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Journal of veterinary internal medicine2024; 38(3); 1892-1905; doi: 10.1111/jvim.17016

Pharmacologic interventions for the treatment of equine herpesvirus-1 in domesticated horses: A systematic review.

Abstract: Equine herpes virus type 1 (EHV-1) infection in horses is associated with upper respiratory disease, neurological disease, abortions, and neonatal death. Objective: Does pharmacological therapy decrease either the incidence or severity of disease or infection caused by EHV-1 in domesticated horses? Methods: A systematic review was preformed searching AGRICOLA, CAB Abstracts, Cochrane, PubMed, Web of Science, and WHO Global Health Index Medicus Regional Databases to identify articles published before February 15, 2021. Selection criteria were original research reports published in peer reviewed journals, and studies investigating in vivo use of therapeutic agents for prevention or treatment of EHV-1 in horses. Outcomes assessed included measures related to clinical outcomes that reflect symptomatic EHV-1 infection or virus infection. We evaluated risk of bias and performed a GRADE evaluation of the quality of evidence for interventions. Results: A total of 7009 unique studies were identified, of which 9 met the inclusion criteria. Two studies evaluated valacyclovir or small interfering RNAs, and single studies evaluated the use of a Parapoxvirus ovis-based immunomodulator, human alpha interferon, an herbal supplement, a cytosine analog, and heparin. The level of evidence ranged between randomized controlled studies and observational trials. The risk of bias was moderate to high and sample sizes were small. Most studies reported either no benefit or minimal efficacy of the intervention tested. Conclusions: Our review indicates minimal or limited benefit either as a prophylactic or post-exposure treatment for any of the studied interventions in the mitigation of EHV-1-associated disease outcome.
© 2024 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC on behalf of American College of Veterinary Internal Medicine.
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Publication Date: 2024-02-21 PubMed ID: 38380685PubMed Central: PMC11099759DOI: 10.1111/jvim.17016Google Scholar: Lookup
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  • Systematic Review
  • 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.

Overview

  • This research article systematically reviews existing studies to determine whether pharmacological treatments reduce the incidence or severity of equine herpesvirus-1 (EHV-1) infection in domesticated horses.
  • The review concludes that available pharmacologic interventions show minimal or limited benefit for preventing or treating EHV-1-related disease outcomes.

Background

  • Equine herpesvirus type 1 (EHV-1) is a significant pathogen in horses causing upper respiratory illness, neurological disease, abortions in pregnant mares, and death of newborn foals.
  • Due to the serious clinical consequences of EHV-1 infections, effective treatments to reduce disease severity or infection rates are needed.

Objective

  • The primary question was: Does pharmacological therapy decrease the incidence or severity of EHV-1 infection or related disease in domesticated horses?

Methods

  • A systematic literature search was conducted across multiple databases: AGRICOLA, CAB Abstracts, Cochrane, PubMed, Web of Science, and WHO Global Health Index Medicus Regional Databases.
  • Articles published before February 15, 2021, were considered.
  • Inclusion criteria:
    • Original research published in peer-reviewed journals.
    • Studies investigating in vivo use of therapeutic agents for prevention or treatment of EHV-1 infection in horses.
  • Outcomes assessed were clinical measures indicating symptomatic EHV-1 infection or virus presence.
  • Risk of bias in studies was evaluated, and the GRADE approach was used to assess the quality of evidence for interventions.

Results

  • From 7009 unique studies identified, only 9 met all inclusion criteria.
  • Interventions evaluated in these studies included:
    • Valacyclovir (antiviral drug) – 2 studies
    • Small interfering RNAs (siRNAs) – 2 studies
    • Parapoxvirus ovis-based immunomodulator – 1 study
    • Human alpha interferon – 1 study
    • Herbal supplement – 1 study
    • Cytosine analog (antiviral agent) – 1 study
    • Heparin (anticoagulant with potential anti-inflammatory effects) – 1 study
  • The types of studies included ranged from randomized controlled trials to observational trials.
  • Risk of bias assessment showed moderate to high risk, indicating potential limitations in study design or execution.
  • Most studies had small sample sizes, limiting the power to detect significant treatment effects.
  • The majority of studies either reported no benefit or only minimal efficacy of the pharmacologic agents tested in preventing or mitigating EHV-1 infection or disease severity.

Conclusions

  • Current pharmacologic interventions do not demonstrate strong or consistent evidence of effectiveness as either preventive or post-exposure treatments against EHV-1 in horses.
  • There is limited benefit observed from the tested drugs and immunomodulatory agents in controlling the clinical consequences of EHV-1 infection.
  • Further well-designed, larger-scale controlled studies are required to better evaluate potential therapeutic options.
  • Until such evidence emerges, management of EHV-1 infections relies primarily on supportive care and prevention strategies rather than pharmacologic treatment.

Cite This Article

APA
Goehring L, Dorman DC, Osterrieder K, Burgess BA, Dougherty K, Gross P, Neinast C, Pusterla N, Soboll-Hussey G, Lunn DP. (2024). Pharmacologic interventions for the treatment of equine herpesvirus-1 in domesticated horses: A systematic review. J Vet Intern Med, 38(3), 1892-1905. https://doi.org/10.1111/jvim.17016

Publication

Journal of veterinary internal medicine
ISSN: 1939-1676
NlmUniqueID: 8708660
Country: United States
Language: English
Volume: 38
Issue: 3
Pages: 1892-1905

Researcher Affiliations

Goehring, Lutz
  • University of Kentucky, College of Agriculture, Food and Environment, Maxwell H. Gluck Equine Research Center, 1400 Nicholasville Road, Lexington, Kentucky 40546-0099, USA.
Dorman, David C
  • College of Veterinary Medicine, North Carolina State University, 1060 William Moore Drive, Raleigh, North Carolina 27607, USA.
Osterrieder, Klaus
  • Institut für Virologie, Freie Universität Berlin, Robert-von-Ostertag-Str. 7, 14163 Berlin, Germany.
Burgess, Brandy A
  • College of Veterinary Medicine, University of Georgia, 2200 College Station Road, Athens, Georgia 30602, USA.
Dougherty, Kelsie
  • College of Veterinary Medicine, North Carolina State University, 1060 William Moore Drive, Raleigh, North Carolina 27607, USA.
Gross, Peggy
  • College of Veterinary Medicine, North Carolina State University, 1060 William Moore Drive, Raleigh, North Carolina 27607, USA.
Neinast, Claire
  • College of Veterinary Medicine, North Carolina State University, 1060 William Moore Drive, Raleigh, North Carolina 27607, USA.
Pusterla, Nicola
  • School of Veterinary Medicine, University of California, Davis, One Garrod Drive, Davis, California 95616, USA.
Soboll-Hussey, Gisela
  • College of Veterinary Medicine, Michigan State University, Veterinary Medical Center, Room G331, 784 Wilson Road, East Lansing, Michigan 48824, USA.
Lunn, David P
  • School of Veterinary Science, University of Liverpool, Leahurst Campus, Chester High Road, Neston CH64 7TE, United Kingdom.

MeSH Terms

  • Animals
  • Horses
  • Herpesvirus 1, Equid / drug effects
  • Horse Diseases / drug therapy
  • Horse Diseases / virology
  • Herpesviridae Infections / veterinary
  • Herpesviridae Infections / drug therapy
  • Antiviral Agents / therapeutic use
  • Valacyclovir / therapeutic use

Conflict of Interest Statement

Authors declare no conflict of interest.

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Citations

This article has been cited 6 times.
  1. 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).
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