Additional confirmed cases of Vesicular Stomatitis (VSV), a reportable animal disease, have been found in Platte County, Laramie County, and Converse County recently. National Veterinary Services Laboratory reported the disease to the Wyoming state veterinarian after testing samples that were submitted by regulatory veterinarians in late July and early August. The samples came from horses with oral lesions suggestive of VSV. Other potentially affected animals in Platte County are being investigated by Wyoming Livestock Board (WLSB) and USDA APHIS veterinarians.
The main symptoms of VSV are slobbering, blisters, sores and sloughing of skin in the mouth, on the tongue, on the muzzle, inside the ears and on the coronary band above the hooves. Lameness and weight loss may also occur. VSV-infected horses have been found in 2019 in Colorado, New Mexico, Oklahoma, and Texas. VSV can threaten other livestock species, including cattle, sheep, goats and pigs.
Flies and midges are the main vectors for VSV. The virus is also spread through direct contact with infected livestock and indirectly through contact with contaminated equipment and tack. Fly control, including eliminating fly breeding and hiding habitat, is the most important step in preventing the disease. Good sanitation and bio-security measures can help avoid exposure.
Wyoming’s most recent previous outbreaks of VSV were in 2005, 2006, and 2015. Nearly all of the affected livestock during those outbreak years were pastured along drainages or had very recent history of exposure to low-lying, riparian areas. We advise livestock owners, if possible, to move their healthy animals to higher, dryer ground until the VSV insect vector season subsides. That is generally after two hard frosts.
VSV is particularly significant because it is clinically indistinguishable from foot-and-mouth disease (FMD), swine vesicular disease, and vesicular exanthema of swine, all serious foreign animal diseases (FAD). Because of similarities to these FADs, it is essential to quickly confirm a diagnosis with laboratory testing. Of the vesicular diseases, VSV is the only one that affects horses, and the presence of lesions is suggestive of VSV. Finding VSV in Converse County is a concern to State Veterinarian Jim Logan due to the upcoming Wyoming State Fair (WSF) and exposure risks to livestock coming to the fair. WSF officials are taking precautions now and during the fair to mitigate exposure risks. Exhibitors are advised to also make every effort to avoid exposure by using insect repellant on their animals and to avoid sharing tack and water or feed buckets between animals. Dr Logan asks that exhibitors be particularly conscientious about their animal’s health and don’t bring unhealthy animals to the fair.
If you suspect VSV in your animals, contact your veterinarian immediately. Vesicular Stomatitis is a reportable disease that should be immediately reported to the Wyoming state veterinarian at 307-857-4140 or to the USDA APHIS Veterinary Services’ Wyoming Office at 307-432-7960.