Love work of @billgates but "mosquitoes kill more people than people do" is just wrong

I truly love the work Bil Gates and the Gates Foundation have been doing over the last years.  Absolutely wonderful stuff.  But I have a bone (or perhaps a proboscis) to pick with this latest effort: The Deadliest Animal in the World | Bill Gates.  The article discusses some “facts” about how many people different animals kill.  And it uses this to argue for the need for more attention to be placed on mosquitoes.  I agree with the conclusion.  Mosquitoes are a big deal and need much much much more work and attention.  But the data is just, well, not sound.  Here is the problem I have

1. Many of the animals, including mosquitoes, are on the list are there because of the diseases they transmit.  For example, dogs are there (for rabies), and tsetse flies are there for sleeping sickness.  That is, they do not kill people directly but indirectly because of a disease they transmit.

2. If we follow that logic, which I am fine with, then we need to add a whole lot of deaths to the “human” column.  After all, humans transmit a whole heck of a lot of diseases that kill humans.  One source I found has the following #s

  • HIV/AIDS: 1.78 million per year
  • Tuberculosis: 1.34 million per year
  • Flu: 250-500,000 per year
  • HAIs: >100,000
  • Syphilis: 100,000
  • Measles: 600,000

and many many many more.   The totals are probably greater than 5 million per year that are killed by infectious diseases where it was humans who transmitted the agent to other humans.  Way more than the mosquitoes.  Again, I agree with the conclusion.  We need lots more attention on mosquitoes.  But there seems little doubt to me which animal is most responsible for the spread of deadly pathogens to humans.  And that animal is us.


Am kind of annoyed at the press coverage of this Gates – mosquitoes are the deadliest animal – concept.  Here are some examples where people just ate up the idea without really asking any questions about its accuracy

And many many more.  It is a cute concept.  And an important one.  It just happens to be wrong.

UPDATE 5/4. Some Tweets of relevance






See Vox post: No, mosquitoes aren’t deadlier than humans

Also see these posts which run with the Gates meme


About Jonathan Eisen

I am an evolutionary biologist and a Professor at U. C. Davis. (see my lab site here). My research focuses on the origin of novelty (how new processes and functions originate). To study this I focus on sequencing and analyzing genomes of organisms, especially microbes and using phylogenomic analysis
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11 Responses to Love work of @billgates but "mosquitoes kill more people than people do" is just wrong

  1. So dicks kill more than mosquito probisci?


  2. Personally, as a microbiologist I'm offended at the credit given to metazoa (including humans) rather than the more capable microbes and viruses in terms of causing human death.


  3. Notice I decided not to address that at all. Although as you might guess, I agree with you.


  4. We could also attribute other human activities that cause morbidity and mortality, like poverty and war. hey aren't infectious diseases, but they get the job done.


  5. Yes, we could add those too. I was just focusing on even just using their logic of infectious diseases. And the #s do not work out in favor of mosquitoes even for that.


  6. naderhasan says:

    207 million cases were recorded at the end of 2013, according to data from the World Health Organization. The organization noted, however, that this has an uncertainty range of 473,000 to 789,000. family lawyer fairfax


  7. Greg Laden says:

    Sorry, while I get your point, I think there is a different way of looking at it.

    When we ask “what is the most dangerous animal” (a question often asked in various contexts) everyone knows we mean how many human deaths are caused by the animal in question going and killing something. People argue over whether hippos are more dangerous than lions, for example (it is an urban myth, btw, that hippos kill more humans; actual data show lions do).

    I agree that counting microbial diseases carried by mosquitos is cheating. But if the comment is phrased correctly, it is a valuable lesson. More people die of diseases carried by mosquitos than die at the hands of other humans in wars or by homicide and similar effects combined. That is correct, and a powerful statement, even though apples (human kills humans) and oranges (mosquito borne illness kills humans) are being compared.

    Taking it in the other direction ends up being just as wrong and the message of course gets lost. Mosquitos kill X people by carrying a diversity of diseases. Humans kill more people than just through homicide and war, because humans also carry diseases. So the way to stop the effects of mosquitos is to kill all the mosquitos. Oh, and the way to stop the effects of humans is to kill all the humans.

    That does not compute, of course, because in both cases it is not the humans or the mosquitos doing the killing, but one or another pathogen.

    I would argue that Gates is not really wrong. It is just that the descriptions need to be framed correctly.

    There is a DIFFERENT part of Gate's statement that I would take exception to that you might want to talk about. There is no such thing as “a mosquito.” The mosquitos that feed on humans constitute a very small subset of the thousands of species. Of those that feed on humans there is usually a close correspondence between species of mosquito and the pathogen it carries. Gate's post says:

    “There are more than 2,500 species of mosquito, and mosquitoes are found in every region of the world except Antarctica. During the peak breeding seasons, they outnumber every other animal on Earth, except termites and ants. They were responsible for tens of thousands of deaths during the construction of the Panama Canal”

    The vast majority of those different mosquito species are innocent! Who speaks for them!

    This has actually been a problem in the past, as I recall, in that mosquito eradication programs have in some cases focused on one subset of species and ignored others (with totally different ecologies and thus different vulnerabilities to eradication programs), and may have had devastating effects on local ecologies. It would be like killing all the hippos to avoid human deaths in Africa from large mammals, but not noticing the lions. Which mosquito is which and which ones carry which diseases seems key.

    So, there's my hyperskeptical analysis of your skeptical analysis. I don't think Gates was totally wrong in developing this messaging. This does not make me any less annoyed at MS Windows, tho, I quickly add.

    Bottom line: Malaria is bad. I've seen many people, including (mostly) infants, die of it while working in the Congo. Yet, there are subregions and countries that have malaria mostly under control, in regions where it was once more prevalent. We should be having more success.


  8. Greg. I pondered writing about the issue of many different kinds of mosquitoes when I wrote the original post. But in the infographic – the first other “organism” lists is “shark”. So whale sharks are lumped together with great whites and hammerheads and golblin sharks and so on. So I decided to accept the organism lumping (not sure why).


  9. Greg Laden says:

    Ha! Good point about the sharks.


  10. ” The totals are probably greater than 5 million per year that are killed by infectious diseases where it was humans who transmitted the agent to other humans. Way more than the mosquitoes.”

    Agreed and thank you,


  11. Val Elizondo says:

    While mosquitoes are very dangerous and have killed tons of people since the beginning of time, I do not believe that they have killed more people than humans have.

    Mosquito Control in North Carolina


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