126 Swine Plague. 



establishment of the etiology of the latter disease (see that disease) it 

 has been proven that in hogs affected with the filterable virus of hog 

 cholera the bipolar bacillus usually produces only secondary processes, 

 so that these cases should properly be considered as hog cholera. 



The over-estimation of the importance of the ovoid bipolar bacilli 

 being present in the affected lung tissue caused many to connect with 

 this disease the chronic catarrhal pneumonia of pigs as the so-called 

 chronic swine plague, but there are no satisfactory proofs for such a 

 conception. On our part we separate this disease from the true swine 

 plague and consider it closely related to other similar pneumonic 

 processes of young animals, and principally as the result of a mixed 

 infection. Likewise the diseased processes caused by the bacillus pyo- 

 genes suis will be discussed here under a separate heading (see pyo- 

 baeillosis), while the name swine plague will be retained for the disease 

 caused by the bacillus suisepticus. This is the disease which is origi- 

 nally and exclusively, or at least principally, caused by this organism 

 and which in its anatomical changes corresponds with the pathogenic 

 nature of this bacterium, and which in its classical form was first 

 described by Loffler and Schiitz. 



Occurrence. Pure swine plague occurs mostly in a sporadic 

 fonn in otherwise healthy herds. Exceptionally it may also 

 attain an enzootic form, but even in such cases it remains con- 

 fined to the directly affected herds without spreading in the 

 usual way of epizootics from place to place. In Hungary the 

 disease occurred as early as in the eighties in the last century 

 as a necrotic pneumonia among fattened hogs, but always in 

 a sporadic form. 



In the conception given a1 ove for pure 

 swine plague the disease is only of slight 

 economic importance. The losses which are, 

 even at the present time, attributed to swine 

 plague are actually the result of either hog 

 cholera or of the catarrhal pneumonia of pigs. 

 The occurrence of acute and destructive epizo- 

 otics of pure swine plague has, at least in cen- 

 tral Europe, never been positively established. 



Borzoni (1908) reported a fatal disease in 

 Sardinia (Angina, su fogale, su niali, de sa 'ula) 

 which occurred especially after long floods, pro- 

 tracted rains, or in poorly fed animals, which 

 caused a loss up to 90 per cent, the blood of the 

 affected animals showing a ' ' cocco bacillus ; ' ' 

 but in this disease inflammatory and necrotic 

 ^. „- r. .77 •4- changes are absent in the organs of the thoracic 



Fig. 29. BacdJus smsepUcus ^^^.^^^ j^^^^^ ^-^c)08) reports an outbreak of 



Smear preparation from the fluid p^^^.^ ^^j^^ pj^^^^^ -^ Capland in which on one 

 of the lung of a hog. Fuchsin f^^.^^ ^^^^ ^^ j()q j^^^^ 40 ^^j^.-j ^^ pieuro-pneu- 

 stainmg ;a^nd subsequent wash- ^^^^^^ rp,^g ^^^^^^ ^^ ^^^^^ ^^^^^ contained 

 ingwith 17o acetic acid. ^^j^ bipolar bacilli. The diagnosis of this out- 



break was, however, based on the autopsy find- 

 ing of only five carcasses. Theiler observed in South Africa in the course of years 

 only one case of swine plague in which hog cholera could be excluded. 



Etiology. The bacillus (bipolaris) suisepticus is charac- 

 terized by the peculiarities of the bacilli of hemorrhagic septi- 

 cemia (see page 79), hut it is usually somewhat larger, can he 

 quite readily isolated from the animal body (especially from the 



