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Journal of veterinary internal medicine2018; 32(4); 1436-1441; doi: 10.1111/jvim.15145

Frequency of shedding of respiratory pathogens in horses recently imported to the United States.

Abstract: Imported horses that have undergone recent long distance transport might represent a serious risk for spreading infectious respiratory pathogens into populations of horses. Objective: To investigate the frequency of shedding of respiratory pathogens in recently imported horses. Methods: All imported horses with signed owner consent (n = 167) entering a USDA quarantine for contagious equine metritis from October 2014 to June 2016 were enrolled in the study. Methods: Prospective observational study. Enrolled horses had a physical examination performed and nasal secretions collected at the time of entry and subsequently if any horse developed signs of respiratory disease during quarantine. Samples were assayed for equine influenza virus (EIV), equine herpesvirus type-1, -2, -4, and -5 (EHV-1, -2, -4, -5), equine rhinitis virus A (ERAV), and B (ERBV) and Streptococcus equi subspecies equi (S. equi) using quantitative PCR (qPCR). Results: Equine herpesviruses were detected by qPCR in 52% of the study horses including EHV-2 (28.7%), EHV-5 (40.7%), EHV-1 (1.2%), and EHV-4 (3.0%). Clinical signs were not correlated with being qPCR-positive for EHV-4, EHV-2, or EHV-5. None of the samples were qPCR-positive for EIV, ERAV, ERBV, and S. equi. The qPCR assay failed quality control for RNA viruses in 25% (46/167) of samples. Conclusions: Clinical signs of respiratory disease were poorly correlated with qPCR positive status for EHV-2, -4, and -5. The importance of γ-herpesviruses (EHV-2 and 5) in respiratory disease is poorly understood. Equine herpesvirus type-1 or 4 (EHV-1 or EHV-4) were detected in 4.2% of horses, which could have serious consequences if shedding animals entered a population of susceptible horses. Biosecurity measures are important when introducing recently imported horses into resident US populations of horses.
Copyright © 2018 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.
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Publication Date: 2018-05-15 PubMed ID: 29761571PubMed Central: PMC6060314DOI: 10.1111/jvim.15145Google Scholar: Lookup
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  • Journal Article
  • Observational Study

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 aimed to investigate how often recently imported horses in the United States shed respiratory pathogens, given that these animals, having undergone recent long-distance transport, could pose significant risks for spreading infectious diseases. The analysis revealed that over half of the study subjects were shedding equine herpesviruses, but it also showed a poor correlation between clinical signs of respiratory disease and the positive presence of such viruses in horses. The study calls for robust biosecurity measures when incorporating newly imported equines into local U.S. horse populations.

Research Methodology

  • The study involved imported horses that were granted owner consent to participate in the research.
  • The timeline for this study was between October 2014 and June 2016.
  • Upon entering a USDA quarantine for contagious equine metritis, all included horses underwent physical examination and nasal secretion collection.
  • If any horse displayed symptoms of respiratory disease during quarantine, additional nasal secretions were collected from them.
  • Collected samples were tested for various pathogens: equine influenza virus (EIV), equine herpesvirus type-1, -2, -4, and -5 (EHV-1, -2, -4, -5), equine rhinitis virus A (ERAV), and B (ERBV), and Streptococcus equi subspecies equi (S. equi) through a quantitative PCR (qPCR) assay.

Research Findings

  • Through qPCR, equine herpesviruses were detected in 52% of the horses involved in the study
  • Among these, EHV-2 was present in 28.7% of horses, EHV-5 in 40.7%, EHV-1 in 1.2%, and EHV-4 in 3.0%.
  • No correlation was found between clinical signs and horses being qPCR-positive for EHV-4, -2, or -5.
  • None of the samples were qPCR-positive for EIV, ERAV, ERBV, and S. Equi.
  • The qPCR assay failed quality control in 25% of the samples strictly related to RNA viruses.

Conclusion and Implications

  • Findings showed poor correlations between clinical respiratory disease signs and being qPCR positive for EHV-2, -4, and -5.
  • The function of γ-herpesviruses (EHV-2 and 5) in respiratory disease is not fully understood.
  • The discovery of equine herpesvirus type-1 or 4 (EHV-1 or EHV-4) in 4.2% of the horses could pose severe implications if such horses entered a population of susceptible horses.
  • The study emphasizes the need for strict biosecurity protocols when introducing recently imported horses into existing US populations of horses in order to prevent potential disease spread.

