[John Valentine]

I object to your use of the condescending term "so-called", but you are right is one sense; I never should have used the term "all". There were many civilzations that rose and fell in the millenia before contact.

I was actually referring to the civilzations in existence at contact. They ALL fell before smallpox, measles, viral hepatitis, and a few more diseases they could not resist.

This tragic outcome of contact is not the fault of the Europeans. It was something that was bound to happen sooner or later.

The result would have been identical if New World explorers had "discovered" the Old World, and taken the pathogens back with them.

[MalcolmS]

This is covered in great detail, with much interesting speculation, in the Novel by Orson Scott Card,

Pastwatch: The Redemption of Christopher Columbus.

Well worth reading for anyone interested in this topic.