Ancient DNA reveals plague was already killing humans 5,500 years ago

Plague was already a deadly killer 5,500 years ago, long before cities, farming, or the rat-infested conditions usually linked to historic outbreaks. By analyzing ancient DNA from hunter-gatherer cemeteries in Siberia, researchers discovered early plague strains in nearly 40% of the individuals studied and found evidence of rapid family-based outbreaks that wiped out many children and young teenagers.