The Deadliest Virus on Earth

The Deadliest Virus on Earth

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In the 1970s thousands of Chickenheads rained from the sky in Europe, making foxes and other wildlife confused and very happy. Why? They were filled with a vaccine to fight the deadliest virus known to humanity – since the 1930s a rabies epidemic had been sweeping across wildlife populations in Europe and humans wanted to finally get rid of the virus once and for all.
Rabies is named after Lyssa, the ancient Greek spirit of mad rage, and has been haunting us for at least 4000 years. It can turn animals into angry beasts and humans into zombies that fear water. But what makes Lyssa fascinating is not just how bizarre and deadly its infection is, but also how incredibly good it is at avoiding our defenses.


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39 Responses

  1. Kurzgesagt – In a Nutshell says:

    Go ‘beyond the nutshell’ at by diving deeper into these topics and more with 20% off an annual subscription!

  2. CG M says:

    It’s actually pretty scary how good nature can be at killing us. Gives us a good perspective of how fragile we are.

  3. Joe G says:

    Lyssa is basically running the optimal Pandemic/Plague Inc. strategy. Super stealthy until the target is fully infected, then rapidly turn extremely lethal

    • Cewla says:

      @Mal-2 KSC “fuck you, everybody’s infected”
      “what the fuck”
      “and now i cause comas”
      “we can deal with those”
      “how about MULTIBLE ORGAN FAILURE”

    • Xanboyyy says:

      Its almost the optimal Plague inc strat, the only thing that it misses is transmitting it. If it spect in to transmitting then it can wait till everyone is infected. and then kill them all

    • machinegun says:

      The problem is that human-to-human infection is so rare, it’s almost non-existent. Maybe a long time ago, but now…
      So close to perfection, and yet it can’t manage to be transmissible.

    • LegendaryTomatoBird says:

      Well yeah, but it has the added trick of the Uno reverse card

    • Darin755 says:

      *Hella Vax

  4. Katherine says:

    This is definitely one of the most frightening yet interesting things I’ve ever learned about!
    Too bad Kurzgesagt upload so late in the evening in my timezone, I will probably dream about scary viruses tonight 😮

  5. B M says:

    Props to the storyboard artist or concepter or whomever in production who decided the person in the animation to be infected should be a child rather than one of the birbs, adds a real oomph emphasizing the scary reality of rabies

    • L Sedge says:

      @Sophie Smith Actually, there is a rabies vaccine for people, and as the video explains, due to the slow speed of progression of the rabies virus, it can be given after you have become infected as long as it is given quickly.

    • crispmiraculous says:

      @Cuvtixo D yes but this ‘scaring’ alerts people who aren’t spoken out about being pro-vax enough to hopefully go to someone they know that is anti-vax and trying to convince them. like bm said the emotional impact can be read as being quite powerful

    • Eyrthren says:

      @Sophie Smith people absolutely can get a rabies vaccine? Usually after an infection, though I think if you’re going to a high risk area you’ll get one too

  6. Merik Malhads says:

    I’ve always found it hard to explain MHC class proteins so being able to display it is quite useful. I know it doesn’t cover the class II’s but I always find it incredibly useful to show these videos to people as my drawing ability is so horrible that I tend to mess up too much to get the point across. (also the motor proteins are borderline impossible to properly explain so that incredible drawing will help too)

    On a completely separate note, I find it intriguing that rabies maintains a lysogenic stage even while active, conventional knowledge is that if a virus is active it is always chewing through cells as well as creating plenty of MHCI markers so it is always impressive to find an exception to the rule. It also is puzzling to me as to how an infection that does not destroy a cell still ends up killing or at least disabling it. Perhaps the viral proteins simply oversaturate protein production making it impossible for crucial proteins to be made meaning it would simply disable the neurons rather than killing them.

    • MrNicoJac says:

      When it comes to brain function, just slightly throwing things out of whack would, presumably, be enough to cause major problems.
      So the cells may be fine individually, and yet the overall effects would still be deadly, perhaps.

    • Cewla says:

      just making sure, motor proteins are like trucks? transporting goods from one place to another?

    • Qwerty David says:

      You should definitely check out the book they wrote, it’s called “Immune: A Journey into the mysterious system that keeps you alive”. It’s basically like a dummy’s guide to your immune system, but it also has all sorts of wonderful illustrations that make the complexity of the immune system a bit easier to understand. It’s obviously not meant to be like an actual serious immunology book, and it oversimplifies a lot of things, but it’s still something I recommend checking out. I’m a big science nerd so I always love learning something new about the hidden and unappreciated complexity of my body or the world around me.

  7. Tux says:

    It has been suggested that the vampire myth originated from people infected with rabies. Since rabies causes light hypersensitivity, hydrophobia, aggression, and occasional biting, it fits the narrative of a typical vampire who goes out at night, is scared of holy water, and sometimes bites people. It’s interesting to think about anyway!

  8. TC says:

    I find it interesting that humans went from using sticks and stones to somehow finding a way to figure out how each cell in the body works

  9. rashkavar says:

    I remember hearing that the first known person to survive an infection of rabies that reached the brain was kept in a particularly deep induced coma for the duration of their infection, which seemed to suppress the encephalitis and also gave the immune system a chance to fight back. And even then, they barely made it and had months of rehab to get over the coma.

  10. K V says:

    Great video as always! I wish you guys talked about rabies hydrophobia. Lyssa causes spasms in the muscles needed to swallow, making it near impossible to drink water or to eat. It is thought to have evolved to cause this so that the virus (which is spread through saliva) can only leave the mouth outwards (to infect something else) and not into the stomach.

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