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The Scariest Biological Weapons in History

Updated June 11, 2019 11.5k votes 2.1k voters 212.6k views15 items

Since the earliest days, humans have employed bioweapons both invisible and nefarious: killers on two legs, four, six, eight - and plenty with no legs at all. All of these agents of biological warfare, fresh with the fury of nature, have taken their turns inspiring terror in enemy forces, and turning the tide of unwinnable battles.

In the modern day, just as many bio-weapons have been employed by terrorists and monsters, "humans" who barely qualify for the title. Yes, history is filled with deadly organisms - viruses, bacteria, harmless looking flowers, and even playful sea mammals. All have seen their fair share of battle, and some were admittedly pretty awesome. But if this otherwise terrifying bioweapons list anything to teach, it may be that nature's most brutal creations are those dogs of war called "man."
  • Photo: United States Army / Wikimedia Commons / Public Domain
    You might like the band, but you wouldn't enjoy infection by Bacillus anthracis. Anthrax has a 45% mortality rate, down from 65% historically, thanks to drugs specifically made to treat infection. But odds of survival aren't the scariest thing about anthrax; this bacteria forms powder-like "spore" shells similar to fungus, and those bacterial shells are tough enough to last for decades - or even centuries. Anthrax-infected dirt has been known to cause infections 70 years after initial contamination, making this bacteria a particularly insidious weapon.
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  • Photo: Thomas W. Geisbert, Boston University School of Medicine / Wikimedia Commons / CC BY 2.5

    There are five families of hemorrhagic fever viruses, but the best known of them is Ebola. Not all are outright deadly, as proven by effective treatment in the United States.

    All of these "flesh-eating viruses" start out with mild flu-like symptoms, and end up literally eating parts of the victim's body. Victims have been known to bleed out through the eyes or skin, die of internal hemorrhaging, or drown in their own blood. Lethality for most types is very high, ranging from 25 to 90%, and infections are as difficult to detect and prevent as the common cold.
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    You've probably heard of the incredibly deadly toxin produced by Clostridium botulinum - cosmetic surgeons sell it as "Botox," and they'll be happy to shoot it into your face for a fee. Or, you can get it for free in the form of food poisoning from spoiled meat.

    Botulism toxin is the most acutely lethal toxin known to man. Botulism paralyzes the lungs exactly as Botox paralyzes facial muscles, and it is 100% lethal in high enough doses. Worse, because the botulism bacteria is tremendously common and easy to cultivate, practically anyone with access to spoiled food could make enough toxin to kill millions.
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  • Photo: Internet Archive Book Images / Wikimedia Commons / Public Domain

    Today, because of vaccination, we tend to think of smallpox as a thing of the past. But this terrifyingly deadly bio-weapon is as deadly today as it ever was - and unless you've been vaccinated against smallpox in the last three to five years, you're probably vulnerable to it.

    This virus is dangerous for its high lethality, contagion potential, and availability. The British were well known to use smallpox as a weapon against the French and Native Americans, and the Soviet Union was developing weaponized smallpox as recently as 1971.
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