We are not sure what is wrong with him, but it does look like something we have seen before – a disease known as VESICULAR STOMATITIS.  Now this name is a mouthful (no pun intended), but all medical terms break down pretty simply. Vesicular refers to vesicle or blister which is characteristic of the disease.  The large sore on his tongue is actually the tissue left after the overlying blister has ruptured.  Stoma refers to opening or mouth, and itis means inflammation.  So the name is simply descriptive – we have inflammation in the mouth characterized by blisters.  This disease is one of several “reportable” diseases and we are required to notify the State Veterinarian of any suspicious cases.  Veterinarians have an important Homeland Security role, as animal diseases not only affect food supply, many are transmissible to humans.  The state veterinarian will come out to draw blood and take swabs of the lesions to make a definitive diagnosis.  In the meantime what should we do to help this horse?



page21. With difficulty eating and drinking you will want to ensure the horse does not become dehydrated. Dehydration often leads to colic in several ways. The lack of fluid in the body can dry out the ingesta moving through the GI tract which can result in an impaction. Also, with poor hydration status there is less blood perfusion of the gut which can slow down the normal peristaltic waves. If the gut slows down it has the opportunity to fill with gas. Filling with gas can lead to displacements or even torsions.  2 ways you could ensure this does not happen is by supporting the horse with intravenous fluids in order to maintain a normal hydration status, and you could also give the horse a gallon of mineral oil via nasogastric tube in order to prevent the formation of impactions.

2. Having difficulty eating is most likely due to pain and inflammation from the oral lesions in the horse. Horses are unique in that their electrolyte balance and daily energy use is highly dependent on consistent feeding.  You will not want a horse to go long without eating.  In order to encourage eating you must control the pain/inflammation.  An easy way to do this would be oral NSAIDS like banamine or bute paste.  However, these drugs can be irritating to the oral mucosa particularly when you already have ulcerative lesions in the mouth.  A much better option would be the daily intravenous use of banamine.


Vesicular Stomatitis is caused by an “organism” (as opposed to a toxin), and as such it will fall into one of the categories in the diagram below. For your homework, look up what category causes Vesicular Stomatitis.  How can you prevent its spread to other horses, and how would you treat it? Can it spread to other species, including you?  Are lesions limited to the mouth?




Well, it’s still early.  We’ve only seen two horses so far today, and we have to move on.  But this next call I am not looking forward to.