Equine Herpesvirus: Welfare Impacts and Management

Equine herpesvirus (EHV) causes respiratory disease, abortion, and potentially fatal neurological disease in horses. Understanding welfare impacts helps owners and facilities protect equine health.

Key Facts

EHV-1 and EHV-4 are the most clinically significant strains, causing respiratory disease and abortion
EHV-1 myeloencephalopathy (EHM) causes progressive ataxia and can be fatal
Latent infection is common - horses can carry and reactivate virus under stress
Outbreaks at equestrian events have affected hundreds of horses in high-profile cases
Biosecurity measures at competitions include temperature monitoring and isolation protocols
Abortion storms can affect multiple mares on a single property from a single introduction
Vaccination reduces disease severity but does not prevent infection or shedding entirely

Welfare Considerations

EHV causes significant welfare impacts across several disease forms. Respiratory illness causes fever, nasal discharge, and lethargy lasting weeks. Abortions typically occur without warning, causing loss at late pregnancy with associated stress. EHM is particularly devastating, progressing to recumbency and death in severe cases. Affected horses endure paralysis, inability to urinate, and profound distress. Neurological cases that survive may have permanent deficits affecting quality of life.

What You Can Do

Vaccinate horses against EHV-1/4 following veterinary guidance on appropriate schedules
Isolate newly arrived horses for 14-21 days before contact with resident horses
Monitor temperatures twice daily during high-risk periods or after exposure events
Practice rigorous biosecurity at competitions - use own water buckets, limit nose-to-nose contact
Report suspected EHV outbreaks to your veterinarian and relevant equine health authorities promptly
Have an isolation facility available for any horse showing fever or respiratory signs
Review event attendance risk carefully during known outbreak periods in your region