Salmonella poisoning wiped out the Aztec Empire

When the Spanish conquistador Hernando Cortés landed in Mexico in 1519, the native population was about 25 million. Just 100 years later, the population had plunged to around 1 million, as a result of war and a number of epidemics.

In 1576, the outbreak of a mysterious disease is estimated to have killed between 7 and 17 million of the Aztec people, effectively destroying the Aztec empire. It was known to the locals as cocoliztli, and presented as red spots on the skin, as well as vomiting and bleeding from various orifices. This epidemic was one of the most deadly in human history, and now scientists may know what caused it.

In a study from the Max Planck Institute for the Science of Human History (MPI-SHH), researchers analyzed ancient teeth and found that the collapse of the Aztec civilization may have been due to an epidemic of salmonella – the food poisoning bacteria. Scientists looked at samples of pulp from inside the teeth of skeletons found in an untouched cemetery in Oaxaca, Mexico. Ten of the skeletons whose burials were dated after the Spanish conquest tested positive for salmonella, but none of the five skeletons buried before the conquest tested positive for the bacteria.

These findings make salmonella “a strong candidate” for the cause of the devastating epidemic that wiped out the Aztecs and other civilizations like the Mixtecs. It did so by leading to a condition called enteric fever, which is still the cause of millions of deaths globally. Spread by poor sanitation – and likely brought by the European travelers – this disease causes high fevers, dehydration, and gastrointestinal complications.

This study is the first example of scientists finding molecular evidence of this bacterium using ancient material from the New World.

“A key result of this study is that we were successful in recovering information about a microbial infection that was circulating in this population, and we did not need to specify a particular target in advance,” says Alexander Herbig of the MPI-SHH and co-author of the study.

Not only have we learned more about the history of the people and civilizations that came before us, but this result was achieved through advancing science and technology in our current world.

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By Connor Ertz, Earth.com Staff Writer