The United States has confirmed new cases of vesicular stomatitis (VS), marking the first detections of the virus in 2025. According to the USDA’s National Veterinary Services Laboratories, two premises in Cochise County, Arizona have tested positive for vesicular stomatitis New Jersey virus (VSNJV). Although the initial cases involve horses, both premises also house cattle, placing broader livestock sectors on alert.
Overview of the Confirmed Cases
Two horses—one on each affected premises—tested positive after showing clinical signs consistent with VS. Viral genome sequencing confirmed VSNJV.
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Premises #1:
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1 confirmed horse
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52 additional horses
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120 cattle (not showing clinical signs)
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Premises #2:
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1 confirmed horse
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6 additional horses
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60 cattle (not showing clinical signs)
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At this time, no cattle have been reported with active lesions, but the presence of susceptible animals means ongoing monitoring is in place.
Both affected premises are under state quarantine, which will remain in effect until 14 days after the last new lesion is observed in any affected animal.
How Vesicular Stomatitis Reaches the U.S.
VS circulates annually between livestock and insect vectors in southern Mexico. It occasionally enters the United States when environmental conditions support northward movement of infected insects.
Confirmed insect vectors include:
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Black flies
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Sand flies
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Biting midges (Culicoides spp.)
Initial epidemiological investigations in Arizona show no recent livestock movement, suggesting the likely source is vector-borne introduction.
The most recent U.S. outbreak occurred from May 2023 to January 2024, affecting 319 premises in California, Nevada, and Texas.
Canadian Import Restrictions Now in Effect
Following these confirmations, the Canadian Food Inspection Agency (CFIA) has implemented movement restrictions on livestock coming from VS-affected U.S. states. These restrictions apply to:
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Horses
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Swine
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Ruminants (including beef and dairy cattle)
Import Suspension
Importation of these animals from affected states is suspended until further notice.
Returning Canadian Livestock
Canadian-owned animals that have stayed in a VS-affected state within the previous 21 days cannot return to Canada, unless they meet strict exemption conditions, including:
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Returning within three days of the USDA declaring a state infected
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Traveling on their original Canadian health certificate
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Veterinary inspection at the Canadian port of entry
Otherwise, the health certificate becomes null and void.
Movement Between U.S. States
Animals currently in an infected state must move to a non-infected state and remain there for 21 days before they can be certified for export to Canada.
Owners are also advised to check individual U.S. state-level requirements, as several impose additional movement controls, permits, or testing.
Transiting Through Affected States
Whenever possible, producers should avoid transiting through VS-affected states. If unavoidable, a Supplementary Declaration must be completed at the Canadian port of entry.
Special Allowances for Major Competitions and Exhibitions
CFIA and USDA maintain pre-approved exemptions for major agricultural events, allowing U.S. and Canadian horses and ruminants from affected states to attend, provided stringent conditions are met.
Pre-approved events include:
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Royal Winter Fair
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Canadian Western Agribition
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Calgary Stampede
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Thunderbirds
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Spruce Meadows
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Longines Global Tour
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Denver Stock Show
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Houston Livestock Show and Rodeo
Animals qualifying for this exemption require:
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CFIA import permit
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USDA health certificate with VS addendum
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c-ELISA testing within 7 days
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Inspection within 7 days
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Protection from insect vectors before and during transport
All animals must undergo CFIA inspection at the port of entry.
Why This Matters for Cattle and Beef Producers
Although the index cases involve horses, cattle are susceptible to VS and can develop:
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Excessive salivation
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Oral ulcers or blisters
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Crusting around the muzzle
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Lesions on teats and coronary bands
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Temporary drop in feed intake, milk production, or weight gain
Quarantine periods can interrupt normal herd management, marketing, and transport—especially during active sale periods or the fall run.
Vector control remains one of the most effective tools to reduce risk, particularly in areas where black flies and midges are common.
Staying Informed
Producers moving livestock into or out of the United States should monitor:
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CFIA’s daily updates on affected states
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USDA’s vesicular stomatitis situation reports
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State-level animal health advisories
Local CFIA district offices can provide the latest movement and certification requirements.
