CHAPTER VI. 

 HOG-CHOLERA. 



BACILLUS SUIPESTIFER (SALMON AND SMITH). 



General Characteristics. An actively motile, flagellated, non- 

 sporogenous, non-chromogenic, non-liquefying, aerobic and optionally 

 anaerobic, aerogenic bacillus pathogenic for hogs and other animals. 

 It stains by the ordinary methods, but not by Gram's method. It 

 ferments dextrose, lactose, and sucrose, but does not form indol or 

 coagulate or acidulate milk. 



Hog-cholera, or "pig typhoid," as the English call it, is a 

 common epidemic disease of swine, which at times kills 90 

 per cent, of the infected animals, and thus causes immense 

 losses to breeders. Salmon estimates that the annual losses 

 from this disease in the United States range from $10,000,000 

 to $25,000,000. 



Although so uniformly present in the disease, and having 

 the expected distribution in the body of the diseased animals, 

 skepticism regarding the specific importance of this organism 

 as the etiological factor began to be felt when DeSchweinitz 

 and Dorset * reported the discovery of a form of hog-cholera 

 not caused by the hog-cholera bacillus. This epidemic 

 arose from unknown causes, but the investigators mentioned 

 were sure that it could not be the hog-cholera bacillus, 

 because they were repeatedly able to transmit the disease 

 from one hog to another in certain of the body fluids that 

 had been passed through the finest porcelain filters and were 

 shown by inoculation and cultivation to be free of bacilli. 



This observation was received with approval by all who 

 had any experience with the effect of hog-cholera bacilli 

 upon hogs, all of whom must have observed that though 

 infection with the bacilli occasionally caused the death of an 

 animal, the dead animal usually did not show the typical 

 lesions of the disease and never infected other animals 

 with which it was kept. Unfortunately, DeSchweintz died 

 before the full fruition of this work was achieved, but it was 



* " Circular No. 41, Bureau of Animal Industry," U. S. Dept. of 

 Agriculture, Washington, D. C. 



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