Horse Equine Herpesvirus: Welfare and Outbreak Management

Equine herpesvirus causes respiratory disease, abortion, and neurological disease in horses. Understanding outbreak management protects both individual and population welfare.

Key Facts

EHV-1 and EHV-4 are the most clinically significant herpesvirus strains
EHV-1 causes respiratory disease, abortion storms, and equine herpes myeloencephalopathy
EHM causes neurological signs including ataxia and bladder paralysis with high fatality rates
The virus establishes lifelong latency with reactivation during stress
Vaccination provides partial protection, particularly against the respiratory and abortion forms

Welfare Considerations

Equine herpesvirus causes diverse welfare impacts depending on the form of disease. Respiratory EHV causes fever, nasal discharge, and cough that are uncomfortable but usually resolve without serious consequences. Abortion caused by EHV-1 is a significant welfare event for both the mare and the lost foal. Equine herpes myeloencephalopathy is the most devastating form, causing bladder paralysis, incoordination, and in severe cases, complete inability to rise. Horses with severe EHM that cannot be managed in recumbency face euthanasia decisions. Outbreak management through immediate isolation and movement restrictions contains spread and protects the wider equine population.

What You Can Do

Maintain current EHV vaccination particularly for horses attending competitions or mixing with others
Implement immediate isolation for horses showing fever, nasal discharge, or neurological signs
Report suspected EHV outbreaks to your vet and relevant equestrian authorities immediately
Follow strict biosecurity including equipment disinfection during outbreaks
Monitor rectal temperature twice daily when EHV is circulating in an area
Inform competition organizers of any horses with recent respiratory illness before attending events