Marine mammals may have carried TB bacterium across the ocean
Seals brought tuberculosis to South America long before Columbus sailed to the New World, a new study shows.
An analysis of tuberculosis DNA recovered from three 700- to 1,000-year-old Peruvian skeletons reveals that the strain of TB in the ancient bones doesn’t match the strain brought to the New World by European explorers. Instead, it closely resembles one that infects seals in the Southern Hemisphere, an international group of researchers reports August 20 in Nature.
Researchers had long thought that Mycobacterium tuberculosis, the bacterium that causes TB, originated in cattle as M. bovis, jumped to humans after dairy cows were domesticated and then came to the Americas with Europeans.
Several pre-Columbian skeletons in the New World, however, have been found with spine and rib deformities suggestive of TB infections, says Christina Warinner, a molecular anthropologist at the