Scientists have found the oldest genome of bacteria that belongs to the family of syphilis.
Oldest Genome of Bacteria in Syphilis Family
DNA research has shown that individuals who dwelled in Brazil's coasts thousands of years ago carried the Treponema pallidum endemicum bacterium, which is a close relative of the bacteria that accounts for venereal syphilis. Because of the infection, it is likely that the group had painful shins and mouth sores.
The DNA of the microbe was discovered in human skeletons from 2,000 years ago. The scientists then used it for the construction of the oldest-known genome of a relative of syphilis that has ever been discovered.
The findings were noted in the "Redefining the treponemal history through pre-Columbian genomes from Brazil" study. The discovery also pushes back the microbe's origins by over 1,000 years.
Syphilis Origins
Since the 1495 endemic that hit Europe, syphilis origins have been debated. While Christopher Columbus and his men were usually blamed for the arrival of the sexually transmitted infection in Europe, recent research shows that the disease was already present in the continent even before they embarked on their transatlantic sojourn.
According to modern research, syphilis is just one of the four conditions that is caused by a close-knit bacterial family. The other three conditions, which are pinta, yaws, and bejel, are not venereal. These three also typically cause chronic skin and mouth infections.
In the last decades, archaeologists from the Americas and in Europe have been investigating syphilis origins as well as the origins of its nonvenereal relatives. They have been doing so by searching for bone changes that exhibit the disease's hallmark characteristics.
However, until now, they were not able to find any genetic evidence of the conditions prior to the first voyage of Columbus across the Americas.
Bacterial DNA Found
Now, the team of Verena Schünemann, a paleogeneticist from the University of Zurich, was able to uncover DNa from the T. pallidum endemicum bacterium among skeletons from Jabuticabeira II's archaeological site, which is situated on Brazil's south coast close to Laguna do Camacho.
Over a 1,500-year period, more than 200 individuals were buried at the site. Each person was curled up tightly and given offerings, such as fish, stone tools, and red ochre. To further examine the remains, the team screened samples of bones from 99 skeletons. They screened for pathogen-sourced DNA.
The scientists were able to discover that 37 skeletons had positive results for treponemal DNA. Four samples produced sufficient data for the researchers to conduct a genomic reconstruction of the pathogen.
The researchers note that the genomes unexpectedly and remarkably resemble the causative agent behind bejel, or endemic syphilis, in modern days. This condition spreads among people through skin or mouse lesion contact. It happens in western Asia and the eastern Mediterranean's hot and arid areas.
While bejel can also be treated with antibiotics, the indigenous people from thousands of years ago likely did not have any effective treatment, implying that they just lived with the condition. Schünemann explains that there are no historical records that describe the symptoms faced by these people 2,000 years ago. However, it is likely that the bacteria led to skin lesions that are similar to modern bejel.
None of the individuals buried at the site appeared to experience ostracization due to their condition. The researchers note that they were not separately buried from others, which suggests that they received equal treatment.
The scientists note that the findings place bejel in South America long before the contact with Europe during the 1500s. It also allows researchers to recalculate the likely date of origin of the bacterium. It places the origins at a time between 780 B.C. and A.D. 450, moving it over a thousand years earlier.
However, the new date of origin does not offer clues regarding venereal syphilis origins. Schünemann notes that they, unfortunately, do not have sufficient data to conclude which subspecies of T. pallidum is the oldest. To do so, more of other subspecies would be necessary.
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