ALBUQUERQUE – On April 13, 2020, the National Veterinary Services Laboratories (NVSL) in Ames, Iowa, confirmed a finding of vesicular stomatitis virus (VSV) infection (Indiana serotype) on an equine premises in Dona Ana County, New Mexico. A single horse on the index premises has met the case definition of infection with compatible clinical signs and virus isolation positive results. A second equine premises in Sierra County, New Mexico subsequently met confirmed VSV case definition with compatible clinical signs and reverse transcription-polymerase chain reaction (RT-PCR)-positive results for VSV (Indiana serotype). This is the 2020 VSV index case for the United States and subsequent VSV case for New Mexico. The epidemiological investigations on both VSV-positive premises indicate that incursion of VSV-infected insect vectors is the likely source of infection in these herds. Biosecurity measures and vector mitigation have been instituted to reduce spread of the virus. Please see the USDA APHIS Veterinary Services website to read the current situation report. What Veterinarians Need to Know: This case in New Mexico indicates that we could see additional cases during the upcoming insect vector season. All suspect VSV cases in horses and livestock must be investigated by state or federal animal health officials. Any vesicular disease of livestock and horses is reportable to the State Veterinarian’s Office in Albuquerque, NM. Report any cases that have clinical signs suggestive of Vesicular Stomatitis Virus (VSV) immediately by calling 505-841-6161. Veterinarians may also contact the state or federal field veterinarian in your area. Vesicular Stomatitis Background: The goal in the management of the disease is to accomplish effective control while minimizing the negative economic impacts to livestock owners. Vesicular Stomatitis is a viral disease that primarily affects horses and cattle and rarely in swine, sheep, goats, llamas, and alpacas. The transmission of VSV is not completely understood, but includes insect vectors such as black flies, sand flies, and biting midges. The incubation period ranges from 2-8 days. Clinical signs include vesicles, erosions, and sloughing of the skin on the muzzle, tongue, teats, ear tips, and coronary bands. Often excessive salivation is the first sign of disease, along with a reluctance to eat or drink. Lameness and weight loss may follow. Humans may become infected when handling affected animals, but this is a rare event. To avoid human exposure, individuals should use personal protective measures when handling affected animals. Tips for Livestock and Horse Owners: • Strict fly control is an important factor to inhibit the transmission of the disease. • Avoid transferring feeding equipment, cleaning tools, or health care equipment from other herds. • New Mexico fairs, livestock exhibitions, and rodeos may institute new entry requirements based on the extent and severity of the VSV outbreak. o If you are participating in an event, please contact the event organizers prior to travel to determine if entry requirements may have changed. o A certificate of veterinary inspection (health certificate) issued within 2-5 days prior to an event can be beneficial in reducing risks. Always check with the state of destination to determine if they have updated their VS requirements. • If moving livestock internationally, contact the USDA APHIS VS to determine if there are any movement restrictions or testing requirements for VSV.