FOOT-AND-MOUTH DISEASE. 391 



In the malignant type of the disease it requires from three months 

 to a year for an animal to recover. The mortality, as already stated, 

 is usually low. The disease is more fatal in young animals that have 

 been fed on infected milk, and produces death in from 60 to 80 per 

 cent of these cases as a result of gastroenteritis. In the 1914 outbreak 

 numerous new centers of infection started among hogs and calves 

 which were fed on unpasteurized, infected milk from creameries. 



Diagnosis. — The recognition of this affection should not, as a rule, 

 be difficult, especially when the disease is known to be in the vicinity ; 

 in fact, the group of symptoms form a clinical picture too decided to 

 be doubted. The combination of high fever, vesicular inflammation 

 of the mouth, and hot, painful, swollen condition of the feet, followed 

 24 to 48 hours later by the appearance of numerous blisters varying 

 in size from that of a pea to that of a walnut on the udder and feet 

 and in the mouth should prevent any serious or long-continued error 

 in the diagnosis ; however, in the inoculation of calves we have a cer- 

 tain and final test. In 24 to 96 hours after inoculation the calves 

 present the characteristic blisters. Such inoculation should be prac- 

 ticed, however, only by officials properly authorized to deal with 

 contagious diseases. 



Differentml diagnosis. — ^The lesions of no other disease of cattle 

 closely simulate the vesicular eruption of foot-and-mouth disease on 

 the lining membrane of the mouth. When the blisters have ruptured, 

 however, and the resulting lesions have become contaminated by 

 numerous secondary forms of microorganisms, the correct recogni- 

 tion of the disease may be involved in considerable difficulty. 



Cowpox or horsepox may be accidentally transmitted by inocula- 

 tion. But the eruption of the " pox " goes on to the development of 

 a pustule, while in foot-and-mouth disease the eruption is never 

 more than a vesicle, even though the contained fluid may become 

 turbid. The inoculation test in the case of cowpox does not respond 

 with fever and eruption for at least 10 days, and often longer. 



Necrotic stomatitis (sore mouth due to a germ) may be distin- 

 guished from foot-and-mouth disease by the fact that in the latter 

 there is a rapid infection of the entire herd, including the adult 

 cattle, as well as the infection of hogs and sheep. The characteristic 

 lesion of foot-and-mouth disease is the appearance of blisters con- 

 taining a serous fluid upon the mucous membrane of the mouth and 

 upon the udder, teats, and feet of the affected animals. In necrotic 

 stomatitis blisters are never formed, destruction of the tissues oc- 

 curring from the beginning and being followed by the formation of 

 yellowish, cheesy patches, principally found involving the lining 

 membrane of the mouth, especially the tongue and cheeks. 



In mycotic stomatitis (sore mouth due to a fungus or mold), por- 

 tions of the lining membrane become inflamed and in a few days it 



