STATE VETERINARIAN’S OFFICE (VS) – Positive Diagnosis in Twelve Colorado Counties
Tips for Livestock Owners and Veterinarians

The number of cases of Vesicular Stomatitis (VS) is increasing in Colorado, as is the number of counties where the disease has been found. Colorado has become the fourth state in the country to have confirmed cases of vesicular stomatitis (VS) in 2015. Previous positive cases of vesicular stomatitis this year have been diagnosed in Arizona, New Mexico and Texas.

“The primary spread of VS is thought to occur through insect vectors; the horses involved in these cases have no history of travel,” said State Veterinarian, Dr. Keith Roehr. “Vesicular stomatitis can be painful for animals and costly to their owners. The virus typically causes oral blisters and sores that can be painful causing difficulty in eating and drinking.”

A 2014 outbreak of VS created 556 livestock investigations in Colorado resulting in 370 quarantines with the final quarantines released in January 2015.

Livestock owners who suspect an animal may have VS or any other vesicular disease should immediately contact their local veterinarian. Livestock with clinical signs of VS are isolated until they are determined to be of no further threat for disease spread. There are no USDA approved vaccines for VS. While rare, human cases of VS can occur, usually among those who handle infected animals. VS in humans can cause flu-like symptoms and only rarely includes lesions or blisters.

New for 2015 VS Investigations:
A notable change in the 2015 State response to VS has come from the US Department of Agriculture (USDA) delisting of VS as a foreign animal disease in horses; VS continues to be listed as a foreign animal disease for cattle and other livestock. This USDA procedural change will allow greater flexibility in how VS is managed in respect to equine cases. The primary change will now be that quarantines may be released as soon as 14 days after the onset of clinical signs of the last affected horse on a premises.

“Science has shown that the transmission of the virus is for a brief period of time after the initial clinical signs of VS. Our goal is to appropriately adjust our response to this disease to reduce the negative economic impact to the equine community,” continued Roehr.
With the delisting of VS as a foreign animal disease, Colorado veterinarians may now take a lead role in the management of the disease in equine cases. In earlier cases, CDA or USDA field vets were required to perform the disease investigations on horses; the delisting now allows local veterinarians to perform the initial investigations, collect samples, and collaborate with animal health officials regarding movement restrictions and quarantines.
The Colorado State University Veterinary Diagnostic Laboratory has been approved to perform VS tests on horses in Colorado. This will provide a more timely response on test results.

Vesicular Stomatitis (VS) Signs and Transmission:
VS susceptible species include horses, mules, cattle, bison, sheep, goats, pigs, and camelids. The clinical signs of the disease include vesicles, erosions and sloughing of the skin on the muzzle, tongue, teats and above the hooves of susceptible livestock. Vesicles are usually only seen early in the course of the disease. The transmission of vesicular stomatitis is not completely understood but components include insect vectors, mechanical transmission, and livestock movement.

Tips for Livestock Owners:
Strict fly control is an important factor to inhibit the transmission of the disease.
Avoid transferring feeding equipment, cleaning tools or health care equipment from other herds.
Colorado veterinarians and livestock owners should contact the state of destination when moving livestock interstate to ensure that all import requirements are met. A list of contact information for all state veterinarians’ offices is available at: http://www.colorado.gov/aganimals.
Colorado fairs, livestock exhibitions, and rodeos may institute new entry requirements based on the extent and severity of the current VS outbreak. Certificates of Veterinary Inspection issued within 2-5 days prior to an event can beneficial to reduce risks. Be sure to stay informed of any new livestock event requirements.

Important Points for Veterinarians:
Any vesicular disease of livestock is reportable to the State Veterinarian’s Office in Colorado – to report call 303-869-9130. If after-hours, call the same number to obtain the phone number of the staff veterinarian on call.
With the delisting of VS as a foreign animal disease, Colorado veterinarians may now take a lead role in the management of the disease in equine cases. In earlier cases, CDA or USDA field vets were required to perform the disease investigations on horses; the delisting now allows local veterinarians to perform the initial investigations, collect samples, and collaborate with animal health officials regarding movement restrictions and quarantines.
In livestock other than equine VS is still considered a foreign animal disease, any case with clinical signs consistent with VS will warrant an investigation by a state or federal foreign animal disease diagnostician (FADD).
When VS is suspected in livestock other than equine the FADD will gather the epidemiological information, take the necessary blood samples, collect the necessary fluid or tissue from the lesions, and inform the owners and the referring veterinarian as to necessary bio-security and movement restrictions.

During the event, important VS disease prevention procedures include minimizing the sharing of water and feed/equipment, applying insect repellent daily (especially to the animal’s ears), and closely observing animals for signs of vesicular stomatitis.

For additional information, contact the Colorado State Veterinarian’s Office at 303-869-9130 or to view the current location of cases and other important updates and information you can visit: http://www.aphis.usda.gov/wps/portal/aphis/ourfocus/animalhealth?1dmy&urile=wcm%3apath%3a%2Faphis_content_library%2Fsa_our_focus%2Fsa_animal_health%2Fsa_animal_disease_information%2Fsa_equine_health%2Fsa_vesicular_stomatitis%2Fct_vesicular_stomatitis.

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