140 ' Enzootic Pneumonia of Pigs. 



of pigs commences with catarrhal processes of the air passages which develop in a 

 broncho-pneumonia when the bacteria which are normally present in the respiratory 

 passages, among them also the bac. suisepticus, will subsequently multiply and 

 aggravate the inflammatory processes; that the bac. suisepticus is not the true 

 causative agent of the disease is further substantiated by the fact that this 

 organism, at least in the artificial infections, always produces acute inflammatory 

 and later necrotic processes, and consequently the anatomical lesions of the pneu- 

 monia of pigs do not correspond with the pathogenic characteristics of this bacillus 

 (see also chapter. Enzootic Inflammations of the Lungs of Young Animals, in 

 Vol. 11.). For the correctness of the conception that the former acute swine 

 plague has changed in Germany to a chronic catarrhal pneumonia, there are no 

 convincing proofs. It is only established that in certain localities this disease 

 occurs quite extensively; it is, however, probable that the disease existed there in 

 former times. The occurrence of the disease is in the first place influenced by 

 local conditions and especially by exposure of the delicate young animals to cold 

 moist stables, and possibly also by attempts to improve the breed by intensive 

 breeding, by the confinement of too many animals in close quarters, the feeding 

 of creamery products, etc. 



Uhleuhuth and his co-workers have proven experimentally the correctness of 

 the conception that the catarrhal affection of the lungs in question is independent 

 of swine plague, and that the disease may develop without the cooperation of the 

 bac. suisepticus in animals in which the vitality has been reduced. They placed 

 pigs in enameled troughs or in sheds in which the floor was covered with cinders 

 which were frequently moistened. These animals became affected with a typical 

 catarrhal pneumonia and the lung tissue contained only streptococci or staphy- 

 lococci. 



The infection from animal to animal may also play an important part in 

 the spread of the disease. The animals weakened by the debilitating influences 

 above mentioned will be rendered more susceptible to infections, if they ingest, 

 with the expectoration and excrements of affected animals, various kinds of faculta- 

 tive pathogenic bacteria in large numbers. Such organisms originating from 

 affected organs possess iisually a high virulence compared with the organisms of 

 the same sjiecies present in the air passages of healthy animals. An infection of 

 adult animals through affected young hogs has not yet been established. 



The recent findings of Frosch & Broil regarding the nature of the enzootic 

 pneumonia of pigs cannot yet be accepted as conclusive. They succeeded in pro- 

 ducing hog cholera in pigs with filtered and unfiltered material of affected pigs 

 from 4 to 6 weeks old, although it is known from experience that animals of that 

 age very rarely become affected with hog cholera. 



The medicinal treatment promises no results. On the other hand, 

 improvement of the hygienic conditions and good nutrition have a 

 favorable influence on the course of the disease. 



A proprietary remedy which is marketed in Germany under the name of 

 " Wassermann 's Vaccine for the Cure of Swine Plague" (aggressin preparation? ) 

 gave Mucha, Eaebiger, Willenberg and Dien satisfactory results. 



According to Ostertag in the prevention of the disease, which 

 should extend also to the protection of the healthy animals in the herd 

 where the disease has already appeared, great caution should be exer- 

 cised in the purchase of animals in limiting to some extent the in- 

 breeding, keeping of the pigs in warm and dry stables with access 

 if possible to outside range. For parturition the animals should be 

 placed in separate sta])les (cow or sheep stables), the pigs should 7iot 

 he weaned too soon, those pigs stunted in growth should l)e removed, and 

 lastly the stables and stable utensils should be regularly disinfected 

 with a 2% hot soda solution. 



Evers considers frequent disinfection as a very difficult proceilure in practice, 

 and in the winter time not without danger; on the other hand, he lays especial stress 

 on the proper building of isolation stables as well as the destruction of all runts. 



Immunization. In Germany the polyvalent swine splague serum of 

 Wassermanu & Ostertag is used quite extensively (see page 137). The 



