It is one of the major points from Guns, Germs and Steel. Most of our major diseases have transferred from domestic animals. For example both measles and smal

It is one of the major points from Guns, Germs and Steel. Most of our major diseases have transferred from domestic animals. For example both measles and smallpox (the two most deadly diseases for Native Americans) come from cows. Europeans successfully domesticated animals, Native Americans did not. So Europeans had diseases that Native Americans were not adapted to.