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

They did. Native Americans of modern US didn’t have many diseases, living off the land and generally pretty healthily (since land was pretty good/habitable). That’s why their immune system was weaker as well.

But in South America, exotic diseases in rainforests and swamps, various ticks and mosquitoes and such did mess with Europeans quite a bit – malaria, yellow fever, and dengue fever and so on.