Dead soldiers’ teeth reveal diseases that doomed Napoleon’s army

In the summer of 1812, the legendary French general Napoleon Bonaparte led an army about half a million strong to invade Russia. The Russians retreated but burned the countryside as they withdrew, using scorched-earth tactics that eventually left Napoleon’s troops occupying a ruined Moscow. By fall, his ill-fated troops began to leave for encampments along the Russian border, where an estimated 300,000 of them were eventually mowed down not by military might, but by illness coupled with extreme cold, starvation and exhaustion.

Historical accounts of Napoleon’s campaign to invade Russia have focused the brunt of the blame on a louse-borne disease, typhus. But a new study of bacterial DNA preserved in the teeth of 13 soldiers adds two new diseases - paratyphoid fever and a relapsing fever -