[Wiseghy]

"I immediately wondered if this disease was connected to other 'lost civilizations' there and in South America"

That is a great point. It is believed now that the Inca and Maya both vanished with out European intervention after extended periods of drought and war. I don't doubt that pandemics played a large roll. This would parallel the rodent spread illnesses that killed large portions of Europe in similar over-crowed urban centers.

[MillerCreek]

It was, from what I've read, due to drought and wars that ensued when competition began to heat up due to deprived resources -- to state the obvious.

The devastating drought in the South and Southwest of North America was the cause of, worse yet, even cannibalism in the Southwest and loss of forests/plant life across much of the Southwest.

It was probably a drought of such proportions that we can only imagine nowadays, extensive and global even, because the Mediterranean shows evidence of similar human populations struggles from about the same time.

[blam]

"It is believed now that the Inca and Maya both vanished with out European intervention after extended periods of drought and war. "

Even the Inca don't know who built Tihuanaco, it was there as long as they can remember.

[MillerCreek]

Actually, the Black Plague (and other terrible infectious plagues) are carried by FLEAS, by the INSECT, the flea.

They are hosts to a parasitic process that lives in their guts and when they bite an animal, they infect the animal. Given the high population of fleas on rodents, then rodents scramble around human habitats and then pass it on.

But, the Black Plague actually originated in Northern and Central Asia, where it was transmitted in the guts of fleas on camels in the import trade from Asia to Europe. And, of course, to rodents after the fleas arrived on the camels, and then to humans in Europe (and eventualy elsewhere).

The hapless rodents simply get to be the method of transmission.