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Management of an outbreak of multiple equine herpesvirus type 1 abortions among vaccinated mares on a large UK Thoroughbred stud farm
  1. Sarah E Moore1,
  2. Camilla L Strang2,3,
  3. Celia M Marr4,
  4. Richard Newton2 and
  5. Ian J Cameron5
  1. 1Rossdales Hertfordshire, Rossdales, Weston, UK
  2. 2Epidemiology Unit, Animal Health Trust, Newmarket, UK
  3. 3Pathobiology and Population Sciences, Royal Veterinary College, London, UK
  4. 4Rossdales Equine Hospital, Rossdales, Newmarket, UK
  5. 5Rossdales Equine Practice, Rossdales, Newmarket, UK
  1. Correspondence to Sarah E Moore; sarah.moore{at}


An outbreak of equine herpesvirus type 1 (EHV-1) abortions on a UK Thoroughbred stud farm between February 23 and April 2, 2016, is described. The outbreak resulted in the loss of 10 Thoroughbred foals, confirmed pathologically and virologically as EHV-1 infection at postmortem. All aborting mares were vaccinated against EHV-1 according to manufacturer’s recommendations, but had contact with the index aborting mare, either as field companions or housed in the American barn at the time she and subsequent mares aborted. Control measures were implemented in accordance with the Thoroughbred Industry’s Code of Practice on recognising the index case and were maintained until the outbreak had resolved. The report illustrates that prompt investigation and management of this disease outbreak can optimise the safe return of the stud farm to normal breeding operations and highlights EHV-1’s continued potential for multiple late gestation pregnancy losses in mares, despite vaccination.

  • equine herpesvirus
  • abortion
  • outbreak management
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  • Contributors SEM was the main author and assistant veterinary surgeon involved in the outbreak. CLS performed analysis of the diagnostic results during the outbreak and wrote the diagnostics section, as well as editing the manuscript. JRN and CMM advised on outbreak management and edited the manuscript. IJC was the primary veterinary surgeon involved in the outbreak and overall supervisor of the manuscript.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement No additional data are available.

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