EABIBS 185 



RABIES 



This disease in nearly every instance runs a rapid and 

 fatal course in the horse. It is characterized by symp- 

 toms of great excitement, violent exhibitions, paralysis 

 and death. Rabies is a disease that has been the subject 

 of much controversy in regard to its true character in 

 animals. Some pathologists of repute have even held 

 that rabies, as a disease, does not exist in the lower ani- 

 mals. The greatest confusion in arguments and theories 

 along this line originates from the fact that an effort 

 is usually made to make rabies conform to the manifesta- 

 tions of hydrophobia as seen in human beings. An intel- 

 ligent conception of rabies is only possible when all con- 

 nections which it is presumed to have with hydrophobia 

 are ignored from a clinical standpoint. 



It is now quite generally held that the bodies of Negri 

 are the etiological factors in this disease. At first looked 

 upon as coincidental to the pathological changes occur- 

 ring in the brain as a result of the disease, they are now 

 accepted as the true causative agents. 



The period of incubation in this disease is from one 

 to ten weeks; an acceptable average can be placed in 

 practice at three weeks. The period of incubation is 

 shortest when the site of inoculation is on parts of the 

 head. Belief is no longer held in exceptionally long 

 periods of incubation. Cases of the disease which occur 

 many months, or even years, after known exposure, are 

 no doubt due to exposure or inoculation which was con- 

 tracted later in an unknown manner. 



Horses are infected most frequently as a result of being 

 bitten by dogs afflicted with the disease ; more rarely from 

 bites of members of their own species. Relatively speak- 

 ing, the horse is a very rare subject of this disease. The 

 percentage of animals which develop rabies as a result of 



