130 Swine Plague. 



by secondary infection pass into a fibrinous or necrotic pneu- 

 monia (such cases, which are observed especially after long 

 transportation, have been taken repeatedly as proof for the 

 identity of the primary chronic and the superimposed acute 

 processes). 



In the pneumonic lungs of animals affected with swine plague other 

 bacteria than the ovoid Ijacilli may often be found in varying numbers 

 in the acute cases, but more so in the chronic cases. Of these strepto- 

 cocci, staphylococci, colon bacilli, bac. viscosus (Preisz), bac. pyogenis 

 suis, bac. necrophorous and others are freciuently present. They come 

 into consideration only as secondary invaders which produce local 

 changes in the already affected tissues (small suppurative centers, etc.). 

 Tlie presence of these organisms may be explained by the fact that 

 they are also frequent inhabitants of the air passages, and may occa- 

 sionally multiply under abnormal conditions. Clearly different are 

 conditions in the enzootic pneumonia of pigs, this disease being in all 

 prohability the result of a mixed infection, and the ovoid bacteria play 

 here probably an unimportant role. This is indicated by the fact that 

 in about one-third of the cases the demonstration of this organism from 

 the pneumonic tissue is not possible. 



The susceptibility of hogs for this disease is principally 

 affected by their condition of health or by the reduction of 

 their natural resistance as a result of weakening influences. 

 Very young animals rarely become affected, otherwise age does 

 not seem to have any influence. 



Those diseases of hogs which sometimes develop in association with 

 hemorrhagic septicemia of other animals are identical in their nature 

 with true swine plague. Thus, simultaneous affection in hogs may 

 especially be o])served during outbreaks of hemorrhagic septicemia in 

 cattle as well as in outbreaks of buffalo dis(>ase (see the latter). Occa- 

 sionally also hogs may be affected while influenza of horses is prevalent 

 (Schindelka), or chicken cholera (Gorges). On the other hand, in 

 outbreaks of swine plague other species of animals may become affected. 

 Thus Galtier observed affections in sheep which were kept in the same 

 stable with affected hogs, or which were pastured in the same field 

 where carcasses of hogs were buried, while Keleti saw lambs die during 

 outbreaks of swine plague. Both authors demonstrated in the organs 

 of the affected sheep bipolar bacilli (see page 119). Lastly Goldstein 

 as well as Chamberland & Jouan observed the death of all the chickens 

 in a flock with manifestations of cholera-like symptoms after they had 

 eaten from a carcass of a hog which died from swine plague. Gorges 

 also has observed geese dying after ingestion of food contaminated 

 by affected hogs. 



Anatomical Changes. In peracnte cases the autopsy reveals 

 lesions of typical hemorrhagic septicemia, viz., numerous small 

 hemorrhages in the skin or subcutaneous fat, in the serous and 

 mucous membranes, in the kidneys and under the endocardium, 

 larger hemorrhages in the perirenal connective tissue, in the 

 mucous membrane of the pelvis of the kidney and the bladder, 



