Salmonella enterica from a soldier from the 1652-siege of Barcelona (Spain) supports historical transatlantic epidemic contacts

Ancient pathogen genomics is an emerging field allowing reconstruction of the origins and spread of past epidemics. Recent studies have provided evidence that the demise of local American populations during the post-contact period may, at least in part, have been caused by paratyphoid fever brought to the New World by European colonizers. In this study, we have retrieved genome-wide data from two Spanish soldiers who were thought to have died of Plague while besieging the city of Barcelona in 1652, during the Reapers' War. We found that one soldier's ancestry likely derived from the Basque region while the other was most similar to present-day Sardinians (at that time, this Mediterranean island was part of the kingdom of Spain). While we could not find solid evidence for the presence of Yersinia pestis DNA -the causative Plague agent- we retrieved from one individual a substantial fraction of the same Salmonella enterica Serovar Paratyphi C lineage that has been linked to paratyphoid fever in colonial period Mexico (1545-1550). Our results support the presence of this phylogenetic clade of Paratyphi C spanning the Atlantic over at least a century and add to a growing body of evidence that Paratyphi C enteric fever was more prevalent in Europe and the Americas in the past than it is today.