Airborne Prions Prove Lethal In Mouse Studies

sgunhouse writes "Wired has a story up on the lethality of airborne prions. It should be noted that prions (which cause 'mad cow disease' and similar disorders) are not normally airborne, and take a long time to kill the infected animal, but so far are 100% lethal if something else doesn't kill the animal first. So, they are not likely to be useful as a biological weapon (my first thought when reading their headline), but they present another safety precaution to consider."

Comments

In other words

[stoolpigeon]

pause, and think a moment before you run that cow through the wood chipper.

Re:In other words

[migla]

pause, and think a moment before you run that cow through the wood chipper.

I have paused to think. And now I can't get this question out of my head: How many cows would a woodchuck chip if a woodchuck would chip cows?

Re:In other words

[ColdWetDog]

More importantly, take more precautions if you work with slaughtered pigs and cows in a meat packing facility/slaughterhouse.

Indeed, just below TFA was this little blurb pointing out exactly that - workers on a pig brain processing line came down with a serious autoimmune disorder linked to heavy exposure to pig brain pieces. Not prion linked apparently, but certainly a potential occupational hazard to all you Zombies out there.

Re:In other words

[RsG]

From one of TFA:

Here we tested the cellular and molecular characteristics of prion propagation after aerosol exposure and after intranasal instillation. We found both inoculation routes to be largely independent of the immune system

Admittedly quoted out of context. But it does mean that no, having an immune system that works properly is not in and of itself enough to protect you from aerosol prions.

And despite what TFS says, I can see uses for this in biological warfare. A person exposed to airborne prions cannot transmit the disease to another human being, as person-to-person transmission has only been observed to occur via ingestion of tissue. So, unlike a viral or bacterial agent, there's no risk of a bioweapon attack spreading out from the initial targets to other populations. At the same time, there's the advantage over chemical weapons, in that an airborne agent needs to be at a minimum concentration in order to kill you, whereas a single prion in your system can start the needed protein chain reaction.

However, in order to make prions into useful weapons, they'd need to be lethal much faster than they are now, something that's a problem with bioweapons already. Chemical agents are more practical if only in that they kill in minutes instead of weeks. My biological understanding of prions is not good enough to make an accurate assessment as to whether they could be made faster acting, but I suspect it can't be done.

The long onset time for symptoms makes prions useless for tactical biological warfare, but they could be used as terror weapons or tools for assassination. Of course, prions can already be used for either of the above without making them airborne first, and haven't been so far as I know. Assassins would likely prefer something faster, and terrorists almost always default to low tech solutions like bombs, which can kill plenty of people reliably without needing any fancy preparation or patience.

Re:In other words

[spazdor]

Next week, on Mythbusters.

Re:In other words

[RsG]

I did cover that with the second paragraph of my post. Prion bioweapons wouldn't be person-to-person contagious the way that viral or bacterial bioweapons are. Hence the comparison between prion weapons and chemical weapons, where in both cases only the people initially exposed will be affected. I should also clarify that I find the notion of actually using bioweapons to be a crime against humanity, but I have no problem hypothesizing about their use.

Also, the comparison to land mines is inept. Land mines last a long time, but only kill or maim one person per mine. Bioweapons don't last a long time, but can kill or main many people per deployment.

you can never clear an area. You could nuke the area, but the biological agents could return, carried by insects or water or birds.

No, this is demonstrably wrong.

Some, not all, pathogens are transmissible through animal vectors. If you were to weaponize bubonic plague then there could still be rodent carriers inside the exposed area after all human beings have been evacuated or died. Not every bioweapon has an animal vector available to it however, and even the ones that do, the animal must be at least partially asymptomatic in order to remain a threat, or it's going to die in short order. The "worst case" would be a disease that can jump species to something ubiquitous, like rats or mosquitoes, and can infect those species without killing them.

If you'd stated that some bioweapons remain a threat in a region after deployment, I would have accepted your argument as valid, but the way your post is written suggests that you think all bioweapons can, which is wrong.

Also, you listed "insects water and birds". Insects and birds belong on that list, and you didn't mention any other animals like rats, but water is another matter entirely. Waterborne transmission due to contamination is temporary. Water itself cannot act as a host. When a disease is waterborne, it either spends part of it's life-cycle in water, like the Guinea Worm, or it's the result of contamination via feces or dead organisms, like cholera.

If something else doesn't kill first?

[0100010001010011]

Birth is 100% lethal.

Well 99.9999% if you count that Jesus guy, Mary and Elisha.

Re:If something else doesn't kill first?

[Monkeedude1212]

Yeah, I heard some guy talking about this big tournament, saying "there can only be one". I assume he meant winner, but, whatever, I wasn't really paying attention. His hair was too long for me to take him seriously.

Thanks for the laugh

[Anonymous Coward]

"100% lethal if something else doesn't kill the animal first."

  In other news, 100% of people are struck by lightning if they don't die before it happens.

Says who?

[Dunbal]

So, they are not likely to be useful as a biological weapon

      A weapon that destroys your enemy's economy in a matter of years is still a viable weapon. Especially if it's hard to detect (ie by the time everyone shows signs of being sick, you are no longer deploying the weapon). This is scary stuff.

Re:Says who?

[CitizenCain]

In fact, this strikes me as a damn near *perfect* biological weapon (if you can find or make enough malformed prions, and the findings apply to large mammals, like people).

