458 FOOT AND MOUTH DISEASE 



the mucosa. Ulcers of a nature similar to those found in the 

 stomach occur in the intestines. On the feet inflammations 

 may follow the simple vesicles about the coronet. These may 

 extend deep into the tissues, pass under the hoof and cause it 

 to slough off, extend into the bone producing necrosis or 

 permanent arthritis. It is stated by some authorities that in 

 the mild non-fatal cases the obvious lesions are so slight that 

 frequently they escape notice. In sheep and swine the lesions 

 are more frequently restricted to the feet. 



The period of diiraiion oi \h& d\SQ2iSQ: xdix'xes from 9 to 14 

 days. The immunity resulting from a natural course of the 

 disease is placed by Penberthy as being brief, probably not to 

 exceed six months. 



§ 364. Differential diagnosis. Foot and mouth dis- 

 ease must be differentiated from (i) various forms of stoma- 

 titis caused by different fungi and often referred to as sporadic 

 aphthae, (2) from stomatitis due to drugs and injuries, (3) 

 from actinomycosis of the tongue and (4) from variola. It 

 must also be differentiated iVom simple cellulitis, often of 

 streptococcic origin, in the subcutaneous tissue about the 

 coronet and from the sloughing of the hoof resulting from the 

 extension of the inflammatory process, and from eczemas due 

 to dietary causes. The means of differentiating these must be 

 found largely in the history of the cases and in the study of 

 the nature of the lesions themselves. 



§ 365. Prevention. Preventive inoculations do not 

 seem to have given satisfactory results. The isolating of the 

 diseased animals and the placing of the well ones in non-in- 

 fected fields and stables tend very largely to the checking of 

 the spread of the disease. The milk of the diseased animal 

 should be sterilized before it is used. 



In England the slaughter of infected animals has fre- 

 quently been resorted to in recent years to stamp out the dis- 

 ease. In the recent outbreak in the United States, the prompt 

 destruction of all infected and exposed animals proved to be 

 very satisfactory. The failure in the past to control the dis- 



