186 Vesicular Inflammation of the Mouth. 



Most veterinary authorities describe this disease under the name of 

 stomatitis aphthosa. The authors believe that this is not quite correct 

 because it is inadmissible to designate vesicles as aphthae. The latter 

 term more properly designates pseudomeml^ranes of the buccal mucosa 

 (see page 188). In distinguishing this affection from foot-and-mouth 

 disease (aphthae epizooticae) it is frequently designated as aphthas 

 sporadicae. 



Occurrence, The disease lias, so far, been observed only in 

 liorses and cattle. It generally occnrs sporadically (Guittard, 

 Iwersen, Vontobel, Pr. Mil. Vb.), but among- horses also en- 

 zootically (Dieckerhoff, Bochberg) or even epizootically 

 (Theiler). Epizootics of the disease have been observed par- 

 ticularly in South Africa. 



Etiology. Pasturing in rape stubble fields or ingesting 

 inuch Swedish clover have frequently been held to be the cause 

 of the disease, which was then believed to be due to mycotic in- 

 vasion (Polydesmus exitiosus, Uromyces occultus). (See also 

 Clover disease.) 



Michaelis observed three cases where the disease came on simul- 

 taneously M'ith an exanthematous eruption near the feet after feeding on 

 potatoes which had already germinated. Bochberg saw five horses o-f 

 one owner affected after they had received mouldy and partly dusty 

 feed. Dieckerhoff saw 50 horses out of 100 of the Trakehn Stud 

 become sick successively, and therefore believed that the disease was 

 infectious and that it found its portal of entrance through a lesion of 

 the buccal mucosa. However, since Dieckerhoff 's and also Bochberg 'g 

 inoculation experiments were not successful, they deny the infectious 

 nature of the disease. Still, Theiler saw in South Africa an infectious 

 vesicular eruption of the buccal mucosa of horses ("Blauwtong" the 

 blue-tongue of the Boers) which could be transferred by inoculation, 

 but which does not spread rapidly by natural infection. 



Symptoms. In horses the buccal mucosa becomes reddened, 

 sensitive and hot and there may occur a slight elevation of tem- 

 perature, at the same time vesicles appear of the size of a millet 

 seed, lentil or bean, filled with a clear watery or yellowish serous 

 fluid, thin-walled, flattened or even umbilicated. These vesicles 

 are seen on the inner surfaces of the lips, on either side of the 

 lingual ligament, on the gums between the teeth, in the neigh- 

 borhood of the angles of the mouth, on the lips and on the sides 

 of the tongue. The vesicles burst in three to four daj^s, leav- 

 ing superficial erosions which remain partly covered for some 

 time by the whitish fragments of the torn wall of the vesicle. 

 Adjoining erosions may become confluent and form irregular 

 defects in the epithelial covering. Vesicular stomatitis occur- 

 ring in South Africa at this stage exhibits a dirty bluish dis- 

 colored tongue (hence the name of the disease). The intensely 

 red base of the erosions soon fills up and a new epithelial cover- 

 ing is formed in five to six days, when all traces of inflamma- 



