Scientists may have finally discovered the disease that killed millions across Mexico during the mid 16th century, according to a study published in Nature Ecology and Evolution.
In 1545, people across the Mexican highlands began dying in large numbers in what would become one of the largest epidemics in human history. The event — which would have a second wave in 1576 — killed an estimated 7 million to 17 million people and contributed to the fall of the Aztec Empire.
People who came down with the illness developed red spots on their skin, and often bled or vomited before they died. Though the disease was terrible, researchers have never been able to determine the exact pathogen behind the outbreak because infectious disease leave behind almost no archaeological evidence.
“There have been different schools of thought on what this disease was,” said study co-author Kirsten Bos, a molecular paleopathologist at the Max Planck Institute in Germany, according to NPR. “Could it have been plague? Could it have been typhoid fever? Could it have been a litany of other diseases?”
To determine the mysterious disease, the team of international researchers used a computer algorithm to analyze DNA from the teeth of 10 people who died during the epidemic. That technology allowed the researchers to match the fragments with a database of known pathogens, a process that revealed evidence of the deadly Salmonella enterica Paratyphi C bacteria.
That finding led the team to believe that the disease may have led to the massive epidemic.
While the research does not pinpoint the exact source of the bacteria — something scientists would love to know — it does shed light on an ancient mystery. Many epidemics of the period came from European invaders who arrived in the region during the early part of the 16th century. However, as past research shows that Europeans also suffered from the disease, it may not have been endemic to Europe.
Even so, there is a chance Europeans may have still been responsible for how it spread among native populations. The team plans to continue their search to see what else they can find out about the disease.
“We know that Europeans very much changed the landscape once they entered the new world,” added Bos. “They introduced new livestock, [and] there was lots of social disruption among the indigenous population which would have increased their susceptibility to infectious disease.”