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, Ventura County, CA
Outbreak Identifier: 5645
Alert ID: 3111
July 21, 2023
Confirmed Case(s) - Official Quarantine


VSV Situation Report 7/21/2023

Since the last situation report (7/13/2023), there have been 9 new VSV-affected equine premises identified (3 confirmed positive, 6 suspect) in California.  There are currently six affected counties in California (Los Angeles, Orange, Riverside, San Bernardino, San Diego, and Ventura Counties).  All confirmed cases have been vesicular stomatitis New Jersey virus (VSNJV) serotype. Updates are as follows:  


  • Riverside County – 1 new confirmed positive and 3 new suspect equine premises 
  • San Bernardino County – 1 new suspect equine premises
  • Ventura County – 2 new confirmed positive and 2 new suspect equine premises 
  • Additionally, 1 equine premises in San Diego County previously reported as suspect has since tested VSV-negative and has been removed from the case counts.
  • Since the last situation report (7/13/2023), the following previously confirmed positive or suspect premises have been released from quarantine: 3 premises in Los Angeles County, 2 premises in Riverside County, 1 premises in San Bernardino County and 3 premises in San Diego County. 


  • No new confirmed positive premises have been identified.

Since the start of the outbreak (5/17), 131 VSV-affected premises have been identified (45 confirmed positive, 86 suspect) in 2 states, California and Texas.  One hundred twenty-eight (128) of these premises have had only equine species clinically affected, two (2) premises have had clinically affected cattle (San Diego County, California), and one (1) premises has had clinically affected rhinoceros (San Diego County, California). 

California has identified 130 affected premises (44 confirmed positive, 86 suspect) in 6 counties (Los Angeles, Orange, Riverside, San Bernardino, San Diego, and Ventura Counties).  Texas identified 1 affected premises (1 confirmed positive) in 1 county (Maverick County, Texas).  

Of the 131 total VSV-affected premises, 76 premises have completed the quarantine period with no new clinical cases and have been released from quarantine.  Fifty-five (55) 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 accessible at the following link: https://www.aphis.usda.gov/aphis/ourfocus/animalhealth/animal-disease-information/equine/vsv/vesicular-stomatitis
Previous Alerts: 3099, 3090, 3085, 3071, 3066, 3060