Disease Alerts

Comments: Since the last situation report (11/26/2025), there has been one (1) new confirmed positive equine premises identified in Arizona (Maricopa County - new affected county). All confirmed cases in the 2025 outbreak have been vesicular stomatitis New Jersey virus (VSNJV) serotype. Updates are as follows: Arizona Maricopa County (New Affected County) – On December 9, the National Veterinary Services Laboratories in Ames, Iowa, detected VSVNJ by PCR on swab samples from a lesioned wild horse from the Salt River Wild Horse Management Group located in the Tonto National Forest. The Arizona Department of Agriculture has issued an Administrative Order temporarily restricting movement of domestic livestock, including horses, into or out of the affected Lower Salt River area on public land. Since the last situation report (11/26/2025), the 1 affected premises in Gila County has been released from quarantine. 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. 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.;