Did marine mammals bring tuberculosis to South America? By Susanne Bard

By Susanne Clara Bard

People in South America were suffering from tuberculosis long before Europeans showed up with their diseases. But it didn’t travel across the Bering Strait, as researchers previously believed. An analysis of DNA from 800-1,000 year-old Peruvian skeletons suggests a unexpected origin – marine mammals. Tuberculosis DNA showed up in lesions found in these skeletons’ bones. An international team of scientists discovered that this DNA most closely matched strains of the disease found in seals and sea lions from South America. I asked one of the researchers – anthropologist Anne Stone from Arizona State – how TB could be passed from the animals to humans. She says the Chiribaya people likely hunted the marine mammals, and TB spread from the animals’ gastrointestinal tracts to humans via undercooked or raw meat.

But the story gets even stranger. Turns out, the pinnipeds probably brought TB with them on long sea voyages from Africa before spreading it to the Peruvians. But Dr. Stone told me that humans in Africa gave TB to animals in the first place. Where they got it is still a mystery.