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TB’s Unexpected Journey

May 6, 2016

Marine mammals brought tuberculosis to South Americans from Africa more than 1000 years ago.


9324074388_23865e503c_k Jerome Paz CC BY-NC 2.0, via flickr

Seal lions may have helped bring TB to the New World. (Jerome Paz CC BY-NC 2.0, via flickr)


TB’s unexpected journey.  I’m Bob Hirshon and this is Science Update.

Tuberculosis hitched a ride from Africa to South America with marine mammals before infecting humans there. Arizona State anthropologist Anne Stone was on a team that analyzed DNA from 1000-year-old human remains from Peru.

ANNE STONE (Arizona State University):

We discovered that the ancient South American human TB samples were most closely related to TB strains found in seals and sea lions. And that of course was a huge surprise, it was not what we were expecting.


Stranger still, she says this strain of TB probably first originated with humans in Africa.


Humans got TB, we don’t really know from where, they then gave it to an animal; it got to seals and sea lions, it spread amongst them, including those that swam to South America.


Stone says hunting was likely to blame for the interspecies disease transmission. I’m Bob Hirshon, for AAAS, the science society.