VSV Update 07/05/2019: Confirmed in Colorado

Vesicular Stomatitis Confirmed in Colorado 


Colorado has become the third state in the country to have a confirmed case of vesicular stomatitis (VSV).  On July 3rd, the National Veterinary Services Laboratory reported positive test results on samples submitted from two horses in Weld County.  The two horses reside on separate locations in Weld County and have been placed under quarantine.  The initial Colorado disease investigation was completed by a field veterinarian from the State Veterinarian’s Office at the Colorado Department of Agriculture. 


Both premises in Colorado are private residences with horses as the only livestock species present.  The index premises has 1 of 2 horses presenting with lesions on the sheath and no history of recent movements on or off the premises. The subsequent positive premises has 1 of 3 horses presenting with lip and tongue lesions with a history of only pleasure riding nearby the premises 2 weeks prior and no other recent movements.  There are no additional animals at either location currently showing clinical signs of VSV.  Both premises are under state quarantine and will remain so until at least 14 days from the onset of lesions in the last affected animal on the premises. 


Previous positive cases of vesicular stomatitis in 2019 have been diagnosed in Kinney and Tom Green counties in Texas and in Sandoval County in New Mexico.  Please see the USDA APHIS Veterinary Services website to read the current situation report for all confirmed cases in the US. 


What Veterinarians Need to Know


Report any cases that have clinical signs suggestive of VSV to the State Veterinarian’s Office at 303-869-9130.  Reporting cases as quickly as possible will benefit your client and is the best way to reduce the negative implications to other owners. 


NON-EQUINE CASESAll suspected VSV in non-equine cases (cattle, sheep, goats, pigs, camelids) must be investigated by state or federal animal health officials




  1. Hold Order:  If you suspect VSV, in addition to reporting the case to the State Veterinarian’s Office, inform the owners that they are under a Hold Order which means that livestock cannot leave the premises until testing is done or the State Veterinarian releases the Hold Order.  Once we receive the report, we will mail a hold order to the owner.  Call our office if you have any questions on the restriction of livestock movement into and out of that facility. 


  1. Lab Submission:  Now that the index case has been confirmed in Colorado, the Colorado State University Veterinary Diagnostic Laboratory (CSU VDL) in Fort Collins has been activated to receive and test samples for equine species only with VSV compatible clinical signs from accredited veterinarians. 
    1. When you call to report the case to the State Veterinarian’s Office, you will be given an investigation number that must be included on the lab submission form.  Here is a link to the General Sample Submission Form
    2. Read the Submission Information Details page for more detailed information about submitting samples and the Sample Shipping Information page for specifics on shipping substances.


  1. Sampling:  When sampling a horse for vesicular stomatitis, you must obtain a minimum of two samples:
    1. Serum (for complement fixation) - at least 2mL, separated from the clot and submitted in a red-top or other sterile tube
      1. Note: CF test can be negatively impacted if serum is not separated from the clot
    2. Sterile swab (for PCR) - (Dacron/polyester with a plastic shaft) of lesions placed in a screw-cap or other sterile tube with a maximum of 3mL TBTB media.  Make sure tube lid is secured so fluid does not leak out of the tube.  Do not use wooden shafted swabs as they contain PCR inhibitors and cannot be accepted. 
    3. Additional samples to the swab may include:
      1. Vesicular tissue (epithelium) placed in a screw-cap tube with TBTB media
      2. Vesicular fluid (from unruptured vesicles) placed in a screw-cap tube.


  1. Supplies:  TBTB media will be made available to accredited veterinarians for sample collection for VSV cases.  Please contact one of the following:


  1. CDA Animal Health Laboratory

300 S Technology Ct, Broomfield, CO  80021


  1. Colorado State University, Veterinary Diagnostic Laboratory

Fort Collins:  2450 Gillette Drive, Fort Collins, CO 80526  Ph. (970)297-1281

Rocky Ford:  27847 Road 21, Rocky Ford, CO 81067

Grand Junction  425 29 Road, Grand Junction, CO 81504

  1. The State or Federal field veterinarian in your area


Health Certificates


Colorado veterinarians and livestock owners should contact the state of destination when moving livestock interstate to ensure that all import requirements are met.  States may impose certain restrictions for horses and livestock coming from VSV affected states. Visit this website for a list of contact information for all state veterinarians’ offices. 


If the destination state requires you to certify that the livestock do not originate within a specified distance of a VSV-quarantined premises (for example a 10 mile circle), call our office at 303-869-9130.  One of our staff can map the location of your client and the location of the nearest quarantine so you can ensure they meet the destination state requirements. 


Vesicular Stomatitis Virus Background


Vesicular Stomatitis is a viral disease that primarily affects horses and cattle and occasionally swine, sheep, goats, llamas, and alpacas.  The transmission of VSV is not completely understood, but includes insect vectors such as black flies, sand flies, and biting midges.  The incubation period ranges from 2-8 days.  Clinical signs include vesicles, erosions, and sloughing of the skin on the muzzle, tongue, teats, and coronary bands.  Often excessive salivation is the first sign of disease, along with a reluctance to eat or drink. Lameness and weight loss may follow. 


Humans may become infected when handling affected animals, but this is a rare event.  To avoid human exposure, individuals should use personal protective measures when handling affected animals.



USDA APHIS Veterinary Services National VSV Update

CDA Vesicular Stomatitis Information

Vesicular Stomatitis Guidelines for Shows and Fairs