Colorado’s first vesicular stomatitis cases of 2015 have been detected in horses, and Colorado State University’s Veterinary Diagnostic Laboratories (CSU VDL) have gained special certification to test for the highly contagious virus, which causes painful sores in animals’ mouths and forces quarantines.

Flies and midges are the main way the virus is spread; it is also spread through horse-to-horse contact and through indirect contact, as when tie-outs, trailers, and grooming or feeding equipment used with an infected horse are later used with a healthy horse.

Veterinarians at CSU join the state veterinarian’s office in urging horse owners to practice strict fly control and infection control while on the road at horse shows, fairs, and rodeos to limit the spread of VS.

Horses on five properties in Montrose County, three in Delta County and one in Montezuma County  have tested positive for vesicular stomatitis this year and have been placed under quarantine, state officials announced July 9