FREE SHIPPING over $40
OVER 10000 FIVE-STAR REVIEWS
5% OFF ALL SUBSCRIPTIONS
100% HAPPINESS GUARANTEE
Analyze Diet
0
Veterinary journal (London, England : 1997)2007; 179(2); 230-239; doi: 10.1016/j.tvjl.2007.09.018

Characterization of viral loads, strain and state of equine herpesvirus-1 using real-time PCR in horses following natural exposure at a racetrack in California.

Abstract: The objective of this study was to determine viral loads, strain (neuropathogenic versus non-neuropathogenic) and state (lytic, non-replicating, latent) of equine herpesvirus-1 (EHV-1) by real-time polymerase chain reaction (PCR) in the blood and nasopharyngeal secretions of adult horses following natural exposure. The index case, a 4-year-old Thoroughbred gelding with confirmed EHV-1 myeloencephalopathy, as well as potentially exposed horses, were sampled over a period of 3 weeks. The study population comprised of 39 adult Thoroughbred horses and 35 adult "pony" and outrider horses of various breeds housed at a racetrack in Northern California. Blood samples and nasopharyngeal secretions (NPS) from all horses were tested on several occasions for EHV-1 DNA viral loads, targeting the glycoprotein B (gB) gene, viral strain, targeting the ORF 30 gene, and transcriptional activity of EHV-1, targeting the gB gene and latency-associated transcripts (LATs). Viral loads and transcriptional activity of the gB gene declined rapidly in the index case following antiviral treatment. The prevalence of EHV-1 infection in NPS determined by PCR slowly decreased over the 22 day study period from 25% to 14%. The initial surveillance showed multiple clusters of exposure, one associated with the index case and two related to horses that had recently returned from a different racetrack. Viral strain differentiation showed that only two horses (the index case and a neighboring horse) were infected with only a neuropathogenic strain, while all other horses were infected with either a non-neuropathogenic strain or were dually infected with both neuropathogenic and non-neuropathogenic strains. In most cases, the virus was present in either a lytic or a non-replicating form, while latent virus was found in blood and NPS much less frequently. The molecular approach used in this study showed promise for assessing the risk of exposing other horses to EHV-1 and for studying viral kinetics in infected horses.
Get Full Text
Publication Date: 2007-11-19 PubMed ID: 18024200DOI: 10.1016/j.tvjl.2007.09.018Google 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
  • Journal Article
  • Research Support
  • Non-U.S. Gov't

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.

The study aimed to assess the levels, types, and activity states of equine herpesvirus-1 (EHV-1) in horses in a California racetrack using real-time PCR tests. The researchers found different strains of the virus and observed its activity decrease after treatment.

Objective and Methodology

  • The research aimed to investigate the viral loads (quantity), strain (neuropathogenic versus non-neuropathogenic), and state (lytic, non-replicating, latent) of equine herpesvirus-1 (EHV-1) in horses naturally exposed to the virus.
  • Real-time polymerase chain reaction (PCR) was used to measure these parameters in the blood and nasopharyngeal secretions of adult horses.
  • The study sample comprised 39 adult Thoroughbred horses and 35 adult “pony” and outrider horses of various breeds, housed at a racetrack in Northern California.
  • Both blood samples and nasopharyngeal secretions (NPS) from all horses were tested repeatedly for EHV-1 DNA viral loads, viral strain, and transcriptional activity of EHV-1.

Findings: Viral Loads and Strains

  • The researchers observed that the viral loads and transcriptional activity of the glycoprotein B (gB) gene dramatically decreased in the index case after antiviral treatment.
  • The incidence of EHV-1 infection in NPS, as established by PCR, gradually lessened over the 22-day study period, dropping from 25% to 14%.
  • At the beginning of the study, multiple exposure clusters were identified. One was related to the index case, and two were linked to horses that had recently returned from another racetrack.
  • Upon differentiating the viral strains, it was found that only two horses (the index and a neighboring horse) were infected solely with a neuropathogenic strain. The rest were either infected with a non-neuropathogenic strain or had contracted both neuropathogenic and non-neuropathogenic strains.

