LECTURE XXXVI 

 FOOT-AND-MOUTH DISEASE 



Foot-and-mouth disease is a very contagious disease, chiefly 

 of ruminant animals and swine, but horses and other animals 

 are susceptible to it. Some outbreaks are much more virulent 

 than others. ^Nlany cases are so mild as to be difficult to recog- 

 nize; but whether they are virulent or mild they are always 

 a serious matter for the owner of the stock, even though no 

 animals die, and a very serious matter for the public because 

 of extreme ease and rapidity of spread, the great difficulty and 

 expense of eradication and actual money losses incurred. Sev- 

 eral outbreaks have occurred in this country due to importa- 

 tions, but they were eradicated and so far as known we have 

 none in America at the present time. 



Cause. — The cause is a filterable and apparently invisible 

 virus. Little is known about it except as to its disease produc- 

 ing power. 



Infection. — Usually takes place by way of the digestive tube. 



Symptoms. — The symptoms are here given for cattle. Sheep 

 and swine show, in general, similar symptoms. 



Foot-and-mouth disease develops in from three to five days 

 after exposure. Affected cattle are first noticed to be sluggish. 

 They shiver and later on are stiff and lame, and inclined to lie 

 down by reason of the sore feet. There is a profuse flow of 

 the saliva, with frequent swallowing motions and smacking of 

 ,the lips. The peculiar lesions of the foot-and-mouth disease 

 are vesicles or small blisters affecting the mouth and the skin 

 above and between the hoofs, and over tiie udder and teats. 

 The vesicles soon break, leaving raw surfaces which, as a rule, 

 heal, but sometimes remain as rather chronic ulcers. The skin 

 and superficial tissues around the hoofs become inflamed and 

 swollen ; the stomach may also be involved ; weight is lost, and 

 the milk flow is checked. Tt should be remembered that the 

 symptoms vary greatly in virulence in different animals and 



177 



