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Equine veterinary journal2001; 33(2); 191-196; doi: 10.1111/j.2042-3306.2001.tb00600.x

Neurological disease associated with EHV-1-infection in a riding school: clinical and virological characteristics.

Abstract: An outbreak of neurological disease caused by EHV-1 infection is described with emphasis on diagnosis and prognosis for recumbent horses. In April 1995, an outbreak of the neurological form of Equine herpesvirus type 1 (EHV-1) occurred in a well-managed riding school with 41 horses: 34 horses showed a temperature spike and 20 some degree of neurological signs, of which 10 were nursed intensively in the indoor arena of the riding school for 3 to 20 days, 8 having to be maintained in slings for 2-18 days, while 9 needed bladder catheterisation b.i.d. for 2-16 days. Within the first 3 days, one horse was subjected to euthanasia and another horse died. Postmortem examination revealed a mild vasculitis with perivascular mononuclear cuffing and axonal degeneration in the central nervous system. Clinical diagnosis was confirmed by serology and virology: 28 horses seroconverted in one or more tests during the outbreak, whereas 12 had already high CF and SN titres in the first sample, suggestive of recent infection. Virus was isolated from nasal swabs of 4 horses, and identified as EHV-1 with type-specific monoclonal antibodies. Restriction enzyme analysis revealed that the EHV-1 strains from this outbreak belonged to genome type EHV-1.IP. The electropherotypes were identical to those from another, epidemiologically unrelated, outbreak of neurological disease 2 months earlier. The timing of the temperature spikes and seroconversions indicated that the infection was probably introduced by a horse purchased 3 weeks before neurological signs occurred. At follow-up one year later, the 10 horses that showed mild neurological signs had recovered completely. Of the 8 horses that survived intensive care, 3 had returned to around their former performance level (2 of which had been in slings), while the other 5 had become pasture-sound. At follow-up 4 years later, all pasture-sound horses had been subjected to euthanasia because of persistent mild ataxia and incontinence. In conclusion, the prognosis for recumbent horses due to EHV-1 infection is grave. For virological diagnosis, extensive and strategic sampling of febrile in-contact horses is required, and the EHV-1-specific glycoprotein G (gG) ELISA is a valuable tool for specific serological diagnosis of EHV-1 infection causing neurological disease.
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Publication Date: 2001-03-27 PubMed ID: 11266070DOI: 10.1111/j.2042-3306.2001.tb00600.xGoogle Scholar: Lookup
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  • 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 a disease outbreak among horses in a riding school caused by the Equine herpesvirus type 1 (EHV-1) infection and studies the clinical and virological components of the disease, including the diagnosis and prognosis for recumbent horses.

Research Context and Objective

  • The research describes an outbreak of neurological disease in a riding school with 41 horses, assumed to be caused by the Equine herpesvirus type 1 (EHV-1) infection.
  • The main focus of the study was to investigate the clinical manifestations of the disease and identify its potential prognosis, particularly in the case of recumbent or downed horses who were unable to rise to their feet.

Methodology and Findings

  • During the outbreak, 34 horses showed a temperature spike and 20 displayed various neurological signs, with 10 requiring intensive care.
  • Diagnosis of the disease was confirmed via serologyโ€”a test that measures the concentration of antibodies in bloodโ€”and virology, studying the characteristics of the virus.
  • The virus was isolated from nasal swabs from four horses and was identified to be EHV-1 using particular monoclonal antibodies. Further analysis showed that the EHV-1 strains belonged to the genome type EHV-1.IP.
  • The virus associated with the outbreak was observed to be identical to another disease outbreak that had occurred two months earlier; however, the two events were not epidemiologically related.

Prognosis and Follow-up

  • One year after the outbreak, horses that displayed minor neurological signs had recovered entirely. However, despite surviving intensive care, only three of eight horses returned to their previous performance levels, with the rest becoming “pasture-sound”โ€”fit for light work or grazing but not for riding or driving.
  • After another three years, all pasture-sound horses had to be euthanised due to ongoing light uncoordination (ataxia) and incontinence.

