In the sixteenth century, some outbreaks devastated Mexico’s native people, inducing the ultimate failure of Aztec society. Now, according to two new investigations of early DNA from gut bacteria recovered from burial sites in Mexico, a fatal form of Salmonella bacteria can happen to be to blame, although the cause behind the outbreaks has for ages been a puzzle.

The pathogens behind historic outbreaks of disorder generally stay unknown, owing to challenges in the healing and sequencing of genetic material that is early. In the very first of the newest studies, published online Feb 8, 2017, in bioRxiv, using a metagenomic tool dubbed MALT overcame those challenges. The researchers used MALT to look for signs of early pathogen DNA recovered from people buried in a graveyard at Teposcolula-Yucundaa Oaxaca,. The site is known as among the primary areas where native Mexicans had contact with Europeans. Also, it is tied to an outbreak that started in 1545 and killed an estimated seven million individuals. Metagenomic analyses successfully identified genetic material in the samples which was comparable to that of the current bacterium Salmonella enterica. Using that information, the researchers had the ability to reconstruct the primeval genome as well as to identify it especially as a kind of S. enterica subspecies known as Paratyphi C, which causes typhoid (enteric) temperature.

The 2nd study, released online Feb 14, 2017, in bioRxiv, analyzed the historic lethality of Paratyphi C by using a draft genome of the pathogen from a skeleton dated to about 1200 which was regained in Trondheim, Norway. The person was supposed to have died from enteric fever. Comparison of the draft genome against a database of possibly associated genomes revealed that Paratyphi C belongs to a lineage of early swine pathogens, indicating that Paratyphi C was circulating in people in Europe for at least several hundred years ahead of the Spanish invasion of Mexico.

Though they’re not authoritative, the newest findings are intriguing.