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.
Conceived and designed the experiments: KNH RDF RH SK GJA. Analyzed the data: KNH FHL SK GJA. Contributed reagents/materials/analysis tools: KNH FHL SK GJA. Wrote the paper: KNH RDF SK. Involved in collecting the samples: RDF RH PNW DHC RMS SCA JT JR MK EKB FHL SK. Carried out the serological and genetic analyses: KNH FHL SK GJA.
It has been known for decades that wild baboons are naturally infected with
In the 1960s and 1970s, researchers demonstrated that wild African primates were naturally infected with
The relationship between baboon and human strains in West Africa, where the majority of past studies have been conducted, has been poorly understood for decades. Investigators have noted that baboons living in regions in which humans had historically suffered from yaws or endemic syphilis appear to have a high seroprevalence of infection with
In contrast to the considerable number of studies in West African primates, research on
Recently, Knauf
Our motivation for this study was to clarify whether treponemal disease was present in baboons at various Kenyan and Tanzanian sites other than GSNP and LMNP, given the paucity of infection in this region suggested by a previous study
Lesions in the anogenital region consistent with those described recently at Lake Manyara National Park
Country | Site | Baboon Type | Years of Collection | Troops Observed | Outward Signs | Serum Sampling Strategy | Sample seroprevalence |
Tanzania | Gombe Stream National Park |
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2003–2004 | 4 | 32/273 (11.7%) | For the most part, sexually mature animals were sampled at random, although some animals with lesions were sampled purposively. A 1∶1 sex ratio was pursued. | 5/8 (62.5%) |
Lake Manyara National Park |
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2003, 2006 | 3 | 2003: 26/390 (6.7%). 2006: 41/300 (13.7%) | See above. | 13/19 (68.4%) | |
Serengeti National Park |
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2003–2004 | 10 | 8/256 (3.1%) | See above. | 12/25 (48.0%) | |
Ngorongoro Conservation Area |
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2003–2004 | 2 | 3/70 (4.2%) | See above. | N/A |
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Mikumi National Park |
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1983, 1985 | 1 | 0/44 | All age and sex classes sampled. | 0/44 (0.0%) | |
Kenya | Masai Mara National Reserve |
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1985, 1987, 1993, 1994 | 7 | 0/63 (0.0%) | Adult males in troop sampled. | 0/63 (0.0%) |
Amboseli National Park |
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1990, 2006 | 5 | 0/48 (0.0%) | Adult males and cycling females from five social groups sampled. | 0/48 (0.0%) | |
Mosiro |
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1977 | 4 | 0/38 (0.0%) | Sampling excluded infants and nursing females. | 0/38 (0.0%) | |
Lake Magadi |
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1977 | 3 | 0/18 (0.0%) | Sampling excluded infants and nursing females. | 0/18 (0.0%) | |
Gilgil |
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1983 | 1 | 0/11 (0.0%) | Adult males in troop sampled. | 0/11 (0.0%) | |
Nanyuki |
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1977 | 3 | 0/40 (0.0%) | Sampling excluded infants and nursing females. | 23/40 (57.5%) |
Sample seroprevalence may be inflated at GSNP, LMNP, and SNP, as some baboons were purposively sampled in the serological survey. Three of eight animals in GSNP, seven of nineteen at LMNP, and five of twenty-five at SNP were included because they displayed anogenital lesions.
GSNP has a history of antibiotic treatment of affected individuals
The collection of biological samples was not permitted at this site.
During a second visit to LMNP in 2006, 300 sexually mature females and males, with a sex ratio of 1∶1, were examined in order to classify the frequency of severe disease manifestations. Up to 14.0% of animals of both sexes (14.0% females, 13.4% males) exhibited macroscopic lesions consistent with infection. In females, ulcerative lesions were frequently found around the genitals and anus, leading in some cases to a severe destruction and scarification of the outer genital structure (
Throughout the two surveys, clinical signs of infection were never observed in juvenile baboons. Clinical signs were seen in subadult males who had begun to mate with female animals.
