I am definitely pro vaccination, and the question is a bit morbid because people would die, but assuming that we didn't treat or vaccinate people for fatal diseases such as Ebola or the black death, would the surviving people pass along a trait that eventually would lead to near immunity for that disease?

Are there any examples of diseases that humans "contract" but they are immune to? Or any examples of immunity through human evolution?

What about in animals? Are there diseases that have been naturally eradicated?



When the Europeans settled the Americas, 90%+ of the native American inhabitants were wiped out due to diseases like smallpox that the Europeans clearly had developed resistance to. Clearly, the surviving native americans had resistance, and the Europeans had gone through some similar event previously in history.

The bubonic plague that was the cause behind the black death wiped out large percentages of populations, but selected for survivors with resistance:

Black Death Left a Mark on Human Genome


  • Often evolving to fight off disease involves mass death, like with >90% of the native american population dying.
  • There is always the chance that a future pandemic can come that human biology fails to simply evolve a resistance for and gets wiped out.
  • The Earth is changing rather quickly. The past is not a guarantee for the future.
  • 1
    $\begingroup$ There is no resistance against small pox. The disease disappeared with vaccinations, not before. This is slightly different for the pest of the middle ages, but still there is not widespread resistance against the pest. Can you please add some references for your small pox claim? $\endgroup$
    – Chris
    Dec 16 '14 at 19:02
  • $\begingroup$ Why else did small pox cause such a higher incidence of death among native indians? A quick google doesn't answer that question, but I just presumed it was enhanced resistance, and I can't think of any other reasons. Europeans didn't have complete immunity of course, but simply more resistance. $\endgroup$
    – clay
    Dec 16 '14 at 23:30
  • $\begingroup$ Do you have a source that it was only small pox? There are a number of other diseases (including flu, measles and so on) which got transferred there. $\endgroup$
    – Chris
    Dec 17 '14 at 7:35

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