Frequency of Detection of Respiratory Pathogens in Nasal Secretions From Healthy Sport Horses Attending a Spring Show in California.
Abstract: The objective of this study was to determine detection frequency of respiratory viruses (equine influenza virus [EIV], equine herpesvirus-1 [EHV-1], EHV-2, EHV-4, EHV-5, equine rhinitis A virus [ERAV], ERBV) and bacteria (Streptococcus equi ss. equi[S. equi], S. equi ss. zooepidemicus[S. zooepidemicus]) in 162 nasal secretions and 149 stall swabs from healthy sport horses attending a spring show in California. Nasal and stall swabs were collected at a single time point and analyzed using qPCR. The detection frequency of respiratory pathogens in nasal secretions was 38.9% for EHV-2, 36.4% for EHV-5, 19.7% for S. zooepidemicus, 1.2% for ERBV, 0.6% for S. equi and 0% for EIV, EHV-1, EHV-4 and ERAV. The detection frequency of respiratory pathogens in stall swabs was 65.8% for S. zooepidemicus, 33.5% for EHV-2, 27.5% for EHV-5, 3.3% for EHV-1, 1.3% for EHV-4 and 0% for EIV, ERAV, ERBV and S. equi. Commensal viruses and bacteria were frequently detected in nasal secretions and stall swabs from healthy sport horses. This was in sharp contrast to the subclinical shedding of well-characterized respiratory pathogens. Of interest was the clustering of five EHV-1 qPCR-positive stalls from apparently healthy horses with no evidence of clinical spread. The results highlight the role of subclinical shedders in introducing respiratory pathogens to shows and their role in environmental contamination. The results also highlight the need to improve cleanliness and disinfection of stalls utilized by performance horses during show events.
Copyright © 2022. Published by Elsevier Inc.
Publication Date: 2022-07-29 PubMed ID: 35908600DOI: 10.1016/j.jevs.2022.104089Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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This study offers insight into the frequency of certain respiratory pathogens found in nasal secretions and stall swabs from healthy sport horses during a spring show in California. It highlights the role of subclinical shedders in potentially spreading these pathogens and underlines the need for improved cleanliness and disinfection practices.
Study Objective and Methodology
- The primary aim of this research was to determine the detection frequency of various respiratory viruses like equine influenza virus (EIV), multiple strains of equine herpesvirus (EHV-1, EHV-2, EHV-4, and EHV-5), equine rhinitis A and B viruses (ERAV and ERBV), as well as bacteria like Streptococcus equi ss. equi (S. equi) and S. equi ss. zooepidemicus (S. zooepidemicus).
- This investigation involved 162 nasal secretions and 149 stall swabs collected from healthy sports horses present at a spring show in California.
- The collection procedure occurred only once, and the samples were analyzed later via quantitative PCR (qPCR), a laboratory technique used to amplify and concurrently quantify a targeted DNA molecule.
Results and Findings
- Among nasal secretions, EHV-2 was detected in 38.9% of the samples, EHV-5 in 36.4%, S. zooepidemicus in 19.7%, ERBV in 1.2%, and S. equi in 0.6%. No instances of EIV, EHV-1, EHV-4, or ERAV were detected.
- In the cases of the stall swabs, S. zooepidemicus was found in 65.8% of the samples, EHV-2 in 33.5%, EHV-5 in 27.5%, EHV-1 in 3.3%, and EHV-4 in 1.3%. The pathogens EIV, ERAV, ERBV, and S. equi were not found at all.
- Notably, the study found a high frequency of commensal (i.e., non-harmful) viruses and bacteria in both nasal secretions and stall swabs of healthy sport horses. This contrasted sharply with a much lower presence of known respiratory pathogens, implying that these horses can be subclinical shedders of these pathogens.
- Interestingly, five of the stalls had EHV-1 qPCR-positive results. These belonged to apparently healthy horses, with no observed clinical spread.
Implications and Conclusions
- The findings of this study underscore the potential role of subclinical shedders—animals that carry and can spread disease while appearing healthy—in introducing respiratory pathogens during shows.
- Furthermore, they also highlight the need for improved cleanliness and disinfection measures especially for the stalls used by performance horses during shows to prevent environmental contamination.
Cite This Article
APA
Pusterla N, Sandler-Burtness E, Barnum S, Hill LA, Mendonsa E, Khan R, Portener D, Ridland H, Schumacher S.
(2022).
Frequency of Detection of Respiratory Pathogens in Nasal Secretions From Healthy Sport Horses Attending a Spring Show in California.
J Equine Vet Sci, 117, 104089.
https://doi.org/10.1016/j.jevs.2022.104089 Publication
Researcher Affiliations
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA. Electronic address: npusterla@ucdavis.edu.
- Pacific Coast Equine Veterinary Services, Ramona, CA.
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA.
- Pacific Coast Equine Veterinary Services, Ramona, CA.
- Fluxergy, Irvine, CA.
- Fluxergy, Irvine, CA.
- Blenheim EquiSports, San Juan Capistrano, CA.
- Blenheim EquiSports, San Juan Capistrano, CA.
- US Equestrian, Lexington, KY.
MeSH Terms
- Animals
- Aphthovirus
- California / epidemiology
- Herpesvirus 1, Equid
- Herpesvirus 4, Equid
- Horse Diseases / diagnosis
- Horses
- Rhadinovirus
- Streptococcus equi
- Viruses
Citations
This article has been cited 13 times.- 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).
- 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.
- Alessiani A, Baffoni M, Averaimo D, Cantelmi MC, Coccaro A, Rulli M, Piersanti V, Pompilii C, Cito F, Chiaverini A, Petrini A. Antimicrobial Resistance and Genetic Characterization of Streptococcus equi subsp. zooepidemicus in Equines from Central Italy: Insights from a One Health Perspective. Animals (Basel) 2025 Sep 16;15(18).
- Stasiak K, Dunowska M, Rola J. Genetic Diversity of Equid Herpesvirus 5 in Temporal Samples from Mares and Their Foals at Three Polish National Studs. Int J Mol Sci 2025 Aug 27;26(17).
- 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).
- 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).
- Wilson HJ, Dong J, van Tonder AJ, Ruis C, Lefrancq N, McGlennon A, Bustos C, Frosth S, Léon A, Blanchard AM, Holden M, Waller AS, Parkhill J. Progressive evolution of Streptococcus equi from Streptococcus equi subsp. zooepidemicus and adaption to equine hosts. Microb Genom 2025 Mar;11(3).
- Ruan L, Li L, Yang R, You A, Khan MZ, Yu Y, Chen L, Li Y, Liu G, Wang C, Wang T. Equine Herpesvirus-1 Induced Respiratory Disease in Dezhou Donkey Foals: Case Study from China, 2024. Vet Sci 2025 Jan 14;12(1).
- Stasiak K, Dunowska M, Rola J. Prevalence and Sequence Analysis of Equine Rhinitis Viruses among Horses in Poland. Viruses 2024 Jul 26;16(8).
- 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).
- 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.
- 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).
- 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).
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