When Napoleon entered Russia in 1812, he brought with him the largest army Europe had ever seen. When he limped back out, he met his match, not in muskets or cannon fire, but in microbes.
Researchers who analyzed DNA from the teeth of soldiers who died during the retreat from Moscow say they have identified two diseases that devastated the emperor’s vaunted Grande Armée.
Since 1812, “people thought that typhus was the most prevalent disease in the army,” said Nicolas Rascovan, head of the microbial paleogenomics unit at the Pasteur Institute and author of the study, published in the journal Current Biology.
Using a technique called shotgun sequencing, Rascovan and his team were able to analyze ancient DNA from the dental remains of 13 soldiers found near Vilnius, Lithuania, and identify two “previously undocumented pathogens.”
“We confirmed the presence of Salmonella enterica belonging to the Paratyphi C lineage,” he told NBC News, referring to the bacteria responsible for paratyphoid fever, as well as “Borrelia recurrentis, the bacteria responsible for relapsing fever,” which causes bouts of fever.
These diseases would have thrived where people “were in very poor sanitary or hygienic conditions,” he added.
The findings match historical descriptions of symptoms experienced by soldiers in Napoleon’s army, such as fever and diarrhea, the researchers said in the study.
A “reasonable scenario” for the deaths would be a “combination of fatigue, cold, and several illnesses, including paratyphoid fever and lice-borne relapsing fever,” they wrote.
“While not necessarily fatal, lice-borne relapsing fever could significantly weaken an already exhausted individual,” they added.
Unlike a 2006 study that found traces of the bacteria that cause typhus or trench fever in four people out of a group of 35, the team found no traces of those diseases.
But Rascovan said that while the previous study was limited by the technology of the time, its results were still valid and, together with the new findings, offered a better picture of the conditions that devastated Napoleon’s army.
“Finding four different pathogens in such a large number of individuals really shows that there was a high prevalence of infectious diseases of all kinds,” he said.
By the time Napoleon’s troops withdrew, an estimated 300,000 men had died. Apparently, not even an emperor can outmatch a microbe.
