There has been many attacks/accidents involving diseases that have been purposefully used with a sole purpose to kill people. In history there has been many examples of mass deaths caused by an incurable bacteria,virus or fungi. Black death or the plague is one of them. Could the estimated 75-100 million deaths have been caused purposefully/accidentally by an experiment that ended very badly.

  • 1
    I think this depends a lot on the interpretation of "weaponized", If you take it in its simplest definition (i.e. used as a weapon) then Alan Ward's answer is correct. If however, you mean that the disease was in some way modified to be more lethal, more contagious/infectitious or easier to deliver to it's target (i.e. a better weapon) then I think it's unlikely given the (mis)understanding of how diseases were spread at the time of the black death.
    – Steve Bird
    Commented Jul 16, 2015 at 19:42
  • @SteveBird That was precisely my own thought process. Manipulating a virus or bacteria to make it more lethal would have been possible only in very recent times (late 20th century). Using an existing strain without modification, on the other hand, merely requires access to infected material - and the will to use it.
    Commented Jul 16, 2015 at 20:20
  • @ALAN WARD: It also requires some understanding of the means by which diseases spread, which wasn't all that common before roughly 1800. (In Europe, anyway: apparently some parts of the world haven't quite gotten the message yet.) So to deliberately spread e.g. the Black Plague, you'd need flea-infested rats...
    – jamesqf
    Commented Jul 17, 2015 at 5:47
  • @jamesqf Indeed, in the case of the Black Death one would have to wait until the end of the 19th century before knowing about the transmission mechanism through fleas. Perhaps we should consider previous use more as an attempt to use it for warfare than effective use. Am updating the answer accordingly.
    Commented Jul 17, 2015 at 7:08
  • 1
    I'm confused by the reopen vote. This question was set "on hold" as unclear. There has been no edits clearing up anything. Just because one person has guessed at an answer does not mean it is 'clearer' now by magic.
    – CGCampbell
    Commented Jul 20, 2015 at 14:40

1 Answer 1


Yes indeed. As early as 1346, corpses with symptoms of the Black Death seem to have been catapulted by the Mongols into the city of Caffa, Crimea during a siege.

Reference: Wheelis M., Biological warfare at the 1346 siege of Caffa. Emerg Infect Dis, Sep 2002. Available here

It may be noted that this use was not very effective, since knowledge of the precise nature and transmission mechanism of the disease was not available until the 1890s. So, this is perhaps more an opportunistic use of sick individuals in a war scenario than a truly weaponised disease.

  • 2
    If you read your reference, you could notice the sentence: "the event was UNIMPORTANT in the spread of the plague pandemic". Indeed, if Mongols had infected corpses in their possession, then their army was already contaminated, and the spread of the disease was inevitable, independently of whether Mongols "weaponized it" or not.
    – Alex
    Commented Jul 16, 2015 at 23:44
  • The reference you mention also says that the plague "devastated the Mongol force". So there is not doubt it would spread to the besieged Italians in any case.
    – Alex
    Commented Jul 16, 2015 at 23:57
  • @Alex, actually I had read that part - which you will agree is both interesting and immaterial in respect to the fact the disease was weaponized or not. It had been weaponized, just not very effectively and causing casualties both on the attacker and the attacked.
    Commented Jul 17, 2015 at 7:03
  • @Alex, have updated my answer to reflect your comments.
    Commented Jul 17, 2015 at 7:17

Not the answer you're looking for? Browse other questions tagged or ask your own question.