Ohio Disease Confirmed as Equine Herpesvirus Type-1

Ohio Department of Agriculture (ODA) officials have reported that equine herpesvirus type-1 (EHV-1) has been confirmed as the cause of the respiratory and neurologic illness that has plagued University of Findlay horses since Jan. 12.

“Our laboratory test results substantiate the initial clinical diagnosis by veterinary experts a few days ago that EHV-1 caused the current outbreak of illness in horses at the university’s English riding facility,” Ohio’s state veterinarian R. David Glauer, DVM said. Ten horses have died or have been euthanized as a result of the virus.

The EHV-1 organism can spread quickly from horse to horse and can cause three different forms of disease: rhinopneumonitis (a respiratory disease of mostly young horses), abortions in pregnant mares, and the neurologic disease EHV-1 myeloencephalopathy, which can be fatal to horses. The stricken horses in Findlay showed symptoms of the respiratory and neurological forms, Glauer said.

Equine herpesvirus diseases are not reportable diseases in Ohio, so University of Findlay personnel are investigating the source of the outbreak, with assistance from the Ohio State University. University of Findlay officials have voluntarily quarantined the James L. Child Jr. Equestrian Complex where the outbreak occurred, and area horse owners have been advised to quarantine their horses.

ODA’s Animal Disease Diagnostic Laboratory (ADDL) detected the virus on Wednesday using a polymerase chain reaction (PCR) test to study the DNA of samples taken from horses that had shown signs of infection. The testing technique examines the genetic fingerprint of a microbe, allowing a quick and accurate determination as to what it is. A gene-sequencing lab at the Ohio State University studied the samples further and provided information that allowed the ADDL to confirm the initial findings.

"This new technology allows us to work quickly in outbreaks like this to identify the agent causing the infection,” Glauer said. “Under our previous standard testing procedures for growing and isolating a virus, we’d be looking at two weeks minimum before we got a confirmed finding.” The lab is conducting tests on additional samples using both techniques, Glauer said.

C. Michael Kerns, DVM, Director of University Equine Veterinary Services at the University of Findlay and Associate Professor of Animal Science, says that the outbreak situation is improving. One neurologic horse remained recumbent as of Thursday night (Jan. 23) at Ohio State’s Veterinary Teaching Hospital. At least 11 horses at the James L. Child Jr. Equestrian Complex were showing neurologic signs at that time, one of which “goes down and gets up occasionally, so it’s still somewhat critical,” said Kerns. “We haven't had any new cases for about two days so we are more hopeful that we are on the downside of this disease,” he added.

“I think everyone’s doing better and we’re looking forward to being over the worst part of it,” said Kerns. “We’ll try to do our homework to see if there’s anything we can do to make it go more quickly.”

About the Author

Stephanie L. Church, Editor-in-Chief

Stephanie L. Church, Editor-in-Chief, received a B.A. in Journalism and Equestrian Studies from Averett College in Danville, Virginia. A Pony Club and 4-H graduate, her background is in eventing, and she is schooling her recently retired Thoroughbred racehorse, Happy, toward a career in that discipline. She also enjoys traveling, photography, cycling, and cooking in her free time.

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