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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.

Los Angeles County, Orange County, San Bernardino County, Riverside County, San Diego County, CA
Outbreak Identifier: 5645
Alert ID: 3060
June 09, 2023
Confirmed Case(s) - Official Quarantine


VSV Situation Report 6/9/2023

Since the last situation report (6/6/2023), there have been 15 new VSV-affected premises identified (4 confirmed positive, 11 suspect) in California with five counties currently affected:  Los Angeles, Orange, Riverside, San Bernardino, and San Diego Counties.  To date, all confirmed cases have been vesicular stomatitis New Jersey virus (VSNJV) serotype. Updates are as follows:  


  • Los Angeles County (New Infected County) – 1 confirmed positive equine premises
  • Riverside County – 6 new suspect equine premises
  • San Bernardino County – 1 new confirmed positive equine premises
  • San Diego County – 2 new confirmed positive premises (1 equine, 1 wildlife park) and 5 new suspect equine premises
  • Since the last situation report (6/6/2023), the following previously confirmed positive or suspect premises have been released from quarantine: 1 equine premises in Riverside County and 4 equine premises in San Diego County.


Since the start of the outbreak, 77 VSV-affected premises have been identified (29 confirmed positive, 48 suspect) in 1 state, California.  Seventy-five (75) of these premises have had only equine species clinically affected in 5 counties (Los Angeles, Orange, Riverside, San Bernardino, and San Diego Counties), one (1) premises has had clinically affected cattle (San Diego County), and one (1) premises has had clinically affected rhinoceros (San Diego County). 

Of the 77 VSV-affected premises, 10 premises have completed the quarantine period with no new clinical cases and have been released from quarantine.  Sixty-seven (67) premises remain quarantined.  

Additional information and maps of the affected area are contained in the attached situation report.  The situation report is posted publicly on the APHIS website and is accessible at the following link:;