Treponema pallidum Infection in the Wild Baboons of East Africa: Distribution and Genetic Characterization of the Strains Responsible

• Type of Material: Article
• Authors: Kristin N. Harper, Columbia University; Robert D. Fyumagwa, Tanzania Wildlife Research Institute; Richard Hoare, Tanzania Wildlife Research Institute; Philemon N. Wambura, Sokoine University of Agriculture; Dorian H. Coppenhaver, University of Texas Medical Branch; Robert M. Sapolsky, Stanford University; Susan C. Alberts, National Museums of Kenya; Jenny Tung, Duke University; Jeffrey Rogers, Baylor College of Medicine; Morris Kilewo, Tanzania National Parks; Emmanuel K. Batamuzi, Sokoine University of Agriculture; Fabian H. Leendertz, Robert Koch-Institute; George Armelagos, Emory University; Sascha Knauf, Leibniz Institute for Primate Research
• Language: English
• Date: 2012-12-20
• Publisher: Public Library of Science (PLoS)
• Publication Version: Final Published Version
• Copyright Statement: © 2012 Harper et al
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1371/journal.pone.0050882
• Title of Journal or Parent Work: PLoS One
• Volume: 7
• Issue: 12
• Grant/Funding Information: This project was supported by dissertation improvement grants from the National Science Foundation (Award Number 0622399) and the Wenner-Gren Foundation to KNH as well as by The Messerli Foundation of Switzerland.
• Keywords: structural damage; yaws; syphilis; bejel; Treponema pallidum; polymorphic region; genetic sequence; baboon; serology; Kenya; Tanzania; genital lesions; bacterium; macroscopic observation
• Research Categories: Biology, Zoology

Abstract

It has been known for decades that wild baboons are naturally infected with Treponema pallidum, the bacterium that causes the diseases syphilis (subsp. pallidum), yaws (subsp. pertenue), and bejel (subsp. endemicum) in humans. Recently, a form of T. pallidum infection associated with severe genital lesions has been described in wild baboons at Lake Manyara National Park in Tanzania. In this study, we investigated ten additional sites in Tanzania and Kenya using a combination of macroscopic observation and serology, in order to determine whether the infection was present in each area. In addition, we obtained genetic sequence data from six polymorphic regions using T. pallidum strains collected from baboons at two different Tanzanian sites. We report that lesions consistent with T. pallidum infection were present at four of the five Tanzanian sites examined, and serology was used to confirm treponemal infection at three of these. By contrast, no signs of treponemal infection were observed at the six Kenyan sites, and serology indicated T. pallidum was present at only one of them. A survey of sexually mature baboons at Lake Manyara National Park in 2006 carried out as part of this study indicated that roughly ten percent displayed T. pallidum-associated lesions severe enough to cause major structural damage to the genitalia. Finally, we found that T. pallidum strains from Lake Manyara National Park and Serengeti National Park were genetically distinct, and a phylogeny suggested that baboon strains may have diverged prior to the clade containing human strains. We conclude that T. pallidum infection associated with genital lesions appears to be common in the wild baboons of the regions studied in Tanzania. Further study is needed to elucidate the infection's transmission mode, its associated morbidity and mortality, and the relationship between baboon and human strains.