Cite This Article

APA
Smith FL, Watson JL, Spier SJ, Kilcoyne I, Mapes S, Sonder C, Pusterla N. (2018). Frequency of shedding of respiratory pathogens in horses recently imported to the United States. J Vet Intern Med, 32(4), 1436-1441. https://doi.org/10.1111/jvim.15145

Publication

Journal of veterinary internal medicine
ISSN: 1939-1676
NlmUniqueID: 8708660
Country: United States
Language: English
Volume: 32
Issue: 4
Pages: 1436-1441

Researcher Affiliations

Smith, Fauna Leah
  • Willian R Pritchard Veterinary Medical Teaching Hospital, University of California Davis, Davis, California.
Watson, Johanna L
  • Department of Medicine and Epidemiology, University of California Davis, Davis, California.
Spier, Sharon J
  • Department of Medicine and Epidemiology, University of California Davis, Davis, California.
Kilcoyne, Isabelle
  • Department of Surgical and Radiological Sciences, University of California Davis, Davis, California.
Mapes, Samantha
  • Department of Medicine and Epidemiology, University of California Davis, Davis, California.
Sonder, Claudia
  • Center for Equine Heath, School of Veterinary Medicine, University of California, Davis, Davis, California.
Pusterla, Nicola
  • Department of Medicine and Epidemiology, University of California Davis, Davis, California.

MeSH Terms

  • Animals
  • Female
  • Herpesviridae Infections / veterinary
  • Herpesviridae Infections / virology
  • Herpesvirus 1, Equid
  • Herpesvirus 4, Equid
  • Horse Diseases / epidemiology
  • Horse Diseases / microbiology
  • Horse Diseases / transmission
  • Horse Diseases / virology
  • Horses / microbiology
  • Horses / virology
  • Male
  • Prospective Studies
  • Quarantine / veterinary
  • Real-Time Polymerase Chain Reaction / veterinary
  • Respiratory Tract Diseases / microbiology
  • Respiratory Tract Diseases / veterinary
  • Respiratory Tract Diseases / virology
  • Rhadinovirus
  • Streptococcal Infections / microbiology
  • Streptococcal Infections / transmission
  • Streptococcal Infections / veterinary
  • Streptococcus equi
  • United States / epidemiology
  • Virus Shedding