Conclusion and Implications

  • The research confirmed the serious prognosis for recumbent horses affected by EHV-1, highlighting the importance of thorough and strategic sampling of febrile horses for effective virological diagnosis.
  • The research also suggested the EHV-1-specific glycoprotein G (gG) ELISA test as a valuable tool for the specific serological diagnosis of EHV-1 infection leading to neurological disease.

Cite This Article

APA
van Maanen C, Sloet van Oldruitenborgh-Oosterbaan MM, Damen EA, Derksen AG. (2001). Neurological disease associated with EHV-1-infection in a riding school: clinical and virological characteristics. Equine Vet J, 33(2), 191-196. https://doi.org/10.1111/j.2042-3306.2001.tb00600.x

Publication

Equine veterinary journal
ISSN: 0425-1644
NlmUniqueID: 0173320
Country: United States
Language: English
Volume: 33
Issue: 2
Pages: 191-196

Researcher Affiliations

van Maanen, C
  • Animal Health Service, Deventer, The Netherlands.
Sloet van Oldruitenborgh-Oosterbaan, M M
    Damen, E A
      Derksen, A G

        MeSH Terms

        • Animals
        • Ataxia / veterinary
        • Disease Outbreaks / veterinary
        • Enzyme-Linked Immunosorbent Assay / veterinary
        • Female
        • Herpesviridae Infections / epidemiology
        • Herpesviridae Infections / veterinary
        • Herpesvirus 1, Equid / isolation & purification
        • Horse Diseases / blood
        • Horse Diseases / epidemiology
        • Horse Diseases / pathology
        • Horses
        • Male
        • Nasopharynx / virology
        • Nervous System Diseases / epidemiology
        • Nervous System Diseases / veterinary
        • Netherlands / epidemiology
        • Prevalence
        • Recreation

