Vesicular stomatitis is a viral disease that primarily affects cattle and horses but can affect sheep, goats, pigs, llamas and alpacas. It is a zoonotic disease, meaning it can be transmitted from infected animals to humans. The etiologic agent, vesicular stomatitis virus (VSV), is a rhabdovirusfamily of viruses in the order Mononegavirales. There are many different serotypes of VSV, but only the New Jersey and Indiana serotypes seem to appear in outbreaks in the U.S.
What Are the Clinical Signs?
Vesicular stomatitis is a short-lived and self-limiting disease, meaning the animal will generally heal on its own. The symptoms commonly seen are excessive drooling (ptyalism), scabs on the lips and ulcers on the cheeks and tongue. Ulcers or blisters can be found on the udder and coronary bandjunction of the leg’s hairline and the hoof, provides the majority of nutrition to the hoof and is the area from which the hoof grows of cattle. Oral blisters are not always seen in animals because they tend to rupture and scab over before the owner or veterinarian knows that the animal is infected. Initially, the animal will have a fever, but by the time the other clinical signs are recognized, the animal usually reaches the normal temperature range. Because of the painful blisters and scabs, most animals will go off feed or become less interested in eating. Once the blisters/scabs heal, the animal should resume eating.
How Is it Spread?
The virus can be spread through direct contact with infected animals with clinical signs of disease or by blood-feeding insects. In the southwestern U.S., black flies (Simulidae) are the most likely biologic insect vector. In endemic areas, sand flies (Lutzomyia) are known to spread the disease.
One of the best ways to prevent vesicular stomatitis is through fly control. Topical insecticides labeled for fly control, fly tags placed in the ears and premises control are all important management techniques that will help reduce the chances of animals contracting the disease. Also, because the black fly reproduces and is most commonly found near sources of moving water, minimizing contact with streams, rivers and irrigation canals is important during outbreaks. Disinfecting equipment and tools that have come in contact with infected animals is important as well. Water buckets, feed troughs, twitches, etc., should be cleaned with bleach or any commercial antimicrobial disinfectant.
What to Do If You Suspect Your Animal Has Vesicular Stomatitis
Do not move your animal off your premises; isolate the animal first. Call your veterinarian or have an ambulatory veterinarian inspect your animal. If your veterinarian suspects that your animal has vesicular stomatitis, he/she will call the Texas Animal Health Commission’s regulatory veterinarian for your region, and they will run confirmatory tests.
Animals with vesicular stomatitis seem to do best on soft feeds like pellets mixed with water to make a mash. Coarse feeds irritate the ulcers and can cause the animal to go off feed. No specific treatment is necessary; however, rinsing the mouth with oral antiseptics can reduce secondary bacterial infection. Also, systemic antibiotics can be used if secondary bacterial infection is present, but this should be discussed with your veterinarian before beginning treatment. This disease rarely causes death, so supportive care is usually all that is necessary.
For up-to-date information on affected counties, please visit the TAHC website at http://www.tahc.state.tx.us/.
Justin Box, DVM, is a graduate of Texas A&M College of Veterinary Medicine who lives in Austin. Dr. Box practices at Justin Box Veterinary Services where he has a special interest in both large and small animals, specifically production animals.