low but most all cases in the US are the sporadic kind. It looks like there were over 500 deaths in the US from CJD in 2019. It’s not really about avoiding infected tissue (for CJD)
A few meat processing plants used compressed air to remove grey matter from animal skulls, and some did not provide adequate PPE to their workers. Several people started to show unique neurological symptoms that seemed to correlate with years of exposure to aerosolized pig brains. One person that I know of sued Hormel in 2008, and the lawsuit was dismissed with prejudice in 2009.
I've always wondered if the case had merit and we just did not have sufficient medical knowledge/techniques at the time to investigate the source, of if someone read about prions and self-diagnosed.
> Several people started to show unique neurological symptoms that seemed to correlate with years of exposure to aerosolized pig brains
I thought those were thought to be autoimmune issues from the person's body learning to treat neurons as a threat? Or is that a separate thing? (Or outright discredited?)
The chance of an airline accident is 1 in 16 million.
441 nuclear reactors have been operating flawlessly for over a decade.
Countless biology labs deal with dangerous pathogens daily with minimal accidents.
This French lab from the article had two separate accidents in three years.
I dislike when people use the term 'accidents happen' in a hand wavy way. There's a whole world of risk calculations to determine if something is safe or not.
441 nuclear reactors have been operating flawlessly for over a decade.
Fascinating choice of timeframe: "over a decade".
How about going back just one more year. We can find multiple nuclear reactors blowing themselves up quite spectacularly on TV:
Over the following three weeks there was evidence of partial nuclear meltdowns in units 1, 2 and 3: visible explosions, suspected to be caused by hydrogen gas, in units 1 and 3; a suspected explosion in unit 2, that may have damaged the primary containment vessel; and a possible uncovering of the Spent fuel pools in Units 1, 3 and 4.
I think my brain is constantly on the lookout for clickbait. When I read the headline of this thread, I immediately thought of a similarly worded clickbait type headline: "Man dies 3 years after eating cheesesteak"...
Is there a post-prick protocol? I'd almost vote for having the tip of my finger amputated post prion-lab accident if it would help and was an option. I get she should have worn gloves, but it seems like there should also be some set procedure.
The lab changes under development should include a protocol for protection _after_ accidental prion-disease needle sticks. Prophylaxis protocols exist for clinicians dealing with HIV, hepatitis, etc. [0]
A radical (barbaric) way might be to immediately tourniquet the finger, anesthetize, and cut off the tip! They could hang a little guillotine next to the eye-wash station....
"A 5-minute soak in a 40% solution of household bleach decontaminated stainless steel wires coated with chronic wasting disease (CWD) prions, according to a new study by National Institutes of Health scientists."
Although it notes: "Notably, the study failed to find an effective method to decontaminate CWD-infected solid tissue. Pieces of CWD-infected brain retained prion activity even after a 30-minute soak in 100% bleach. Investigators note that bleach fails to penetrate tissues and should be used only as a surface decontaminant."
I was thinking the other day of that story and came to the same conclusion: since prions are always fatal, why not cut the finger/hand in case of infection? It's radical yes but better safe than sorry.
Can anybody speak to how this story relates to prions found in deer (and so venison) in Michigan and the Midwest? My family are hunters and now send all deer to be tested before eating, but most don't.
> In June 2019, an INRAE lab worker named Émilie Jaumain died at age 33, 10 years after pricking her thumb during an experiment with prion-infected mice.
The HN headline:
> Woman dies seven years after pricking finger in prion research lab (science.org)
Tragic. It’s always scary to handle needles in a lab. Even with good needle safety protocols, accidents are bound to happen.
There’s this case that my PI showed me of a student who pricked his finger with a needle filled with DCM [1] (which is very common solvent in used in lab). The residual DCM at the tip of the needle caused the damage shown in the pictures.
When your work involves handling tens of needles daily, accidents are bound to happen. I pricked myself once with a needle. Thankfully it was brand new and dry, so nothing happened. It was just the idea of it was terrifying. In an alternate world, I could’ve gone to the ER because of it. Hope someone invents a safer needle.
Just my opinion, but that’s not DCM residue on a needle, that’s someone using a needle to transfer and forcing DCM under their skin.
I drenched myself in DCM and stick myself with needles a few times.
Not to say the lab isn’t dangerous. I knew one person who peppered their abdomen with glass when a perchlorate exploded, scarred their face when a peroxide exploded and burned themselves with an organolithium.
But a simple needle stick with DCM residue won’t do that.
