Oldest DNA from syphilis ‘cousin’ found in SC – 01/24/2024 – Science

Analysis carried out on skeletons around 2,000 years old, found on the coast of Santa Catarina, brought to light the oldest DNA of the bacteria responsible for causing syphilis and other similar diseases around the world.

The genetic data reinforces the idea that these microbes already had an extremely long history on the American continent before causing epidemics in the Old World from the end of the 15th century. Apparently, therefore, they were taken from the Americas to Europe for the first time. time after the pioneering voyages of explorers such as Christopher Columbus, who crossed the Atlantic from Spain in 1492.

Published in this week’s edition of the scientific journal Nature, one of the most important in the world, the work is a partnership between USP researchers and European experts. People infected with bacteria of the subspecies Treponema pallidum endemicum they were buried at the Jabuticabeira II archaeological site, in the Laguna region (SC).

The burials took place in a sambaqui, a structure similar to an artificial hill built with shells and sediments that was important for millennia in different parts of the Brazilian coast. Apparently, shell middens functioned as funerary monuments (some had hundreds of burials) and territorial markers for coastal groups. In them it is possible to find remains of funeral meals, made in honor of the deceased, as well as figurines of marine and terrestrial animals and other stone artifacts.

According to one of the Brazilian authors of the study, doctor José Filippini, the work began with his doctoral thesis at the Biological Anthropology Laboratory at USP, which was completed in 2012.

“That was when we carried out a systematic study to diagnose treponematoses [as doenças causadas pelas bactérias do gênero Treponema] in more than a thousand individuals from archaeological sites, such as middens on the coasts of the South and Southeast of Brazil”, he said. From this large sample, he says that 22 suspected cases of treponematosis were identified.

This is where the problem begins from the point of view of the deep history of these diseases. Today, there are three different illnesses caused by slightly different versions of the same bacterial species. Syphilis itself – a sexually transmitted disease that, before the invention of antibiotics, could be lethal, cause deformities and destroy the nervous system of patients – is associated with the subspecies Treponema pallidum pallidum.

But there is also yaws, which causes damage to the skin, bones and joints and is caused by T. p. belongand bejel, which usually starts with lesions in the mouth and skin and is linked to T. p. endemicum.

Today, only syphilis is usually transmitted through sexual contact, and only syphilis has spread throughout the world. Bejel is endemic to dry, hot regions, such as the Middle East, and yaws still occurs in Africa and South America. Bone lesions are often an indication that some form of these bacteria was present in the past.

“These are changes that we call periostitis, in which the surface of the bone presents fistulas (cloacas, perforations), with the bone remodeled (thicker than normal). And all of this in more than just one bone”, explains Filippini.

“We are talking about general indications of treponemal infection. But it is often problematic to separate the subspecies based on bone lesions alone, because all studies with ancient DNA show that all subspecies of this type of bacteria caused very similar manifestations to each other in the past.” , explains the study coordinator, Verena Schuenemann, from the University of Zurich, Switzerland. Therefore, only DNA analysis is capable of separating one type of infection from another.

This is what the researchers achieved with the extraction of genetic material and its sequencing (roughly speaking, “spelling”) of four people buried in the Jabuticabeira II sambaqui (two of them identified as female via DNA, the other two with skeletons compatible with the male sex, but without corresponding genetic data).

Because it is from the subspecies T. p. endemicum, the bacteria found in shell midden skeletons are considered to be associated with modern bejel. In fact, a “family tree” of microbe genomes shows that it underlies the lineage associated with this disease.

“There is no doubt that, in the Americas, the bacterial strains of these diseases are very ancient and may have even been brought by the first groups of human beings who arrived on our continent”, summarizes bioanthropologist Sabine Eggers, who worked at USP and is now a researcher from the Natural History Museum in Vienna.

It remains to be seen, however, why they do not appear to have caused much destruction before Europeans’ first contact with the people of the Americas, when syphilis first made an explosive advance. One possibility has to do with the fact that the people of the Old World, having never had contact with the microbe, had no natural defenses against it and therefore suffered more.

“Another old hypothesis is that these diseases were less aggressive in tropical regions, where little clothing was worn and transmission was through simple skin-to-skin contact. With the arrival of a temperate climate, the bacteria adapted to transmission through sexual contact and would have become more virulent,” says Eggers.