Horse Equine Herpesvirus: Welfare and Biosecurity

Equine herpesvirus causes respiratory disease, abortion, and neurological disease in horses, with biosecurity and vaccination the primary welfare interventions.

Key Facts

Equine herpesvirus type 1 (EHV-1) causes respiratory disease in young horses, abortion in pregnant mares, and neurological disease (EHM) in adults
A 2021 outbreak of neurological EHM at European competitions affected hundreds of horses causing deaths and widespread industry disruption
The neurological form of EHV-1 causes ataxia, weakness, and inability to urinate causing significant welfare harms
Horses that survive neurological EHM require intensive nursing care including bladder management and physical support
Vaccination reduces respiratory disease and abortion risk but does not prevent neurological disease effectively

Welfare Considerations

Equine herpesvirus creates multiple distinct welfare challenges. Mares experiencing EHV-1 abortion suffer reproductive loss stress. Neurological EHM causes severe functional impairment with ataxia, bladder dysfunction, and profound weakness. Nursing care for EHM-affected horses requires intensive management including manual bladder expression to prevent secondary urinary complications. Strict biosecurity during competition and event mixing is the most effective welfare intervention given vaccination limitations for the neurological form. Quarantine protocols when cases are detected limit welfare harms by preventing outbreak spread.

What You Can Do

Implement strict biosecurity protocols when horses mix at competitions, sales, or training facilities
Vaccinate horses against EHV-1 and EHV-4 to reduce respiratory disease and abortion risk
Isolate and seek immediate veterinary care for horses showing neurological signs including ataxia or hind limb weakness
Support equine infectious disease research developing more effective EHM prevention strategies