Blunt needles are a thing. They are used for example in electronics as a way to dispense tiny amounts of solder paste or flux on components pads on a PCB. Presumably when transferring solutions from container to container, you don't need a sharp needle, unless the container is closed with a membrane that needs to be pierced.
There are also gloves that protect against puncture. If you're using both sharp needles and non-protecting gloves then it is probably time to revise the procedures.
Does anyone know what the typical safety rules around needles and blades are in a BSL-3 lab? I assume this was a BSL-3 lab as this was a human prion strain.
Or were these experiments actually done in a BSL-2 lab?
I'm a complete layman in this field, but the logical conflict between these two sections concerned me:
> she stabbed her left thumb with a curved forceps while cleaning a cryostat — a machine that can cut tissues at very low temperatures — that she used to slice brain sections from transgenic mice infected with a sheep-adapted form of BSE
Then later:
> Aguzzi declined to comment on the French CJD cases, but told Science his lab never handles human or bovine prions for research purposes, only for diagnostics. "We conduct research only on mouse-adapted sheep prions, which have never been shown to be infectious to humans," Aguzzi says.
Am I missing something, or is the logical conclusion that Aguzzi thinks his lab is avoiding disaster by only using mouse-adapted sheep prions, but the lady is suspected to have been infected by an injury related to "transgenic mice infected with a sheep-adapted form of BSE". I hope there's some nuance here, because otherwise it sounds like Aguzzi's lab isn't actually avoiding infection. Perhaps the lady's case isn't considered to have definitely confirmed infectiousness due to uncertainty (though no uncertainty seemed to be mentioned)? Or the mouse-adapted sheep prions Aguzzi's lab uses are different to the transgenic mice infected with a sheep-adapted form of BSE? I have no idea; it's just that the apparent conflict between these two sections jumped out to my layman's eyes.
I don't think there's any logical conflict. They stated that they thought the type of prion they were handling couldn't infect humans. They see now they were likely wrong.
I don't read any implication that they see they were likely wrong. According to the article, he actually refused to comment on the French cases and said their own lab "only use mouse-adapted sheep prions, which have never been shown to be infectious to humans." Not even "_had_ never been shown". It seems unclear what his view is.
It immediately goes on to talk about their own discovery 10 years ago that prions could be spread through aerosols which "totally shocked" them and might "warrant re-thinking on prion biosafety guidelines" but that seems an entirely separate thing from the decision to use only sheep prions for research.
193 comments
[ 0.70 ms ] story [ 129 ms ] threadWhat is the reason that we can thank for prion diseases not being much more common?
A human analogy might be a disgruntled but charismatic worker who starts spreading a disruptive attitude until morale and productivity plummet in their department. As long as one of that team remains, the issue can still spread. Coincidentally, both the potted plants and highly compensated leadership are unaffected.
I’m far from knowledgeable in this area, but the model in my head is: the $foo_protein can be folded in at two important ways, $foo_v1 is what you want, $foo_v2 is a catalyst for refolding $foo_v1 into $foo_v2 but doesn’t refold much (or anything?) else.
They don’t “want” to exist, even to the minimal extent of a virus, they just happen.
Today we have international animal shipping and trade, and global distribution. Prions are able to spread from exposure to shared pastures. A couple years of contamination used to be no big deal - today, if missed, it can spread all through the food supply.
In particular when you feed cows proteins made from dead cows it's making it more likely to create prion problems than when wild animals live in small herds in forests (and the ones that are sick are killed by predators or starvation before they can infect others more than likely).
So it doesn’t require it, it just increases the odds (and they don’t eat each other to spread it - it’s highly infectious and demonstratively infects if they share browsing/grazing land).
It doesn’t appear to spread between them and humans, but it definitely makes me nervous.
The chance of any infectious agent "jumping the species" due to cramped conditions or because of exposure of workers to contaminated animal parts in unclean slaughterhouses is immense - the current SARS-CoV-2 pandemic in my opinion is a warning signal of something much worse to come, and no matter what kind of agent it will be, we're pretty much screwed. Half the population or more of the world doesn't believe in vaccination, a quarter or more don't have access to vaccines or any kind of modern medicine at all, we are already running out on reserve antibiotics...
Prions are in that sense no different - they are just less successful.
Viruses that don’t “want” reproduction fail to do so and disappear.
The essential idea is roughly "we end up with more of the things that replicate more". Despite the redundancy, there is a crucial idea in here. If we allow the use of the word "want" metaphorically then anything that replicates "wants" to reproduce including memes, crystals, prions and computer viruses.
