FREE SHIPPING over $40
OVER 10000 FIVE-STAR REVIEWS
5% OFF ALL SUBSCRIPTIONS
100% HAPPINESS GUARANTEE
Analyze Diet
0
Journal of equine veterinary science2023; 128; 104869; doi: 10.1016/j.jevs.2023.104869

Equine Herpesvirus-1 Outbreak During a Show-Jumping Competition: A Clinical and Epidemiological Study.

Abstract: A total of 752 horses were involved in the CES Valencia Spring Tour 2021. Due to an equine herpesvirus-1 (EHV-1) outbreak, the competition was cancelled and the site was locked down. The objective of this study was to describe epidemiological, clinical, diagnostic, and outcome data of the 160 horses remaining in Valencia. Clinical and quantitative polymerase chain reaction (qPCR) data were analysed for 60 horses in a retrospective case-control observational study. The risk of developing clinical manifestations was explored using a logistic regression approach. EHV-1 was detected by qPCR, genotyped as A2254 (ORF30) and isolated on cell culture. From the 60 horses, 50 (83.3%) showed fever, 30 horses (50%) showed no further signs and 20 (40%) showed neurological signs, with eight horses (16%) hospitalised, of which two died (3%). Stallions and geldings were six times more likely to develop EHV-1 infection compared to mares. Horses older than 9 years, or housed in the middle of the tent were more likely to develop EHV-1 myeloencephalopathy (EHM). These data show that for EHV-1 infection, the risk factor was male sex. For EHM the risk factors were age > 9-year old and location in the middle of the tent. These data highlight the crucial role of stable design, position, and ventilation in EHV-outbreaks. It also showed that PCR testing of the horses was important to manage the quarantine.
Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.
Get Full Text
Publication Date: 2023-06-18 PubMed ID: 37339699DOI: 10.1016/j.jevs.2023.104869Google Scholar: Lookup
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
LinkedInCopy
  • Observational Study
  • Veterinary
  • Journal Article

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

This research explores an outbreak of equine herpesvirus-1 (EHV-1) during a horse show in Valencia in 2021. The authors discovered that certain factors, such as the sex and age of the horse as well as their location within the stables, played a significant role in the likelihood of EHV-1 infection and the development of potentially fatal complications.

Study Context and Aims

The study was carried out in the aftermath of a significant outbreak of EHV-1 at a show-jumping competition in Valencia in 2021. The goal of the research was to gather and evaluate epidemiological, clinical, diagnostic data, and the outcome of the remaining 160 horses onsite after the competition was cancelled. The study also aimed to identify risk factors associated with the manifestation of clinical symptoms of EHV-1, including the more severe condition, EHV-1 myeloencephalopathy (EHM).

  • The researchers used quantitative polymerase chain reaction (qPCR) to test for EHV-1. The virus they detected was genotyped as A2254.
  • The data was analysed using logistic regression, a statistical model frequently used in medical and social sciences for its capacity to predict two-way outcomes.

Key Findings

The research identified a number of directives which could influence the likelihood of a horse contracting EHV-1 and developing EHM.

  • 83.3% of the 60 horses studied presented a fever, an initial sign of EHV-1 infection.
  • 50% of the horses did not develop any further symptoms, while the other half displayed neurological signs. This indicated progression to EHM.
  • Two of the eight hospitalised horses died, attributing to a mortality rate of 3% among affected horses.
  • Male horses (stallions and geldings) were six times more likely than mares to contract EHV-1.
  • Older horses (above 9 years) and horses kept in the middle of the tent were more prone to develop EHM, the severe complication of EHV-1 infection.

Implications of the Findings

The research sheds light on key risk factors that make horses more susceptible to EHV-1 infection and to progression to EHM.

  • Gender and age were identified as risk factors for infection and EHM respectively. This indicates a possible need for targeted preventative measures.
  • The significant risk associated with the horse’s location within the stables underscores the importance of stable design, arrangement and ventilation in managing EHV-1 outbreaks. This finding suggests that improvements in stable design could potentially reduce the risk of outbreaks.
  • The successful use of PCR testing also highlighted its importance in managing quarantine protocols, aiding in early detection and helping prevent virus spread.

Overall, the study contributes towards further understanding of EHV-1 and potentially developing better prevention and management strategies in the event of an outbreak.

