Equine Transport and Changes in Equid Herpesvirus' Status.
Authors: Muscat Katharine E, Padalino Barbara, Hartley Carol A, Ficorilli Nino, Celi Pietro, Knight Peter, Raidal Sharanne, Gilkerson James R, Muscatello Gary
Journal: Frontiers in veterinary science
Summary
# Editorial Summary: Equine Transport and Equid Herpesvirus Status Transport stress is well established as a trigger for respiratory disease in horses, yet the viral ecology underpinning this risk remains poorly characterised. Muscat and colleagues investigated herpesvirus reactivation and shedding in twelve horses subjected to an 8-hour road journey, collecting nasal swabs, tracheal wash samples and serum at multiple timepoints to screen for EHV-1, -2, -4 and -5 using qPCR and serology. Whilst no horses seroconverted to the alphaherpesviruses (EHV-1/-4) or shed these agents, the gammaherpesvirus picture differed substantially: five horses showed increased EHV-2 shedding post-transport with reduced qPCR cycle threshold values, seven of eleven post-transport EHV-2 positive cases shared genetically similar strains suggesting transmission between horses, and four of nine horses pre-transport positive for EHV-2 or EHV-5 later developed subclinical neutrophilic airway inflammation. Whilst the pathogenic significance of EHV-2 and -5 remains unclear, these findings suggest that transport-associated respiratory disease cannot be attributed solely to alphaherpesvirus reactivation; instead, the immunomodulatory capacity of gammaherpesviruses warrants closer investigation as potential contributors to post-transport immunosuppression and respiratory compromise, particularly in horses harbouring latent infections.
Read the full abstract on PubMed
Practical Takeaways
- •Transport-related respiratory disease may involve gammaherpesvirus (EHV-2 and EHV-5) reactivation and shedding, not just the traditionally monitored alphaherpesviruses; consider this when managing post-transport respiratory issues
- •Grouped transport facilitates viral transmission between horses; manage post-transport stabling and monitor for respiratory signs even when clinical disease is not immediately apparent
- •Subclinical respiratory inflammation is common after transport (50% in this study); incorporate respiratory assessment into post-transport health protocols for competition or training horses
Key Findings
- •Six of 12 horses (50%) developed neutrophilic airway infiltrates indicative of subclinical respiratory disease post-transport
- •No horses seroconverted to EHV-1 or EHV-4, but 5 of 12 showed increased EHV-2 shedding (reduced Cq values) after transport
- •Four of 9 horses (44%) positive for EHV-2 or EHV-5 prior to transport developed neutrophilic airway inflammation
- •Seven of 11 horses (64%) positive for EHV-2 after transport shared genetically similar viral strains, suggesting transmission between transported horses