Are we aware of a "bug" (virus, bacterium, prion, ...) that has completely exterminated an entire species? Either through direct observation or maybe some form of archeological evidence? If not, are there realistic scenarios where this could happen?

I am primarily interested in cases where the disease was the driving factor of extinction of an otherwise well established and healthy population, but examples of species that were in bad shape to begin with are welcome as well.

My understanding is that this is unlikely, since very deadly infections tend to burn out or evolve towards being less deadly. Killing your host is not conducive to your survival. But maybe it would be possible to reduce the number of individuals so much that reproduction became problematic. I imagine a species confined to an island or something might be susceptible.

I'm asking this because in an interview I saw, an epidemiologist said that his usual research interest are "bugs with species ending potential". The interview was on COVID-19 so he didn't elaborate on what he meant by that or give any examples.

For the special case of humans, I was able to find this article that claims such an event to be unlikely, but I suppose we are the best equipped species that has ever existed on this planet to deal with such a threat.

  • $\begingroup$ Can you provide a link to the interview and the name of the epidemiologist? Have you tried looking at some of his papers or his website (many academics have one devoted to their research)? Those would seem like good ways to find out what kind of microbe(s) he might have in mind ... $\endgroup$
    – tyersome
    Mar 29, 2020 at 19:20
  • $\begingroup$ @tyersome Have been looking for that since I asked the question. Had watched so many interviews that it took a while. It was actually the interviewer (Sam Harris) introducing the interviewee Amesh Adalja: youtu.be/E9vIUtXa9ug?t=150 . He mentions a bird flu with a 60% case fatality rate becoming highly infectious for people but no details. $\endgroup$
    – user35915
    Mar 29, 2020 at 21:07
  • 1
    $\begingroup$ Not a species, but the Gros Michel was almost driven to extinction by a fungus. Apparently the now-dominant variety of bananas is also being attacked by fungus and isn’t doing so well. The other noteworthy thing here is that these bananas are sterile and must be asexually reproduced by humans (creating clones of no genetic diversity). $\endgroup$
    – Laurel
    Mar 30, 2020 at 4:01

1 Answer 1


From the vantage point of other species, humans might be considered "bugs" in the sense that we are organisms that are causal in the ongoing extinction of numerous species. We're doing a pretty good job of it, so far:

The included extinctions span numerous families of plants[4] and animals, including mammals, birds, amphibians, reptiles and arthropods. With widespread degradation of highly biodiverse habitats such as coral reefs and rainforests, as well as other areas, the vast majority of these extinctions are thought to be undocumented, as the species are undiscovered at the time of their extinction, or no one has yet discovered their extinction. The current rate of extinction of species is estimated at 100 to 1,000 times higher than natural background rates.

  • $\begingroup$ Well, maybe you can interpret the question like this, but it is not what I meant at least :-). I mean none of the species we exterminated could be classified as hosting us. $\endgroup$
    – user35915
    Apr 2, 2020 at 8:51
  • $\begingroup$ @user1136 That's an interesting theory and it would definitely be an answer to the question. $\endgroup$
    – user35915
    Apr 2, 2020 at 8:52

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