The 500-year mystery behind the fall of the Aztec civilization might have been a deadly salmonella strain, according to a new study. Salmonella enterica serotype Paratyphi C were found in the DNA of on ten Aztecs who died of the fatal cocoliztli.
In the latest issue of Nature Ecology and Evolution journal, Åshild Vågene revealed the findings of this study. After conducting DNA tests on ten Aztec remains on the Teposcolula-Yucundaa burial side for those affected with cocoliztli, findings reveal the deadly outbreak might have been salmonella.
As reported in National Geographic, the Salmonella strain found on Aztec DNA is a rare strain but results will be the same if it happened today. Vågene explained that this deadly salmonella strain caused enteric fever similar to typhoid. Eating contaminated water and food will be fatal. Afflicted individuals will experience vomiting, fever, and will most likely develop a rash.
Experts suspected cocoliztli to be a blood-borne disease since local and Spanish artists depicted victims coughing up blood and having nosebleeds. Since the skeletons had no visible marks, researchers had to rely on the DNA from the teeth of the 24 remains in the burial site to figure out what caused the epidemic. The team used the computational program MALT to analyze the DNA sequence.
According to the study’s co-author, Alexander Herbig, they didn’t have to test any hypothesis since they can match the DNA with the pathogens in the MALT database. Of the 24 remains, 10 had signs of the deadly salmonella strain. Aside from discovering the probable cause of the outbreak, they also found that five remains buried before the arrival of the Europeans showed no signs of salmonella.
Herbig and Vågene admit their working hypothesis was that the Europeans caused the salmonella outbreak. Europeans brought several infectious diseases when they arrived in the Americas including measles and smallpox. The natives were greatly affected since they had no immunity to these diseases. The same incident might have occurred when the Spanish arrived in Mexico.
University of Wisconsin-Madison researcher on infectious diseases Caitlin Pepperrell suspects deadly salmonella was not solely to blame and multiple agents caused the epidemic.
While a deadly salmonella outbreak may be partly responsible for wiping out the Aztec civilization, researchers have to conduct more tests to confirm their initial findings.