Maybe you're just saying that a prion isn't as good at replicating as a virus? It seems like a difference of degree rather than kind.
They are qualitatively different.
A virus infects a cell, and critically, can quickly adapt (through random mutations) in an unthinking war between the various forces of the immune system and transmission mode efficacy; A prion does not evolve, it's a misfold of a single type of protein. If you want to compare it to a virus, it's like a virus that is incapable of replicating anything other than an exact copy - and can also only replicate itself using a particular cell (one type of protein).
Why the human body cannot effectively defend itself against particular propagating misfolded proteins is a mystery to me though... perhaps it's too low level to be identified by the immune system as something to attack, much like a poison.
That a virus can be a big and complicated structure does not mean that smaller and simpler structure is fundamentally different.
Viruses themselves also have many different modes of operation, with things like virophages, satellite virus and giant virus showing just how unclear the term "virus" is.
They are countable, but yes there are many ways, but that alone doesn't mean it's capable of meaningfully evolving. It's a search space multiple orders of magnitude smaller than a piece of DNA, so it's easy to see how a different successfully propagating misfold will be significantly less likely when starting from an existing propagating misfold.
If you are suggesting one propagating misfolded protein can, by chance, misfold into another propagating misfolded protein at a rate fast enough to become adaptive... then it's qualitatively the same as a virus, but I don't see this as likely given the significantly smaller search space.
The space of possible proteins - and thus prions - is not at all limited, neither figuratively nor literally. It is most certainly not "countable" without some Nobel-prize inducing discovery.
The only known human prion proteins seem to be a few orders of magnitude smaller than that though, and they don't appear to adapt.
Are you saying it's possible for prions to emerge from large proteins with the ability to adapt?
The viruses we see are common because they reproduce, it's not that they reproduce because they have some drive to become common.
Thus prions are less common because they aren't as successful in spreading (for some reason(s) I don't know either).
I don't believe they reproduce in any but the broadest sense either. Don't they just cause other proteins of the same type to misfold as well? It's not really a transfer of genetic material, it's a change in the emergent structure of the protein.
The prion's mode of operation isn't just "bump into stuff". It reaches the brain, causes other materials (DNA aptamers) to clump together, and causes other prions to be created.
That one happens to have a part that looks like genetic material and the other looks like a misfolded protein is merely a small implementation detail to me.
(Disclaimer: I, like everyone else I'm this thread, is not a qualified source of medical information.)
I've never heard of prions targeting certain tissues. I need to do some reading, as it's been a while since my last bio course. Do you have an article that explains how that works? In order to have that ability, they would have to be more complicated than I understand them to be.
The difference is that viruses have many more tools available in order to evolve and adapt. Prions, like crystal polymorphs, merely have the configuration space of the molecule. Viruses have the configuration space of dozens of proteins, and complexity can increase, so in theory there is no upper bound.
So I guess yes, they are all replicators that differ in extent by the amount of phase space available to their lifecycle. But the complexity jump between prions and viruses is huge, and prions are inherently bounded.
https://www.pnas.org/content/100/5/2180.
One main "behavior" difference between crystals, prions and viruses is that a crystal only forms by recruiting its equals when in high concentration - growth, but no replication.
Most virus is way more complicated than prions as you say, but a blue whale is also more complicated than a single-celled myxozoa and yet they are both animals. I do not think a comparison of complexity is meaningful in this debate.
One should also consider that there are countless proteins to misfold in any number of ways, so the prion space is not necessarily that limited. Virus do have the upper hand by using our well-oiled evolutionary machinery though.
I guess what I am saying is that either you are right and that can be extrapolated all the way up the chain to humanity. Or that you are wrong and you can apply free will all the way down the chain.
Prions can't self replicate from raw resources: they depend on inducing conformational change in other proteins. The host has to produce, and use, the specific protein they can target in an accessible location.
The upshot of this for prions is that lacking genetic code, or a need for replication machinery, and being a variant of the protein they target, they are perfectly adapted for their environment and host and currently impossible to destroy without also damaging the normal correct protein form.
One reason is that we don't eat each other which would spread certain prion diseases like https://en.m.wikipedia.org/wiki/Kuru_(disease)
Not really on both parts. It's only transferred by eating meat so the defence is as soon as prion infection is detected all possibly infested livestock is culled and severe bans on trading are placed. Cannibalism in animal feed is also disallowed which makes transmission rare. Being vegetarian is also a complete defence.