Cite This Article

APA
Couroucé A, Normand C, Tessier C, Pomares R, Thévenot J, Marcillaud-Pitel C, Legrand L, Pitel PH, Pronost S, Lupo C. (2023). Equine Herpesvirus-1 Outbreak During a Show-Jumping Competition: A Clinical and Epidemiological Study. J Equine Vet Sci, 128, 104869. https://doi.org/10.1016/j.jevs.2023.104869

Publication

Journal of equine veterinary science
ISSN: 0737-0806
NlmUniqueID: 8216840
Country: United States
Language: English
Volume: 128
Pages: 104869

Researcher Affiliations

Couroucé, Anne
  • BIOTARGEN UR7450, Université de Caen Normandie, Caen, France; RESPE, 3 rue Nelson Mandela, Saint Contest, France; ONIRIS, CISCO-ONIRIS, Route de Gachet, Nantes, Cedex, France. Electronic address: anne.courouce@oniris-nantes.fr.
Normand, Camille
  • BIOTARGEN UR7450, Université de Caen Normandie, Caen, France; LABÉO, 1 route de Rosel, Saint Contest, France.
Tessier, Caroline
  • ONIRIS, CISCO-ONIRIS, Route de Gachet, Nantes, Cedex, France.
Pomares, Rita
  • Clinique vétérinaire, LD Le Tremoulet, Legeuvin, France.
Thévenot, Jérôme
  • Clinique vétérinaire, 1600 Roqueville, Issus, France.
Marcillaud-Pitel, Christel
  • RESPE, 3 rue Nelson Mandela, Saint Contest, France.
Legrand, Loïc
  • BIOTARGEN UR7450, Université de Caen Normandie, Caen, France; LABÉO, 1 route de Rosel, Saint Contest, France.
Pitel, Pierre-Hugues
  • LABÉO, 1 route de Rosel, Saint Contest, France.
Pronost, Stéphane
  • BIOTARGEN UR7450, Université de Caen Normandie, Caen, France; LABÉO, 1 route de Rosel, Saint Contest, France.
Lupo, Coralie
  • RESPE, 3 rue Nelson Mandela, Saint Contest, France.

MeSH Terms

  • Horses
  • Animals
  • Male
  • Female
  • Herpesvirus 1, Equid / genetics
  • Retrospective Studies
  • Horse Diseases / epidemiology
  • Case-Control Studies
  • Disease Outbreaks / veterinary
  • Herpesviridae Infections / epidemiology
  • Herpesviridae Infections / veterinary

