52 SWINE PLAGUE 



Formalin, solution 1-2000 kills in 5 minutes. 



Trikresol, ji per cent, kills in 5 minutes. 



Pathogenesis. — This organism is pathogenic for rabbits, guinea pig» 

 and mice among the smaller experimental animals and for swine. With 

 the virulent form rabbits inoculated either subcutaneously or in the vein 

 with very small, o.ooi c. c. doses, die of septicaeemia in from 16 to 24 

 hours. Guinea pigs are slightly less susceptible. When inoculated sub- 

 cutaneously with 0.1 to 0.2 c. c. of a bouillon culture, they die in from 

 30 to 72 hours. Mice succumb in about 24 hours when inoculated with 

 a drop of the culture. Pigs inoculated intravenously usually die from 

 acute septicaemia in from 18 to 36 hours. If they live longer there may 

 be decided lung lesions. (See report on swine plague. Smith.) 



§ 48. Symptoms. It is frequently difficult to recognize 

 symptoms distinctive of swine plague. The peculiarities of 

 swine render it exceedingly difficult to obtain evidence on 

 physical examination of lung disease. Sometimes this affec- 

 tion runs a very rapid course, the animal dying of septicaemia. 

 Usually it is more protracted, lasting from a few days to a 

 week or longer. Animals affected with the more chronic form 

 where there are lung lesions, eat very little, or refuse food 

 altogether. They cough considerably, especially when forced 

 to run. The back is usually arched and the groins sunken. 

 The whites of the eyes are reddened. The skin over the ventral 

 surface of the body, nose and ears is frequently flushed. The 

 cough, however, is the most reliable indication we have of 

 swine plague ; but in some cases of hog cholera the coexistence 

 of broncho-pneumonia also causes the animal to cough when 

 forced to move rapidly. 



i^ 49. Morbid anatomy. There are many known varia- 

 tions in the appearance of the internal organs of hogs which 

 have died of swine plague. The characteristic lesions are, as 

 previously stated, to be found in the lungs. Frequently the 

 abdominal viscera appear to be normal although a careful 

 examination will usually reveal slight changes. In the lungs, 

 however, the disease is usually obvious. 



The variety of lesions produced by the inoculation of swine- 

 plague bacteria is not so great as that observed in the naturally 

 contracted disease. While there are outbreaks in which con- 

 siderable uniformity is observed, there are others in which 

 each animal is a surprise to the pathologist. In general it may 



