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.

Outbreak Identifier: 5645
Alert ID: 3263
August 31, 2023
Confirmed Case(s) - Official Quarantine


VSV Situation Report 8/30/2023

Since the last situation report (8/22/2023), there have been 4 new VSV-affected premises identified (0 confirmed positive, 4 suspect) in California.  All confirmed cases have been vesicular stomatitis New Jersey virus (VSNJV) serotype. Updates are as follows:  


  • Riverside County – 1 new suspect equine premises
  • San Luis Obispo County – 1 new suspect equine premises
  • Santa Barbara County – 1 new suspect equine premises
  • Ventura County – 1 new suspect equine premises 
  • Since the last situation report (8/22/2023), the following previously confirmed positive or suspect premises have been released from quarantine: 1 premises in Los Angeles County, 1 premises in San Diego County, 3 premises in San Luis Obispo County, 2 premises in Santa Barbara County, and 2 premises in Ventura County. 

Nevada and Texas

  • No new confirmed positive premises have been identified.
  • Since the last situation report (8/22/2023), the one equine premises in Shackelford County, Texas has been released from quarantine. 

Since the start of the outbreak (5/17/2023), 200 VSV-affected premises have been identified (68 confirmed positive, 132 suspect) in 3 states, California, Nevada, and Texas.  One hundred ninety-seven (197) of these premises have had only equine species clinically affected, three (3) premises have had clinically affected cattle (San Diego County and Santa Barbara County, California), and one (1) premises has had clinically affected rhinoceros (San Diego County, California). 

California has identified 197 affected premises (65 confirmed positive, 132 suspect) in 9 counties (Fresno, Los Angeles, Orange, Riverside, San Bernardino, San Diego, San Luis Obispo, Santa Barbara, and Ventura Counties).  Texas identified 2 affected premises (2 confirmed positive) in 2 counties (Maverick and Shackelford Counties).  Nevada identified 1 affected premises (1 confirmed positive) in 1 county (White Pine County, Nevada).  

Of the 200 total VSV-affected premises, 166 premises have completed the quarantine period with no new clinical cases and have been released from quarantine.  Thirty-four (34) 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: 3210, 3174, 3152, 3145, 3126, 3115, 3111, 3099, 3090, 3085, 3071, 3066, 3060