Conflict of Interest Statement

Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Citations

This article has been cited 19 times.
  1. Tallmadge RL, Laverack M, Lejeune M, Crossley B, Diel DG. A multiplex real-time PCR assay for detection of equid herpesvirus 1 and 4. Sci Rep 2025 Oct 31;15(1):38201.
    doi: 10.1038/s41598-025-22043-wpubmed: 41173927google scholar: lookup
  2. Kambayashi Y, Bannai H, Nemoto M, Kawanishi N, Niwa H, Tsujimura K. Comparative analysis of 3 qPCR primer-probe sets for the detection of equid alphaherpesvirus 1. J Vet Diagn Invest 2026 Jan;38(1):77-83.
    doi: 10.1177/10406387251379857pubmed: 41055561google scholar: lookup
  3. Durán MC, Suazo M, Maturana A, Vargas MP, García A, Ahumada C, Pezoa A, Goehring LS, Lara F. First Equine Herpes Myeloencephalopathy (EHM) Outbreak in Chile. Animals (Basel) 2025 Aug 11;15(16).
    doi: 10.3390/ani15162344pubmed: 40867672google scholar: lookup
  4. Fiedler JM, Rosanowski S, Ayre ML, Slater JD. Horse Activity Participants' Perceptions About Practices Undertaken at Activity Venues, and Horse Welfare and Wellbeing. Animals (Basel) 2025 Jul 24;15(15).
    doi: 10.3390/ani15152182pubmed: 40804971google scholar: lookup
  5. Musoles-Cuenca B, Padilla-Blanco M, Vitale V, Lorenzo-Bermejo T, de la Cuesta-Torrado M, Ballester B, Maiques E, Rubio-Guerri C, Velloso Alvarez A. First Molecular Evidence of Equine Herpesvirus Type 1 (EHV-1) in Ocular Swabs of Clinically Affected Horses. Viruses 2025 Jun 18;17(6).
    doi: 10.3390/v17060862pubmed: 40573453google scholar: lookup
  6. Pusterla N, Lawton K, Barnum S, Flynn K, Hankin S, Runk D, Mendonsa E, Doherty T. Management of an Equine Herpesvirus-1 Outbreak During a Multi-Week Equestrian Event. Viruses 2025 Apr 24;17(5).
    doi: 10.3390/v17050608pubmed: 40431620google scholar: lookup
  7. de la Cuesta-Torrado M, Vitale V, Velloso Alvarez A, Neira-Egea P, Diss C, Cuervo-Arango J. The Effect of Vaccination Status on Total Lymphocyte Count in Horses Affected by Equine Herpes Virus-1 Myeloencephalopathy. Animals (Basel) 2025 Apr 1;15(7).
    doi: 10.3390/ani15071019pubmed: 40218411google scholar: lookup
  8. Germann JA, O'Sullivan TL, Greer AL, Spence KL. Predictors and barriers for biosecurity uptake and risk understanding among Ontario horse owners. Can Vet J 2025 Mar;66(3):288-297.
    pubmed: 40070939
  9. de la Cuesta-Torrado M, Velloso Alvarez A, Santiago-Llorente I, Armengou L, Nieto F, Ríos J, Cruz-López F, Jose-Cunilleras E. Risk Factors and Long-Term Outcomes in Horses After the 2021 Outbreak of Equine Herpesvirus 1 Myeloencephalopathy, Valencia, Spain. J Vet Intern Med 2025 Mar-Apr;39(2):e70040.
    doi: 10.1111/jvim.70040pubmed: 40055829google scholar: lookup
  10. de la Cuesta-Torrado M, Velloso Alvarez A, Cárdenas-Rebollo JM, Neira-Egea P, Vitale V, Cuervo-Arango J. Comparison of clinical variables and outcome of 2 natural equine herpesvirus myeloencephalopathy outbreaks induced by equine herpesvirus-1 A2254/N752 strain in sport horses. J Vet Intern Med 2025 Jan-Feb;39(1):e17287.
    doi: 10.1111/jvim.17287pubmed: 39778904google scholar: lookup
  11. Pusterla N, Lawton K, Barnum S, Ross K, Purcell K. Investigation of an Outbreak of Equine Herpesvirus-1 Myeloencephalopathy in a Population of Aged Working Equids. Viruses 2024 Dec 21;16(12).
    doi: 10.3390/v16121963pubmed: 39772269google scholar: lookup
  12. Khan A, Olajide E, Friedrich M, Holt A, Goehring LS. Evaluation of Non-Invasive Sampling Techniques for the Molecular Surveillance of Equid Herpesviruses in Yearling Horses. Viruses 2024 Jul 7;16(7).
    doi: 10.3390/v16071091pubmed: 39066254google scholar: lookup
  13. Hu Y, Wu G, Jia Q, Zhang B, Sun W, Sa R, Zhang S, Cai W, Jarhen, Ran D, Liu J. Development of a live attenuated vaccine candidate for equid alphaherpesvirus 1 control: a step towards efficient protection. Front Immunol 2024;15:1408510.
    doi: 10.3389/fimmu.2024.1408510pubmed: 39021566google scholar: lookup
  14. Öhrmalm J, Cholleti H, Theelke AK, Berg M, Gröndahl G. Divergent strains of EHV-1 in Swedish outbreaks during 2012 to 2021. BMC Vet Res 2024 Jun 22;20(1):270.
    doi: 10.1186/s12917-024-04096-7pubmed: 38909196google scholar: lookup
  15. Normand C, Thieulent CJ, Fortier C, Sutton G, Senamaud-Beaufort C, Jourdren L, Blugeon C, Vidalain PO, Pronost S, Hue ES. A Screening Study Identified Decitabine as an Inhibitor of Equid Herpesvirus 4 That Enhances the Innate Antiviral Response. Viruses 2024 May 8;16(5).
    doi: 10.3390/v16050746pubmed: 38793627google scholar: lookup
  16. de la Cuesta-Torrado M, Velloso Alvarez A, Neira-Egea P, Cuervo-Arango J. Long-term performance of show-jumping horses and relationship with severity of ataxia and complications associated with myeloencephalopathy caused by equine herpes virus-1. J Vet Intern Med 2024 May-Jun;38(3):1799-1807.
    doi: 10.1111/jvim.17070pubmed: 38609161google scholar: lookup
  17. Lunn DP, Burgess BA, Dorman DC, Goehring LS, Gross P, Osterrieder K, Pusterla N, Soboll Hussey G. Updated ACVIM consensus statement on equine herpesvirus-1. J Vet Intern Med 2024 May-Jun;38(3):1290-1299.
    doi: 10.1111/jvim.17047pubmed: 38497217google scholar: lookup
  18. White N, Pelzel-McCluskey A. Cross-Sectional Survey of Horse Owners to Assess Their Knowledge and Use of Biosecurity Practices for Equine Infectious Diseases in the United States. Animals (Basel) 2023 Nov 17;13(22).
    doi: 10.3390/ani13223550pubmed: 38003167google scholar: lookup
  19. Lawton K, Runk D, Hankin S, Mendonsa E, Hull D, Barnum S, Pusterla N. Detection of Selected Equine Respiratory Pathogens in Stall Samples Collected at a Multi-Week Equestrian Show during the Winter Months. Viruses 2023 Oct 11;15(10).
    doi: 10.3390/v15102078pubmed: 37896855google scholar: lookup
Subscribe to our newsletter
Join 99,780 horse owners like you who receive our email updates on horse health and nutrition.