New Study Suggests Salmonella Epidemic May Have Wiped Out the Aztec Empire

Salmonella, the dangerous bacteria caused by contaminated food (and the reason the CDC cautions against eating undercooked eggs), has now been connected to an ancient epidemic, which may have contributed to the annihilation of the Aztec empire almost 500 years ago.

The disease was named cocoliztli, meaning “pest,” in the native Aztec tongue. It proved to be far more than a nuisance, however, as between 1545 and 1550 CE it decimated an estimated 80% of the civilization’s population — a population already struggling with European arrival and an extreme drought.

A mysterious epidemic killed nearly 80% of Mexico’s population between 1545 and 1550.
(Image: By Daphne Breemen via Wikimedia Commons)

This ancient illness, in addition to today’s symptoms of diarrhea and vomiting, led to body-covering red spots and horrific bleeding. The cause of the cocoliztli epidemic has remained a mystery for centuries, a topic of constant debate, but research has finally shed light on the mysterious pestilence.

With the help of a new algorithm and DNA from ten Aztec skeletons, the epidemic at least partially responsible for the civilization’s demise has been linked to a Salmonella variant, Salmonella enterica Paratyphi C, according to paper published in Nature Ecology & Evolution.

The bodies themselves date back to the 1540s and were exhumed from an ancient cemetery in Oaxaca, Mexico thought to have been specifically connected with the epidemic.  Discovered within each set of ancient DNA lay traces of the Salmonella bacterium.

 Today, Salmonella (commonly associated with food-poisoning though not always its direct cause) represents something of an afterthought — worrisome, but not often cause for great alarm.

Though now its symptoms are certainly uncomfortable, the rarity of Salmonella poisoning and the advent of modern medicine mean the risk of death due to the bacterium is very, very low.

Evidently, this was not the case during the 16th century.