Clinical Signs & Diagnosis When ves

Clinical Signs & Diagnosis

When vesicular stomatitis occurs in horses, blister-like lesions develop on the tongue, mouth lining, nose and lips. In some cases, lesions also develop on the coronary bands, or on the udder or sheath. When VS is suspected, an exact diagnosis should be obtained by testing the blood for virus-specific antibodies. Testing is necessary to rule out the possibility that the lesions are caused by photosensitivity (sunburn), irritating feeds or weeds, or toxicity from non-steroidal anti-inflammatory medications like phenylbutazone.

VS should not be confused with foot and mouth disease(FMD), which does not affect horses, and was eradicated from the U.S.A. in 1929. The incubation period for vesicular stomatitis – meaning the time from exposure until the first signs appear – ranges from 2 to 8 days. A fever may develop initially as blisters form on the tongue, gums, or coronary bands. One of the most obvious clinical signs is drooling or frothing at the mouth. This occurs following rupture of the blisters that create painful ulcers in the mouth. The surface of the tongue may slough. Excessive salivation is often mistaken as a result of a dental problem just as a horse that is not eating well may be suspected as having colic. Weight loss may be a secondary effect, as a horse with mouth ulcers finds it too painful to eat. If lesions form around the coronary band, inflammation within the foot may result in lameness or laminitis. In severe (but rare) cases, the lesions on the coronary band may cause the hoof to slough.

The disease generally runs its course within two weeks, although it may take as long as two months for the sores to entirely heal. Until the ulcers are completely healed, the horse remains infective and the potential remains for disease to spread.