INFECTIOUS DISEASES 



307 



cholera consist of a typical croupous pneumonia and in the later 

 stages of necrosis. 



Verminous pveimojiid. — May be differentiated from swine plague 

 by the chronicity of the attack, the wheezing respiration, and the 

 demonstration on autopsy of the Strongylus paradoxus. The ver- 



Fig. 88. A group of pigs showing various symptoms. Note the spotted 

 pig at the left holding its right front foot up. Rheumatic arthritis is 

 present, due to circulation of toxins in the system. 



minous pneumonia caused by the development of the larval form of 

 the Ascaris suum is embolic in character and may be identified by 

 demonstration of the larvae microscopically. 



Catarrhal pneumonia. — Is differentiated from swine plague pneu- 



Fig. 89. A bad bunch of sick hogs. Some went down, others had paroxysms 

 of coughing: many went down in the back. 



monia by the fact that the former disease occurs only in young pigs 

 and is sporadic, and rarely are the necrotic centers typical of swine 



