Historical Leiden Researchers discover 350-year-old syphilis bacteria

So far the oldest syphilis bacterium discovered

What has long been thought impossible has now been achieved by an international research team with the participation of the Max Planck Institute for the History of Humanity. Scientists were able to recover three genomes of the syphilis bacterium Treponema pallidum from ancient human remains of the Mexican colonial era. The remains are around 350 years old. Researchers hope to gain new insights from the samples on the untreated syphilis, a disease that continues to cause millions of new infections each year worldwide.

Researchers from the Max Planck Institute for Human History in Jena, the University of Tübingen, the National School of Anthropology and History in Mexico City and the University of Zurich formed the team for the study. The find consists of three samples of the Treponema pallidum bacterium, which could be divided into two subspecies in the investigations. The one subspecies (see Pallidum) triggers syphilis, while the other subspecies (see Pertenue) triggers the tropical disease Frambösie. It was not possible to differentiate these two diseases from each other using bone finds. The study results were recently published in the journal "PLOS Neglected Tropical Diseases".

The elongated bacterium Treponema pallidum can cause either syphilis or frambosa depending on the subspecies. (Image: Tatiana Shepeleva / fotolia.com)

Syphilis - an old acquaintance of humanity

According to the researchers, the sexual disease syphilis is currently spreading again. The often unrecognized affliction does not show itself until several weeks after the infection by ulcers at the places, where the bacteria penetrated, thus for example at mouth or genitals. After the ulcers have healed, it often comes to a second outbreak. It will then itching rashes and fever. If the bacterium remains in the body, so-called neurosyphilis is threatened with severe tissue damage in the brain and spinal cord.

Frambösie - the raspberry epidemic

The tropical disease Frambösie is triggered by a subgenus of the syphilis pathogen and is already contagious through skin contact and droplet infection. The name derives from the French word for raspberry (framboise), as develop as a result of infection reddish papules, reminiscent of raspberries. The disease occurs primarily only in humid tropical countries of Southeast Asia, Africa and Latin America. Left untreated, the pathogens can survive in the body for decades, causing severe damage and inflammation of bones and joints.

Syphilis plagues humanity again and again with epidemics

"Despite their historical significance, the origin and evolution of syphilis and related diseases are not well understood," the researchers write in a press release on the study. In the case of the syphilis pandemic in late-15th-century Europe, it is still unknown whether the origin was in the New or the Old World. Syphilis-related diseases such as ovarian bone leave similar traces on the bones and therefore can not be clearly identified without the associated bacterium.

About the finds

The remains, from which historical syphilis bacteria could be salvaged for the first time, came from three individuals who were discovered in the former monastery of Santa Isabel and buried about 350 years ago. The historic site was used from 1681 to 1861 by nuns of the Franciscan Order.

Frambösie and syphilis - so far historically indistinguishable

The differences between Frambösie and syphilis in historical finds were so far hardly distinguishable on the basis of external characteristics. "Our work confirms the value of a molecular identification of the old pathogens," says the first author of the study, Professor Verena Schünemann from the University of Zurich. Above all, this applies to diseases related to syphilis, which lead to similar bone changes.

Evolutionary history re-illuminated

Researchers want to shed new light on the evolutionary history of the disease. While some scientists hypothesize that syphilis is a New World disease that was introduced to Europe during the colonial period, others believe it was widespread in the European population before the late-fifteenth century pandemic. A final clarification is only possible through further samples from all over the world.

"Further research into additional ancient samples from around the world will further refine our understanding of the disease," concludes co-author Professor Johannes Krause of the Max Planck Institute for the History of Mankind confidently. (Vb)