Serum samples were taken at LMNP, GSNP, and SNP; unfortunately, no invasive sampling was permitted at NCA. Samples from all three of the affected sites were positive for
Serum samples from one additional site in Tanzania (Mikumi National Park) and six sites in Kenya (Masai Mara National Park, Amboseli National Park, Mosiro, Lake Magadi, Gilgil, and Nanyuki) were examined using the very sensitive and specific
In this study, DNA from one sample from SNP was successfully sequenced at six polymorphic regions:
Phylogenies were constructed using both Maximum Parsimony and Maximum Likelihood methods to analyze 25 polymorphisms in six concatenated regions of the
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744 | 759 | 459 | 579 | 1592 | 1964 | 1966 | 1967 | 2010 | 2101 | 2209 | 2326 | 2388 | 2382–2399 | 2405 | 2408 | 2421 | 137 | 143 | 151 | 92 | 121 | 303 | 117 | 122 |
TPC =
Deletion from nucleotide residues 2384–2398.
In this survey of wild East African baboons, we found that exposure to
This map is based on the results presented in this paper (East African sites) as well as the results in
Reports of genital-associated disease in nonhuman primates with a suspected link to
The simian strain from LMNP could not be distinguished from human subsp.
While our study offers a preliminary overview of seroprevalence and manifestations of
It is possible that the species of the baboon host has an effect upon the clinical manifestations and seroprevalence of infection. Previously, the only reports of
At present, there is no clear geographical trend differentiating affected and non-affected sites (
In conclusion, this study demonstrates that a genital ulcer-associated
The field investigations at Gombe Steam National Park (GSNP), Lake Manyara National Park (LMNP), Serengeti National Park (SNP), and Ngorongoro Conservation Area (NCA) were done by the Tanzania Wildlife Research Institute (TAWIRI), in accordance with TAWIRI's
Three-hundred and four additional serum samples from baboons examined in this study were collected at various sites in Kenya and Tanzania during the course of prior research studies. Fieldwork at Mikumi National Park was approved by the appropriate Animal Use Committees at Yale and Washington Universities as well as the Tanzanian National Scientific Research Council (now called COSTECH), TANAPA, and TAWIRI. Fieldwork at Masai Mara National Reserve and Gilgil was approved by the Animal Usage Committee of the Division of Laboratory Animal Medicine at Stanford University (Protocol # 9459) as well as the Office of the President and the Ministry of Tourism and Wildlife in Kenya. All protocols used at Amboseli National Park adhered to the laws and guidelines of Kenya (Kenya Research Permit numbers NCST 5/002/R/777 to SCA, and NCST 5/002/R/776 to JA) and were approved by the Animal Care and Use Committees at Duke University (A0840903) and Princeton University (1689) as well as the Office of the President and the Kenya Wildlife Service. Work at Mosiro, Lake Magadi, and Nanyuki was approved by the Northwestern institutional research compliance committees that oversaw animal care and use as well as the Office of the President and the Ministry of Tourism and Wildlife in Kenya. Permission to use all of the samples described in the current study was granted by the research groups who gathered them, all of which include authors of the current article. As specified above, each of these past studies had the permission of the appropriate authorities in the Kenyan or Tanzanian government as well as local landowners, where relevant.
Throughout each field study, animal welfare and ethical issues were taken into consideration during the immobilization of the baboons in order to minimize stress and discomfort, as described in greater detail for each site in the methods sections that follow.
Only data analysis was performed at Columbia University. Therefore, permission from an animal use committee was not required at this site.
A study of four protected areas in Tanzania was conducted from February 2003 to July 2004: GSNP, LMNP, SNP and NCA (
Serum sampling was also conducted at GSNP, LMNP, and SNP at this time. For the most part, samples were collected at random from adults and subadults. However, a sex-ratio of 1∶1 was attempted when choosing animals for immobilization, and if a baboon with clinical signs of infection was encountered, it was purposively sampled. Baboons were captured using remote-distance injection via cold-gas tranquilizer-gun. Baboons were temporarily immobilized using a combination of ketamine hydrochloride (10 mg/kg) (Rotex Medica GmBH, Germany) and xylazine hydrochloride (0.5 mg/kg) (Kyron Laboratories (Pty) Ltd, South Africa) following a standardized protocol. Blood was collected from the femoral vein, and after separation serum was kept frozen in liquid nitrogen. In addition, a tissue biopsy was collected from an animal at SNP, using a 6-mm biopsy punch, and stored frozen in RNAlater Solution (Ambion, Inc., Germany) for subsequent DNA analysis. During the sampling procedure, animals were captured for only a short time and returned to their group afterwards without problems.
