For decades, the origins of syphilis have remained a mystery. In the spring of 1495, a devastating disease swept through Europe, leaving victims with severe physical and mental damage. This outbreak, linked to King Charles VIII of France’s military campaign in Italy, marked the first recorded instance of syphilis, a sexually transmitted infection that would eventually spread worldwide.
The outbreak’s timing—occurring soon after Christopher Columbus and his crew returned from their voyages to the Americas—gave rise to the Columbian Theory. This widely accepted idea suggests that syphilis was brought to Europe by sailors who contracted the disease in the New World.
Debating the origins of syphilis with new DNA study
Not all experts agree with the Columbian Theory. The Pre-Columbian Theory argues that syphilis existed in Europe long before Columbus’s expeditions but was misdiagnosed as other illnesses. Supporters of this theory cite skeletal remains with bone lesions resembling syphilis, dating back to before 1492. Historical records also describe illnesses with symptoms similar to syphilis, suggesting the disease may have been present but unrecognized.
To address the debate, scientists have turned to ancient DNA analysis. In a study published in Nature, researchers led by Kirsten Bos and Johannes Krause of the Max Planck Institute for Evolutionary Anthropology analyzed DNA from historical remains found in Mexico, Chile, Peru, and Argentina. These regions displayed evidence of syphilis-like lesions in ancient bones.
Using advanced genetic techniques, the team recovered five ancient genomes linked to treponemal diseases, including syphilis, yaws, and bejel. The findings indicate that the Americas were a center of diversity for these diseases long before European contact. “The data clearly supports a root in the Americas for syphilis and its known relatives,” said Bos.
The introduction of syphilis to Europe likely explains the explosion of cases after 1500. European expansion, human trafficking networks, and trade routes played significant roles in the global spread of the disease. “While indigenous American groups harbored early forms of these diseases, Europeans were instrumental in spreading them around the world,” Bos explained.
Lingering debates and alternative theories
Despite strong evidence supporting the Columbian Theory, debates continue. Skeletal remains with syphilis-like lesions in pre-1492 Europe fuel the Pre-Columbian Theory, but these marks could also result from diseases like leprosy or tuberculosis. Without definitive DNA evidence, this theory remains speculative.
Another idea, the Unitarian Theory, suggests that syphilis, yaws, and bejel are variations of the same pathogen, Treponema pallidum, which adapted to different climates. Tropical regions experienced yaws, arid areas saw bejel, and colder climates endured syphilis. This theory implies that treponemal diseases have existed globally for millennia.
The Mutation or Evolutionary Theory offers yet another perspective, proposing that syphilis evolved from a non-venereal form of Treponema pallidum already present in Europe or Africa. Environmental changes, social practices, and increased trade may have triggered its mutation into a sexually transmitted infection.
While ancient DNA research provides significant insights, the full story of syphilis’s origins remains elusive. “The search will continue to define these earlier forms, and ancient DNA will surely be a valuable resource,” said Krause. “Who knows what older related diseases made it around the world in humans or other animals before the syphilis family appeared.”