They're also rare to appear, otherwise eating livestock would have regularly wiped out humans already. They're basically non-existent if you don't eat humans and livestock isn't fed to livestock.
Lady in the story could have been a Vegetarian yet still died from a Prion. As others have pointed out swimming in bodies of water is possible vector for prions.
Tell that to deer dying of CWD.
Your condescending sic is, ironically, misplaced.
Another way to look at it is that the combined lifespans of the organisms of a food chain are shorter than the time it would take for one mis-folded protein to be likely to occur and then also cascade to a degree that would affect the health of the top organism. Prion diseases only show up when you introduce a loop in the food chain.
In addition, your body probably has evolved to use proteins that aren't particularly susceptible to misfolding AND accumulation. (Perhaps a long time ago, it WAS quite common?)
Viruses rely on the machinery of nucleic acids to replicate. That machinery is complex and robust and the result of some long period of continuous evolution, which means viruses exists in a fairly smooth fitness space where mutation and recombination are effective means of improving fitness.
Prions by contrast seem more like isolated spikes in a much sparser fitness space. Presumably the equivalents of mutation and recombination for prions lead to molecules that almost never retain the capacity to replicate, so they have limited potential to become fitter over time.
But: consuming bush meat, brains, feeding dead animals to other animals, being careless with sharps and so on are all excellent ways to contract them.
We kinda take this for granted, but it may be the case that our deeply-rooted psychological disgust and aversion to eating human flesh is a product of prion disease killing populations of ancestors who did. Or perhaps, even our tendencies to ceremonies of death helped us: those that feared the bodies of the dead, or were more likely to create rituals of destruction and avoidance, were more likely to persist and pass on their genes :)
Previous discussion:
https://news.ycombinator.com/item?id=27982991
Prion diseases like mad cow kill within one year after 5-10 years of infection.
The massive wave of death and terror would end society as we know it
> Cattle are believed to have been infected from being fed meat and bone meal (MBM) that contained the remains of other cattle who spontaneously developed the disease or scrapie-infected sheep products. The outbreak increased throughout the United Kingdom due to the practice of feeding meat-and-bone meal to young calves of dairy cows
[1] https://en.wikipedia.org/wiki/Bovine_spongiform_encephalopat...
https://en.m.wikipedia.org/wiki/United_Kingdom_BSE_outbreak
I know it’s obviously not that simple in a medical research environment, but I do wonder if the basic idea of a sewing thimble could be adapted into a contoured, finger-shaped thin metal layer that’s mounted inside special gloves for the researchers to wear. It would have to be done in such a way as to not hinder their dexterity, but I’d think that’s quite doable if said “thimble” was confined to the first segment of each finger.
> and did not wear both metal mesh and surgical gloves, as she was supposed to
Even the article itself doesn't seem to ask these questions.
It's especially dangerous with unscrupulous bosses, who will just shrug and not have a fight with their own employees over making them follow the regulations.
But why much more than a virus or bacteria? I am terrified of rabies, sure, but not in the same way. Something about prions rubs me in the weirdest of ways.
Maybe it has to do with them not being an "external" assailant (even if originally acquired externally), but an inherent defect of some part of myself?
Articles make it sound like our entire being unwinds in their presence, while the real outcome is likely much less exciting: clumps slowly forming that fail to get cleared and end up causing problems as they accumulate. Fatal and no available cure once there are symptoms, but... Less scary.
(Disclaimer: I, like everyone else in this thread, is not a qualified source of medical information.)
The problem is that there are a minuscule number of prion deaths in the developed world, so I don't see it getting a huge amount of attention.
On the other hand, the Covid RNA vaccines were basically invented by a handful of people looking at a string of nucleotides over the course of five days. (It took large companies to actually develop the vaccine itself, of course.) This could end up being something that's solved by more accurate protein-folding simulations (perhaps Google's AlphaFold) and a couple of grad students.
The only reliable prion disease diagnostic is brain tissue biopsy.
Even Ebola with a microscopic amount of contact and immediate treatment you can recover.
Prions, not so much. Death sentence.
I think my own fear of rabies is actually somewhat similar, but yours may be different.
If I suspect I've had contact with a meat or blood of a prion-infected animal, what could I do about it?
However, your chances of getting prions is very low. As long as you avoid "exotic" meat like monkey brains and stay in countries with strong regulatory bodies (like the US/EU etc) the risk of exposure is extremely limited. Bonus points if you avoid swimming in random bodies of water to not get contaminated water with brain-eating amoeba traveling up your nose.
