The Texas Animal Health Commission (TAHC) reported three horses in Pecos County tested positive for vesicular stomatitis (VS), a highly contagious virus that mimics foot-and-mouth disease and also affects cattle, reports NewsWest 9 of Midland.

This is the first confirmed case of VS in Texas this year. Testing conducted by the U.S. Department of Agriculture’s (USDA) National Veterinary Services lab in Ames, Iowa later confirmed the New Jersey serotype of virus in the horses.

The horses are kept at premises approximately 30 miles north of Fort Stockton and were taken to a local veterinarian after the owner observed blistering and swelling on the animals’ tongues and lips. The virus can be spread by insect vectors and contact between animals and humans.

Livestock should be monitored for any changes in behavior, appetite or appearance. Any swelling, discoloration or ulceration—“basically anything that doesn’t look like nice, pink gums—should be reported immediately to a veterinarian, said Dr. Tita Burnham, veterinarian. Vesicles commonly appear on the gumline and surface of the tongue.