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Updates on current disease outbreaks are listed here as they occur and will include the date listed, disease name, location and current status. Specific premises will not be named but the general location by town, county and state will be listed. When locations, events or horses are at risk they will be listed. Updates will be posted as they are received.



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Equine Herpesvirus- Neurologic
Orange County, CA
Outbreak Identifier: 5089
Alert ID: 2438
February 25, 2022
Confirmed Case(s) - Official Quarantine

California Department of Food and Agriculture

Number Confirmed: 2;
Number Suspected: 9;
Number Exposed: 86;
Age: 10; Gender: Gelding; Breed: Warmblood (WB); Onset of Clinical Signs: 2/22/2022;
Clinical Signs: Fever; Confirmation Date: 2/24/2022; Horse Status: Affected And Alive;
Age: 16; Gender: Mare; Breed: Warmblood (WB); Onset of Clinical Signs: 2/22/2022;
Clinical Signs: Nasal discharge, neurologic; Confirmation Date: 2/24/2022; Horse Status: Euthanized;
Notes: A 16-year-old Warmblood mare in Orange county displaying neurological signs on February 22nd was confirmed positive for Equine Herpesvirus Myeloencephalopathy (EHM) secondary to equine herpesvirus-1 (EHV-1 non-neuropathogenic strain) on February 24th. The horse was euthanized due to severity of clinical signs. Additionally, a 10-year-old Warmblood gelding on the same premises displaying fever only with no neurological signs was confirmed positive for EHV-1 on February 24th. The febrile gelding was part of a cohort of horses that attended the event premises in Riverside county that has an active EHM incident, and the neurological mare was exposed to the cohort of horses returning to the home premises from the event in Riverside County. Eighty-six (86) exposed horses on the home premises have been isolated and quarantined. CDFA will continue to closely monitor this situation. To learn more about EHM go to: EHM factsheet. 
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