SWINE ERYSIPELAS 293 



Etiology. — The. Bacterium erysipelatis, a fine bacillus found 

 in the acute form of the disease in the blood, skin, and lymph 

 glands. _ In the chronic form they are found in the dis- 

 eased tissue, particularly in the valvular vegetations in the 

 heart. 



Natural Infection. — (a) Via the mouth with food and water 

 contaminated with the feces and urine. The blood and flesh 

 are also infectious. 



(jb) Via wounds. The disease is usually first introduced by 

 infected hogs or by apparently healthy "germ carriers," 

 swine which have recently recovered from erysipelas but still 

 carry germs in the bowels and tonsils. Fields on which the 

 bodies of dead hogs have lain or were not buried deep enough 

 or where the feces and urine of diseased animals are deposited 

 are most dangerous sources of infection. The disease is not 

 directly contagious, but is disseminated largely through soil 

 infection. Hogs from three months to one year are most 

 susceptible. Sucklings and old animals are usually quite 

 resistant. 



Necropsy. — In the acute form very little change is noted 

 postmortem. The small intestines are catarrhally inflamed. 

 Peyer's patches and the solitary follicles are swollen and small 

 ulcerations are noted. The spleen is somewhat enlarged. 

 Ecchymoses and petechia? are prone to appear in the mucous 

 and serous membranes, especially in the epi- and endocardium 

 and in the subcutaneous connective tissue. The kidneys are 

 swollen, and on section the cortex is grayish-red, dotted with 

 punctiform hemorrhages, the medullary substance dark. As 

 a rule the lungs are not involved. In chronic cases the prin- 

 cipal lesion is found in the heart, the atrioventricular valves 

 showing lesions of verrucous or ulcerous endocarditis. 



Symptoms. — The period of incubation is three to five days. 

 The clinical symptoms vary, but the following forms are 

 fairly well distinguished. 



(a) Skin Form. — Urticaria Type {"Diamond Disease?"). 

 —After a short period, during which the hog seems languid 

 and fails to eat well, there appear in the skin on the sides of 

 the chest, back, neck and legs, sometimes all over the body, 

 violet-colored spots and sometimes vesicles. The spots are 



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