Biosecurity Can Help Prevent Spread of EHV-1 Infections

The neurologic form of the equine herpesevirus-1 (EHV) called equine herpesvirus myeloencephalopathy (EHM), a potentially fatal disease of horses, can largely be avoided by instituting and maintaining standard biosecurity measures, which are readily available from the American Association of Equine Practitioners.

A real-life example is a 6-year-old North Carolina mare that was confirmed EHV-1 positive last week. According to investigators, ideal biosecurity measures such as isolating all horses entering the premises--even those returning from shows--for three weeks, were not standard protocol on the mare's home farm. The proprietors of the property weren't alone in that respect--the majority of stables and equine facilities share similar practices, investigators said.

"The farm now has strict biosecurity measures in place," affirmed Tom Ray, DVM, MPH, director of Livestock Health Programs for the North Carolina Department of Agriculture and Consumer Services. "Some of the most important measures include separate food and water buckets, individual tack that is not shared, separation of horses returning to the facility from shows, sales, trail rides, and twice-a-day temperatures for five to seven days on any horses exhibiting any unusual signs."

At present, the source of the infection remains unclear and may never be determined.

"The mare, which is North Carolina's first ever reported case of EHM, had not been off the farm, and the other horses on the farm have remained free of signs of EHM infection since the mare was confirmed to have this disease," said Ray. "During the investigation, any horse that had been in contact with the infected mare (such as those shipping in to train at the facility) dating back to Nov. 1, 2011, was contacted. None of those horses had any evidence of infection either."

Although owners are encouraged to ensure their horses are fully vaccinated to prevent the spread of certain diseases, "Vaccination for equine herpes virus, which protects against the 'typical' form of the disease that causes with respiratory signs and abortions, does not protect against the neurological form of the disease (EHM) which is so often fatal," noted Ray.

According to Sam Jones, DVM, PhD, Dipl. ACVIM, North Caroline State University professor of equine medicine, "The mare with confirmed EHV-1 in our hospital isolation facility is continuing to be treating and her condition is improving daily."

About the Author

Stacey Oke, DVM, MSc

Stacey Oke, MSc, DVM, is a practicing veterinarian and freelance medical writer and editor. She is interested in both large and small animals, as well as complementary and alternative medicine. Since 2005, she's worked as a research consultant for nutritional supplement companies, assisted physicians and veterinarians in publishing research articles and textbooks, and written for a number of educational magazines and websites.

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