100% lethal, non-communicable (so you don't have to worry about travelers spreading it back to "your people"), virtually impossible to detect and a long enough incubation period to make it impossible to quarantine or trace back to the source. Like you said, so what if people don't start dropping dead for a couple of years? That's a *selling* point in a bio weapon. People won't even know anything's wrong until long after you've gotten away with it, and far too late to do anything about it as well.

On a completely unrelated note, does anyone know if there's a place near Washington D.C. that sells malformed human prions? Preferably one that's willing to offer a volume discount.

Prions straddle living/non living gap

[140Mandak262Jamuna]

Prions are strange in the sense, they are almost on the dividing line between living and non living. They have no DNA/RNA, no need to breath or even to eat, but they replicate that makes them different from venom and poison. How long do the exist in prion form left to themselves I wonder. Can they exist in some dried powder form forever? Or do they spontaneously disintegrate into constituent compounds?

Leather tanning industry has some really weird mix of chemicals and some of them involve brain matter. Hope the left over prions on the leather jackets degrade or wear off.

Re:Prions straddle living/non living gap

[PCM2]

How long do the exist in prion form left to themselves I wonder. Can they exist in some dried powder form forever? Or do they spontaneously disintegrate into constituent compounds?

Scientists have taken prion-infected tissue and reduced it to ashes in a crucible at 600 C, and there were still viable, infective prions in the ashes.

Tagline is wrong

[PCM2]

I am not a biologist, but based on my reading of TFA, the scientists successfully infected immunodeficient and immunocompetent mice. It's counterintuitive, but the fact that the disease incubated in the immunodeficient mice at the same rate as the immunocompetent mice is what makes the research significant.

The immune system actually seems to play some kind of a role in prion diseases, acting as a kind of Trojan horse mechanism to spread the infection. It's not totally clear how this works, but the research supports that it happens. So what these scientists did is they inoculated immunodeficient mice with prions and observed them coming down with the prion disease in pretty much the exact same way as the immunocompetent ones. This establishes that a functioning immune system is not actually necessary for infection via aerosol. This means that an immunodeficient mouse, even when kept in semi-isolation, can potentially come down with a prion disease from an aerosol source even when it doesn't come in direct contact with any infected tissues.

That's a pretty big deal when you consider a lot of scientists in research laboratories might be working with immunodeficient mice, in the mistaken assumption that the mice will be safe from prion infection. The recommendation of this paper is that research lab safety guidelines note aerosols as a possible vector for prion infections, which they do not do now. I don't think this is really a warning aimed at keeping people from being infected. For the time being, at least, it's more about keeping research from being spoiled when lab animals come down with infections from unforeseen aerosol sources.

Who the F^-* ??

[gr8_phk]

Who would even do an experiment with such things?

Re:Who the F^-* ??

[Anonymous Coward]

Who would even do an experiment with such things?

People who then know more than those that don't bother checking. Tribes with this characteristic are thought to optimize their use of limit resources slightly over people who would never think to check for themselves.

One could call them ... winners.

Re:Prions: Bunch of Hooey

[ihaque]

After 15+ years of this "ice 9" business I'm still waiting for results that in any way meet Koch's Postulates.

OK, this one will cover a lot of ground. Weber P et al. Cell-free formation of misfolded prion protein with authentic prion infectivity. Proc. Natl. Acad. Sci USA 2006 October 24; 103(43): 15818–15823. It's open-access, so no excuses about being stuck behind a paywall.

Making claims that biochemists working on prions "don't like to get dirty" is both insulting and disingenuous. Animal models are, in fact, used here to demonstrate that purified PrPsc (misfolded prion protein) is infectious in live hosts, in addition to triggering misfolding in vitro. No one uses farm animals because they're large, expensive, and there's no compelling reason to incur that cost when simpler model animals (here, hamsters) will do.

why not entertain the notion that this is a slow virus and that the symptomatic misfolded protein is a mere phenotype, possibly detrimental, but not causal

Well, because the linked paper was able to amplify the infective population of PrPsc in a cell-free system, which would not be conducive to the amplification of a virus.

I understand the appeal of an underdog hypothesis, but unless you can present a better argument that isn't comprised of ad hominems, vague conspiracy theories, and a smattering of scientific claims answered by 5-year-old literature, I'm not convinced.

Re:100% lethal

[WinstonWolfIT]

You just described Jerry Springer

Re:Prions: Bunch of Hooey

[PCM2]

After 15+ years of this "ice 9" business I'm still waiting for results that in any way meet Koch's Postulates.

But Laura Manuelidis is claiming that vCJD and others are caused by "a slow-acting virus"... and Koch's Postulates aren't strictly applicable to viruses either. The best that Manuelidis has managed to do is to isolate "virus-like DNA signatures" -- which does not even prove the presence of a virus, let alone that a virus is causative. So in the best case scenario, Manuelidis may have raised some questions, but has been no more successful at meeting your preconditions for accuracy than anybody else. You apparently just think she's "fighting the good fight" because -- much like Jenny McCarthy -- she questions the prevailing theory. That attitude is bad science.

they aren't living

[circletimessquare]

is silver iodide used in rainmaking living? it catalyzes a chain reaction

is a bit of ice in supercooled water living? it catalyzes a chain reaction

take a prion, put it at the right spot in a susceptible brain, and it makes a cascade of prions. this is chemistry, not life. if you call a prion living, lots of chain reactions in nature you would have to call living

now a virus, that's the border between living and nonliving