More Questions:
What is known about the diseases the natives had to fight before Colonization? What were the symptoms?
Were they at all comparable to something like a cold or the flue?
Did any of the diseases native to the americas, say an "NA small pox 2.0", spread to Europe, other parts of the world or still exists?
While there’s always more to say about the subject, you might be interested in this previous answer from u/anthropology_nerd: