390 The Diseases of Animals 



weeks before allowing other susceptible dogs to oc- 

 cupy them. 



HOG CHOLERA AND SWINE PLAGUE 



Hog cholera and swine plague are difiEerent dis- 

 eases, and yet they are so closely associated that 

 one disease rarely appears without the other. Swine 

 plague is an infectious pneumonia, that attacks swine 

 when in poor, unthrifty condition, or when run down 

 from an attack of hog cholera. It is probable that 

 germs of swine plague are widely distributed wherever 

 hogs are kept in large numbers, but the natural power 

 of resistance of the animal's system is sufficient to 

 prevent them from developing after entering the sys- 

 tem. When, however, the system becomes weakened 

 from disease or other injurious influences, the germs 

 obtain a foothold and often cause serious damage, not 

 only from the deaths that directly result from the 

 pneumonia but from the hog cholera, with which the 

 swine plague is usually associated. 



Hog cholera is an infectious disease of the intestinal 

 tract, that resembles typhoid fever in man. The hog 

 cholera is aggravated by the pneumonia, and between the 

 two diseases the vital powers of the animal are greatly 

 lessened. In man, typhoid fever and pneumonia are 

 often associated. The losses from hog cholera and swine 

 plague are diflSeult to estimate accurately. Persons famil- 

 iar with the subject estimate that the losses caused by 

 these diseases are gi-eater than those caused by any other 

 disease of domestic animals. Others go further, and 



