302 SWINE PRACTICE 



The presence of this disease in the United States is now apparently 

 accepte.d ,by: practically all investigators and state sanitary officials. 

 This disease is. not so fatal,. neither is it so widespread, as cholera. It 

 may occiar 'sporadically or enzootically, ..but it rarely assumes an epi- 

 zootic form. The "percentage of losses in affected herds varies mark- 

 "edly,' reaching as high as 75- in some instances.. The greatest losses 

 occur; when animals are not kept in proper sanitary quarters, such 

 as dusty or muddy pens, or in animals sleeping in wet, or damp 

 quarters. 



Etiology. — The. cause of swine plague is the B. suisepticus. This 

 micro-organism is representative of the hemorrhagic septicemia group. 

 The B. .suisepticus is a', short, bipolar-staining, polymorphic non-mo- 

 tile organism,: and does. not. form, spores. , The- organisin grows read- 

 ily on practically all culture media, aerobically or anaerobically. It 

 does not liquefy gelatirre^^OT coagulate" miik,~ and T:sTit)t ""stained by 

 Gram's method. 



Its vitality is prolonged for from five to fifteen days in soil, feces 

 and water when not exposed to sunlight, but is destroyed in two or 

 or three days by desiccation, and is easily destroyed by weak anti- 

 septics. The organism is killed in twenty minutes by a temperature 

 of fifty-eight degrees Centigrade. 



Fowls, rabbits and guinea pigs are susceptible to the pathogenic 

 action of these organisms. The virulence of the B. suisepticus is 

 quite ^variable and is likely to vary .quite suddenly. Intrapulmonary 

 injections into swine usually produce multiple catarrhal pneumonia 

 sueseeded by necrotic pneumonia. 



Cahill has produced hemorrhagic septicemia in swine immune to 

 hog cholera by the injection of blood from a pig dead of hemorrhagic 

 septicemia; also by the injection of pure cultures of B. suisepticus. 



There is some doubt as to just what factors are necessary to bring 

 about an outbreak of swine plague. Certain it is that the infection 

 is more widespread than the disease. It appears that something to 

 lower the normal resistance of the animal is necessary in addition 

 to the B. suisepticus to bring about the disease. Swine plague is 

 prone to appear in animals suffering from cholera; in animals sub- 

 ject to the hardships of shipping; in pigs at weaning time; in herds 

 suddenly placed on green corn for feed ; in young animals subjected 

 to unusual exposure, as to a cold rain in early spring or late fall, 

 and, as is well recognized, in animals kept in dusty quarters. 



Further, swine plague is quite apt to occur in swine recently 



