NEW YORK – New research has revealed details about the history of the syphilis-causing bacterial species Treponema pallidum, suggesting that it was present in the Americas prior to the arrival of European explorers in 1492, who brought it back to Europe.
"The data clearly support a root in the Americas for syphilis and its known relatives, and their introduction to Europe starting in the late 15th century is most consistent with the data," Kirsten Bos, a molecular paleopathology group leader at the Max Planck Institute for Evolutionary Anthropology who co-led the work, said in a statement.
Bos noted that though Indigenous American groups "harbored early forms of these diseases, Europeans were instrumental in spreading them around the world."
Although syphilis is believed to be behind a well-known disease outbreak that spread within Europe in 1495, there has been an ongoing debate over the source of this outbreak, with the pre-Columbian and Columbian theories positing that T. pallidum was present in Europe before and after contact with the Americas, respectively.
"Several genomes from the syphilis family have been reconstructed from archaeological bone, but these haven't been able to address core questions related to the pre- or post-Columbian theories surrounding syphilis," Bos said, noting that the new data "clearly support a root in the Americas for syphilis and its known relatives, and their introduction to Europe starting in the late 15th century."
As they reported in Nature on Wednesday, Bos and Johannes Krause, director of the Max Planck Institute for Evolutionary Anthropology's archaeogenetics department, led a team of investigators who used ancient DNA sequencing to determine whether the T. pallidum bacteria behind the diseases syphilis, yaws, bejel, and pinta were present in the Americas before Columbian settlers arrived.
After screening for ancient T. pallidum DNA in bone samples with syphilis-like lesions from dozens of individuals at pre-Columbian archaeological sites in Chile, Mexico, Peru, and Argentina, the researchers relied on capture-based sequencing to put together genome sequences for five ancient T. pallidum pathogens from pre-European contact and peri-European contact samples.
In combination with dozens of modern T. pallidum genomes, the data pointed to the early American presence of the T. pallidum lineages T. pallidum pallidum, T. pallidum pertenue, and T. pallidum endemicum, which are linked to syphilis, jaws, and bejel, respectively.
"We see extinct sister lineages for all known forms of this disease family, which means syphilis, yaws, and bejel are the modern legacies of pathogens that once circulated in the Americas," co-first author Rodrigo Barquera, a postdoctoral researcher with the Max Planck Institute for Evolutionary Anthropology, said in a statement.
Based on the genetic patterns present in the ancient American T. pallidum isolates, the investigators estimated that the most recent common ancestor for existing T. pallidum lineages goes back more than 5,000 years, though further research is needed to determine whether it arose in the Americas or arrived with early inhabitants.
"Given the rarity of cases recovered from our screening, DNA alone may not permit reconstruction of the treponemal historical narrative to the satisfaction of all discussants," the authors wrote. "While we anticipate tangible contributions from molecular data in the coming years, debates are likely to continue based on balanced review of the available evidence."