CHAPTER VI. 

 HOG-CHOLERA* 



BACILLUS SUIPESTIFER (SALMON AND V 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. 



The bacillus of hog-cholera was first found by Salmon and 

 Smith,* but was for a long time confused with the bacillus 

 of "swine-plague," which it closely resembles and in asso- 

 ciation with which it frequently occurs. It is a member of 

 the group of bacteria to which Bacillus icteroides and Bacil- 

 lus typhi murium belong. 



The organism was secured by Smith from the spleens of 

 more than 500 hogs. It occurs in the blood and in all the 

 organs, and has also been cultivated from the urine. Al- 

 though so uniformly present in the disease and formerly 

 accepted as its cause, the recent discovery that the serum 

 of infected animals retains its infectivity after filtration 

 through porcelain and the undoubted removal of any 

 bacilli that it may formerly have contained, makes it very 

 doubtful whether the so-called hog-cholera bacilli are more 

 than accidental factors in the etiology of the disease. 



Morphology. The organisms appear as short rods with 

 rounded ends, 1.2-1.5 p. long and 0.6-0.7 /Jt in breadth. 



*" Reports of the Bureau of Animal Industry," 1885-91; and 

 "Centralbl. f. Bakt. u. Parasitenk.," Bd. ix, Nos. 8, 9, and 10, March 

 2, 1891. 



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