Asked by: Geoff Dunwell, Maidenhead


Debate has long raged over what caused the epidemics that wiped out large sections of Aztec society after Europeans arrived in the 16th Century.

Some suggest that Europeans had some natural disease protection after a long history of living in close quarters with domesticated animals and their waste. The Aztecs had few domesticated animals, depending heavily on corn in their diet, which was supplemented with insects, fish and some wild game. They also had more hygienic living conditions than many Europeans, with a system of aqueducts bringing in fresh water.

The most devastating epidemics – called cocoliztli – have been blamed variously on measles, smallpox and typhus. Recent analysis of DNA from the teeth of people buried during a cocoliztli suggests that Salmonella enterica may have been partly to blame. It is possible to carry salmonella without falling ill, so healthy Spaniards could feasibly have infected Aztecs lacking resistance.


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