Long-term performance of show-jumping horses and relationship with severity of ataxia and complications associated with myeloencephalopathy caused by equine herpes virus-1.
Authors: de la Cuesta-Torrado María, Velloso Alvarez Ana, Neira-Egea Patricia, Cuervo-Arango Juan
Journal: Journal of veterinary internal medicine
Summary
# Editorial Summary: EHV-1 Myeloencephalopathy and Return to Sport During a natural EHM outbreak at an international jumping event, researchers retrospectively analysed clinical outcomes in 26 EHV-1 positive horses using hospital records, competition data from the International Equestrian Federation, and owner/rider surveys to determine whether affected animals could return to pre-outbreak performance levels and which clinical variables predicted prognosis. Whilst 68% of affected horses resumed exercise, only 52.9% achieved their previous competitive standard, with notably poorer outcomes in horses presenting with ataxia grades ≥4/5 at admission (10% return rate, increased fatality). Critically, none of the horses presenting with concurrent vascular and urinary complications returned to their pre-outbreak performance, and urinary involvement independently associated with 43.7% fatality. Prior EHV-1 vaccination correlated with elevated fatality rates (71.4%), a counterintuitive finding warranting further investigation, whilst ataxia severity at presentation emerged as the most consistent prognostic indicator affecting both survival and sporting capability. For practitioners involved in managing EHM cases, these findings suggest that initial clinical assessment—particularly quantifying ataxia grade and identifying systemic complications—provides valuable prognostic information for owners, and that the presence of multiple complications significantly diminishes realistic expectations for return to competitive sport.
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Practical Takeaways
- •Ataxia severity at presentation is a critical prognostic indicator—horses with grade ≥4/5 ataxia have poor prognosis for return to sport and high mortality risk
- •Development of urinary complications and vasculitis signs warrant guarded prognosis; horses with both complications showed zero return to previous performance
- •Most EHM-affected horses can return to some level of exercise, but pre-outbreak performance recovery is uncertain; owners should manage expectations and plan for potential permanent career changes
Key Findings
- •68% of EHM-affected horses returned to exercise, with 52.9% achieving their pre-outbreak performance level
- •Horses with ataxia grade ≥4/5 at admission had increased fatality rate and only 10% chance of returning to pre-outbreak performance
- •None of the horses with both vascular and urinary complications returned to previous performance level
- •Prior EHV-1 vaccination and urinary complications were associated with 71.4% and 43.7% fatality rates respectively