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

Europeans lived with and amongst our beasts of burden in cities. The American cultures did not. So diseases which passed from animal to human was relatively rare.

Diseases kill their prey only by accident. Ideally they live inside, and feed on the host for years and decades. But a disease which knows how to feed on a pig just right, keeping it healthy enough to sustain the disease. May inadvertently kill a human host, or any other animal for that matter.