Vesicular Stomatitis (VS) virus first showed up this year on July 18, when four horses in Weld County tested positive for the disease and were placed under quarantine.
“Fast forward five weeks,” said CSU Extension Agent Karen Crumbaker, “to August 28, when the Colorado Department of Agriculture confirmed 313 horses and 7 cows have tested positive for VS in Colorado, causing 222 quarantines. The spread of VS went from one county to eight, Larimer County being one of the counties with 56 quarantined locations.”
The concern according to Crumbaker is many of these horses had no history of leaving their property. Although not completely understood, says Crumbaker, it is believed the spread may be by insects, mechanical transmission, and livestock movement. According to the CDA, strict fly control is an important factor to inhibit the transmission of the disease, as well as avoiding transferring feeding equipment, cleaning tools and health care equipment from other herds.
According to Paul Morley, a DVM at CSU Veterinary Teaching Hospital, “The viral infection itself is not deadly. The most common signs we see in these animals is that the infection is irritating and not much fun for the animals, but it is not life threatening.”
Crumbaker says horses, mules, cattle, bison, sheep, goats, pigs and camelids are VS susceptible species. The clinical signs of the disease include vesicles (blisters), erosions and sloughing of the skin on the muzzle, tongue, teats and above the hooves. Vesicles are usually only seen early in the course of the disease. “Vesicular stomatitis can be painful for animals and costly to their owners,” said State Veterinarian, Keith Roehr. “The virus typically causes oral blisters and sores that can be painful causing difficulty in eating and drinking”.
According to CSU Veterinary Extension, the disease closely resembles foot and mouth disease in cattle, therefore it is vitally important to have the disease correctly identified. The virus is not typically transferred to humans, although people working closely with infected animals may become infected with the virus. The saliva from animals with ulcers in their mouth is infectious, so wearing gloves when handling infected animals is recommended.
Veterinarians and livestock owners who suspect an animal may have VS should immediate contact state or federal animal health authorities. Livestock with clinical signs of VS should be isolated until they have healed and determined to be of no further threat to spread the disease. There are no USDA approved vaccines for VS.
Colorado State University hosted an interactive online discussion about VS and the presentation can be viewed at csu-cvmbs.colostate.edu. Viewing the presentation will help all interested horse and livestock owners understand the disease, its transmission, reasons for quarantine, economic concerns during the current outbreak, the fate of horse shows and events, disease treatment and preventative measures.
For additional information, contact the Colorado State Veterinarian’s office at 303-869-9130.