Vesicular Stomatitis in the Horse
Vesicular stomatitis is a contagious disease
caused by a rhabdovirus. The two major serotypes are New
Jersey and Indiana.
Aside from horses, the virus may affect swine, cattle, goats,
sheep, llamas, wild animals and humans. The lesions include
vesicles up to 2 cm in diameter on the mouth and lips and
less frequently on the hooves, prepuce and teats. These
vesicles quickly rupture, leaving large painful erosions
and ulcers. Horses may display ptyalism, pyrexia and anorexia.
The rhabdovirus is believed to be spread via insect bite
and direct contact, and may have morbidity of 5-10% in affected
herds. Incubation time is 1-3 days and the course of the
disease is 1-2 weeks, with solid immunity possible for up
to 6 months. Diagnosis of vesicular stomatitis is based
on history, signs, serology and virus isolation. Histopathology
reveals non-specific hyperplasia and edema (intra- and intercellular)
of the epidermis, reticular degeneration, spongioticmicrovesicles,
focal necrosis and superficial and deep perivascular dermatitis.
Due to the rapid course of the disease, treatment is usually
not indicated. However, mild septic mouthwashes and softened
pelleted feed may be used as palliative treatment for the
painful ulcers. Of high clinical significance is its similarity
to foot-and-mouth disease, thus making vesicular stomatitis
reportable.
NOTE: At the time this article was written,
areas in Colorado
were still under quarantine for vesicular stomatitis in
horses.
- by Lisa Wisz, Class of 1999
- edited by Jason Baldwin, DVM
|
