Determining whether or not syphilis existed in the Old World prior to 1495 is complicated. Descriptions of a disease with similar symptoms to syphilis are found in the medical writings of Hippocrates (460-370 BC), and bone lesions have been found in pre-Columbian human remains that have been interpreted as evidence of syphilis, though this diagnosis is controversial because of the difficulty of dating the bones precisely or of distinguishing between syphilis and the other skin, bone and joint diseases caused by the Treponema pallidum bacterium- yaws, pinta, and bejel.
Seeking to introduce some clarity to the question is Kristin Harper, of Emory University in Atlanta, US, who recently published a family tree showing the evolution of the T. pallidum genome in the Public Library of Science’s Journal of Neglected Tropical Diseases. Kristin concluded that the now nearly-eradicated tropical skin disease, yaws, is very ancient and has existed in the Old World for millennia, but that syphilis is a relatively recent descendant of a strain of the disease. What is more, it most closely resembles a New World condition found until recently in Guyana, South America, suggesting that the progenitor of syphilis did indeed arise in the New World.
What remains unclear is how this tropical skin disease, associated with a tropical environment, evolved into a sexually transmitted disease in the temperate Old World. Kristin speculates that ‘a non-venereal strain, much like those we found in Guyana, may have rapidly evolved into syphilis after its introduction into cold European cities where lots of clothes were the norm and sexual practices were extremely different. There would have been strong pressure for the pathogen to adapt quickly to a new transmission mode under these conditions, and documentary evidence indicates that in the first years of the epidemic the symptoms of the disease changed rapidly, which could be consistent with rapid evolutionary change.’
The simple explanation – that a form of syphilis already existed in the New World and was transferred to the Old World by homecoming sailors, cannot be entirely ruled out, but paleopathologists believe this unlikely because some of those initially infected had not yet reached sexual maturity. ‘Because most yaws and bejel strains no longer exist to be studied’, concludes Kristin, ‘it’s not clear that we will ever have a satisfactory answer to this question, but more sequencing of the strains that we do have may shed a little more light on syphilis’s history in due course.’
This article is an extract from the full article published in World Archaeology Issue 28. Click here to subscribe