There are many factors that over the decades have been identified by historians as determining factors in the famous defeat of Napoleon’s army in 1812 in the Russian campaign, including cold and various illnesses, and even hypotheses bordering on legend have been formulated. But now a group of scientists led byPasteur Institute (France) found scientific evidence of two deadly bacteria that may have actually helped decimate the soldiers.
Napoleon’s famous Russian campaign in 1812, also known asPatriotic War of 1812” ended – as is well known – with the retreat of the French army. And its historical significance was enormous: the defeat truly changed the course of history, allowing the Russian army to regain control of Moscow and inflicting a heavy blow on the Emperor’s strategy.
Now researchers have genetically analyzed the remains of former soldiers who retreated from Russia in 1812, detecting two pathogens, bacteria responsible for paratyphoid fever and relapsing fever, related to the symptoms described in historical accounts.
To identify the species of bacteria they extracted and analyzed, in particular, the DNA of 13 soldiers of the Napoleonic army exhumed in Vilnius (Lithuania) in 2002 during the excavations conducted by the team ofUniversity of Aix-Marseille specialized in archaeoanthropology, using next generation sequencing techniques applied to genetic material.
Their research identified the genetic signatures of two infectious agents: Salmonella enterica subsp. enteric (serotype Paratyphi C), responsible for paratyphoid fever, e Borrelia recurrentisresponsible for relapsing fever, a disease transmitted by lice and characterized by attacks of fever followed by periods of remission.
Although these two diseases are different, they can cause similar symptoms such as high fever, fatigue and digestive problems, and their simultaneous presence may have contributed to the worsening of the soldiers’ conditions, especially since they were already weakened by cold, hunger and lack of sanitation.
Of the 13 Napoleonic soldiers exhumed a VilniusIn fact, the teeth of four tested positive for S. enterica Paratyphi C and two a B. recurrentis. This study provides the first genetic evidence of these two largely unsuspected infectious agents, although their precise role in the high number of deaths in Napoleon’s army during the retreat from Russia is unknown.
Confirmation of the presence of these two bacteria comes after a previous study identified the typhoid agentRickettsia prowazekiiand that of trench fever, Bartonella quintanapathogens long thought to be associated with retreat based on historical accounts.
Given the low number of samples analyzed compared to the thousands of bodies found, it is impossible to determine to what extent these pathogens contributed to the very high mortality observed. The scientists’ analysis was in fact based on a limited number of samples (13 out of over 3,000 bodies in Vilnius and around 500,000-600,000 army soldiers, around 300,000 of whom died during the retreat).
But this does not limit the scope of the discovery, which demonstrates the incredible development of genetic technologies and which could also have repercussions on today’s studies on infectious diseases.
Accessing genomic data of pathogens that circulated in historical populations helps us understand how infectious diseases evolved, spread and disappeared over time, and to identify the social or environmental contexts that played a role in these developments – explains Nicolás Rascovan, who led the study – This information provides us with valuable insights to better understand and address infectious diseases today
The work was published on Cell.
Sources: Institut Pasteur / Cell
