The oldest syphilis bacterium discovered to date
An international team of researchers with the participation of the Max Planck Institute for the History of Humanity has now succeeded in what was long thought impossible. Scientists were able to recover three genomes of the syphilis bacterium Treponema pallidum from ancient human remains from the Mexican colonial period. The remains are around 350 years old. The researchers hope to use the samples to gain new insights into syphilis, which has not yet been well researched, a disease that still causes millions of new infections every year worldwide.
The team for the study was made up of 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. The find involved three samples of the Treponema pallidum bacterium, which could be divided into two subspecies in the studies. One subspecies (sp. Pallidum) triggers syphilis, while the other subspecies (sp. Pertenue) triggers the tropical disease framosia. It has not been possible to distinguish these two diseases from one another on the basis of bone finds. The study results were recently published in the specialist journal "PLOS Neglected Tropical Diseases".
Syphilis - an old acquaintance of mankind
According to the researchers, the sexual disease syphilis is currently spreading again. The often unrecognized condition only becomes apparent several weeks after infection by ulcers in the places where the bacteria have penetrated, for example on the mouth or genitals. After the ulcers have healed, there is often a second outbreak. Itchy rashes and fever then appear. If the bacterium remains in the body, the so-called neurosyphilis threatens severe tissue damage in the brain and spinal cord.
Frambösie - the raspberry plague
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 is derived from the French word for raspberry (framboise), as an infection creates reddish papules that are reminiscent of raspberries. The disease primarily occurs only in the humid tropical countries of Southeast Asia, Africa and Latin America. If left untreated, the pathogens can survive in the body for decades and cause serious damage and inflammation of the bones and joints.
Syphilis repeatedly plagues mankind with epidemics
"Despite their historical importance, the origin and evolution of syphilis and related diseases have not been well researched," the researchers write in a press release about the study. In the pandemic of syphilis in Europe in the late 15th century it is still unknown whether the origin was in the New or the Old World. Diseases related to syphilis such as frambösie leave similar traces on the bones and can therefore not be clearly identified without the associated bacteria.
About the finds
The remains from which historical syphilis bacteria could be recovered for the first time came from three individuals that were discovered in the former Santa Isabel monastery and were buried about 350 years ago. The historic site was used by Franciscan nuns from 1681 to 1861.
Frambösie and Syphilis - historically indistinguishable
The differences between frambösie and syphilis in historical finds have so far been difficult to distinguish based on external characteristics. "Our work demonstrates the value of molecular identification of the old pathogens," reports the first author of the study, Professor Verena Schünemann from the University of Zurich. Above all, this applies to the diseases related to syphilis, which lead to similar bone changes.
Evolution history re-examined
With the research, the scientists 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 in the colonial era, others assume that the disease was widespread among the European population before the pandemic in the late 15th century. A final clarification is only possible through further samples from all over the world.
"Further examinations of additional old samples from all over the world will further refine our understanding of the disease," said co-author Professor Johannes Krause from the Max Planck Institute for the History of Humanity. (vb)