Although transmission of the disease is not completely understood, direct contact between animals, shared equipment which has not been sanitized, and insect transmission are all factors. Blisters on the lips and tongue may rupture, causing affected animals to stop eating. Even though vesicular stomatitis has been ruled out for the 15 Yamhill County horses, Clark hopes the event will alert the horse industry to the need for proper testing and certification. By state law, all livestock entering Oregon must have a valid Certificate of Veterinary Inspection, an Oregon Import Permit obtained from the office of the State Veterinarian, and, in some cases, negative tests for certain diseases. Horses from states known to have vesicular stomatitis outbreaks must have their health inspection within 24 hours of leaving for Oregon.
States currently affected are New Mexico, Arizona, and Colorado.
Most of these horses come into the state without proper documentation. This poses a disease threat to local livestock. They should also check with their liability insurance carrier concerning coverage exclusions if they do not have such requirements.