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horses and riders

Equine Herpes Virus (EHV-1) has frequently been in the news recently, and is a concern of many horse owners, but what is EHV-1?   It's one of the most common respiratory diseases affecting horses, commonly found in horse populations worldwide.  There are at least four equine herpes viruses.  EHV-1 and EHV-4 are the two herpes viruses that commonly cause respiratory disease.

EHV-1 is also well known for causing reproductive disease, and was previously referred to as the equine abortion virus, but it can also cause neurological disease. In horses infected with the neurologic strain of EHV-1, clinical signs may include: nasal discharge, uncoordination, hind end weakness, recumbency, lethargy, urine dribbling and diminished tail tone.

Transmission occurs when infected and uninfected horses come in either direct (nose to nose contact) or indirect contact (through buckets, clothing, blankets that are contaminated) with nasal discharges of infected horses. The virus can travel via aerosol (in the air) for short distances.

Recent Events
Horses participating at the National Cutting Horse Association's (NCHA) Western Championships show in Ogden, Utah during the period of April 30 through May 8, 2011 are believed to have had opportunity of exposure to EHV-1. A statement from the National Cutting Horse Association regarding the reported cases of EHV-1 at the event can be found at

According to the Colorado Department of Agriculture, there have been 6 confirmed cases of horses with EHV-1, as of May 18, 2011. There are also 14 suspect cases. Suspect cases are those horses that are believed to have been exposed to EHV-1 but confirmatory tests are still pending.

For updated and accurate information regarding the EHV-1 situation, visit the United States Department of Agriculture (USDA) website. 

In Nebraska...
Currently, five horse premises in Nebraska have been quarantined by Nebraska Department of Agriculture (NDA) due to horses that participated in the NCHA Western Championships.  However, to date none of these horses have shown signs of the disease. NDA has not implemented any additional commerce or import requirements on horse movement at this time. This status could change, and it would be prudent for horse owners to check the NDA website prior to the date of any travel for updates.

NDA encourages all horse producers to follow biosecurity measures on their operations, including: requiring individuals to wash their hands before and after contact with each horse; avoid contact with other horses; disinfect boots and change clothes that come into contact with horses other than your own; isolate horses returning from shows or events for 2-3 weeks.

Managing EHV-1: Online Resources

Many information resources are available for horse owners, enabling them to learn more about this disease and implement good management practices on their farms and acreages.

American Association of Equine Practitioners (AAEP) Resources on EHV
Find EHV-1 updates, informational resources and information on individual states on The American Association of Equine Practitioners' (AAEP) EHM & EHV Resources webpage.

Extension Resources and Publications on EHV-1

Neurologic Equine Herpes Virus (EHV-1), Utah State University
Informational publication written by Dr. Kerry A. Rood, Utah Extension Veterinarian and Dr. L. Earl Rogers, Utah State Veterinarian. Read more about the background, clinical signs, diagnosis and prevention of Neurologic Equine Herpes Virus (EHV-1).

Equine Herpes Virus, Colorado State University
Informational article about EHV, including the mode of transmission, the primary and secondary symptoms, the treatment options, applicable vaccinations and what you can do to prevent your horse from contracting the disease.

Biosecurity Information/Resources for Horse Farms

Protect Your Barn and Horses from Disease,
Learn about evaluation methods and advice for prevention, protection, and proactive ways of minimizing disease risk in your horse facility by watching this recorded webcast, hosted by Dr. Betsy Greene, Professor of Animal Science and Extension Equine Specialist at the University of Vermont.

USDA Horse Biosecurity Brochure
The United States Department of Agriculture has provided this brochure with general suggestions and guidelines regarding biosecurity on horse farms, including topics on transporting horses and using disinfectants.

AAEP Biosecurity Guidelines & Recommendations
The American Association of Equine Practitioners has organized this document with various biosecurity guidelines and recommendations for farms that house horses with EHV-1 or horses that have been exposed to the virus. Read about management of manure and bedding, as well as methods of disinfection horse equipment and facilities.

By Kathleen Anderson, Nebraska Extension Horse Specialist