Equine Rhinitis A Virus Infection at a Standardbred Training Facility: Incidence, Clinical Signs, and Risk Factors for Clinical Disease.
Authors: Rossi Tanya M, Moore Alison, O'Sullivan Terri L, Greer Amy L
Journal: Frontiers in veterinary science
Summary
# Editorial Summary: Equine Rhinitis A Virus in Standardbred Training Facilities Respiratory disease costs the racing industry substantially through compromised welfare and lost training time, yet prevention strategies remain underdeveloped because risk factors driving infection spread through training facilities are poorly understood. Rossi and colleagues monitored 96 standardbred racehorses across a multi-barn facility for 41 days, recording daily clinical signs alongside demographic, serological, and contact network data, whilst using multivariable logistic regression to identify associations with Equine Rhinitis A virus (ERAV) disease. The outbreak affected 52.5% of the population (incidence risk), with yearlings disproportionately affected at 87.9%, and was characterised primarily by mucopurulent nasal discharge (100% of cases) and ocular discharge (62.3%), though fever and inappetence were notably absent in most affected horses—a presentation that may delay clinical recognition. Each additional year of age reduced disease risk substantially (odds ratio 0.011, p<0.001), suggesting that immunity develops rapidly or that older horses were simply less susceptible to this particular outbreak. These findings have clear implications for practice: yearlings entering training facilities warrant targeted disease control through vaccination programmes and strict isolation protocols for newly arrived horses, particularly those sourced from high-risk environments such as auctions, rather than applying uniform biosecurity measures across all age groups.
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Practical Takeaways
- •Yearlings entering training facilities are at highest risk for ERAV infection—implement targeted vaccination and isolation protocols for young horses, particularly those from auctions
- •Watch for mucopurulent nasal discharge and ocular discharge as primary clinical indicators of ERAV; fever and inappetence are unreliable signs for detecting infection in this population
- •Implement daily clinical monitoring systems at multi-barn facilities to detect respiratory disease early and enable rapid isolation to reduce transmission across barns
Key Findings
- •Total incidence risk of respiratory disease was 52.5% with yearling-specific incidence risk of 87.9% over 41 days
- •ERAV seroconversion occurred in 75% of clinical cases, characterized by mucopurulent nasal discharge (100%), ocular discharge (62.3%), and cough (37.7%)
- •Age was a significant protective factor with negative association to disease (OR=0.011, p<0.001), with yearlings at substantially higher risk than older horses
- •Fever and inappetence were uncommon clinical signs, occurring in only 15.2% and 3.8% of cases respectively