Etiology, Symptoms. 357 



exceptionally 1/2 to 1 year old colts and calves and even steers 

 may become affected. In these cases the infection develops by 

 contact with the infected animals, being transmitted by straw 

 contaminated with infectious secretions, stable floors or manure, 

 further by sponges and by the hands of the attendants. Affected 

 mares may transmit the disease to the lips of their colts during 

 sucking. 



Cattle are most susceptible to the disease, horses consid- 

 erably less, and to a still slighter degree sheep, goats and hogs. 

 Recovery from the disease reduces the susceptibility for a time ; 

 the duration of the immunity however is unknown, and excep- 

 tionally the same animal may become repeatedly infected at 

 short intervals (Fenner, Kalb). 



The relation of the affection to other diseases, which are also asso- 

 ciated with a vesicular exanthema, has not yet been established. The 

 supposition towards its identity with foot-and-mouth disease (Zlamal, 

 Hertwig) or with dourine (Spinola), has been discarded, but French 

 authors (Trasbot, Peuch, Nocard & Leclainche) consider it, even in 

 recent times, as a form of pox. The majority of authors consider the 

 affection as a disease by itself, which view corresponds with its inde- 

 pendent occurrence, and its almost invariable localization upon the 

 genital organs. 



It has likewise not been definitely established whether the disease 

 is caused by the same virus in the various species of animals, as inocu- 

 lation experiments have failed to give uniform results. According to 

 observations made it usually spreads among the animals of the same 

 species, and does not pass from horses to cattle, or vice versa. Neverthe- 

 less the almost complete resemblance of the clinical appearance in the 

 various species indicates an identity, or at least a very close relation- 

 ship of the affections, and the veterinary police treat the trouble among 

 horses and cattle in this sense. 



Exceptionally the transmission of the virus to man has also been 

 observed, when a pustular exanthema appears on the hands and on 

 the face, and the affected person infected other members of the family. 



Symptoms. The time of incubation is as a rule from 3 

 to 6 days, in exceptional cases the symptoms may appear even 

 in from 24 to 48 hours after the infection, while in some in- 

 stances the period of incubation may extend to 10 or 11 days 

 (Friedberger & Frohner, Dieckerhoff). 



The characteristic signs of the disease develop on the ex- 

 ternal genital organs. In female animals the reddened, and 

 exceptionally also the hemorrhagic mucous membrane of the 

 vagina, shows in from 2 to 3 days, lentil to pea-sized vesicles, 

 which are filled with a clear, yellowish fluid. The vesicles appear 

 on a reddened and swollen base, especially on the upper commis- 

 sure, and in the vicinity of the clitoris, as well as on the inner sur- 

 face of the vulva, in male animals on the glans penis in the vicinity 

 of the urethral opening, in rare cases also on the immediately 

 surrounding skin. Small nodules may also appear, later chang- 



