The United States has confirmed new cases of vesicular stomatitis (VS), marking the first detections of the virus in 2025. The National Veterinary Services Laboratories in Ames, Iowa, have identified vesicular stomatitis New Jersey virus (VSNJV) on two premises located in Cochise County, Arizona.
Although the index cases involve horses, both affected premises also house cattle, placing a range of livestock species at potential risk.
Details of the Confirmed Cases
Two horses—one on each premises—tested positive for VSNJV after showing lesions consistent with vesicular stomatitis. Additional susceptible animals are also present:
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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 (none 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 (none showing clinical signs)
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State officials have placed both premises under quarantine, which will remain in effect until 14 days after the last newly affected animal develops lesions.
How Vesicular Stomatitis Spreads
VS circulates each year in southern Mexico between livestock and insect vectors. Occasionally, when environmental conditions allow, infected insects spread north into the United States.
Confirmed vectors include:
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Black flies
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Sand flies
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Biting midges (Culicoides spp.)
Epidemiological review indicates no recent animal movements on or off either premises, supporting a vector-related introduction.
The last U.S. outbreak ran from May 2023 through January 2024, affecting 319 premises across California, Nevada, and Texas.
Canadian Import Restrictions Now in Effect
Following confirmation of VS in Arizona, the Canadian Food Inspection Agency (CFIA) has implemented import restrictions for livestock originating from affected U.S. states. These restrictions apply to:
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Horses
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Swine
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All ruminants (including dairy and beef cattle, goats, sheep, bison)
Import Suspension
All imports of listed species from VS-affected states are paused until further notice.
Returning Canadian Livestock
Canadian-owned animals are not permitted to return to Canada if they have been in an infected state within the previous 21 days.
Exception:
Animals traveling on their original Canadian health certificate may return within 3 days of the USDA declaring a state infected, provided they undergo veterinary inspection at the Canadian port of entry.
Movement Between U.S. States
Animals located inside a VS-affected state must be transported to a non-affected state, remain there for 21 days, and be certified by USDA before export to Canada.
Transiting Affected States
Producers and haulers should avoid transiting VS-affected states when possible.
If transit is unavoidable, a Supplementary Declaration must be completed at the Canadian port of entry.
Exceptions for Pre-Approved Major Events
CFIA and USDA jointly allow certain pre-approved livestock events to receive animals from VS-affected states under strict conditions. These include:
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Royal Winter Fair
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Agribition
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Calgary Stampede
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Spruce Meadows
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Thunderbird competitions
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Longines Global Tour
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Denver Stock Show
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Houston Livestock Show and Rodeo
Animals using this pathway must meet additional testing, vector-protection, inspection, and permitting requirements and must be inspected by CFIA upon arrival at the Canadian border.
What Livestock Producers Should Watch For
VS can affect multiple species, including horses, cattle, swine, sheep, goats, and llamas. Clinical signs include:
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Drooling or foamy saliva
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Blisters or ulcers in the mouth or on the muzzle
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Lesions on hooves or coronary bands
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Crusting or swelling around the nostrils
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Reduced feed intake or discomfort
VS rarely causes death, but it can lead to production losses, movement restrictions, and extended quarantine periods.
Producers are encouraged to:
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Monitor animals for lesions or excessive salivation
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Reduce exposure to biting insects
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Review movement plans, especially across borders
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Stay updated on state and federal advisories
Staying Informed
Producers should monitor:
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CFIA updates on VS-affected states
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USDA situation reports
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Local and provincial/state livestock health alerts
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Transportation and event-specific health requirements
Your local CFIA district office can provide the most current guidance on movement and certification.
