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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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Sonoma and Sacromento Counties, CA
Outbreak Identifier: 4776
Alert ID: 2139
July 25, 2021
Confirmed Case(s) - Official Quarantine

California Department of Food and Agriculture

Number Confirmed: 5;
Number Suspected: 4;
Number Exposed: 19
Facility Type: Showgrounds;
Horse #1: Age: 6; Gender: Mare; Breed: Warmblood (WB); Onset of Clinical Signs: 7/23/2021;
Clinical Signs: Hind-end Weakness, Limb edema, Nystagmus, Recumbency; Confirmation Date: 7/24/2021; Horse Status: Euthanized; Vaccination Status: Vaccinated;

Horse #2: Age: 15; Gender: Gelding; Breed: Warmblood (WB); Onset of Clinical Signs: 7/22/2021;
Clinical Signs: Ataxia, Cranial Nerve Deficit, Fever, Neurologic Signs, Urine Dribbling; Confirmation Date: 7/23/2021; Horse Status: Affected And Alive; Vaccination Status: Status Unknow

Notes: A 6-year-old Warmblood mare displaying neurological signs has been confirmed positive for EHM secondary to EHV-1. She attended a show in Sonoma County from 7/19-7/24 but did not compete, and event management has notified all participants to monitor temperatures twice daily and report any fevers or neurologic signs to their veterinarians and CDFA, as well as isolate all horses returning from shows at their home premises for at least 7 days. CDFA was onsite, and 19 exposed horses from the index mare’s barn were removed from the show facility and have been isolated and quarantined at the home premises in Sacramento County with the remaining 18 horses at the home premises with twice daily temperature monitoring and enhanced biosecurity measures. Six (6) horses from the home premises displaying fever and/or limb edema have also tested positive for EHV-1. A 15-year-old Warmblood gelding at the home premises that was febrile and tested positive for EHV-1 began displaying neurological signs, ataxia, urine dribbling, and cranial nerve deficits and was moved to isolation under quarantine at a veterinary hospital for care. CDFA continues to actively monitor the situation.;  For more information go to:  Equine Herpesvirus Myeloencephalopathy