“Not to say the Great Die Off didn’t happen, but it was a virus ~ hanta virus ~ that regularly ravages the Americas. It comes back sometimes after a long drought. The rains return. The grass grows. The rodents expand their populations. They spread hanta to the people and the twenty somethings die like flies.”
I don’t know about the North American continent, but in South America it was the virus Smallpox (Variola), transported from Europe, that did the most killing. It could be said that Smallpox, not Cortez, conquered South America. Also, there is evidence that it did the same along the Eastern Coast of Northern America after explorers exposed the Native Americans.
I thought there were two major outbreaks of a disease in the 1540s and 1580s (if I remember correctly) that killed huge numbers of indians in Central and South America. The Europeans recorded the symptoms and they did not resemble smallpox (of which the Europeans were more than familiar).
"Recently developed tree-ring evidence has allowed the levels of precipitation to be reconstructed for north central Mexico, adding to the growing body of epidemiologic evidence and indicating that the 1545 and 1576 epidemics of cocoliztli (Nahuatl for "pest") were indigenous hemorrhagic fevers transmitted by rodent hosts and aggravated by extreme drought conditions."
"The epidemic of cocoliztli from1545 to 1548 killed an estimated 5 million to 15 million people, or up to 80% of the native population of Mexico (Figure 1). In absolute and relative terms the 1545 epidemic was one of the worst demographic catastrophes in human history, approaching even the Black Death of bubonic plague, which killed approximately 25 million in western Europe from 1347 to 1351 or about 50% of the regional population." link
The internet has numerous pieces about the 5% to 15% death rate from hanta among UN troops during the Korean War.
The death rates among Indians during the Peruvian, Mexican and North American epidemics are far closer to what we expect out of hanta than out of smallpox.
A major smallpox epidemic leaves enough survivors that they can continue to live their own civilization. A major black plague epidemic leaves enough resistant survivors that further spread stops ~ you can even contain the epidemic if you know the cause. However, civilization changes direction.
A major hanta epidemic of the worst sort DESTROYS YOUR CIVILIATION. Whatever your ancestors developed and learned is all lost. A milder epidemic might do nothing more than wipe out your agricultural working class ~ and you'll need to go out and capture another tribe and reduce them to peonage to do the hard work so you can continue to worship the gods in your stone and brick cities.
Of all these diseases the least dangerous are diptheria, thyphoid, black plague, AIDS, cholera ~ and that's simply because we have a fairly substantial population of people who have an inherited NATURAL IMMUNITY to them. They cannot destroy us all!