Paratyphoid fever and relapsing fever in 1812 Napoleon's devastated army

During Napoleon's retreat from Russia in 1812,¹ countless soldiers of the French army succumbed to infectious diseases, but the responsible pathogen or pathogens remain debated.^2,3,4,5 We recovered and sequenced ancient DNA from the teeth of 13 soldiers who, based on historical records, likely died from infectious diseases, aiming to identify the pathogens responsible for their deaths.⁶ Our results confirmed the presence of Salmonella enterica subsp. enterica belonging to the lineage Paratyphi C, the causative agent of paratyphoid fever⁷; and Borrelia recurrentis, responsible for relapsing fever transmitted by body lice.⁸ We were not able to detect Rickettsia prowazekii (the agent of typhus) and Bartonella quintana (the cause of trench fever), which had previously been associated with this deadly event, based on PCR results and historical symptom descriptions.³ The presence of these previously unsuspected pathogens in these soldiers reveal that they could have contributed to the devastation of Napoleon's Grande Armée during its disastrous retreat in 1812.