In November 2006, a second study was conducted at LMNP to investigate the prevalence and outward signs of advanced infection in more depth. A total of 300 adult and subadult baboons (the first 150 males and first 150 females encountered) were observed using binoculars. Animals were classified as 1) clinically unaffected (no visible signs of infection); 2) clinically affected, with mild to moderate outward signs of genital ulceration (lesions consistent with infection, including small ulcers on the genitals for males and females; or 3) clinically affected with advanced signs of infection (massive genital ulceration with severe, irreversible mutilation of genital structures).
In 2007, tissue biopsies were obtained from several baboons at LMNP, using the methods described above, and stored frozen in RNAlater for subsequent DNA analysis. Briefly, baboons were temporarily immobilized using a combination of ketamine hydrochloride (10 mg/kg) and xylazine hydrochloride (0.5 mg/kg) following a standardized protocol. The capture time was brief, and animals were immediately reunited with their group.
In order to investigate the seroprevalance of
Baboons were captured by darting or trapping. The animals were tranquilized with ketamine hydrochloride, given at 10 mg/kg of the animal's body weight. Blood was drawn from the femoral vein into vacutainer tubes containing either sodium heparin or EDTA. Blood was centrifuged in order to separate plasma within eight hours of collection, and plasma was frozen in liquid nitrogen.
Animals were treated humanely throughout the study, in accordance with National Institutes of Health guidelines. Individual baboons were darted using a blowpipe and anesthetized with phencyclidine HCL (approximately 2 mg/kg/body weight). Blood samples were collected within 15 minutes of darting.
Individual baboons were captured one at a time using a hand-held blowpipe in an unobtrusive manner, with a dart bearing Telazol (4 mgl/kg), a combination of tiletamine and benzodiazepine. Blood was drawn from the saphenous vein into a serum separator tube, and serum was stored at ambient temperatures for 24–48 hours before being frozen. Darted animals were released when fully awake (after 3–4 hours) and rejoined their social group with no adverse effects. At this site, serum was diluted 1∶3 parts with RNAlater before being frozen. Control serum obtained from
Baboons were captured using dropping-door traps baited with corn. The traps were visited at least twice daily, at which time any captured animals would be sedated and removed. Captured baboons were sedated with Sernylan (Parke Davis, discontinued) using a pole syringe, then brought to camp for blood collection. Baboons in this study were processed within 24 hours of capture and released after sampling.
Sera obtained during the Tanzanian field studies were tested for
DNA extraction was performed on the tissue biopsy samples from LMNP, as well as the tissue biopsy sample gathered from SNP in 2003–2004, using the Qiagen DNEasy Blood and Tissue Kit (Valencia, CA). Extraction was performed according to the manufacture's instructions.
Nested primers were constructed around 2,352 nucleotides in six polymorphic regions that have been shown to differentiate subsp.
Gene | Primers (5′ to 3′) | Anneal. temp. °C | Product size (bp) | Source documenting polymorphisms |
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F: |
57 | 171 |
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F: |
55 | 331 |
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F: |
55 | 501 |
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55 | 556 | |
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55 | 1030 | |
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60 | 1830 | |
F: |
56 | 100 | ||
F: |
55 | 161 | ||
F: |
55 | 171 | ||
F: |
55 | 189 | ||
F: |
55 | 152 | ||
F: |
55 | 980 | ||
F: |
55 | 599 |
primers found in
primers found in
Polymorphisms which fell within regions in which no signature of recombination was detected were concatenated and aligned in ClustalX version 1.83
In Modeltest
(DOCX)
We thank Tanzania Wildlife Research Institute (TAWIRI), especially J. Keyyu; Tanzania National Parks (TANAPA), especially I.A. Lejora, T. Mlengeya and M. Kilewo; LMNP headquarter staff; the Ngorongoro Conservation Area Authority (NCAA); and the Tanzania Commission for Science and Technology (COSTECH) for their support during this study. We also thank M. Mdaki, K. Sarakikya, and E. Kihwele for their assistance in sample collection; J. Altmann, P. Whitten, T. Turner, and S. Lukehart for providing samples; J. Thomas and S. Altizer for the use of their laboratories; B. Steiner, A. Wehrend, F. J. Kaup, D.A. Collins, R.A. Muhala, A. Lawrenz, S. Tacke, and K. Maetz-Rensing for their scientific advice; J. Tesch and A. Kuss for their help with sequencing; and A. Keebaugh, L. Huynh, E. Holmes, the Altizer lab and three anonymous reviewers for their helpful comments.