INFECTIOUS DISEASES 207 



in about one week, but more rarely the disease becomes 

 chronic. 



The chronic form is evidenced by spasmodic cough, 

 temperature of about 104 degrees Fahrenheit, poor appe- 

 tite, emaciation, and weakness, the animals usually dying 

 of exhaustion in from four to eight weeks. 



Diagnosis. The diagnosis of swine plague is attended 

 with considerable difficulty. The septicemic form can 

 be distinguished from the uncomplicated septicemic form 

 of hog cholera only by the demonstration in the blood of 

 the Bacillus suisepticus or the presence of hog-cholera 

 virus by the production of hog cholera by inoculation 

 with the filtered blood. 



From the pulmonary form of hog cholera the usual 

 form of swine plague is differentiated only by autopsy. 

 The lung lesions in hog cholera consist of a typical croup- 

 ous pneumonia, but in swine plague they consist of a 

 catarrhal pneumonia and, in the later stages, of necrosis 

 Pleuritic lesions are frequently present in swine plague. 



Verminous pneumonia can be differentiated from swine 

 plague by the chronicity of the attack, the wheezing respi- 

 ration, and the demonstration on autopsy of the Stron- 

 gylus paradoxus. 



Catarrhal pneumonia is differentiated from swine 

 plague by the fact that the former disease occurs only 

 in young pigs and is sporadic, and rarely are the necrotic 

 centers typical of swine plague found in the lung. Pleuri- 

 tic complications are also the exception in catarrhal 

 pneumonia. 



Treatment. Prevention by the enforcement of 

 sanitary regulations is much more effective than curative 

 treatment. The disease appears to be favored by dry 

 weather, which usually insures dusty pens. Wetting of 

 the pens with water or some dilute disinfectant prevents 

 or diminishes the spread of the disease. 



The use of a bacterin made from the Bacillus suisep- 

 ticus, tried out in a few herds, has not given uniformly 

 good results, but this method is worthy of further trial 

 and it is possible that a polyvalent bacterin prepared 



