Host and environmental reservoirs of infection for bovine digital dermatitis treponemes Nicholas J. Evans a,b, *, Dorina Timofte b,g , Diana R. Isherwood a , Jennifer M. Brown a , Jonathan M. Williams b , Kenneth Sherlock c , Michael J. Lehane c , Richard D. Murray d , Richard J. Birtles e , C. Anthony Hart f , Stuart D. Carter a,b a Department of Infection Biology, Institute of Infection and Global Health, University of Liverpool, Liverpool L69 7ZJ, UK b School of Veterinary Science, University of Liverpool, Leahurst, Neston CH64 7TE, UK c Vector Group, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK d Institute of Translational Medicine, School of Veterinary Science, University of Liverpool, Leahurst, Neston CH64 7TE, UK e School of Environment & Life Sciences, University of Salford, Salford, Greater Manchester M5 4WT, UK f Department of Medical Microbiology, University of Liverpool, Liverpool L69 3GA, UK g University of Agricultural Sciences and Veterinary Medicine, ‘‘Ion Ionescu de la Brad’’ Iasi, Faculty of Veterinary Medicine, Iasi, Romania 1. Introduction Bovine digital dermatitis (BDD) is a major form of dairy cattle lameness caused by lesions in their hind feet (Blowey and Sharp, 1988). The disease is very painful and has considerable economic implications such as reduction in reproductive performance and milk yield. BDD was originally considered a polymicrobial disease, although the majority of recent research now identifies it as polytreponemal in aetiology. Cloning bacterial 16S rRNA genes indicated five phylotypes of treponemes in BDD lesions from Germany (Choi et al., 1997). Three of these phylotypes have been isolated from lesions in USA and UK (Evans et al., 2008; Stamm et al., 2002; Walker et al., 1995) and described as ‘‘Treponema medium-like’’, ‘‘Treponema Veterinary Microbiology 156 (2012) 102–109 ARTICLE INFO Article history: Received 24 May 2011 Received in revised form 23 September 2011 Accepted 27 September 2011 Keywords: Bovine digital dermatitis Spirochetes PCR Treponema ABSTRACT Bovine digital dermatitis (BDD) is a global infectious disease causing lameness of cattle and is responsible for substantial animal welfare issues and economic losses. The causative agents are considered to be spirochetal bacteria belonging to the genus Treponema, which have consistently been identified in BDD lesions worldwide. One potential means of controlling infection is the disruption of transmission; however, the infection reservoirs and transmission routes of BDD treponemes have yet to be elucidated. To address these issues, we surveyed for evidence of BDD treponeme presence in the dairy farm environment, in bovine tissues and in bovine gastrointestinal (GI) tract contents. A total of 368 samples were tested using PCR assays specific for each of three currently recognised, isolated phylotypes of BDD treponemes. All environmental samples, together with insects and GI tract content samples were negative for BDD treponeme DNA from the three phylotypes. However, we identified BDD treponemes in two non-pedal bovine regions: the oral cavity (14.3% of cattle tested) and the rectum (14.8% of cattle tested). Whilst only single phylotypes were detected in the oral cavity, two of the rectal tissues yielded DNA from more than one phylotype, with one sample yielding all three BDD treponeme phylotypes. Whilst it might be considered that direct skin to skin contact may be a major transmission route of BDD treponemes, further studies are required to characterise and determine the potential contribution of oral and rectal carriage to BDD transmission. ß 2011 Elsevier B.V. All rights reserved. * Corresponding author at: Department of Infection Biology, Institute of Infection and Global Health, Veterinary Science Building, University of Liverpool, Crown Street, Liverpool L69 7ZJ, UK. Tel.: +44 151 794 4755; fax: +44 151 794 4219. E-mail address: evansnj@liverpool.ac.uk (N.J. Evans). Contents lists available at SciVerse ScienceDirect Veterinary Microbiology journal homepage: www.elsevier.com/locate/vetmic 0378-1135/$ – see front matter ß 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.vetmic.2011.09.029