The Maryland State Veterinarian’s Office has confirmed a case of Equine Herpesvirus (EHV) / Equine Herpesvirus Myeloencephalopathy (EHM) in Cecil County, identified on December 29, 2025. The affected horse exhibited neurological signs and is currently recovering. The premises, along with all horses housed at the facility, are under quarantine at this time.

Additional horses from the premises traveled out of state during the month of December. MDA’s Animal Health Program has coordinated with the affected states to provide appropriate traceback information.

This ongoing EHV/EHM outbreak serves as a reminder of the disease risks associated with  commingling equine events and highlights the importance of timely disease reporting and adherence to animal movement requirements, including veterinary inspection and health certificates prior to travel.

Horse Owners: If your horses traveled to an equine event where EHV exposure may have occurred, please contact our office directly at 410-841-5810. We will provide guidance regarding isolation and monitoring:  

• Exposed horses should be isolated for 21 days after last known exposure.
• Appropriate isolation includes restricted access to other horses, avoiding the sharing of equipment or personnel, and utilization of protective barrier precautions.
• Exposed horses should be monitored twice daily for elevated temperature (above 101.5^oF), respiratory signs (nasal discharge, coughing), and for clinical signs consistent with Equine Herpes Myeloenceophalopathy (neurologic symptoms including inability to stand, difficulty walking, lethargy, and urine dribbling).
• If elevated temperature, respiratory signs, or EHM-compatible clinical signs are noticed, contact your veterinarian.

Upcoming equine events: Equine Herpes Virus can be shed for prolonged periods of time, including in clinically healthy horses, which increases risk for continued disease spread during a EHV/EHM outbreak.

• Event Organizers: We recommend you consult with your veterinarian and understand the risks associated with hosting equine events during a multi-state outbreak and the execution of biosecurity strategies for these events.
  • A Certificate of Veterinary Inspection (CVI) issued by a Category II Accredited Veterinarian is required. A CVI is required whether the movement of the animal to that show is interstate or intrastate.
  • Please keep in mind the Maryland Department of Agriculture is responsible for enforcing both intrastate and interstate animal movement requirements and event organizers have the power to implement as strict entry requirements to their event as they see fit.
  • We encourage event organizers to reach out to us at animalhealth.mda@maryland.gov with any specific questions and to make us aware of events planned in the near future (within the next 28 days). Please provide specific points of contact of individuals with decision making authority using the MDA Notification of Livestock Event form.
  • The Department does NOT get involved in setting additional entry requirements to equine events. We will implement quarantine authority or prohibit movement to events if the disease risk is deemed too great.
  • Consider working with a private veterinarian to provide CVI review at the event.
  • Cancellation or postponement of events may be important to stop continued spread of disease.
• Horse Owners: We recommend that you consult with your veterinarian on the risks associated with travel to upcoming equine events. EHV is a ubiquitous virus and commonly present in the environment, so biosecurity measures are paramount to decreasing potential for disease transmission.

Veterinarians: If you have a horse with signs of acute neurologic disease, please contact our office at 410-841-5810. If it is after hours, please call 410-841-5971 to reach the veterinarian on call. We will provide guidance on isolation and testing. Diagnosis of EHV can be difficult as periods of viral shedding and viremia may vary - paired samples, including nasal swab and whole blood, is critical.

Interstate Movement: Please note that many states may be implementing movement restrictions or new import requirements for equines during this outbreak. Please always check with the state of destination to ensure that you are following import restrictions.

Routine Veterinary, Dentistry and Farrier Care:  Standards of equine care shall continue without interruption pursuant to MD Code, Criminal Law § 10-604. During this disease outbreak, all veterinarians, equine dentists, and farriers are directed to maintain and enforce enhanced biosecurity protocols to prevent further transmission of EHV/EHM.

Equine Herpes Virus Information:

EHV-1 is spread from horse to horse through contact with nasal discharge or spread as aerosol droplets. Infected horses may not show clinical signs of the virus but may still act as carriers.

Horses can also contract the virus by coming into contact with contaminated surfaces such as stalls, water, feed, tack, and transport vehicles. People can spread the virus from horse to horse by contaminated hands and clothing. It is important for owners to watch for signs and symptoms and practice biosecurity measures. Good biosecurity practices include extensive cleaning and

disinfection of surfaces and equipment that come in contact with affected horses, and individuals who treat or come into contact with infected horses need to follow appropriate disinfection protocols when handling multiple horses.

Visit the department’s website for the list of Reportable Diseases. Additional information and resources:

●       Keeping Horses Healthy During Weekend Events

●       A Guide to Understanding the Neurologic Form of EHV Infection

●       AAEP EHV FAQ

●       AAEP General Biosecurity Guidelines

●       CDFA - AHFSS - AHB - Biosecurity Toolkit for Equine Events

●       EDCC - Updated EHV-1 Outbreak Information

●       AFJ - Farrier Biosecurity

●       APF - Farrier Biosecurity 

●       MDA Notification of Livestock Event

 

Please see the accompanying document with the updated equine CVI requirements for movement within and into Maryland, and frequently asked questions. These documents are also available on the MDA Animal Health webpage.

The Maryland Department of Agriculture State Veterinarian’s Office may be reached any time at

410-841-5810.

 

Regards, 

Dr Jennifer P Trout, DVM
Maryland State Veterinarian

 

Emergency EHV Maryland Requirements and FAQ’s

 

Updated equine movement requirements on the MDA website:

Due to the current Equine Herpes Virus (EHV-1) multi-state outbreak, Maryland is instituting the following actions. Effective immediately:

1. The use of EECVI's is suspended until further notice.
2. Interstate certificates of veterinary inspection (ICVIs) for equids originating from all states are required.
3. An intrastate certificate of veterinary inspection is required for all equine events within Maryland.
4. Equids originating from states, other than Maryland, with confirmed positive EHV-1 cases will need a CVI to be issued within 5 days of travel.
5. The following statement must be included on all equid CVI's:

“The equine(s) listed on this CVI have, during the 21 days prior to the shipment date, not originated from a premises under EHV-1 quarantine, not been exposed to an EHV-1 positive equine, and not attended any event where an EHV-1 positive equine has been confirmed or suspected.”

These actions supersede the current animal import regulations on the website. Failure to comply with these requirements may result in regulatory or legal action.

Please be aware that many states are changing their entry requirements for equids. You will need to contact the state of destination for the most current requirements.

An updated, confirmed cases can be found on the EDCC website.