264 Hog Cholera. 



stock dealers, eastrators and wandering gypsies (the latter by- 

 taking with them the hog carcasses and throwing the viscera 

 about in different pastures) contribute materially to the spread 

 of the contagion. 



In herds of hogs which have been healthy the disease is in 

 most cases introduced by sick animals, and not alone by those 

 in which acute symptoms may be detected, but also through the 

 so-called runts in whose bodies the filterable virus may also be 

 concealed. Infection may also occur during the pasturing of 

 the animals, in the piggeries, during driving on highways or 

 transportation in railroad cars, which have been contaminated 

 by the excrements of affected animals days or weeks previously. 

 The contagion may be spread from one locality to the other 

 by flowing water, into which carcasses of hogs have been thrown, 

 and carcasses which have been left in pastures or which have 

 not been buried satisfactorily may also occasionally be the cause 

 of an outbreak of the disease. 



Although hogs of all breeds and of any age may become 

 affected with hog cholera, the higher bred stock and young hogs 

 are much more susceptible to the disease. Sucking pigs become 

 affected only very exceptionally, and as a rule the influence of 

 age is especially marked in localities in which the disease has 

 existed for a long time. Thus during the first years of the 

 existence of the disease in Hungary the older hogs became 

 affected quite frequently, while since that time the disease is 

 confined more and more to younger animals. The greater 

 resistance of the older animals in infected localities is in all 

 probability due to the fact that they passed through a mild form 

 of the disease while young. 



Pathogenesis. According to the most recent experimental 

 investigations the disease is without a doubt caused by a fil- 

 terable hog cholera virus, which enters the body fluids and multi- 

 plies there. It causes directly a febrile condition, with acute 

 catarrh of the mucous membrane, and in case of a severe infec- 

 tion death results with manifestations of hemorrhagic septi- 

 cemia. In the great majority of cases however secondary inflam- 

 matory changes of different organs may become associated with 

 the general blood infection. Such secondary changes occur espe- 

 cially in the pharynx, stomach and intestines, in the correspond- 

 ing lymph glands and in the lungs, being caused without a doubt 

 by the bacillus suipestifer or the bacillus suisepticus. The 

 etiological part of these organisms came into the proper light 

 only after the virulence of the filtered blood of affected animals 

 had been established. 



Contrary to the former conception by which the bacillus 

 suipestifer was considered as the original and true cause of the 

 disease, there now exists hardly any doubt that it participates 

 only in a secondary manner, yet though it is only granted an 

 inferior part in the transmission of the disease it is very active, 



