344 Foot-and-Mouth Disease. 



parts of the heart iimsele, the presence of the virus in the heart muscles 

 suggests at least the symptoms of the heart weakness. The malignant 

 character of the affection is not influenced by outside conditions, espe- 

 cially by dietetic or hygienic conditions, and Imminger observed in 

 Bavaria that most of the deaths during the disease occurred in clean, 

 well ventilated stables. 



Course. In the great majority of cases foot-and-mouth 

 disease usually runs "a typical and favorable course. The 

 development and healing of the vesicles require on an average 

 5 to 6 days. In spite of this however the disease extends even 

 in the mild cases, from 2 to 3 weeks, as the different parts of the 

 body do not become affected simultaneously, but usually suc- 

 cessively. The cases in which the affection is localized in the 

 mucous* membrane of the mouth usually recover inside of a 

 week. Eecovery is protracted somewhat longer in the hoof 

 affections, on account of the delayed healing of the ulcerations. 

 In those cases however in wdiich the affection of the mucous 

 membrane of the mouth is associated with lesions in the hoofs, 

 a still longer time is required for recovery. After healing 

 of the local changes the animals usually regain their former 

 condition very rapidly. 



In cases running an unfavorable course with the exception 

 of young animals affected with gastro-intestinal catarrh, death 

 ensues as a rule from pyemia or septicemia, as a result of 

 absorption of septic substances from the ulcers, abscesses or 

 suppurating w^ounds, while in other cases a gangrenous pneu- 

 monia is the cause of death. In the malignant form of foot-and- 

 mouth disease toxin poisoning, or paralysis of the heart may 

 be the immediate cause of death. 



In a certain percentage of cases various permanent affec- 

 tions remain, which more or less reduce the value of the animals. 

 Such affections are, in the first place, chronic disturbances of 

 the hoofs, which develop from extensive inflannnation of the 

 feet, and especially from the loss of hoofs. Such conditions 

 result in an irregular development of the new hoofs, as well 

 as in chronic arthritis and tendonitis. In exceptional cases a 

 proliferation of granulation tissue is observed, which originates 

 from the ulcerations on the coronary band, heels, and the inter- 

 digital space. In such instances the hoofs are forced apart, 

 and the lesions consist in sore, ulcerative masses (Schenkl). 

 Of further importance is the diminished milk production which 

 usually lasts until the following parturition, but may also 

 remain constant, especially when the severe affection of the 

 udder has resulted in atrophy of the glandular substance. 



Horvath observed in the course of an acute affection a marked difficulty in 

 respiration, and that the animal failed to shed the hair during the summer. The 

 number of respirations iluring rest amounted to 60-80 per minute, but after 

 short exercise as well as in warm weather, it rapidly increased to 120-160, while 

 the pulse numbered 40-60 per minute. Jn the meantime the appetite and the milk 

 production were diminished; pregnant animals gave birth to poorly developed calves, 