I'm sure I'm not particularly unusual in this respect. Most of friends have similar preferences.
Especially when you see micrographs of the little demon: https://www.newsweek.com/brain-eating-amoebae-strike-again-t...
After all you almost certainly put them at more risk just driving them there.
I didn't say they stopped swimming, but it just added some bullshit on top that I would have rather done without.
Lots of Westerners travel to Asia/Africa/middle East/Latin America. (And yeah, sometimes they catch diseases).
Also, you have to think whether people who normally live in those countries (non westerners) get exposed and face the consequences regularly.
South-East Asia is a hugely popular destination. Do we know different demographics?
[1] https://www.cbsnews.com/news/woman-dies-from-brain-eating-am...
This has all gone a bit off track. To bring this back to the original context:
> Doing that sort of travel is, for most citizens of the industrialized west, pretty unusual.
"Pretty unusual" is what I'm disputing. I'd say it's far from "pretty unusual" for average, regular people to go on holiday outside Europe.
"Strange women lyin' in ponds distributin' swords is no basis for a system of government!"
But the comment that I was responding to was "Doing that sort of travel is, for most citizens of the industrialized west, pretty unusual." which seems to be more about "outside of Europe" than it was "and swimming in freshwater. That was the part I found strange. I think there's a couple of countries with much lower than average travel (the US already mentioned and I seem to recall that the French tend to stay within their own borders more than the average)
Apparently 42% of Americans have passports now, but it was about half that just a decade ago, and I'd attribute most of the growth to immigration, not vacations. Anecdotal, I'd say in SEAsia the "foreigners" I encountered were like 80% European. In Central America, the cheapest/shortest flight from the US, it was still like 50% Europeans. Whenever we're finally able to visit my wife's family again, she's goin to have to get special permission to take unpaid vacation time or else change jobs in order to be get enough time to make the trip to Asia worthwhile. That's pretty typical here.
We do have a fair amount of people who go to Mexico, but even then, It's extremely common to not go.... anywhere, unless you have money, and especially not go anywhere regularly, mostly because it's expensive and nobody can afford time off work even if they could afford plane tickets.
It's semi-possible, but as far as I can tell lot of people don't really save up and make it a priority.
I wonder if this whole disagreement is actually about the fact that Americans tend to travel abroad less than those from other Western countries.
https://www.merckmanuals.com/home/brain,-spinal-cord,-and-ne...
So scary.
As noted in the article, prions are also responsible for 'mad cow disease', Bovine Spongiform Encephalopathy (BSE) as well as Creutzfeldt–Jakob disease. If you really want to get into prions you can start with the wikipedia entries for those. They're pretty incredible from a physics / biology standpoint.
The thing the article doesn't point out that is important to keep in mind is that CJD is a really awful neurological wasting disease and it's likely that in those seven years Émilie Jaumain and her family suffered terribly.
and scrapie in sheep, and Chronic Wasting Disease in deer and other wild Cervidae in North America. The latter is increasingly common in the US, although its wide spread is recent enough that little is known as to whether it is being transmitted back to humans through hunting and processing of deer.
Anyone care to modify my plot to make it spicier?
I'm assuming that bleach is insufficient for this purpose.
https://www.cdc.gov/prions/cjd/occurrence-transmission.html?...
Here’s some basic info and radiology https://radiopaedia.org/articles/creutzfeldt-jakob-disease?l...
Also, be very careful with the water that you use in a neti pot.
I've always wondered if the case had merit and we just did not have sufficient medical knowledge/techniques at the time to investigate the source, of if someone read about prions and self-diagnosed.
https://www.austindailyherald.com/2009/02/hormel-qpp-lawsuit...
Wow! Thanks for one of the most disgusting imaginations I had in a while! :-)
I thought those were thought to be autoimmune issues from the person's body learning to treat neurons as a threat? Or is that a separate thing? (Or outright discredited?)
Why don't they just hire competent people?
We have BSL level 4 and people don't often prick themselves.
What gives?
Wuhan Institute of Virology was BSL level 4, and yet here we are.
People aren’t perfect. Accidents happen.
441 nuclear reactors have been operating flawlessly for over a decade.
Countless biology labs deal with dangerous pathogens daily with minimal accidents.
This French lab from the article had two separate accidents in three years.
I dislike when people use the term 'accidents happen' in a hand wavy way. There's a whole world of risk calculations to determine if something is safe or not.
Fascinating choice of timeframe: "over a decade".
