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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.



Maricopa County, AZ
Outbreak Identifier: 7304
Alert ID: 4848
January 27, 2026
Confirmed Case(s) - Official Quarantine

Animal and Plant Health Inspection Service of the United States Department of Agriculture

Comments: Since the last situation report (1/9/2026), there has been one (1) new confirmed VSV positive equine premises identified in Arizona (Maricopa County). All confirmed cases in the 2025-26 outbreak have been vesicular stomatitis New Jersey virus (VSNJV) serotype. Updates are as follows: Arizona • Maricopa County – 1 new equine premises confirmed VSV-positive • Since the last situation report (1/9/2026), 1 VSV-affected premises was released from quarantine in Santa Cruz County. Classification of Cases Premises that have diagnostic laboratory confirmation of VSV are categorized as confirmed positive premises. Once a county is confirmed as VSV-positive, new equine premises presenting with clinical signs of VSV in that county are not required to be tested for confirmation of the disease, but the premises will be quarantined and classified as a presumptive positive premises. Premises may also be classified as presumptive positive if clinical animals on the premises fail to meet confirmed case definition, but there is diagnostic laboratory evidence of recent VSV infection. Quarantines Confirmed and presumptive positive premises are quarantined for at least 14 days from the onset of lesions in the last affected animal on the premises.;

For more information, go to https://www.aphis.usda.gov/livestock-poultry-disease/cattle/vesicular-stomatitis