In Amateur Entomologists' Society, it is stated that:

But the most serious flea borne disease is Yersinia pestis, or plague (known in the Middle Ages as the Black Death). This is a disease of rats and other rodents, and rodent fleas can transmit it to man. Plague carried in this way has probably caused more deaths than all the wars in history. This began when man brought disease carrying rats to Europe in ships from Africa, in the middle ages.

In another site, Illinois Department of Public Health:

All told, perhaps 200 million people have died of plague – more than have died in all the wars in history.

Again, another site, this time it is Critter Control:

[...] As carriers of the bubonic plague, fleas were responsible for killing one-third of the population of Europe in the 14th century.

Are then fleas responsible of more deaths from plague than all wars in history? I understand that it isn't possible to count every death in every war, but perhaps we can reach an acceptable answer?

  • Maybe not more deaths than wars over all human history, but I've read that the bubonic plague wiped out between 30–60% of Europe when it hit. Although by the same measure, wars have been responsible for entire populations being wiped out so it might trump even the bubonic plague.
    – rjzii
    Aug 10, 2012 at 15:48
  • Excellent question. But even without looking up the numbers, I suspect that 200m deaths won't be more than war even in recent history. But lets look at actual estimates and perhaps consider deaths as a percentage of the population (black death certainly caused deep and long lasting reductions in the number of people alive in europe.)
    – matt_black
    Aug 10, 2012 at 15:56
  • @matt_black Yes, I find it hard to believe that it caused more deaths than war. But well, I've seen "obvious truths" being discredited in the past. :)
    – Alenanno
    Aug 10, 2012 at 15:58
  • @Alenanno On the other hand, it could be that the 200m deaths from plague are an underestimate. That is one reason why it is a good question to pose.
    – matt_black
    Aug 10, 2012 at 16:08
  • @matt_black Yes, that's also true. :)
    – Alenanno
    Aug 10, 2012 at 16:16

1 Answer 1


More deaths have been attributed to war than have been caused by flea-carried plague.

Deaths caused by the plague

Bubonic plague has been confirmed to be the cause of the Plague of Justinian in AD 511-512 in the Eastern Roman Empire. (Wade, 2010) A high estimate is that this outbreak of the plague killed 25 million people. (Rosen, 2007)

During the Black Death, the plague is estimated to have killed 75 million (Dunham, 2008) to 200 million people (BBC News, 2001).

It killed 12.5 million during the Third Plague at the beginning of the 20th century. (Orent, 2004)

That gives a high-end estimate of 237.5 million deaths caused by the flea-caused Bubonic plague.

Deaths caused by wars

Wikipedia gives a list of wars by death toll. "These numbers usually include both the deaths of military personnel which are the direct results of battle or other military wartime actions, as well as the wartime/war-related deaths of civilians, which are the results of war induced epidemics, diseases, famines, atrocities, genocide etc."

  • 60,669,200-84,589,300 – World War II (1939–1945)
  • 30,000,000–60,000,000 – Mongol conquests (1206-1324)
  • 27,000,000 – Second Sino-Japanese War (1937-1945)
  • 25,000,000 – Qing dynasty conquest of Ming Dynasty (1616–1662)
  • 20,000,000 – Taiping Rebellion (1850–1864)
  • 16,563,868-30.000.000 – World War I/Great War (1914–1918)
  • 16,000,000 – White Lotus Rebellion (1794-1804)
  • 13,000,000 - An Lushan Rebellion (755–763)
  • 10,000,000 – Era of Warring States (475 BCE–221 BCE)
  • 10,000,000 - Red Eyebrows Rebellion (9-24)
  • 8,000,000–12,000,000 – Dungan revolt (1862 –1877)
  • 7,500,000 – Chinese Civil War (1927–1949)

These are only the top 12 of the estimated 3,023 wars (http://www.vency.com/wars.html) in recorded human history and the low-end estimate for the death toll across these wars is already 245 million.


BBC News. Decoding the Black-Death. October 3, 2001.

Dunham, William. Black death 'discriminated' between victims. ABC Science. January 29, 2008.

Orent, Wendy. Plague: The Mysterious Past and Terrifying Future of the World's Most Dangerous Disease. Simon and Schuster, 2004.

Rosen, William. Justinian's Flea: The First Great Plague and the End of the Roman Empire. Penguin, 2007.

Wade, Nicholas. Europe’s Plagues Came From China, Study Finds. New York Times. October 31, 2010.

  • So the top 12 recorded wars caused more deaths than the top 1 flea carried disease. But what about other flea-borne diseases?
    – Ian
    Oct 1, 2013 at 9:15
  • Also, it's possible that "deaths caused by war" (wrongly) only refers to violent deaths. It would be interesting to see the numbers without "induced epidemics, diseases, famine"
    – npst
    Oct 1, 2013 at 9:37
  • @Ian I don't know. The notable claims that were quoted refer to the plague, and one of them even bolded the plague, so that is what this question is about. I edited the question to make that clear.
    – user5582
    Oct 1, 2013 at 15:44
  • @Ian Here is a list. But this is off-topic now, and better for a separate question, or Skeptics Chat.
    – user5582
    Oct 1, 2013 at 15:51
  • Another problem with this answer is that it applies different criteria to the inclusion of data in each category. For deaths caused by the plague, only direct deaths are included. For deaths caused by war, indirect deaths (e.g. famine) are included. What about indirect deaths from plague such as famine, or murdering of jews? Direct deaths is a better approach because you can more clearly define what you are looking at.
    – JBentley
    Nov 25, 2015 at 19:58

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