On June 2, 2015, horses on two Montrose and one Delta County premises in Colorado tested positive for the disease and have been placed under quarantine. 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. On July 2nd, the National Veterinary Services Laboratory reported positive tests on samples submitted from horses in Montrose and Delta Counties. The initial Colorado disease investigations were accomplished by field veterinarians from the State Veterinarian’s Office at the Colorado Department of Agriculture.

“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.