Vesicular Stomatitis in Horses

Vesicular stomatitis virus
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Understanding Vesicular Stomatitis is very important because it is a zoonotic disease and is a concern to livestock producers. That means the disease can be caught and carried by many different mammals including humans. During outbreaks, humans have to be careful about handling infected livestock as they can carry the virus between animals. Vesicular Stomatitis tends to occur in the warmer areas of North and South America but does appear occasionally in cooler regions. In the last few years Texas, New Mexico, and Colorado have had outbreaks. While not a deadly disease, it's a worry because in cattle, the symptoms are very similar to hoof and mouth disease (also called foot and mouth disease or Aphtae epizooticae).

Horses don't get hoof and mouth disease but cloven-hoofed animals such as cattle, goats, and llamas can and the results can be devastating. VS causes a reduction in dairy milk production and can interfere with meat production, which is not a concern for horse owners but is for many agricultural sectors. Because horses may be able to transmit the virus to other livestock, any outbreak needs to be controlled. In most states, in Canada and other areas. VS is a reportable disease—you must report any outbreak to the proper authorities. Outbreaks often result in lengthy quarantines and livestock transportation restrictions.


How VS is spread is not completely understood. Flying insects, animal-to-animal contact, and human or equipment-to-animal contact may be responsible. Vesicular Stomatitis may be carried by the phlebotomine sand fly, a small biting insect that lives in tropical climates.


It can take up to eight days after initial contact for the disease to appear. The horse will have a slight fever that lasts for several days and about the same time, small blisters appear on the tongue, lips, nostrils, gums and corners of the mouth. The horse may drool excessively. Lesions may also appear on the coronet band and heels, causing areas of tissue to slough off and look eroded. The disease in horses is more inconvenient, and certainly uncomfortable for the horse than deadly.


Because Vesicular Stomatitis can appear similar to other another diseases including hoof and mouth disease, chemical poisoning, clover poisoning, blister beetle poisoning and gum disease, blood tests are needed to confirm the presence of the virus. A veterinarian will draw blood and look for the VSIV, a virus in the same family as the rabies virus.


Usually, there are no long-term effects of VS. A horse may find it uncomfortable to eat and drink water, and if the hooves are affected, may become lame. Very rarely, the horse may suffer severe and lasting hoof damage. Severe weight loss and dehydration is possible. VS is rarely deadly unless infections of the lesions themselves occur. It runs its course in about two weeks after which time the horse should be fully recovered.


There is no treatment for VS. If there appear to be infected blisters, your veterinarian may recommend antibiotics. Horses that are unwilling to eat will lose weight, so horse owners can try softer foods such as soaked hay cubes or beet pulp. Antiseptic mouth rinses may be used.


If you suspect Vesicular Stomatitis it's essential to have your veterinarian confirm the diagnoses with a blood test. Until the results of the blood test are known, no horses should be moved from, or brought to your property. Your horse will be quarantined from other horses and livestock. You should keep its environment scrupulously clean and control flying insects. Any buckets, brushes or other equipment should be cleaned thoroughly and not used for any other horses or livestock. Because VS is transmissible to humans, take precautions to avoid contact with saliva and lesions by wearing disposable gloves. VS causes flu-like symptoms in humans.