Disease Alerts

Number Confirmed: 1; 
Facility Type: Boarding Facility; 

Horse 1: 
Age: 13; Gender: Gelding; Breed: Quarter Horse (QH); Usage: Pleasure Riding; Clinical Signs: mucopurulent nasal discharge, intermittent cough, fever (102), moderate lymphadenopathy without drainage; Confirmation Date: 8/26/2026; Horse Status: Recovering; Vaccination Status: Status Unknown;

Number Confirmed: 1; 

Horse 1: 
Age: 10; Gender: Gelding; Breed: Paint; Onset of Clinical Signs: 8/28/2026; Clinical Signs: ataxia, muscle fasciculations, hypermetric, hypersensitivity; Confirmation Date: 9/3/2026; Horse Status: Affected And Alive; Vaccination Status: Vaccinated;

Comments: The tenth (10th) equine case of West Nile Virus in California in 2026 was confirmed in Sutter County. On September 3, 2026, a 10-year-old vaccinated Paint gelding in Sutter County displaying neurologic signs was confirmed positive for West Nile Virus. The gelding is alive and recovering. The gelding currently resides in Contra Costa County but was exposed in Sutter County.;

Number Confirmed: 1; 

Horse 1: 
Age: 3; Gender: Mare; Breed: Oldenburg; Onset of Clinical Signs: 8/27/2026; Clinical Signs: ataxia, muscle fasciculations, hypermetric, hypersensitivity; Confirmation Date: 9/3/2026; Horse Status: Affected And Alive; Vaccination Status: Undervaccinated;

Comments: The ninth (9th) equine case of West Nile Virus in California in 2026 was confirmed in Sacramento County. On September 3, 2026, a 3-year-old undervaccinated Oldenburg mare in Sacramento County displaying neurologic signs was confirmed positive for West Nile Virus. The mare is alive and recovering.;

Number Confirmed: 1; 
Number Exposed: 3; 
Facility Type: Private Facility; 

Horse 1: 
Age: 11; Gender: Mare; Breed: Quarter Horse (QH); Usage: Roping; Onset of Clinical Signs: 8/25/2026; Clinical Signs: 1 week of anorexia and ADR which progressed to ataxia, down and fever; Confirmation Date: 9/3/2026; Horse Status: Recovering; Vaccination Status: Unvaccinated;

Number Confirmed: 1; 
Number Suspected: Unknown; 
Number Exposed: 1; 
Facility Type: Farm; 

Horse 1: 
Age: 11; Gender: Gelding; Breed: Paint; Usage: Trail Riding; Onset of Clinical Signs: 8/31/2026; Clinical Signs: mild, infrequent cough, and some nodules that were originally assumed to be bee stings but are large and now opening and weeping; Confirmation Date: 9/4/2026; Horse Status: Affected And Alive; Vaccination Status: Status Unknown;

Comments: A new USDA Vesicular Stomatitis situation report, including quarantine release information, is available here https://www.aphis.usda.gov/sites/default/files/vsv-sitrep-9-3-26.pdf

Number Confirmed: 1; 
Number Exposed: 20; 
Facility Type: Private Facility; 

Horse 1: 
Age: 1; Gender: Mare; Breed: Quarter Horse (QH); Usage: Farm/Ranch; Onset of Clinical Signs: 8/30/2026; Clinical Signs: Weakness Ataxia Anorexia Teeth Grinding Fever; Horse Status: Affected And Alive; Vaccination Status: Unvaccinated;

Number Confirmed: 1; 
Number Suspected: Unknown; 
Number Exposed: Unknown; 

Horse 1: 
Age: 6; Gender: Mare; Breed: Quarter Horse (QH); Onset of Clinical Signs: 8/25/2026; Clinical Signs: hyperesthesia, muscle fasciculations; Confirmation Date: 9/3/2026; Horse Status: Affected And Alive; Vaccination Status: Unvaccinated;

Number Confirmed: 20; 
Number Exposed: Unknown; 
Facility Type: Private Facility; 
Comments: large outbreak under vet care. Guttoral pouch lavage samples. Disease has been going on since June.;

Number Confirmed: 1; 
Comments: Sample Type: Blood; Testing Method: ELISA;