References

This article includes 26 references
  1. Pusterla N, Kass PH, Mapes S. Surveillance programme for important equine infectious respiratory pathogens in the USA.. Vet Rec 2011;169:12.
    pubmed: 21676986
  2. Legrand LJ, Pitel PH, Marcillaud‐Pitel CJ. Surveillance of equine influenza viruses through the RESPE network in France from November 2005 to October 2010.. Equine Vet J 2013;45:776–783.
    pubmed: 23662725
  3. Smyth GB, Dagley K. Internet‐based survey of horse owners for mortality and morbidity related to equine influenza in the 2007 Australian epidemic.. Aust Vet J 2011;89:23–25.
    pubmed: 21711277
  4. Smyth GB, Dagley K, Tainsh J. Insights into the economic consequences of the 2007 equine influenza outbreak in Australia.. Aust Vet J 2011;89 Suppl 1:151–158.
    pubmed: 21711317
  5. Padalino B, Raidal SL, Carter N. Immunological, clinical, haematological and oxidative responses to long distance transportation in horses.. Res Vet Sci 2017;115:78–87.
    pubmed: 28160731
  6. Stull CL, Spier SJ, Aldridge BM, Blanchard M, Stott JL. Immunological response to long‐term transport stress in mature horses and effects of adaptogenic dietary supplementation as an immunomodulator.. Equine Vet J 2004;36:583–589.
    pubmed: 15581322
  7. Pusterla N, Mapes S, Wademan C, White A, Hodzic E. Investigation of the role of lesser characterised respiratory tract infections in horses.. Vet Rec 2013;172:315.
    pubmed: 23423483
  8. Mapes S, Leutenegger CM, Pusterla N. Nucleic acid extraction methods for detection of EHV‐1 from blood and nasopharyngeal secretions.. Vet Rec 2008;162:857–859.
    pubmed: 18587063
  9. Dunowska M, Wilks CR, Studdert MJ, Meers J. Viruses associated with outbreaks of equine respiratory disease in New Zealand.. N Z Vet J 2002;50:132–139.
    pubmed: 16032259
  10. Torfason EG, Thorsteinsdottir L, Torsteinsdottir S, Svansson V. Study of equid herpesviruses 2 and 5 in Iceland with a type‐specific polymerase chain reaction.. Res Vet Sci 2008;85:605–611.
    pubmed: 18336849
  11. Williams KJ, Robinson NE, Lim A. Experimental induction of pulmonary fibrosis in horses with the gammaherpesvirus equine herpesvirus 5.. PLoS One 2013;8:e77754.
    pmc: PMC3795644pubmed: 24147074
  12. Rushton JO, Kolodziejek J, Tichy A, Nell B, Nowotny N. Detection of equid herpesviruses 2 and 5 in a herd of 266 Lipizzaners in association with ocular findings.. Vet Microbiol 2013;164:139–144.
    pubmed: 23434188
  13. Vander Werf K, Davis E. Disease remission in a horse with EHV‐5‐associated lymphoma.. J Vet Intern Med 2013;27:387–389.
    pubmed: 23458852
  14. Marenzoni ML, Coppola G, Maranesi M. Age‐dependent prevalence of equid herpesvirus 5 infection.. Vet Res Commun 2010;34:703–708.
    pubmed: 20842426
  15. Pusterla N, Magdesian KG, Mapes SM, Zavodovskaya R, Kass PH. Assessment of quantitative polymerase chain reaction for equine herpesvirus‐5 in blood, nasal secretions and bronchoalveolar lavage fluid for the laboratory diagnosis of equine multinodular pulmonary fibrosis.. Equine Vet J 2017;49:34–38.
    pubmed: 26639080
  16. Traub‐Dargatz JL, Bischoff B. Prevalence of Elevated Temperatures Among Horses Presented for Importation to the United States.. AAEP Proc 2011;252–259.
  17. van de Goor LH, van Haeringen WA, Lenstra JA. Population studies of 17 equine STR for forensic and phylogenetic analysis.. Anim Genet 2011;42:627–633.
    pubmed: 22035004
  18. Sevinga M, Vrijenhoek T, Hesselinks JW, Barkema HW, Groen AF. Effect of inbreeding on the incidence of retained placenta in Friesian horses.. J Anim Sci 2004;82:982–986.
    pubmed: 15080317
  19. Gnann JW Jr, Whitley RJ. Herpes simplex encephalitis: an update.. Curr Infect Dis Rep 2017;19:13.
    pubmed: 28251511
  20. Dunowska M, Wilks CR, Studdert MJ, Meers J. Equine respiratory viruses in foals in New Zealand.. N Z Vet J 2002;50:140–147.
    pubmed: 16032260
  21. Schrader C, Schielke A, Ellerbroek L, Johne R. PCR inhibitors ‐ occurrence, properties and removal.. J Appl Microbiol 2012;113:1014–1026.
    pubmed: 22747964
  22. Boyle AG, Rankin SC, D￮ L, Boston RC, Wheeler‐Aceto H. Streptococcus equi detection polymerase chain reaction assay for equine nasopharyngeal and guttural pouch wash samples.. J Vet Intern Med 2016;30:276–281.
    pmc: PMC4913660pubmed: 26678318
  23. Lindahl S, Baverud V, Egenvall A, Aspán A, Pringle J. Comparison of sampling sites and laboratory diagnostic tests for S. equi subsp. equi in horses from confirmed strangles outbreaks.. J Vet Intern Med 2013;27:542–547.
    pubmed: 23527817
  24. Mason DK, Watkins KL, McNie JT, Luk CM. Haematological measurements as an aid to early diagnosis and prognosis of respiratory viral infections in thoroughbred horses.. Vet Rec 1990;126:359–363.
    pubmed: 2159670
  25. Ohmura H, Hobo S, Hiraga A, Jones JH. Changes in heart rate and heart rate variability during transportation of horses by road and air.. Am J Vet Res 2012;73:515–521.
    pubmed: 22452498
  26. Browne A, Ahmad SS, Beck CR, Nguyen‐Van‐Tam JS. The roles of transportation and transportation hubs in the propagation of influenza and coronaviruses: a systematic review.. J Travel Med 2016;23:tav002.
    pmc: PMC7539332pubmed: 26782122

