A recent outbreak of Equine Herpesvirus Myeloencephalopathy (EHM), a highly contagious and sometimes fatal neurological disease in horses, originated from a championship rodeo event in Waco, Texas, in early November 2025. The disease has since spread to multiple states, including confirmed cases in Pennsylvania unrelated to the Texas outbreak. Authorities such as the Pennsylvania Equine Council (PEC), Equine Disease Communication Center (EDCC), and Pennsylvania Department of Agriculture (PDA) are urging horse owners to implement strict biosecurity measures, including quarantines, limiting travel, and careful monitoring of horses for symptoms like fever, nasal discharge, and neurological signs. Several equine events in Pennsylvania have been postponed or scaled back as a precaution.
The virus spreads easily through respiratory secretions and contaminated equipment, with a fatality rate estimated between 30-50%. While there is no cure for EHM, supportive care and vaccination against related strains (EHV-1 and EHV-4) can help manage the disease. The outbreak has prompted increased vigilance among veterinarians and horse owners, emphasizing quarantine protocols and hygiene practices to prevent further transmission. The Pennsylvania Department of Agriculture continues to track exposed horses and enforce quarantine orders, while educating the equine community on containment strategies to mitigate the outbreak’s impact.
