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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.

Transcript

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)

BOB HIRSHON (host):

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.

HIRSHON:

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

STONE:

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.

HIRSHON:

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