EHV-1 Prevalence in Horses With Respiratory Disease

Submitting blood and nasal secretion samples gives vets the best chance of accurately diagnosing EHV, researchers found.

No account yet? Register


Few horse health conditions have garnered as much attention across the country in recent years as equine herpesvirus-1 (EHV-1). And for good reason. When it comes to a virus that can hide dormant in a horse for decades or kill him in a matter of weeks, owners can’t seem to get enough information.

While veterinarians have a good grasp on many aspects of EHV-1, researchers are always working to better understand this ubiquitous ailment. Case in point: Nicola Pusterla, DVM, PhD, Dipl. ACVIM, a professor at the University of California, Davis, School of Veterinary Medicine, recently completed a study in which he and colleagues, with support from colleagues at Merck Animal Health, sought to better understand EHV-1 prevalence in horses with signs of upper respiratory tract infection. He presented the results at the 2015 American Association of Equine Practitioners’ Convention, held Dec. 5-9 in Las Vegas.

Equine herpesvirus-1 causes varying clinical signs. In young horses it typically appears as a respiratory virus with clinical signs such as fever, lethargy, anorexia, mandibular lymphadenopathy (enlarged lymph nodes), and profuse clear nasal discharge. In adult horses EHV-1 can produce similar clinical signs, but it could also remain subclinical (meaning the horse shows no outward signs of disease), cause abortions in pregnant mares, or result in neurologic complications (a condition termed equine herpesvirus myeloencephalopathy).

In their recent study, Pusterla and colleagues sought to gain a better understanding of EHV-1 prevalence and epidemiology. They tested more than 4,000 voluntarily submitted nasal secretion and blood samples from equids with fever, signs of respiratory infection, and/or neurologic disease using qPCR, an assay that detects bacterial and viral DNA. The team also collected responses from a questionnaire regarding the horses’ background and clinical signs

Create a free account with to view this content. is home to thousands of free articles about horse health care. In order to access some of our exclusive free content, you must be signed into

Start your free account today!

Already have an account?
and continue reading.


Written by:

Erica Larson, former news editor for The Horse, holds a degree in journalism with an external specialty in equine science from Michigan State University in East Lansing. A Massachusetts native, she grew up in the saddle and has dabbled in a variety of disciplines including foxhunting, saddle seat, and mounted games. Currently, Erica competes in eventing with her OTTB, Dorado.

Related Articles

Stay on top of the most recent Horse Health news with

FREE weekly newsletters from

Sponsored Content

Weekly Poll

sponsored by:

What do you think: Can pituitary pars intermedia dysfunction (PPID) be managed by medication alone?
171 votes · 171 answers

Readers’ Most Popular

Sign In

Don’t have an account? Register for a FREE account here.

Need to update your account?

You need to be logged in to fill out this form

Create a free account with!