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

Nicola Pusterla; Madalyn Kalscheur; Duncan Peters; Lori Bidwell; Sara Holtz; Samantha Barnum; Kaila Lawton; Matt Morrissey; Stephen Schumacher

doi:10.3390/v15061225

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):1225. doi: 10.3390/v15061225.

Authors

Nicola Pusterla¹, Madalyn Kalscheur², Duncan Peters², Lori Bidwell², Sara Holtz², Samantha Barnum¹, Kaila Lawton¹, Matt Morrissey³, Stephen Schumacher⁴

Affiliations

¹ Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA.
² East-West Equine Sports Medicine, Lexington, KY 40583, USA.
³ Morrissey Management Group, LLC, Wellington, FL 33414, USA.
⁴ US Equestrian Federation, Lexington, KY 40511, USA.

Abstract

Little information is presently available regarding the frequency of the silent shedders of respiratory viruses in healthy sport horses and their impact on environmental contamination. Therefore, the aim of this study was to investigate the detection frequency of selected respiratory pathogens in nasal secretions and environmental stall samples of sport horses attending a multi-week equestrian event during the summer months. Six out of fifteen tents were randomly selected for the study with approximately 20 horse/stall pairs being sampled on a weekly basis. Following weekly collection for a total of 11 weeks, all samples were tested for the presence of common respiratory pathogens (EIV, EHV-1, EHV-4, ERAV, ERBV, and Streptococcus equi ss equi (S. equi)) using qPCR. A total of 19/682 nasal swabs (2.8%) and 28/1288 environmental stall sponges (2.2%) tested qPCR-positive for common respiratory pathogens. ERBV was the most common respiratory virus (17 nasal swabs, 28 stall sponges) detected, followed by EHV-4 (1 nasal swab) and S. equi (1 nasal swab). EIV, EHV-1, EHV-4 and ERAV were not detected in any of the study horses or stalls. Only one horse and one stall tested qPCR-positive for ERBV on two consecutive weeks. All the other qPCR-positive sample results were related to individual time points. Furthermore, only one horse/stall pair tested qPCR-positive for ERBV at a single time point. The study results showed that in a selected population of sport horses attending a multi-week equestrian event in the summer, the frequency of the shedding of respiratory viruses was low and primarily restricted to ERBV with little evidence of active transmission and environmental contamination.

Keywords: environmental samples; healthy sport horses; nasal swabs; qPCR; respiratory pathogens; surveillance.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Herpesviridae Infections*
Herpesvirus 1, Equid*
Horse Diseases*
Horses
Seasons
Viruses*

Grants and funding

This work was funded by the United States Equestrian Federation, the Center for Equine Health, School of Veterinary Medicine, University of California, Davis, with additional contributions from public and private donors and an Advancement in Equine Research Award, Boehringer Ingelheim Animal Health (2022).