Salmonella enterica genomes from victims of a major 16th century epidemic in Mexico

Indigenous populations of the Americas experienced high mortality rates during the early contact period as a result of infectious diseases, many of which were introduced by Europeans. Most of the pathogenic agents that caused these outbreaks remain unknown. Introducing a new metagenomic analysis tool called MALT, applied here to search for traces of ancient pathogen DNA, we were able to identify Salmonella enterica in individuals buried in an early contact era epidemic cemetery at Teposcolula-Yucundaa, Oaxaca in southern Mexico. This cemetery is linked, based on historical and archaeological evidence, to the 1545-1550 CE epidemic, which affected large parts of Mexico. Locally this epidemic was known as “cocoliztli”, the pathogenic cause of which has been debated for over a century. Here we present genome-wide data from ten individuals for Salmonella enterica subsp. enterica serovar Paratyphi C, a bacterial cause of enteric fever. We propose that S. Paratyphi C be considered a strong candidate for the epidemic population decline during the 1545 cocoliztli outbreak at Teposcolula-Yucundaa.