Searching for Syphilis: Ancient Treponema pallidum from human remains sheds light on its evolutionary history

Searching for Syphilis: Ancient Treponema pallidum from human remains sheds light on its evolutionary history

The evolutionary history and origin of syphilis, and other diseases caused by the spiral-shaped bacteria treponema, is a hotly debated topic by scholars. Scholars who theorize syphilis originated in the “New World” and preceded the 15th century have been in fierce debate with scholars who theorize a multiregional origin followed by the 15th century pandemic spread.

In a new study published with PLOS Neglected Tropical Diseases, Dr. Johannes Krause of the Max Planck Institute for the Science of Human History along with his colleagues, contribute to this long-lasting debate by, for the first time, successfully reconstructing T. pallidum genomes from the human remains of Post-Columbian period humans. Their findings reveal that both reconstructed sub-species of T. pallidum genomes, T. pallium ssp. pallidum (associated with syphilis in infants) and T. pallium ssp. pertenue (the causative agent of yaws) can show similar visual symptoms, such as bone and joint lesions. The similar symptoms provide strong evidence for the rearrangement of this ancient DNA as a tool.

Although the individuals included in the study presented skeletal changes consistent with treponematosis, such as roughness of the bone caused by periostitis, the researchers were unable to visually differentiate between the genomes due to the shared signs of yaws and syphilis and the varying degrees of skeletal preservation. However, their genomic testing did successfully identify syphilis in two individuals and yaws in one infant.

“Our study demonstrates that retrieval of authentic ancient T. pallidum DNA from historic tissues to the resolution of genomic reconstruction is indeed possible, despite earlier pessimism.  We also demonstrate the value of molecular identification of ancient pathogens. This identification is particularly important when applied to treponemal diseases where skeletal responses to pathogenic subspecies are often shared, challenging the development of a confident diagnosis through osteological observation,” the researchers note. “Our finding that two T. pallidum subspecies likely caused similar skeletal manifestations in the past may suggest a more complex evolutionary history of T. pallidum than previously assumed.”

 

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Research Article: Schuenemann VJ, Kumar Lankapalli A, Barquera R, Nelson EA, Iraíz Hernández D, et al. (2018) Historic Treponema pallidum genomes from Colonial Mexico retrieved from archaeological remains. PLOS Neglected Tropical Diseases 12(6): e0006447. https://doi.org/10.1371/journal.pntd.0006447

Image Caption:

“Examples for bone lesions for the three positively diagnosed individuals. Skeletal collection from Santa Isabel Convent, Mexico City, in custody of the Laboratory of Osteology, Post Graduate Studies Division, National School of Anthropology and History (ENAH), Mexico” Krause, et al (2018).

Author

Avren Keating is a Publications Assistant for PLOS Neglected Tropical Diseases. They received their MFA in Creative Writing from Mills College. You can contact them at akeating@plos.org.

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