Breaking News
Survey Assess Horse Owner's Biosecurity Practices
Learn More
Learn More

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.

Mariposa, Madera, Fresno, Tulare County, CA
Outbreak Identifier: 5645
Alert ID: 3450
October 26, 2023
Confirmed Case(s) - Official Quarantine

California Department of Food & Agriculture

Number Confirmed: 4; 
Number Suspected: 4; 
Number Exposed: Unknown; 
Comments: VSV Situation Report 10/25/2023 Briefing Since the last situation report (10/20/2023), there have been 8 new VSV-affected premises (4 confirmed positive, 4 suspect) identified in California, including a new affected county, Mariposa County. All confirmed cases to date have been vesicular stomatitis New Jersey virus (VSNJV) serotype. Updates are as follows: California • Fresno County – 2 new confirmed positive (1 equine, 1 with both equine and cattle affected) and 2 new suspect equine premises • Mariposa County (New Infected County) – 1 confirmed positive equine premises • Madera County – 2 new suspect equine premises • Tulare County – 1 new confirmed positive equine premises • Counties with current VSV quarantines: Fresno, Madera, Mariposa, and Tulare Counties Nevada and Texas • No new confirmed positive premises have been identified. Since the start of the outbreak (5/17/2023), 236 VSV-affected premises have been identified (78 confirmed positive, 158 suspect) in 3 states, California, Nevada, and Texas. Two hundred thirty-one (231) of these premises have had only equine species clinically affected, three (3) premises had only clinically affected cattle (San Diego County and Santa Barbara County, California), one (1) premises had both equine and cattle clinically affected (Fresno County, California), and one (1) premises had clinically affected rhinoceros (San Diego County, California). California has identified 233 affected premises (75 confirmed positive, 158 suspect) in 12 counties (Fresno, Los Angeles, Madera, Mariposa, Orange, Riverside, San Bernardino, San Diego, San Luis Obispo, Santa Barbara, Tulare, 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 236 total VSV-affected premises, 209 premises have completed the quarantine period with no new clinical cases and have been released from quarantine. Twenty-seven (27) premises remain quarantined in California. Additional information and maps of the affected area are at the following link:; 
Previous Alerts: 3436, 3413, 3401, 3376, 3350, 3314, 3282, 3263, 3210, 3174, 3152, 3145, 3126, 3115, 3111, 3099, 3090, 3085, 3071, 3066, 3060