74 HOG CHOLERA 



Rouget or swine erysipelas does not exist in 

 the United States. The septicemic form of the 

 disease resembles hog cholera very closely. It 

 has a shorter incubation period than the latter 

 disease, but resort must often made to microscop- 

 ical examination, in order to distinguish between 

 them. 



Rinderpest does not occur in the United States, 

 and in countries in which it is prevalent, swine do 

 not contract it readily. For this reason it is not 

 well characterized, but in case of necessity it may 

 be distinguished from hog cholera by nitration 

 experiments in which cattle are used as test ani- 

 mals. Both viruses are filterable, but that of 

 rinderpest is the only of the two which affects 

 bovines. 



Prognosis 



In the individual, hog cholera runs a rapid and 

 fatal course, and even when recoveries occur, they 

 may be slow and incomplete. Therefore in all 

 hogs visibly sick the prognosis is bad, but it is the 

 herd as a unit which we must consider, for we are 

 frequently called on to estimate the salvage which 

 may be expected. The ability to do this with a 

 reasonable degree of accuracy is acquired only by 

 experience, and it is a great asset to one who han- 

 dles hog cholera in the field. We can indicate -only 

 the guiding principles upon which the progno- 

 sis depends. 



