Horse Equine Herpesvirus Welfare and Biosecurity

Equine herpesvirus (EHV) causes respiratory disease, abortion storms, and neurological disease (EHM), requiring stringent biosecurity to prevent outbreaks with devastating welfare consequences.

Key Facts

EHV-1 and EHV-4 cause respiratory disease, abortion, and occasionally severe neurological disease
Equine herpesvirus myeloencephalopathy (EHM) causes paralysis and is often fatal or results in euthanasia
The 2021 EHM outbreak in Europe affected horses at equestrian competitions across multiple countries
The virus is spread through direct contact, respiratory secretions, and aborted fetuses
Vaccination reduces respiratory disease severity but does not reliably prevent neurological disease
Isolation of suspected EHV cases and respiratory illness is the most important biosecurity measure
Large gatherings of horses from multiple sources create the highest outbreak risk

Welfare Considerations

EHV outbreaks can have catastrophic welfare consequences. EHM causes rapid-onset neurological signs including ataxia, hindlimb weakness, and paralysis that is deeply distressing to witness and experience. Affected horses that cannot rise are at immediate risk of further injury. Many EHM cases result in euthanasia for humane welfare reasons. Abortion storms cause significant loss - mares abort developed fetuses to which they have formed some bond. The respiratory disease form causes widespread illness across affected herds. The 2021 outbreak demonstrated how rapidly EHV can spread through equestrian events, affecting horses across multiple countries within weeks.

What You Can Do

Isolate any horse with respiratory illness immediately and notify your veterinarian
Implement temperature monitoring and isolation protocols at equestrian competitions
Maintain current EHV vaccination in horses traveling to competitions
Report suspected EHV cases to veterinary authorities - rapid response limits outbreak spread
Avoid high-density horse gatherings during active EHV outbreaks in your region
Follow return-to-competition biosecurity requirements after attending events near confirmed EHV cases