Vesicular stomatitis (VS) has been confirmed in three horses on two farms in Colorado, resulting in the quarantine of affected premises and transportation restrictions on Colorado livestock to two other states. One affected farm with two VS horses is in Las Animas County, which is on the southeast border of the state, and one Douglas County horse is affected in Central Colorado. Veterinarians suspect VS in an additional two Las Animas animals, a beef cow and a horse, on a separate premise from the equine cases.

According to Wayne Cunningham, DVM, MS, Colorado state veterinarian, the index (first) case, which occurred on the Las Animas site with two affected horses, began showing clinical signs of VS on June 27. Signs included blister like lesions on the mouth, tongue, and nostrils. This horse and the others in Las Animas County, “Are backyard horses, were not traveling, and were staying in one spot,” said Cunningham. “The one horse in Douglas County had been to New Mexico a week or so prior.”

The suspected bovine case is located five to six miles away from the other Las Animas premises. Blood samples have been sent to the USDA’s Plum Island foreign animal disease laboratory in New York. “I think that will be a confirmed case–it will be tomorrow or Thursday before we hear (results),” said Cunningham. “The reason we (sent this sample to Plum Island) is because we have to differentiate vesicular stomatitis from foot and mouth disease (FMD). You can’t tell them apart clinically, but certainly it’s most likely VS. We just want to err on the side of caution.”

Horses are not affected by the foreign animal disease FMD, which infects cloven-hooved livestock. Foot and mouth disease could have devastating ramifications to national and international movement of livestock. Since horses have shown VS in Las Animas County, it is expected that VS is what is ailing the cow