EHV-1 Outbreak: Utah State Veterinarian Ends Quarantines

Utah State Veterinarian Bruce King, DVM, has officially released from restriction all previously quarantined premises in his state related to the May and June equine herpesvirus-1 (EHV-1) outbreak. Eight Utah-based horses tested positive for EHV-1, two of which were euthanized after becoming recumbent (unable to rise after lying down). A press release from the state Department of Agriculture and Food noted that no additional cases of EHV-1 have been reported in Utah since the end of May.

"The outbreak is believed to have originated at the National Cutting Horse Association (NCHA) Western National Championships held in Ogden, Utah, that ended on May 8, 2011," the press release continued. "A number of horses both in Utah and around the country came down with the sometimes fatal disease shortly after the event. Private practice veterinarians and veterinarians with The Utah Department of Agriculture and Food's Division of Animal Industry confirmed 16 horses in Utah contracted the disease with two of the animals having to be humanely euthanized. A total of seven private farms or facilities in five counties were under quarantine while horses there were observed and tested for the disease."

"EHV-1 is a virus that is present in many horses, but remains dormant until triggered by stress or other circumstances," King said. "EHV was here before the Ogden event, and it will be here after the event."

In the press release King advised that "horse owners should feel free to participate in rodeos, horse shows, parades, and other horse events with no more risk of contracting the disease than before the recent outbreak. Owners are encouraged to practice good biosecurity to help protect the industry."

Although it's not transmissible to humans, EHV-1 is highly contagious among horses and camelids, and it is generally passed from horse to horse via aerosol transmission (when affected animals sneeze/cough) and contact with nasal secretions. The disease can cause a variety of ailments in equines, including rhinopneumonitis (a respiratory disease usually found in young horses), abortion in broodmares, and myeloencephalopathy (EHM, the neurologic form). Myeloencephalopathy is characterized by fever, ataxia (incoordination), weakness or paralysis of the hind limbs, and incontinence.

About the Author

Erica Larson, News Editor

Erica Larson, news editor, 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.

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