Findings: Status of the Virus

  • The researchers discovered that, in most cases, the virus was present in a lytic or non-replicating state.
  • Latent viruses were found much less frequently and were detected in blood and NPS samples.

Significance and Potential Applications of the Study

  • The molecular technique used in this study provides a potential tool for evaluating the risk of EHV-1 transmission among horses and for studying viral kinetics in horses already infected.

Cite This Article

APA
Pusterla N, Wilson WD, Mapes S, Finno C, Isbell D, Arthur RM, Ferraro GL. (2007). Characterization of viral loads, strain and state of equine herpesvirus-1 using real-time PCR in horses following natural exposure at a racetrack in California. Vet J, 179(2), 230-239. https://doi.org/10.1016/j.tvjl.2007.09.018

Publication

Veterinary journal (London, England : 1997)
ISSN: 1090-0233
NlmUniqueID: 9706281
Country: England
Language: English
Volume: 179
Issue: 2
Pages: 230-239

Researcher Affiliations

Pusterla, Nicola
  • Department of Medicine and Epidemiology, University of California, Davis, CA 95616, USA.
Wilson, W David
    Mapes, Samantha
      Finno, Carrie
        Isbell, Diane
          Arthur, Rick M
            Ferraro, Gregory L

              MeSH Terms

              • Animals
              • California
              • DNA, Viral / chemistry
              • DNA, Viral / genetics
              • Disease Outbreaks / veterinary
              • Disease Reservoirs / veterinary
              • Disease Reservoirs / virology
              • Female
              • Herpesviridae Infections / epidemiology
              • Herpesviridae Infections / transmission
              • Herpesviridae Infections / veterinary
              • Herpesviridae Infections / virology
              • Herpesvirus 1, Equid / isolation & purification
              • Horse Diseases / epidemiology
              • Horse Diseases / transmission
              • Horse Diseases / virology
              • Horses
              • Male
              • Polymerase Chain Reaction / methods
              • Polymerase Chain Reaction / veterinary
              • Prevalence
              • Viral Load / veterinary
              • Virus Latency