        Citations

        This article has been cited 18 times.
        1. Klouth E, Zablotski Y, Petersen JL, de Bruijn M, Grรถndahl G, Mรผller S, Goehring LS. Epidemiological Aspects of Equid Herpesvirus-Associated Myeloencephalopathy (EHM) Outbreaks. Viruses 2022 Nov 21;14(11).
          doi: 10.3390/v14112576pubmed: 36423188google scholar: lookup
        2. Pusterla N, Barnum S, Young A, Mendonsa E, Lee S, Hankin S, Brittner S, Finno CJ. Molecular Monitoring of EHV-1 in Silently Infected Performance Horses through Nasal and Environmental Sample Testing. Pathogens 2022 Jun 24;11(7).
          doi: 10.3390/pathogens11070720pubmed: 35889966google scholar: lookup
        3. Price D, Barnum S, Mize J, Pusterla N. Investigation of the Use of Non-Invasive Samples for the Molecular Detection of EHV-1 in Horses with and without Clinical Infection. Pathogens 2022 May 13;11(5).
          doi: 10.3390/pathogens11050574pubmed: 35631095google scholar: lookup
        4. Nielsen SS, Alvarez J, Bicout DJ, Calistri P, Canali E, Drewe JA, Garin-Bastuji B, Gonzales Rojas JL, Gortรกzar C, Herskin M, Michel V, Miranda Chueca Mร, Roberts HC, Padalino B, Pasquali P, Spoolder H, Stรฅhl K, Calvo AV, Viltrop A, Winckler C, Carvelli A, Paillot R, Broglia A, Kohnle L, Baldinelli F, Van der Stede Y. Assessment of listing and categorisation of animal diseases within the framework of the Animal Health Law (Regulation (EU) No 2016/429): infection with Equine Herpesvirus-1. EFSA J 2022 Jan;20(1):e07036.
          doi: 10.2903/j.efsa.2022.7036pubmed: 35035581google scholar: lookup
        5. Klouth E, Zablotski Y, Goehring LS. Apparent Breed Predilection for Equid Herpesvirus-1-Associated Myeloencephalopathy (EHM) in a Multiple-Breed Herd. Pathogens 2021 Apr 29;10(5).
          doi: 10.3390/pathogens10050537pubmed: 33947126google scholar: lookup
        6. Laval K, Poelaert KCK, Van Cleemput J, Zhao J, Vandekerckhove AP, Gryspeerdt AC, Garrรฉ B, van der Meulen K, Baghi HB, Dubale HN, Zarak I, Van Crombrugge E, Nauwynck HJ. The Pathogenesis and Immune Evasive Mechanisms of Equine Herpesvirus Type 1. Front Microbiol 2021;12:662686.
          doi: 10.3389/fmicb.2021.662686pubmed: 33746936google scholar: lookup
        7. Stasiak K, Dunowska M, Rola J. Outbreak of equid herpesvirus 1 abortions at the Arabian stud in Poland. BMC Vet Res 2020 Oct 6;16(1):374.
          doi: 10.1186/s12917-020-02586-ypubmed: 33023592google scholar: lookup
        8. Tallmadge RL, ลฝygelytฤ— E, Van de Walle GR, Kristie TM, Felippe MJB. Effect of a Histone Demethylase Inhibitor on Equine Herpesvirus-1 Activity In Vitro. Front Vet Sci 2018;5:34.
          doi: 10.3389/fvets.2018.00034pubmed: 29594155google scholar: lookup
        9. Stasiak K, Rola J, Ploszay G, Socha W, Zmudzinski JF. Detection of the neuropathogenic variant of equine herpesvirus 1 associated with abortions in mares in Poland. BMC Vet Res 2015 May 1;11:102.
          doi: 10.1186/s12917-015-0416-7pubmed: 25929692google scholar: lookup
        10. Walter J, Seeh C, Fey K, Bleul U, Osterrieder N. Clinical observations and management of a severe equine herpesvirus type 1 outbreak with abortion and encephalomyelitis. Acta Vet Scand 2013 Mar 5;55(1):19.
          doi: 10.1186/1751-0147-55-19pubmed: 23497661google scholar: lookup
        11. Garrรฉ B, Shebany K, Gryspeerdt A, Baert K, van der Meulen K, Nauwynck H, Deprez P, De Backer P, Croubels S. Pharmacokinetics of acyclovir after intravenous infusion of acyclovir and after oral administration of acyclovir and its prodrug valacyclovir in healthy adult horses. Antimicrob Agents Chemother 2007 Dec;51(12):4308-14.
          doi: 10.1128/AAC.00116-07pubmed: 17846132google scholar: lookup
        12. Nugent J, Birch-Machin I, Smith KC, Mumford JA, Swann Z, Newton JR, Bowden RJ, Allen GP, Davis-Poynter N. Analysis of equid herpesvirus 1 strain variation reveals a point mutation of the DNA polymerase strongly associated with neuropathogenic versus nonneuropathogenic disease outbreaks. J Virol 2006 Apr;80(8):4047-60.
          doi: 10.1128/JVI.80.8.4047-4060.2006pubmed: 16571821google scholar: lookup
        13. Frampton AR Jr, Smith PM, Zhang Y, Grafton WD, Matsumura T, Osterrieder N, O'Callaghan DJ. Meningoencephalitis in mice infected with an equine herpesvirus 1 strain KyA recombinant expressing glycoprotein I and glycoprotein E. Virus Genes 2004 Aug;29(1):9-17.
          doi: 10.1023/B:VIRU.0000032785.19420.14pubmed: 15215680google scholar: lookup
        14. Cooper CJ, Arroyo LG, Hammermueller JD, Botts MM, Pearl DL, Wootton SK, Lillie BN. Molecular prevalence of equine alphaherpesvirus-1 shedding in healthy broodmares in Ontario. Can J Vet Res 2026 Jan;90(1):16-24.
          pubmed: 41585008
        15. Durรกn MC, Suazo M, Maturana A, Vargas MP, Garcรญa 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
        16. 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
        17. de la Cuesta-Torrado M, Velloso Alvarez A, Santiago-Llorente I, Armengou L, Nieto F, Rรญos J, Cruz-Lรณpez 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
        18. de la Cuesta-Torrado M, Velloso Alvarez A, Cรกrdenas-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
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