As any student of history knows, Spanish conquistadores conquered Mexico not with deeds of warrior prowess, but by exposing the hapless natives to Western diseases like smallpox and typhus, for which they had no natural immunity.
Acuña-Soto's trips into the woods with Stahle and the Mexican researchers continue to fill in epidemiological details. "I have evidence from 24 epidemics from 1545 to 1813," he says. "I am comparing the tree-ring data with each of them." In each case, he sees the same pattern. He also thinks he may have solved one of the other great mysteries of cocolitzli—namely, why it hit the Aztecs hard but left the Spanish largely unaffected.This is going to severely irritate those who really liked having a foreigner to blame cultural failures on. One would be "Guns, Germs and Steel" author Jared Diamond. It also discomfits those psuedo-anti-racists who use similar arguments as ways to demonstrate Western societies were just lucky.
Hemorrhagic viruses affect human populations that are already stressed, Acuña-Soto says. "The natives were poor and probably near starvation and living in unsanitary conditions where the rats would congregate. They also worked in the fields, where they'd be exposed to the rat droppings. The Spanish made up the upper classes."
Cortés and his soldiers defeated, enslaved, and murdered the Aztecs, but now it seems that cocolitzli, a disease brought about by a native virus, is what really finished them off. Today the Aztec kingdom exists only in museums and ruins, but the virus could still be out there. As Mexico enters into yet another period of severe drought, could the killer reemerge?
The upshot for me is that all groups of people had battles to fight - some with each other, some with their environments. It's not just chance, nor is it purely genes, but expecting population quotas to be maintained over millenia as proof we are all equal is nonsense.