After centuries of searching, scientists may have discovered the secret behind the mysterious disease that wiped out Mexico's Aztec Empire roughly 500 years ago.
Three to four days of high fevers, headaches and bleeding from the eyes, mouth and nose preceded the ultimate demise of 15 million people in the Indigenous empire during 16th century Mexico. According to researchers, roughly 80 percent of the population was killed off by “cocoliztli” or "pestilence" in the native tongue.
“The 1545-50 cocoliztli was one of many epidemics to affect Mexico after the arrival of Europeans, but was specifically the second of three epidemics that were most devastating and led to the largest number of human losses,” said Ashild Vagene of the University of Tuebingen in Germany.
For years, disease experts have debated the mass death, assuming the cause was due to smallpox, measles, mumps or influenza. However, through the DNA samples harvested from the teeth of 10 victims, scientists discovered strains of salmonella which contributed to a typhoid-like fever, the team of researchers announced in a science journal Monday.
“The cause of this epidemic has been debated for over a century by historians and now we are able to provide direct evidence through the use of ancient DNA to contribute to a longstanding historical question,” Vagene said.
The bodies were uncovered in a mass grave site and researchers analyzed 29 skeletons. According to the study, which was made possible through the use of sophisticated computer technology, the only traceable germ pathogens were those of salmonella enterica, which they believe could have been brought to Mexico from Spanish conquistadors.
"This is the first time that ancient DNA has been successful in identifying a candidate pathogen for it," study author and molecular palaeopathology expert Kirsten Bos told CNN.
“One limitation that we, and everyone else, face is that we can only look for pathogenic organisms that we already know exist and that have been genetically characterized today," said Vagene, a primary author behind the study and a medical archaeogenetics student at Max Planck Institute for the Science of Human History.
“We cannot say with certainty that salmonella enterica was the cause of the cocoliztli epidemic,” Bos said. “We do believe that it should be considered a strong candidate.”
The sheer number of victims erased by the disease rivals history’s largest and most deadly epidemic: the medieval black plague, which killed an estimated 25 million people in Europe during the 1300s.