How about going back just one more year. We can find multiple nuclear reactors blowing themselves up quite spectacularly on TV:
Over the following three weeks there was evidence of partial nuclear meltdowns in units 1, 2 and 3: visible explosions, suspected to be caused by hydrogen gas, in units 1 and 3; a suspected explosion in unit 2, that may have damaged the primary containment vessel; and a possible uncovering of the Spent fuel pools in Units 1, 3 and 4.
https://en.wikipedia.org/wiki/Fukushima_Daiichi_Nuclear_Powe...
Other than that, Mrs. Lincoln, how did you enjoy the play?
I never said that nuclear reactors don't have problems I would be an idiot to say that. Everyone on Earth knows nuclear reactors have problems.
Statistically though it's a very very unlikely.
What it sounded like you were saying is that because human error exists....we should shut down all nuclear reactors and biology labs.
I don't agree with that.
Maybe I just think about cheesesteaks too much.
A radical (barbaric) way might be to immediately tourniquet the finger, anesthetize, and cut off the tip! They could hang a little guillotine next to the eye-wash station....
[0] https://www.cdc.gov/niosh/topics/bbp/emergnedl.html
"A 5-minute soak in a 40% solution of household bleach decontaminated stainless steel wires coated with chronic wasting disease (CWD) prions, according to a new study by National Institutes of Health scientists."
Although it notes: "Notably, the study failed to find an effective method to decontaminate CWD-infected solid tissue. Pieces of CWD-infected brain retained prion activity even after a 30-minute soak in 100% bleach. Investigators note that bleach fails to penetrate tissues and should be used only as a surface decontaminant."
I mean… probably, but you’d need a bigger guillotine. And now having a hand sized guillotine in the lab is a bigger safety hazard.
Come on now, it's not like it would be a giant curved blade hanging freely from the ceiling into middle of the room.
> In June 2019, an INRAE lab worker named Émilie Jaumain died at age 33, 10 years after pricking her thumb during an experiment with prion-infected mice.
The HN headline:
> Woman dies seven years after pricking finger in prion research lab (science.org)
Where did the "seven" year quote come from?
There’s this case that my PI showed me of a student who pricked his finger with a needle filled with DCM [1] (which is very common solvent in used in lab). The residual DCM at the tip of the needle caused the damage shown in the pictures.
When your work involves handling tens of needles daily, accidents are bound to happen. I pricked myself once with a needle. Thankfully it was brand new and dry, so nothing happened. It was just the idea of it was terrifying. In an alternate world, I could’ve gone to the ER because of it. Hope someone invents a safer needle.
[1]: https://www.chemistryworld.com/news/gruesome-accident-prompt...
I drenched myself in DCM and stick myself with needles a few times.
Not to say the lab isn’t dangerous. I knew one person who peppered their abdomen with glass when a perchlorate exploded, scarred their face when a peroxide exploded and burned themselves with an organolithium.
But a simple needle stick with DCM residue won’t do that.
There are also gloves that protect against puncture. If you're using both sharp needles and non-protecting gloves then it is probably time to revise the procedures.
Or were these experiments actually done in a BSL-2 lab?
> she stabbed her left thumb with a curved forceps while cleaning a cryostat — a machine that can cut tissues at very low temperatures — that she used to slice brain sections from transgenic mice infected with a sheep-adapted form of BSE
Then later:
> Aguzzi declined to comment on the French CJD cases, but told Science his lab never handles human or bovine prions for research purposes, only for diagnostics. "We conduct research only on mouse-adapted sheep prions, which have never been shown to be infectious to humans," Aguzzi says.
Am I missing something, or is the logical conclusion that Aguzzi thinks his lab is avoiding disaster by only using mouse-adapted sheep prions, but the lady is suspected to have been infected by an injury related to "transgenic mice infected with a sheep-adapted form of BSE". I hope there's some nuance here, because otherwise it sounds like Aguzzi's lab isn't actually avoiding infection. Perhaps the lady's case isn't considered to have definitely confirmed infectiousness due to uncertainty (though no uncertainty seemed to be mentioned)? Or the mouse-adapted sheep prions Aguzzi's lab uses are different to the transgenic mice infected with a sheep-adapted form of BSE? I have no idea; it's just that the apparent conflict between these two sections jumped out to my layman's eyes.
It immediately goes on to talk about their own discovery 10 years ago that prions could be spread through aerosols which "totally shocked" them and might "warrant re-thinking on prion biosafety guidelines" but that seems an entirely separate thing from the decision to use only sheep prions for research.