DNA Analysis Uncovers the True Cause Behind the Demise of Napoleon’s Army in 1812

During the retreat of Napoleon’s formidable 500,000-strong army from Russia in 1812, nearly half of the troops fell victim to disease, starvation, and freezing temperatures. Recent advanced DNA analysis is shedding light on the pathogens involved in this tragic demise.

In the summer of 1812, Napoleon amassed an army of 600,000 to invade Russia but was compelled to withdraw from Moscow, depleting the city of resources, and retreat toward the Polish border for the winter. From October to December 1812, around 300,000 French soldiers perished from famine, exposure, and illness.

Survivor accounts from that era indicate that typhoid fever and trench fever were leading causes of mortality and suffering among the troops, a premise that was further validated by genetic testing conducted nearly two decades ago.

Recently, Nicholas Rascovan and his team at the Pasteur Institute in Paris analyzed DNA extracted from the teeth of 13 soldiers interred in Vilnius, Lithuania.

The research team identified the presence of Salmonella enterica, which triggers peritoneal fever, and Borrelia recurrentis, a louse-borne pathogen that leads to recurrent fever.

Unlike earlier studies that relied on methods to amplify specific DNA sequences, Rascovan and his colleagues utilized advanced metagenomic techniques to detect genetic material from pathogens in the samples, allowing for a more extensive analysis.

“Considering our findings, it is plausible that the deaths of these soldiers were due to a combination of various illnesses, including fatigue, colds, lactophoreal fever, and louse-borne recurrent fever,” Rascovan and his team noted in an unpublished report. The team opted not to comment further on the story.

While not always lethal, louse-borne recurrent fever can considerably debilitate individuals who are already in a weakened state, according to the researchers.

Sally Wasef from the Queensland Institute of Technology in Australia opines that historical accounts of symptoms may correspond to multiple infectious diseases beyond those identified in the recent study.

Traces of microbial DNA were isolated from ancient remains, according to Wasef. “In my opinion, this implies that the conclusions drawn are more suggestive than definitive.”

Rascovan and his colleagues also acknowledge the necessity of examining a greater number of soldiers who perished during 1812.

The research underscores the potential of novel methodologies to identify possible infectious agents in historical populations, Wasef explains. She advocates for applying these techniques to study diseases in populations post-contact in regions like the US or Australia.

“Such research holds great promise for uncovering the impact of disease on historical population declines, particularly when written records are sparse or biased,” states Wasef.