From their magnificent capital of Tenochtitlan, the Aztecs built an intricate social, political, and religious society that flourished over the course of two centuries. Then came the arrival of invaders led by the Spanish conquistador Hernán Cortés, who overthrew the Aztec Empire in 1521. Disaster struck again when a series of epidemics wiped out 80 percent of the Aztec population in roughly 50 years. The locals called the plagues cocoliztli, and they resulted in high fevers, headaches, and bleeding from the eyes, mouth, and nose -- followed by death in three or four days. However, the precise identification of the pathogen responsible for the epidemics had eluded scientists until a team of paleopathologists found evidence of a deadly strain of salmonella by studying DNA from the teeth of 29 skeletal victims.
The painful fall of an empire:
- The DNA research found traces of the Salmonella enterica bacterium, of the Paratyphi C variety, which is known to cause enteric fever. The Mexican subtype rarely infects humans today.
- Many strains of salmonella are spread via infected food or water, and this one may have traveled to Mexico with the domesticated animals brought by the Spanish conquistadors, the researchers said.
- Identifying the pathogen has been difficult because infectious diseases leave behind few archaeological clues. The new study was published in January 2018 in Nature Ecology & Evolution.