Citations

This article has been cited 16 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. van Maanen K, van den Wollenberg L, de Haan T, Frippiat T. Epidemiology of Infectious Pathogens in Horses with Acute Respiratory Disease, Abortion, and Neurological Signs: Insights Gained from the Veterinary Surveillance System for Horses in The Netherlands (SEIN). Vet Sci 2025 Jun 10;12(6).
    doi: 10.3390/vetsci12060567pubmed: 40559804google scholar: lookup
  3. Pinn-Woodcock TL, Aprea MS, Lejeune M, Tomlinson JE. Molecular detection of pathogens in an equine fever diagnostic panel: 2019-2023. Equine Vet J 2026 Mar;58(2):486-496.
    doi: 10.1111/evj.14527pubmed: 40384355google scholar: lookup
  4. Stasiak K, Dunowska M, Rola J. Prevalence and Sequence Analysis of Equine Rhinitis Viruses among Horses in Poland. Viruses 2024 Jul 26;16(8).
    doi: 10.3390/v16081204pubmed: 39205178google scholar: lookup
  5. 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
  6. Tavanaeimanesh H, Alinia Z, Sadeghian Chaleshtori S, Moosavian H, Mohebi Z, Daneshi M. The efficacy of N-acetylcysteine in decreasing airway inflammation and mucus accumulation in horses with 18 hours of head confinement. J Vet Intern Med 2024 Mar-Apr;38(2):1224-1231.
    doi: 10.1111/jvim.16976pubmed: 38236790google scholar: lookup
  7. 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
  8. Pusterla N, Kalscheur M, Peters D, Bidwell L, Holtz S, Barnum S, Lawton K, Morrissey M, Schumacher S. Investigation of the Frequency of Detection of Common Respiratory Pathogens in Nasal Secretions and Environment of Healthy Sport Horses Attending a Multi-Week Show Event during the Summer Months. Viruses 2023 May 24;15(6).
    doi: 10.3390/v15061225pubmed: 37376525google scholar: lookup
  9. Finger MA, Biava JS, Dornbusch PT, Perotta JH, Ullmann LS, Serpa PBDS, Kmetiuk LB, Dos Santos AP, Biondo AW, Leutenegger C, Filho IRB. Molecular detection of equid herpesvirus in bronchoalveolar lavage fluid from asymptomatic horses in Southern Brazil. Vet World 2022 Nov;15(11):2597-2602.
    doi: 10.14202/vetworld.2022.2597-2602pubmed: 36590117google scholar: lookup
  10. Wilcox A, Barnum S, Wademan C, Corbin R, Escobar E, Hodzic E, Schumacher S, Pusterla N. Frequency of Detection of Respiratory Pathogens in Clinically Healthy Show Horses Following a Multi-County Outbreak of Equine Herpesvirus-1 Myeloencephalopathy in California. Pathogens 2022 Oct 8;11(10).
    doi: 10.3390/pathogens11101161pubmed: 36297218google scholar: lookup
  11. 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
  12. Mira F, Canuti M, Di Bella S, Puleio R, Lavazza A, Lelli D, Vicari D, Purpari G, Cannella V, Chiaramonte G, Schirò G, Castronovo C, Guercio A. Detection and Molecular Characterization of Two Gammaherpesviruses from Pantesco Breed Donkeys during an Outbreak of Mild Respiratory Disease. Viruses 2021 Aug 2;13(8).
    doi: 10.3390/v13081527pubmed: 34452391google scholar: lookup
  13. Miller AB, Harris PA, Barker VD, Adams AA. Short-term transport stress and supplementation alter immune function in aged horses. PLoS One 2021;16(8):e0254139.
    doi: 10.1371/journal.pone.0254139pubmed: 34411137google scholar: lookup
  14. Pavulraj S, Eschke K, Theisen J, Westhoff S, Reimers G, Andreotti S, Osterrieder N, Azab W. Equine Herpesvirus Type 4 (EHV-4) Outbreak in Germany: Virological, Serological, and Molecular Investigations. Pathogens 2021 Jun 25;10(7).
    doi: 10.3390/pathogens10070810pubmed: 34202127google scholar: lookup
  15. Salco R, Bowers J, Hernandez V, Barnum S, Pusterla N. Prevention of respiratory infections with alpha- and gamma-herpesviruses in weanling foals by using a modified live intra-nasal equine influenza vaccine. Can Vet J 2020 May;61(5):517-520.
    pubmed: 32355351
  16. Dall Agnol AM, Beuttemmuller EA, Pilz D, Leme RA, Saporiti V, Headley SA, Alfieri AF, Alfieri AA. Detection of Equid gammaherpesvirus 2 and 5 DNA in the upper respiratory tract of asymptomatic horses from Southern Brazil. Braz J Microbiol 2019 Jul;50(3):875-878.
    doi: 10.1007/s42770-019-00100-7pubmed: 31187445google scholar: lookup
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