Can the teeth of 10 people solve a centuries-old mystery? According to a study published Monday in Nature Ecology and Evolution, perhaps. Its authors suggest that an epidemic that killed as many as 17 million people over the course of two outbreaks in the 16th century and had a hand in the elimination of the Aztec empire may be due to salmonella. This after molecular paleopathologist Kirsten Bos with the Max Planck Institute and her colleagues analyzed DNA from the aforementioned teeth, which came from people buried in a cemetery in Oaxaca, Mexico. The researchers say the cemetery is tied to the initial 1545-1550 outbreak through "historical and archaeological evidence." Phys.org says it's actually the only cemetery to be associated with the outbreak. But it wasn't just the teeth that were key.
As NPR explains, it was a new algorithm that Bos explains "offers a method of analyzing many, many, many small DNA fragments that we get, and actually identifying, by species name, the bacteria that are represented." So running the teeth's DNA fragments through the computer program enabled them to eventually land on the Salmonella enterica Paratyphi C bacteria, "a bacterial cause of enteric fever" that also spurs dehydration and gastro-intestinal issues, per the study. What the study doesn't do is shed light on where the bacteria may have come from. One unaffiliated researcher called it a "super-cool study" in comments to Nature upon the preprint release of some findings in February, but one evolutionary geneticist expressed skepticism, noting that if the culprit was a virus, rather than bacteria, the algorithm wouldn't have been able to spot it. (Deep beneath Mexico City, a chilling find was made.)