Did a Tropical Disease Cause a 15th Century Epidemic in Europe?
In the late 15th century, a mysterious disease spread across Europe, and many think it was Christopher Columbus' fault.
According to the popular hypothesis, the controversial Italian explorer and his crew triumphantly returned to Portugal in 1493 after their transatlantic journey to the Americas, returning with tales of adventure, foreign riches, and... syphilis. Marauding armies then helped spread the venereal disease across the continent.
However, a new study published to the journal Scientific Reports challenges this tidy narrative. Researchers primarily based out of the Max Planck Institute for the Science of Human History in Germany and Vilnius University in Lithuania examined plague burials in Vilnius, Lithuania dated to the 15th and 16th centuries. They were not surprised to find signs of Yersinia pestis, the bacterium that causes plague, but they were surprised to identify Treponema pallidum pertenue, the bacterium that causes yaws, a tropical infection of the skin, bones and joints. The disease's signature signs are inflamed lesions that can appear anywhere on the body which turn crusty and yellow before scarring over.
Today, yaws is readily treated with antibiotics, but in the 15th century it would have wreaked havoc.
According to the authors, "In the late 15th century, historical accounts begin to accumulate in Europe and the Middle East that describe a physically disfiguring disease seemingly unknown to medicine at the time... In subsequent decades the illness took on many names such as the “French pox” or the “Pox of Naples”, all of which were more reflective of political and social tensions of the era than biological truths."
The epidemic is commonly attributed to syphilis, caused by the bacterium Treponema pallidum pallidum, which is intimately related to the bacterium that causes yaws. It's likely that both diseases were circulating in Europe at the time, but yaws may have been more prevalent owing to its transmissibility – it spreads via direct touch while syphilis spreads via sexual contact. Moreover, as the authors write, yaws had a clear path to wide transmission in Europe from its origins in Africa.
"Increased European presence in West Africa in the mid- to late-15th century would have provided a means for intercontinental disease movement. The lure of West African gold motivated the Portuguese establishment of Elmina (modern Ghana) in 1478, though its activities quickly expanded beyond trade of minerals to include importation of African people to Europe as slaves. By the mid-sixteenth century, an estimated 10% of Lisbon’s population was of African descent. Introduction of a highly contagious skin infection such as yaws during this period could have easily led to its presence in the 20,000 strong 1494 mercenary army of Charles VIII, whose contingent was assembled from a wide recruitment of men across Europe."
Today, yaws is nowhere to be found in Europe. Almost 85% of of the 50,000 or so yearly infections occur in three countries: Ghana, Papua New Guinea, and Solomon Islands. The World Health Organization aims to eradicate the disease this decade.
Source: Giffin, K., Lankapalli, A.K., Sabin, S. et al. A treponemal genome from an historic plague victim supports a recent emergence of yaws and its presence in 15th century Europe. Sci Rep 10, 9499 (2020). https://doi.org/10.1038/s41598-020-66012-x