Horse Infectious Disease Biosecurity and Welfare

Infectious disease outbreaks in horse populations cause significant individual suffering and require biosecurity practices to prevent spread.

Key Facts

Equine herpesvirus (EHV-1) myeloencephalopathy causes neurological disease, paralysis, and death and is untreatable once neurological
Strangles (Streptococcus equi subsp. equi) is the most common infectious disease of horses globally causing painful abscessation
Equine influenza spreads rapidly through competitive facilities, with transmission distances exceeding 35 meters in aerosol form
MRSA and other antibiotic-resistant bacteria are emerging concerns in equine facilities with implications for both horses and humans
Vaccination programs significantly reduce disease severity and prevalence but cannot provide complete protection
Quarantine of newly arriving horses for 21 days is the gold standard biosecurity measure preventing introduction of new pathogens
Communal water troughs and shared equipment are primary transmission routes for most equine pathogens

Welfare Considerations

Infectious disease in horses causes welfare impacts ranging from the severe acute pain of strangles abscess formation and rupture to the neurological deficits and potential paralysis of EHV-1 myeloencephalopathy. Strangles causes horses to experience severe lymph node swelling under the jaw and throat that interferes with breathing and swallowing, with animals often unable to lower their heads or eat normally for weeks. EHV-1 neurological cases face prognosis-dependent welfare dilemmas ranging from supportive care through euthanasia for severe hindquarter paresis. Disease outbreaks at competition venues create sudden welfare emergencies requiring isolation and monitoring of exposed horses. Individual horse welfare during isolation for infectious disease requires careful attention to social needs since horses are social animals and prolonged solitary confinement causes behavioral stress in addition to any disease-related suffering.

What You Can Do

Maintain current vaccination programs against equine influenza, EHV-1/4, and tetanus as foundational welfare prevention
Implement 21-day quarantine for all new horse arrivals to your property regardless of source certification
Test horses with respiratory signs for EHV-1 before exposing them to other horses at shared facilities
Learn to recognize strangles early signs including nasal discharge and lymph node swelling to enable prompt isolation