EHM in California: Case Diagnosed in San Mateo County

The 24-year-old Arabian mare, who was exhibiting neurologic signs of disease, has been quarantined.
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ehm in california
In many horses, the first or only sign of EHV-1 infection is fever, which can go undetected. | Photo: Kevin Thompson/The Horse

The California Department of Food and Agriculture (CDFA) reported Nov. 7 that a San Mateo County horse has been diagnosed with equine herpesvirus myeloencephalopathy (EHM), the neurologic form of equine herpesvirus-1 (EHV-1).

The 24-year-old Arabian mare was exhibiting neurologic signs of disease.

“The mare was removed from the property and placed in isolation and quarantined,” the CDFA said. “(The) CDFA is investigating to identify exposed horses which will be monitored for clinical signs and temperatures taken twice daily. Any horse displaying a fever or compatible clinical signs will be tested

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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.

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