4 BULLETIN 662, U. S. DEPARTMENT OF AGRICULTURE 
Burton?! in describing a disease under the name stomatitis con- 
tagiosa of horses, but which appears to be identical with vesicular 
stomatitis, reports that mules, though by no means immune, are 
not so susceptible as horses and that the affection is transmissible 
to man. He cites three cases of human infection, one of which was 
himself. However, vesicular stomatitis has not been reported in 
man in North America, and mules have not been observed to be less 
susceptible than horses. 
SYMPTOMS AND LESICNS 
The first phenomenon of vesicular stomatitis consists in the for- 
mation of reddened patches on the buccal mucosa, especially of the 
tongue. These are quickly succeeded by vesicles or blisters of 
grayish-red color only slightly elevated and of various sizes from a 
dime to a silver dollar, filled with clear or yellowish serous fluid. 
These blisters may be isolated, but frequently they coalesce to form 
a large vesicle. They usually rupture in a very short time, which 
accounts for their not being recognized at times even in the early 
stages of the disease. The rupture of the vesicles results in exposing 
the raw underlying surfaces, which appear as reddened erosions with 
the grayish-white fragments of the torn mucous membrane of the 
preexisting vesicles still attached to the irregular borders like a 
fringe. These erosions may become confiuent, varying from the 
size of a dime to that of the palm of the hand, and may evén involve 
practically the entire upper surface of the tongue in horses. Heal- 
ing varies, but usually occurs quite rapidly in from 8 to 15 days in 
uncomplicated cases. 
While these lesions in horses are principally confined to the upper 
surface of the tongue, they may involve the inner surface of the 
lips, the angles of the mouth, and the gums. In cattle lesions may 
occur on the tongue, hard palate, lips, and gums, sometimes extend- 
ing to the muzzle and around the nostrils. Often the lips of the 
horse are swollen and itchy, which causes the animal to rub the 
muzzle against any near-by object. In a very few cases fresh cows 
have shown similar lesions on the teats when their infected calves 
have been sucking them. 
In one outbreak in which the disease seemed to be of unusual 
virulence and infected more than 30 herds, a large proportion of the 
cows in three dairy herds developed large vesicles on the teats, the 
virus evidently being carried on the hands of the milker from cow 
to cow. In none of the affected cows were vesicles observed on the 
udder proper. 
While foot lesions were reported to occur in horses by Capt. A. C. 
Burton, of the English Army Veterinary Corps, in 1917, and while 
they have been produced by bureau investigators in the feet of both 
horses and cattle in a few cases by inoculation, no lesions on the feet, 
in either of these animals, due to natural infection, were observed in 
the United States in the outbreaks occurring before 1925. Since 
then, however, a few cases in which foot lesions developed in cattle 
have been observed in the field. In nearly all of these cases the 
1 Bourton, A. C. “ STOMATITIS CONTAGIOSA’’ IN HORSES. Vet. Jour. (n. s. 24) 78: 234- 
242, illus. 1917. 
