As a young teen, bioarchaeologist Riaan Rifkin spent vacations exploring an Iron Age settlement near his home north of Pretoria, South Africa. Hooked on the pursuit, Rifkin now searches for much smaller artifacts of prehistoric life: the DNA of ancient pathogens.
“Imagine living in a cave five or 10 or a hundred thousand years ago,” he says. “You never vacuumed or swept. So every meal you had, every visitor you had, everything you did in the cave, there would be bits of DNA of those activities within the sediment.”
With the advent of agriculture and livestock, the Iron Age saw the rise of diseases, such as measles, that spread in crowds. Other illnesses, such as mosquito-borne malaria, predate human settlements. Studying diseases’ origins could help prevent them today.