Swine-plague 607 



Bacillus Suisepticus (Loffler and Schutz) 



General Characteristics. — A non-motile, non-flagellated, non-sporogenous, 

 non-liquefying, non-chromogenic, non-aerogenic, aSrobic and optionally anaero- 

 bic bacillus,, pathogenic for hogs and many other animals, staining by the ordi- 

 nary methods, but not by Gram's method. 



The bacillus of swine-plague, or Bacillus suisepticus of Loifler and Schtitz* and 

 Salmon and Smith,t but slightly resembles the bacillus of hog-cholera (q.v.), 

 though it was formerly confounded with it and at one time thought to be iden- 

 tical with it. The species have sufficient well-marked characteristics, however, 

 to make their differentiation easy. 



Swine-plague is a rather common and exceedingly fatal epidemic disease. It 

 not infrequently occurs in association with hog-cholera, and because of the lack 

 of sufficiently well-characterized symptoms — sick hogs appearing more or less 

 alike — ^is often mistaken for it. The confusion resulting from such faulty diag- 

 nosis makes it difficult to determine exactly how fatal either may be in uncom- 

 plicated cases. 



Morphology. — The bacillus of swine-plague much resembles that of chicken- 

 cholera. It is a short organism, rather more slender than the related species, 

 not possessed of flagella, incapable of movement, and producing no spores. 



Staining. — The bacillus stains by the ordinary methods, sometimes only at the 

 poles, then closely resembUng the bacillus of chicken-cholera. It is not colored 

 by Gram's method 



Cultivation. — In general, the appearance in culture-media is very similar to that 

 of the hog-cholera bacillus. Kruse,t however, points out that when the bacillus 

 grows in bouillon the liquid remains clear, the bacteria gathering to form a floc- 

 culent, stringy sediment if dextrose or saccharose be added to the bouillon, a 

 strongly acid reaction develops, but no gas is formed. If lactose be added neither 

 acidity nor gas appears. Indol is sometimes but not always formed. The organ- 

 ism does not grow upon ordinary acid potato, but if the reaction of the medium be 

 alkaline, a grayish-yeUow patch is formed. In milk a slight acidity is produced, 

 but the milk is not coagulated. 



Vital Resistance. — The vitality of the organism is low, and it is easily de- 

 stroyed. Salmon says that it soon dies in water or when dried, and that the tem- 

 perature for its growth must be more constant and every condition of life more 

 favorable than for the hog-cholera bacillus. The organism is said to be widely 

 distributed in nature, and is probably present in every herd of swine, though not 

 pathogenic except when its virulence becomes increased or the vital resistance 

 of the animals (fiminished by some unusual condition. 



Rabbits, mice, and small birds are very susceptible to the infection, usually 

 dying of septicemia in twenty-four hours; guinea-pigs are less susceptible, except 

 very young animals, which die without exception. Chickens are more immune, 

 but usually succumb to large doses. Hogs die of septicemia after subcutaneous 

 injection of the bacilli. There is a marked edema at the point of injection. If 

 injected into the lung, a pleuropneumonia follows, with multiple necrotic areas in 

 the lung. In these cases the spleen is not much swoUen, there is slight gastro- 

 intestinal catarrh, and the bacilli are present everywhere in the blood. 



Animals can be infected only by subcutaneous, intravenous, and intraperito- 

 neal inoculation, not by feeding. 



As seen in hogs, the symptoms of swine-plague closely resemble those of hog- 

 cholera, but differ in the occurrence of cough, swine-plague being prone to affect 

 the lungs and oppress the breathing, which becomes frequent, labored, and pain- 

 ful, while hog-cholera is chiefly characterized by intestinal symptoms. 



The course of the disease is usually rapid, and it may be fatal in a day Or two. 



Lesions. — At autopsy the lungs are found td be inflamed, and to contain nu- 

 merous small, pale, necrotic areas, and sometimes large cheesy masses i or 2 inch^ 

 in diameter. Inflammations of the serous membranes affecting the pleura, peri- 

 cardium, and peritoneum, and associated with fibrinous inflammatory deposits on 

 the surfaces, are common. There may be congestion of the mucous membrane of 

 tie intestmes, particularly of the large intestine, or the disease in this region niay 

 bean intense croupous inflammation with the formation of a fibrinous exudative 

 deposit on the surface. A hemorrhagic form of the disease is said to be common 

 in Europe, but, according to Salmon, is rare in the United States. 



* "Arbeiten aus den kaiserlichen Gesundheitsamte," i. 

 f t "Zeitschrift f . Hygiene," x. 

 t Flugge's "Die Mikroorganismen, 1896," p. 419. 



