When Napoleon entered Russia in 1812, he brought with him the largest army Europe had ever seen. When he limped back, he met his match—not in musket or cannon fire, but in microbes.
Researchers who analyzed DNA from the teeth of soldiers killed during the retreat from Moscow say they have identified two diseases that devastated the emperor's vaunted Grand Army.
Since 1812, “people believed that typhus was the most common disease in the army,” said Nicholas Rascovan, head of microbial paleogenomics at the Pasteur Institute and an author of the study. published in Current Biology.
Using a technique called shotgun sequencing, Raskovan 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 have confirmed the presence of Salmonella enterica, which is a member of the Paratyphi C lineage,” he told NBC News, referring to the bacteria responsible for paratyphoid fever, as well as “Borrelia recurrentis, the bacterium responsible for relapsing fever,” which causes bouts of fever.
These diseases would thrive where people were “in very poor hygienic conditions,” he added.
The findings are consistent with 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 death would be “a combination of fatigue, cold and several illnesses, including paratyphoid and relapsing fever, which is transmitted by lice,” they wrote.
“Although lice-borne relapsing fever is not necessarily fatal, it can significantly weaken an already debilitated person,” they added.
Unlike a 2006 study that found traces of bacteria that cause typhus or trench fever in four people out of a group of 35 people, the team found no traces of these diseases.
But Rascovan said that while the earlier research was limited by the technology of the time, its findings remained valid and, combined with new discoveries, provided a better understanding of the conditions that devastated Napoleon's army.
“The discovery of four different pathogens in so many people really shows that there was a high prevalence of infectious diseases of all types,” he said.
By the time Napoleon's troops retreated, some 300,000 people had died. It seems that even the emperor cannot defeat the microbe.
