On the origin of the treponematoses: a phylogenetic approach

Background

Since the first recorded epidemic of syphilis in 1495, controversy has surrounded the origins of the bacterium Treponema pallidum subsp. pallidum and its relationship to the pathogens responsible for the other treponemal diseases: yaws, endemic syphilis, and pinta. Some researchers have argued that the syphilis-causing bacterium, or its progenitor, was brought from the New World to Europe by Christopher Columbus and his men, while others maintain that the treponematoses, including syphilis, have a much longer history on the European continent.

Methodology/Principal Findings

We applied phylogenetics to this problem, using data from 21 genetic regions examined in 26 geographically disparate strains of pathogenic Treponema. Of all the strains examined, the venereal syphilis-causing strains originated most recently and were more closely related to yaws-causing strains from South America than to other non-venereal strains. Old World yaws-causing strains occupied a basal position on the tree, indicating that they arose first in human history, and a simian strain of T. pallidum was found to be indistinguishable from them.

Conclusions/Significance

Our results lend support to the Columbian theory of syphilis's origin while suggesting that the non-sexually transmitted subspecies arose earlier in the Old World. This study represents the first attempt to address the problem of the origin of syphilis using molecular genetics, as well as the first source of information regarding the genetic make-up of non-venereal strains from the Western hemisphere.

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.

Pinta in Austria (or Cuba?): import of an extinct disease?

BACKGROUND

Pinta, 1 of the 3 nonvenereal treponematoses, is supposed to be extinct in most areas in South and Central America, where it was once endemic. Only scattered foci may still remain in remote areas in the Brazilian rain forest, and the last case from Cuba was reported in 1975.

OBSERVATION

A native Austrian woman, who had lived for 7 years in Cuba and was married to a Cuban native, developed a singular psoriasiform plaque on her trunk and several brownish papulosquamous lesions on her palms and soles during a visit to her home in Austria. Positive serological findings for active syphilis and the detection of spirochetes in the trunk lesion indicated early secondary syphilis, but an extensive case history and the clinical appearance fulfilled all criteria for pinta.

CONCLUSION

The acquisition of a distinct clinical entity, pinta, in a country where it was formerly endemic but now is believed to be extinct raises the question of whether the disease is in fact extinct or whether syphilis and pinta are so similar that no definite distinction is possible in certain cases.