              Citations

              This article has been cited 22 times.
              1. Tsai MS, François S, Newman C, Macdonald DW, Buesching CD. Infection with a Recently Discovered Gammaherpesvirus Variant in European Badgers, Meles meles, is Associated with Higher Relative Viral Loads in Blood. Pathogens 2022 Oct 6;11(10).
                doi: 10.3390/pathogens11101154pubmed: 36297210google 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. Thieulent CJ, Sutton G, Toquet MP, Fremaux S, Hue E, Fortier C, Pléau A, Deslis A, Abrioux S, Guitton E, Pronost S, Paillot R. Oral Administration of Valganciclovir Reduces Clinical Signs, Virus Shedding and Cell-Associated Viremia in Ponies Experimentally Infected with the Equid Herpesvirus-1 C(2254) Variant. Pathogens 2022 May 4;11(5).
                doi: 10.3390/pathogens11050539pubmed: 35631060google scholar: lookup
              5. Pusterla N, Barnum S, Miller J, Varnell S, Dallap-Schaer B, Aceto H, Simeone A. Investigation of an EHV-1 Outbreak in the United States Caused by a New H(752) Genotype. Pathogens 2021 Jun 13;10(6).
                doi: 10.3390/pathogens10060747pubmed: 34199153google scholar: lookup
              6. Samoilowa S, Giessler KS, Torres CEM, Hussey GS, Allum A, Fux R, Jerke C, Kiupel M, Matiasek K, Sledge DG, Goehring LS. Equid herpesvirus-1 Distribution in Equine Lymphoid and Neural Tissues 70 Days Post Infection. Pathogens 2021 Jun 5;10(6).
                doi: 10.3390/pathogens10060707pubmed: 34198884google scholar: lookup
              7. Giessler KS, Samoilowa S, Soboll Hussey G, Kiupel M, Matiasek K, Sledge DG, Liesche F, Schlegel J, Fux R, Goehring LS. Viral Load and Cell Tropism During Early Latent Equid Herpesvirus 1 Infection Differ Over Time in Lymphoid and Neural Tissue Samples From Experimentally Infected Horses. Front Vet Sci 2020;7:621.
                doi: 10.3389/fvets.2020.00621pubmed: 33102556google scholar: lookup
              8. Lechmann J, Schoster A, Ernstberger M, Fouché N, Fraefel C, Bachofen C. A novel PCR protocol for detection and differentiation of neuropathogenic and non-neuropathogenic equid alphaherpesvirus 1. J Vet Diagn Invest 2019 Sep;31(5):696-703.
                doi: 10.1177/1040638719871975pubmed: 31477001google scholar: lookup
              9. Tallmadge RL, Žygelytė 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
              10. Hue ES, Richard EA, Fortier CI, Fortier GD, Paillot R, Raue R, Pronost SL. Equine PBMC Cytokines Profile after In Vitro α- and γ-EHV Infection: Efficacy of a Parapoxvirus Ovis Based-Immunomodulator Treatment. Vaccines (Basel) 2017 Sep 19;5(3).
                doi: 10.3390/vaccines5030028pubmed: 28925977google scholar: lookup
              11. Abdelgawad A, Damiani A, Ho SY, Strauss G, Szentiks CA, East ML, Osterrieder N, Greenwood AD. Zebra Alphaherpesviruses (EHV-1 and EHV-9): Genetic Diversity, Latency and Co-Infections. Viruses 2016 Sep 20;8(9).
                doi: 10.3390/v8090262pubmed: 27657113google scholar: lookup
              12. Abdelgawad A, Hermes R, Damiani A, Lamglait B, Czirják GÁ, East M, Aschenborn O, Wenker C, Kasem S, Osterrieder N, Greenwood AD. Comprehensive Serology Based on a Peptide ELISA to Assess the Prevalence of Closely Related Equine Herpesviruses in Zoo and Wild Animals. PLoS One 2015;10(9):e0138370.
                doi: 10.1371/journal.pone.0138370pubmed: 26378452google scholar: lookup
              13. 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
              14. 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
              15. Smith KL, Li Y, Breheny P, Cook RF, Henney PJ, Sells S, Pronost S, Lu Z, Crossley BM, Timoney PJ, Balasuriya UB. New real-time PCR assay using allelic discrimination for detection and differentiation of equine herpesvirus-1 strains with A2254 and G2254 polymorphisms. J Clin Microbiol 2012 Jun;50(6):1981-8.
                doi: 10.1128/JCM.00135-12pubmed: 22493339google scholar: lookup
              16. Heerkens TM. Equine herpesvirus-1, non-neurogenic pathotype, in a 9-year-old American Saddlebred with neurological signs. Can Vet J 2009 Mar;50(3):297-300.
                pubmed: 19436483
              17. 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
              18. 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
              19. 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
              20. 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
              21. Pusterla N, Lawton K, Barnum S. Investigation of the Use of Environmental Samples for the Detection of EHV-1 in the Stalls of Subclinical Shedders. Viruses 2024 Jul 3;16(7).
                doi: 10.3390/v16071070pubmed: 39066232google scholar: lookup
              22. Pusterla N, Dorman DC, Burgess BA, Goehring L, Gross M, Osterrieder K, Soboll Hussey G, Lunn DP. Viremia and nasal shedding for the diagnosis of equine herpesvirus-1 infection in domesticated horses. J Vet Intern Med 2024 May-Jun;38(3):1765-1791.
                doi: 10.1111/jvim.16958pubmed: 38069548google scholar: lookup
              Subscribe to our newsletter
              Join 99,780 horse owners like you who receive our email updates on horse health and nutrition.