title: Polymerase chain reaction-based national surveillance programme to determine the distribution and prevalence of Taylorella equigenitalis in South African horses.
abstract: BACKGROUND
  The response to the first outbreak of contagious equine metritis in South Africa included pioneering a web-based platform to coordinate key aspects of a national, real-time polymerase chain reaction (qPCR)-based stallion screening programme to determine the distribution and prevalence of Taylorella equigenitalis in stallions and exposed mares.
  
  
  OBJECTIVE
  To define the hypothesised pre-existing status of T. equigenitalis in the South African equine population and progression of the epidemiological investigation via the implementation of a molecular diagnostic-based surveillance programme.
  
  
  METHODS
  Retrospective case series.
  
  
  METHODS
  Screening for T. equigenitalis was via a qPCR assay on genital swabs obtained from predilection sites in stallions and mares with subsequent confirmation using bacterial culture according to prescribed methods.
  
  
  RESULTS
  The initial outbreak investigation identified 4 horses including the index stallion and mare. Traceback of in-contact horses identified 26 horses, including a subpopulation focus at the South African Lipizzaner Centre where 24/33 resident stallions tested positive for T. equigenitalis on qPCR. The national screening programme identified an additional 9 stallions. A total of 39 horses (36 stallions and 3 mares) tested positive for T. equigenitalis by qPCR and T. equigenitalis was isolated from 23 of these stallions and 2 of these mares. In addition to the index property, an artificial breeding centre where the index case was first identified, an additional 12 properties with infected horses were identified in 3/9 provinces. Horses on 11 of these 12 properties were directly linked to the index property. Two incidents of T. equigenitalis transmission associated with artificial insemination were recorded.
  
  
  CONCLUSIONS
  T. equigenitalis was present in a subpopulation focus within the South African horse population prior to the outbreak identification in April 2011. Horizontal fomite-associated spread was the most probable route of transmission between stallions. The targeted surveillance of stallions and exposed mares using a qPCR-based screening programme expedited investigation of the distribution and prevalence of T. equigenitalis infection in South African horses. The application of qPCR provided a sensitive and practical screening test for identification of T. equigenitalis-positive animals as part of an emergency response to the first identified cases of T. equigenitalis infection in South African horses.
authors.affiliation: Section of Reproduction, Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa.
authors.forename: C E
authors.initials: CE
authors.lastname: May
authors.affiliation: Equine Research Centre, University of Pretoria, Onderstepoort, South Africa.
authors.forename: A J
authors.initials: AJ
authors.lastname: Guthrie
authors.affiliation: Companion Animal Clinical Studies Department, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa.
authors.forename: B
authors.initials: B
authors.lastname: Keys
authors.affiliation: Equine Research Centre, University of Pretoria, Onderstepoort, South Africa.
authors.forename: C
authors.initials: C
authors.lastname: Joone
authors.affiliation: Equine Research Centre, University of Pretoria, Onderstepoort, South Africa.
authors.forename: M
authors.initials: M
authors.lastname: Monyai
authors.affiliation: Section of Reproduction, Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa.
authors.forename: M L
authors.initials: ML
authors.lastname: Schulman
mesh_terms: D000818:Animals; D005260:Female; D016905:Gram-Negative Bacterial Infections / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D006734:Horse Diseases / Q000453:epidemiology / Q000382:microbiology*; D006736:Horses; D008297:Male; D016133:Polymerase Chain Reaction / Q000662:veterinary*; D015231:Sexually Transmitted Diseases, Bacterial / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D013019:South Africa / Q000453:epidemiology; D020625:Taylorella equigenitalis / Q000302:isolation & purification*
keywords: Taylorella equigenitalis; fomite transmission; horse; qPCR