CHICAGO (Reuters) - New genetic evidence supports the theory that Christopher Columbus brought syphilis to Europe from the New World, U.S. researchers said Monday, reviving a centuries-old debate about the origins of the disease.

They said a genetic analysis of the syphilis family tree reveals that its closest relative was a South American cousin that causes yaws, an infection caused by a sub-species of the same bacteria.

"Some people think it is a really ancient disease that our earliest human ancestors would have had. Other people think it came from the New World," said Kristin Harper, an evolutionary biologist at Emory University in Atlanta.

"What we found is that syphilis or a progenitor came from the New World to the Old World and this happened pretty recently in human history," said Harper ...

She said the study lends credence to the "Columbian theory," which links the first recorded European syphilis epidemic in 1495 to the return of Columbus and his crew.

"When you put together our genetic data with that epidemic in Naples in 1495, that is pretty strong support for the Columbian hypothesis," she said.