When the Europeans travelled to the New World and brought the diseases that wiped out so many Native Americans, why didn’t the local diseases have the same impact on them?

Question

Were the endemic diseases just less severe?

In: Other

Answer 1

Lots of different answers in these comments. Let me point out something I didn’t see mentioned.

There WERE in fact diseases that the Europeans were not accustomed to. The mortality rate of new colonies was very high, with many colonies disappearing completely. Some of these colonies disappeared and we don’t know what happened, but I think the simplest answer was they were wiped out by disease.

People do not realize how dangerous bacteria used to be. IIRC during WWI bacteria killed more people than bullets. Part of it was harsh conditions and battle wounds, but part of it was the mass migrations of soldiers spreading their disease.

The thing was, Europeans who got disease in the US would most likely die or recover before they could bring them back to Europe.

I say this not in inclusion, but in addition to some of the things some of the other commenters have said.