152 DISEASES OF SWINE 



dogs must be considered the principal factor in the 

 ■spread of the disease. Some writers state that 

 the bite of a rabid hog may produce the disease. 



In hogs a large per cent, of the animals bitten 

 develop the disease. The average period of incu- 

 bation is from two to three weeks. 



Symptoms. — Rabies in swine is characterized 

 by very much the same train of symptoms as de- 

 velop in other animals. Two forms of rabies, 

 the furious and dumb, occur. The furious is the 

 more common in hogs. The animal is very rest- 

 less and excited. If lyings down in the litter, it 

 may jump up suddenly, squeal and run about as if 

 pursued. Sometimes, it backs up into a corner of 

 the pen. The animal is very nervous and easily 

 startled. If a person enters the pen, it will run 

 at him. The eyes are at times fixed, or are rolled 

 about, and there is an abundant secretion of saliva 

 which dribbles from his mouth. Frequently it 

 will gnaw the boards around the pen, make desperate 

 efforts to get out, swallow indigestible objects, and 

 attempt to bite other animals. Paralysis soon comes 

 on, the hog has difficulty in swallowing and is unable 

 to move about. 



The duration of the disease is short. Paralysis 

 comes on early in the attack, and the aninjal is 

 seen lying or hiding in the Utter and pays no at- 

 tensian to its surroundings. It does not become 

 excited when approached, is very weak, and dies 

 in a few days. 



Lesions. — The tissue changes are not constant 



