Grade school history lessons often have it that American Indians largely were wiped out by diseases such as whooping cough, chicken pox, influenza and tuberculosis brought to the New World by European explorers.
One report says, while estimates vary, about 20 million people lived in the Americas shortly before Europeans arrived, and roughly 95 percent of them were killed by European diseases.
But new research led by anthropological geneticists Anne Stone of Arizona State University and Johannes Krause of the University of Tubingen in Germany indicates the diagnosis of what devastated American Indian populations is a little more complicated, particularly when it comes to tuberculosis.
Their study of pre-Columbian Mycobacterial tuberculosis genomes published today in the journal Nature reveals that tuberculosis may have had a hand in American Indian deaths prior to the influx of European diseases. The research concludes seals and sea lions likely brought the disease to South America and spread it to people there long before Christopher Columbus arrived in 1492.
"What we found was really surprising," said Stone, referring to her team's examination of tuberculosis DNA from roughly 1,000-year-old human skeletons found in Peru that produced the discovery.
The results, the researchers write, provide unequivocal evidence that a member of the M. tuberculosis complex caused human disease in the pre-contact New World.
"Skeletal evidence of tuberculosis is present in the archaeological records in both the Old World and New World," said Elizabeth Tran, Biological Anthropology program director in the National Science Foundation's Division of Behavioral and Cognitive Sciences.
"The source of tuberculosis in the New World long has been a question for researchers. This paper provides strong evidence that marine mammals may have been the likely culprits, bringing tuberculosis to South America long before Europeans arrived there."