The Origin of Syphilis

Syphilis is first clearly seen in Europe in 1495, when it appeared as a plague (though it was not "the blague" ... Yersinia pestis) among Charles VIII's troops. When these troops went home shortly after the fall of Naples, they brought this disease with them, staring an epidemic. The level of mortality in Europe was truly devastating. Is it the case that syphilis was brought to Europe by Columbus and his men just prior to the plague-like outbreak of 1495?

The origin of syphilis has been debated for years, really since the actual 1495 event itself. Some researchers have asserted that syphilis is present in the writings of Hippocrates, placing it squarely in the old world thousands of years prior to Columbus. Others, as suggested above, have argued that Columbus brought syphilis over to the Old World . A third (Crosby's "combination theory") asserts, essentially, that syphilis is both an Old World and New World disease, and that the history of the disease is complicated by the innately complex relationship between any pathogen and human populations with variable immunities, both of which tend to evolve.

A new paper is being published as we speak in PLoS Neglected Tropical Diseases, by Harper et al , called "On the Origin of the Treponematoses: A Phylogenetic Approach." Studiously ignoring Crosby's discussion (and I'm sure there is some unseemly story of academic infighting to explain that), the paper examines the Old World vs. New World origins hypotheses.

Here is the author's summary from the paper:

For 500 years, controversy has raged around the origin of T. pallidum subsp. pallidum, the bacterium responsible for syphilis. Did Christopher Columbus and his men introduce this pathogen into Renaissance Europe, after contracting it during their voyage to the New World? Or does syphilis have a much older history in the Old World? This paper represents the first attempt to use a phylogenetic approach to solve this question. In addition, it clarifies the evolutionary relationships between the pathogen that causes syphilis and the other T. pallidum subspecies, which cause the neglected tropical diseases yaws and endemic syphilis. Using a collection of pathogenic Treponema strains that is unprecedented in size, we show that yaws appears to be an ancient infection in humans while venereal syphilis arose relatively recently in human history. In addition, the closest relatives of syphilis-causing strains identified in this study were found in South America, providing support for the Columbian theory of syphilis's origin.

The authors looked at 21 strains of the bacterium Treponematoses pallidum and conducted a detailed genetic (phylogenetic) study of these genomes to come to the conclusion that syphilis originates in the new world. However, a commentary on the paper, published along side it in PLoS, brings the conclusion into question. The commentary by Lukehart and Norris notes that the genetic data from the New World (which the main paper's authors assert points to a New World origin) is weak. In addition, there are problems, partly outlined in the commentary and partly fairly obvious to anyone who reads the paper, that the issue of evolutionary change in both the pathogens and the humans who harbor them has not been sufficiently taken into account.

In my view, a detailed phylogenetic study such as the one presented here is fundamentally important, but is very unlikely on its own to definitively answer the question of origin and evolution of syphilis.

Need more research...