Disease Alerts

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.

Riverside County, CA
Outbreak Identifier: 5541
Alert ID: 2936
March 16, 2023
Confirmed Case(s) - Official Quarantine

California Department of Food and Agriculture

Number Confirmed: 1
Number Exposed: 9
Facility Type: Event Center
Age: 17; Gender: Mare; Breed: Polo pony; Usage: Polo; Onset of Clinical Signs: 3/11/2023
Clinical Signs: Dragging pelvic limb 2 days prior to decreased appetite, ataxia, and reactivity on cervical spinal palpation, then found recumbent and unable to rise the following morning. Afebrile.; Horse Status: Euthanized; Vaccination Status: Status Unknown
Comments: A 17-year-old polo horse mare at a polo facility in Riverside County displaying nonspecific lameness followed by severe neurological signs on March 14th was confirmed positive for Equine Herpesvirus Myeloencephalopathy (EHM) secondary to Equine Herpesvirus-1 (EHV-1, non-neuropathogenic strain) on March 16th. The mare had not participated in any practices or matches over the past week, and was euthanized due to severity of clinical signs. Nine (9) horses housed with the index case were immediately isolated at an adjacent empty premises and subsequently quarantined with enhanced biosecurity measures implemented. CDFA is working with the attending veterinarian and polo club management to ensure all horses that have visited the polo facility in the past two weeks are monitored closely and owners adhere to biosecurity recommendations both at the polo facility and their home premises. Out of abundance of caution, all polo activities in the local area have been voluntarily postponed until further notice. CDFA will continue to closely and actively monitor the situation. For more information and updates, go to: https://www.cdfa.ca.gov/ahfss/Animal_Health/equine_herpes_virus.html