Of all the classic blunders, the most famous is getting involved in a land war in Asia (source: The Princess Bride). Napoleon Bonaparte’s troops learned this lesson the hard way during their disastrous retreat from Moscow at the wintry tail of 1812, which claimed the lives of 300,000 soldiers—more than half of the French army—largely from exposure and disease.
While the epic death toll has been notorious for centuries, the exact pathogens responsible for the losses have remained a matter of debate. Contemporaneous reports from the field suggested that typhus and trench fever commonly afflicted the army. But when scientists sequenced DNA from the teeth of 13 soldiers, they did not find the bacteria that causes those diseases.
Instead, the results revealed the presence of “previously unsuspected pathogens” that suggest paratyphoid fever and relapsing fever were major killers during the mad rush from Moscow, according to a new study.