What killed Napoleon’s army? Scientists find clues in DNA from fallen soldiers’ teeth : Shots

By 1812 Napoleon was all-powerful. Almost all of Europe was under his control. He succeeded in banning most of the continent from trading with Britain in an attempt to subjugate the island nation. And he was married to Marie Louise, the daughter of the Emperor of Austria, a major superpower at the time. (The dazzling emerald and diamond necklace he gave her when they married was one of the items stolen last weekend. robbery at the Louvre.)

But the Russian Empire resisted his attempts to cut off all trade with Great Britain. That summer he ordered his army of about 600,000 men to invade Russia. This will turn out to be a terrible decision.

“This is one of the most shameful military campaigns in recent centuries,” says Nicholas RaskovanHead of the Department of Microbial Palaeogenomics at the Pasteur Institute in Paris. “He believed he could more or less conquer the whole world. This was probably the beginning of the end.”

In October, Napoleon recalled his soldiers after barely engaging the Russian army. It wasn't a defeat, but it wasn't a victory either. While we were walking home, winter came early.

“They began to die from cold, hunger, and also from infectious diseases,” says Raskovan. In total, hundreds of thousands died.

And in a new study published in the journal Current biologyRaskovan and his colleagues say the diseases likely include two unexpected pathogens that could hasten the deaths of soldiers.

Combined with earlier work, it became clear that these people were under microbial attack on all fronts.

“These wars were far from glamorous,” says Michaela Bindera bioarchaeologist from Novetus, an archaeological company based in Vienna, who was not involved in the study. “For some of them, dying in battle would be a relief.”

A rich and bloody history, reconstructed

Typhoid and trench fever were long believed to be among the ailments that Napoleon's soldiers suffered from. This is based on a body of historical evidence, the discovery of body lice on the remains of soldiers (who carried disease-transmitting pathogens) and DNA tests carried out almost ten years ago.

But molecular techniques have improved significantly since then.

So a pair of archaeologists asked Raskovan, who studies the DNA of ancient pathogens, to see what other ailments he could find in the remains of a mass grave in Lithuania. This place was discovered by chance during construction in one of the northern suburbs of Vilnius in 2001. Soon after his death, between two and three thousand of Napoleon's men were buried here.

“Europe has such a rich history that there are archaeological sites almost everywhere,” says Raskovan. “So you dig a hole in the ground and then you find something.”

Among the remains that archaeologists unearthed were 13 teeth, each belonging to a different soldier. Blood had been flowing inside these teeth for a long time.

“If you have pathogen DNA in your blood due to an infection, that DNA can get into the tooth,” Raskovan explains. “So it's sort of a time machine where you can actually see the blood of a person from that time.”

Only after the teeth were disinfected, ground into powder, and bone dust dissolved could ancient DNA be studied. But, naturally, this genetic code was in rough form. It consisted of ultra-short fragments that had undergone chemical changes.

Raskovan sequenced it all. Some of the genetic material came from the soldiers themselves. Some of them came from organisms in the soil in which they were buried. And in part – perhaps – it was the pathogens that helped kill these people.

“Once we have a huge list of all the objects that have been detected, we will try to find species that match the human pathogen,” he says. “It's like solving a puzzle.”

“A Tale of Hardship”

After Raskovan and his team solved this puzzle, they had two successes. Both were bacteria: one caused paratyphoid fever and the other caused relapsing fever, a pathogen transmitted by body lice and dating back to the Iron Age.

“This article clearly shows how complex these types of analyzes are and the extraordinary level of skill required to work with these types of data,” says Leslie Quaida paleopathologist from the Austrian Archaeological Institute who was not involved in the study.

She says understanding the emergence, spread and evolution of diseases in the past can also help us navigate modern pathogens.

“Understanding how certain types of pathogens have evolved may give us a better chance of anticipating what the pathogen's next move might be,” Quaid says. Additionally, if a once widespread pathogen has become rare today, these infection-filled historical events can provide lessons in learning how to prevent its return and contain other similar modern pathogens.

These results are another reminder that war has always been terrible, Binder says. “In our museums we have pictures of soldiers in shining armor, Napoleon on horseback, smart young men going into battle.”

“But at the end of the day, when we look at human remains, we see a completely different picture,” she says.

It is a picture of lifelong malnutrition, broken legs from marching too far and too fast, and bodies riddled with disease.

“Their bones tell a story of adversity,” Binder says.