Skip to content

EHV-1 Neurological Disease Incident from the AHC

From the American Horse Council:

State and federal animal health officials confirmed several cases of Equine Herpes Virus (EHV-1) and Equine Herpes Virus Myeloencephalopathy (EHM) in horses that attended a cutting horse event in Ogden, Utah held from April 29 to May 8, 2011.

The National Cutting Horse Association (NCHA) implemented immediate biosecurity protocols and notified state veterinarians of individual horses, potentially exposed to the reportable disease EHV-1 during the Ogden event, which may have reentered their respective states. Horses which were exposed at the event in Utah and have since left the event may expose horses at their home farm or other equine facilities.

Following confirmation of the EHV-1 neurological disease, the American Horse Council (AHC) and the American Association of Equine Practitioners (AAEP) contacted the U.S. Department of Agriculture (USDA) and requested federal coordination for data collection, dissemination, and communication efforts among state and federal veterinarians in order to protect the health of horses and mitigate the economic implications of further EHV-1 transmission within states not yet affected.

Current Status
In response, USDA has reached out to state veterinarians, federal Area-Veterinarians-In-Charge (AVICs) and private practitioners to collect current information on the EHV-1 disease incident and develop a coordinated response among state, federal, and industry partners. The full scope of the current EHV-1 situation and a complete accounting for the number of horses affected and/or exposed has yet to be determined.

USDA and state veterinarians have initiated an epidemiological investigation and incident response effort, and we anticipate USDA releasing the initial incident report on the exact number of horses confirmed EHV-1 positive in the coming days. USDA anticipates updating and releasing future incident reports on the current EHV-1 incident on a weekly basis going forward. If the current incident results in wide-spread exposure or a large influx of positive horses, we anticipate that USDA will provide that information as it becomes available.

There have been numerous articles citing a wide variation in the number of confirmed cases of the EHV-1 neurological disease in horses. This large disparity in epidemiological information underscores the importance of allowing USDA and state veterinarians to collect the appropriate data, verify the information gathered, and disseminate factually correct information.

Until state and federal animal health officials are able to gather, verify, and disseminate accurate information on the scope of the current incident, it is critical individual horse owners and organizations undertake appropriate and responsible actions to mitigate the welfare and economic implications of potential future transmissions.

New Travel Requirements for Horses Entering Colorado
As of the release of this notice, only Colorado has implemented enhanced entry requirements in response to the on-going EHV-1 disease situation. Colorado's requirement reads as follows:

Standard requirements for horses entering Colorado include a health issued certificate within 30 days of their arrival and a negative Coggins test within 12 months. The new requirement consists of a permit to enter the state. Horse owners who wish to bring their horse into Colorado must first call their veterinarian. That veterinarian can then contact the Colorado Department of Agriculture's State Veterinarian's Office at (303) 239-4161 and request a permit number. That number would then be included on the health certificate.

Please contact the Colorado State Veterinarian's office (303-239-4161) for additional information on these requirements. Additionally, if you anticipate transporting your horse across state lines it is recommended you contact the each respective state veterinarian's office prior to departure to determine if there are any restrictions or enhanced entry requirements due to the current EHV-1 incident.

In the interim, the AHC stresses the importance of responsible ownership practices and informed communication among industry organizations. Please see the following links for additional information on EHV-1 transmission risks and disease mitigation strategies.

Additional Resources

USDA-APHIS website:
EHV information sheets, color brochures, historical information, and a review of disease mitigation strategies are available on the USDA-APHIS website:

AAEP website:
General EHV resources through the American Association of Equine Practitioners:

Neurologic Disease Guidelines:

Equine Herpes Virus:

Biosecurity Guidelines:

Biosecurity Instructions for Caretakers - English & Spanish:

National Cutting Horse Association (NCHA) website:
For history of the current outbreak and additional outreach materials:

ACVIM Consensus Statement on EHV-1:

More Stories