When Native Americans first encountered Europeans,what led to the European diseases being so deadly?

Question

Quizplus · Accepted Answer

Centuries of continental isolation meant that the Native Americans had no exposure to the diseases that had developed in Europe and Asia. As a result, they had no natural immunity to these diseases when they were introduced by Europeans, which led to high mortality rates. It has been estimated that up to 90% of the Native American population was killed by European diseases within the first century of contact.

When Native Americans First Encountered Europeans,what Led to the European