During Equine Herpesvirus Myeloencephalopathy (EHM) incidents, the State Animal Health Officials’ (SAHO) goal is to prevent the spread of the disease agent. Science-based disease control protocols, adapted to the specific incident, control disease spread while ensuring compliance and minimizing the impact on equine movement. There is no single protocol that can be applied to all EHV incidents as there are multiple factors that must be considered when determining the optimal disease containment response

Regulatory authority and response to Equine Herpesvirus incidents will vary from state to state. Veterinary professionals should always consult with their SAHO when responding to EHV incidents. This guidance document provides SAHOs with science and field experience based control guidance to be considered during an EHM incident. This guidance document is an evolving document. Elements of this guidance document may be utilized for response to non-neurologic EHV-1 and neurologic EHV-4 cases.

Resource Type

  • Guideline

Publish Date

November 15, 2025