A Boulder County premises is under quarantine after equine vesicular stomatitis (VS) was confirmed there, and a number of other premises in the surrounding area are being investigated.

Last week, four horses on two Weld County premises were placed under quarantine after testing positive for VS. Colorado is the second state in the country to have VS; previous positive cases in 2014 have been diagnosed in Texas.

“Strict fly control is an important factor to inhibit the transmission of vesicular stomatis," said Colorado State Veterinarian Keith Roehr, DVM. "One of the most important disease prevention practices … is insect control for both the premises and the individual animals.”

Equids, mules, cattle, bison, sheep, goats, pigs, and camelids are all susceptible to VS. The clinical signs of the disease include vesicles, erosions, and sloughing of the skin on the muzzle, tongue, teats, and above the hooves of affected livestock. Vesicles are usually only seen early in the course of the disease. The transmission of VS is not completely understood but components include insect vectors, mechanical transmission, and livestock movement