The origin of syphilis, a bacterial infection that is transmitted mainly through sexual contact, has divided scientists for decades. The most widespread version states that the disease was present in America since pre-Hispanic times and with the incipient human exchange inaugurated by transatlantic travel at the end of the 15th century. Critics of this hypothesis argue that by then, the as-yet-unidentified condition was already being transmitted in Europe. A new study of the ancient DNA of the bacteria that causes this and other diseases, Treponema paleprovides evidence that reinforces the first theory in tune with the historical context: syphilis was already wreaking havoc in America before the arrival of Columbus, however, its global expansion was due to European colonialism.
The study, carried out by an international team led by the Max Planck Institute for Evolutionary Anthropology in Leipzig (Germany), analyzed five genomes of the bacteria Treponema pale found in five remains of human skeletons that inhabited Mexico, Peru, Chile and Argentina, four of them dated before 1492, when Columbus arrived in America. Analysis of bones with syphilitic-type lesions, typical of an advanced infection, are key in the search for the origin of the disease, until now a mystery. The samples studied yielded different types of ancient DNA from treponemes, as the group of four diseases caused by subspecies of the same genus of bacteria that cause syphilis is called.
In the case of the samples from Mexico, the study analyzed the skeletons of two children who lived in the center of the country more than 500 years ago: the first, a four-year-old whose bone remains date from between 1300 and 1397; and the second, a probably two-year-old Mexica boy, who lived between 1444 and 1616. The pathogenic DNA was obtained from multiple syphilitic lesions on his bones. Both remains correspond to findings made by the INAH in the north of Mexico City.
“The data clearly supports that syphilis and its known relatives have roots in the Americas, and its introduction to Europe beginning in the late 15th century is consistent with the data,” explains lead author Kirsten Bos in a . “While Native American groups harbored early forms of these diseases, Europeans were instrumental in their spread throughout the world.” or measles, introduced to pre-Hispanic peoples after the arrival of the conquerors to America, the natural history of syphilis suggests a transmission caused after contact between populations separated for millennia. This case, however, went in the opposite direction, from the American continent to Europe, where it took place in 1495, a date that temporarily coincides with the return of Columbus after his first American voyage just two years earlier, in March 1493. Syphilis epidemics with a high mortality rate were a constant in Europe during the 16th century.
The study, published on December 18, emphasizes that the genomes found are not identical to those currently known. These are extinct variants, ancient relatives of the currently circulating lineages of the bacteria. However, its discovery provides new weighty evidence to confirm the suspicions that hovered over its arrival in Europe and a rich previous diversity in America. “The genomes of ancient pathogens from skeletons before 1492 confirm their introduction from America, but their global spread remains a dark legacy of the colonial period,” explains the Max Planck Institute in a statement.
