Non-Neurologic EHV-1 Quarantine Released in Monterey Co.

A Monterey County, Calif., equine facility has been released from quarantine imposed after two horses residing there tested positive for a non-neurologic strain of equine herpesvirus-1 (EHV-1), according to an April 4 statement from the California Department of Food and Agriculture (CDFA). A San Diego Country property, quarantined in connection with the same non-neurologic EHV-1 outbreak, was released from quarantine last week, the statement noted.

Three geldings--two on one premises in Monterey County and one in San Diego County--tested positive for the non-neurologic strain of EHV-1 in mid- to late March after attending the final week of the HITS Thermal Horse Show March 5-11, 2012, in Thermal, Calif. The horses displayed clinical signs including hind limb ataxia (incoordination) and mild neurologic signs, and were confirmed positive in mid- to late March, according to previous CDFA statements.

On March 30 a mare in Los Angeles County tested positive for non-neurologic EHV-1.

"Epidemiologic investigation indicates this horse may be a secondary exposure to horses from this facility that attended the HITS Thermal Horse Show," the CDFA relayed. "The CDFA continues to monitor the situation."

On March 29, the Snohomish, Wash.-based Pilchuck Veterinary Hospital released a statement indicating that four horses on two premises had tested positive for the non-neurologic strain of EHV-1. Citing the Washington State Veterinarian, Pilchuck Veterinary Hospital reported that three of the four affected horses attended the HITS event; the fourth was considered secondary exposure.

No further information regarding the horses' conditions was immediately available. As of press time, phone calls to the Washington State Veterinarian's office seeking further information on the confirmed cases have not yet been returned.

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).

"(The strain of virus confirmed in California) is responsible for the more common respiratory EHV-1 cases," the CDFA said in a previous statement. "A small percentage of non-neuropathogenic EHV-1 infected horses can display neurologic signs and are classified as equine herpes myeloencephalopathy cases, which is a reportable condition in California." will continue to provide updates as more information becomes available.

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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