Treponema pallidum Infection in the Wild Baboons of East Africa: Distribution and Genetic Characterization of the Strains Responsible Kristin N. Harper 1 *, Robert D. Fyumagwa 2 , Richard Hoare 2 , Philemon N. Wambura 3 , Dorian H. Coppenhaver 4 , Robert M. Sapolsky 5,6 , Susan C. Alberts 6,7 , Jenny Tung 8,9 , Jeffrey Rogers 10 , Morris Kilewo 11 , Emmanuel K. Batamuzi 12 , Fabian H. Leendertz 13 , George J. Armelagos 14 , Sascha Knauf 15 1 Department of Environmental Health Sciences, Columbia University Medical Center, New York, New York, United States of America, 2 Wildlife Veterinary Program, Tanzania Wildlife Research Institute, Arusha, Tanzania, 3 Department of Veterinary Microbiology and Parasitology, Faculty of Veterinary Medicine, Sokoine University of Agriculture, Morogoro, Tanzania, 4 Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America, 5 Biological Sciences, Stanford University, Stanford, California, United States of America, 6 Institute of Primate Research, National Museums of Kenya, Nairobi, Kenya, 7 Department of Biology, Duke University, Durham, North Carolina, United States of America, 8 Department of Evolutionary Anthropology, Duke University, Durham, North Carolina, United States of America, 9 Population Research Institute, Duke University, Durham, North Carolina, United States of America, 10 Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas, United States of America, 11 Department of Ecology, Tanzania National Parks, Arusha, Tanzania, 12 Department of Veterinary Surgery and Theriogenology, Sokoine University of Agriculture, Morogoro, Tanzania, 13 Research Group Emerging Zoonoses, Robert Koch- Institute, Berlin, Germany, 14 Department of Anthropology, Emory University, Atlanta, Georgia, United States of America, 15 Pathology Unit, German Primate Centre, Leibniz Institute for Primate Research, Go ¨ ttingen, Germany 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. Citation: Harper KN, Fyumagwa RD, Hoare R, Wambura PN, Coppenhaver DH, et al. (2012) Treponema pallidum Infection in the Wild Baboons of East Africa: Distribution and Genetic Characterization of the Strains Responsible. PLoS ONE 7(12): e50882. doi:10.1371/journal.pone.0050882 Editor: Paul J. Planet, Columbia University, United States of America Received June 11, 2012; Accepted October 25, 2012; Published December 20, 2012 Copyright: ß 2012 Harper et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: 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. KNH was a Cancer Epidemiology Training Fellow (5-R25-CA 094061), a Robert Wood Johnson Health & Society Scholar, and a Howard Hughes Medical Institute Pre-doctoral Fellow at the time of this work. SK received support from the German Academic Exchange Program (grant No. D/06/43974), the Christian Vogel Fond 2006, World Association of Zoos and Aquariums (project No. 07002), University of Leipzig, Justis Liebig University, and the Wuppertal Zoo. The German Primate Centre, Robert-Koch-Institute, Scil Animal Care Company, Telinject Inc., and Translogistic Inc. also supported analyses. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: This project received support from the Scil Animal Care Company, Telinject Inc., and Translogistic Inc. This does not alter the authors’ adherence to all the PLOS ONE policies on sharing data and materials. * E-mail: kh2383@columbia.edu Introduction In the 1960s and 1970s, researchers demonstrated that wild African primates were naturally infected with Treponema pallidum, the bacterium that causes syphilis (subsp. pallidum), yaws (subsp. pertenue), and bejel (subsp. endemicum) in humans. Serological surveys in West Africa showed that animals in many baboon troops were seropositive for T. pallidum, with seroprevalence surpassing 60% in certain areas of Senegal and Guinea [1,2]. However, the clinical signs of infection described by researchers tended to be mild, when present at all, consisting of enlarged lymph nodes and small ulcers on the muzzle or near the armpit, which harbored high numbers of treponemes [3,4]. PLOS ONE | www.plosone.org 1 December 2012 | Volume 7 | Issue 12 | e50882