DNA from Napoleon’s Ill-Fated 1812 Army Reveals Likely Causes of Soldier Deaths
Newly discovered DNA evidence from Napoleon Bonaparte’s 1812 Russian campaign has revealed startling insights into what likely contributed to the demise of his army during one of the most disastrous military retreats in history. For years, the death of thousands of soldiers has been attributed to a combination of battle, starvation, freezing temperatures, and a devastating typhus epidemic. However, recent advancements in genetic sequencing have uncovered two previously undetected pathogens, suggesting that multiple infectious diseases may have played a significant role.
Published on Friday in Current Biology, the study analyzes DNA remnants from the fallen soldiers, whose mass grave was uncovered in Vilnius, Lithuania, in 2001. The research provides a deeper understanding of the health crisis that crippled Napoleon’s army during its brutal retreat from Moscow.
A Deeper Look at Napoleon’s Army’s Demise
In the winter of 1812, Napoleon’s forces, numbering over half a million, embarked on what would become one of the most catastrophic military campaigns in history. The French army was forced to retreat after Moscow was abandoned and scorched by Russian forces. The bitter cold, lack of supplies, and incessant harassment from Russian troops left the French with few options for survival. By the time they reached the border, only a fraction of the original force made it back to France, with tens of thousands of soldiers perishing along the way.
For decades, historians and researchers have attributed the high death toll to a combination of factors, but a 2006 study was the first to suggest that typhus, caused by the bacterium Rickettsia prowazekii, might have been the primary cause of death among the soldiers. However, the recent study has revealed that typhus was not the only culprit. Using cutting-edge DNA sequencing technology, researchers have now identified the presence of two additional bacterial pathogens: Salmonella enterica and Borrelia recurrentis, which cause paratyphoid fever and relapsing fever, respectively.
Advanced Technology Unlocks New Insights
Lead author Rémi Barbieri, a former postdoctoral fellow at the Institut Pasteur in Paris, explained that earlier studies were limited by the technology available at the time. “Previously, we just thought that there was one infectious disease that decimated Napoleon’s army — the typhus,” Barbieri said. “But our findings open the door to discovering other diseases that could have contributed to the soldiers’ demise.”
The team analyzed teeth samples from 13 fallen soldiers, which had been preserved for over 200 years in the mass grave. With high-throughput sequencing—a powerful technique capable of sequencing millions of DNA fragments at once—the researchers were able to extract and analyze highly degraded DNA. This allowed them to identify genetic material from pathogens that had been buried with the soldiers.
While the study did not find evidence of typhus in the samples, it does not completely rule out its role in the deaths, as the sample size was relatively small. However, the detection of Salmonella and Borrelia provides compelling evidence that multiple infections were likely involved, and there may be other pathogens yet to be uncovered.
A Mix of Diseases in the Harsh Russian Winter
The discovery of these additional pathogens sheds new light on the health conditions that Napoleon’s army faced during its harrowing retreat from Moscow. By the time the French troops entered the Russian capital, they were already suffering from the effects of prolonged exposure to the elements, a lack of food, and poor hygiene. With Moscow abandoned and stripped of supplies, the soldiers were left to survive the harsh winter with little more than the clothes on their backs.
Rickettsia prowazekii, the bacterium responsible for typhus, had already been detected in the soldiers’ remains in previous studies. However, the new research, which employed more advanced technology than the 2006 study, showed that there were other infectious agents at play. The introduction of Salmonella and Borrelia into the mix paints a more complex picture of how disease spread rapidly among the troops.
The Salmonella enterica pathogen is responsible for paratyphoid fever, a disease that causes fever, abdominal pain, and general weakness. Borrelia recurrentis, which causes relapsing fever, leads to cycles of fever and chills, often debilitating the infected person. Both diseases are transmitted by lice or contaminated food and water, which would have been prevalent among the soldiers during their grueling retreat.
The Implications for Modern Disease Research
This breakthrough in ancient DNA analysis highlights not only the advancements in technology but also the role that such studies can play in understanding the evolution of infectious diseases. Nicolás Rascovan, co-author of the study and head of the Microbial Paleogenomics Unit at the Institut Pasteur, emphasized the importance of these findings for modern science.
“These kinds of projects can give us a much clearer picture of the landscape of infectious disease in the past, and how historical events shaped the evolution of diseases today,” Rascovan said. The study underscores how ancient pathogens have contributed to the emergence of present-day diseases, and understanding their role in history may help predict how future infectious threats might evolve.
A Lasting Legacy: The Fall of Napoleon’s Army
Napoleon’s army was never the same after its catastrophic retreat from Russia. The losses weakened his military power and set the stage for his eventual downfall. While Napoleon himself survived the retreat, his dwindling forces could not recover from the significant losses they had suffered—both on the battlefield and through disease.
The new findings not only contribute to our understanding of the tragic events of 1812 but also highlight the critical role of ancient DNA research in unearthing new insights into history. As technology continues to evolve, it is likely that more mysteries surrounding past epidemics and military campaigns will be uncovered, offering a clearer view of how infectious diseases have shaped history.
Final Thoughts: A New Era of Ancient DNA Studies
As the research into Napoleon’s ill-fated 1812 campaign demonstrates, the ability to analyze ancient DNA has revolutionized how we understand historical events. The detection of previously unknown diseases from the remains of soldiers provides a nuanced perspective on the harsh conditions that led to their deaths. With the continued advancement of sequencing technologies, historians and scientists alike can look forward to uncovering even more secrets from the past, shedding light on how disease and warfare intersected in shaping our world.
