252 DISEASES OF THE BRAIN 



tabiiity and sometimes paralysis of the throat and general 

 paralysis. 



Occurrence. — Bulbar paralysis was first definitely recog- 

 nized in Hungary in 1902. The disease has been noted in the 

 United States, especially in the Southern States (Alabama), 

 where it is much confused with rabies. 



Etiology. — ^The cause of the disease is unknown. It may be 

 readily transmitted by inoculating brain tissue from animals 

 which have died of it into healthy cattle, sheep, and goats. 

 Horses and asses do not seem to be as susceptible to artificial 

 inoculations as other animals. Dogs, cats, rabbits, guinea 

 pigs, rats, and mice also acquire the disease when injected 

 with virulent material. The virus seems most potent in the 

 tissue at the point of inoculation, next in the blood, and then 

 in the central nervous organs. Bile, saliva and urine do not 

 seem to be infective. The virus does not pass through fine 

 porcelain filters. Infection through the digestive tract has 

 been produced. 



Symptoms. — In horses and mules the first symptom is 

 usually an itching of the skin, especially about the head, 

 which causes the patient to rub the part often so violently 

 that it may be denuded of hair, excoriated, or even lacerated. 

 The patients are further excitable, irritable, show dysphagia, 

 salivation, gritting of the teeth, and finally paralysis. The 

 temperature usually does not rise much above normal. 



In cattle the infection generally appears about the head, 

 lips and nose which parts the animal rubs violently, produc- 

 ing hemorrhage and inflammatory swellings which extend 

 over the head, throat, and sometimes the neck. The patient 

 is restless, moves its legs convulsively, keeps rubbing the head 

 against objects, or scratches it with its hind feet. Salivation 

 and inability to swallow are often noted. In some cases the 

 digestion is impaired, the patient showing flatulency. The 

 animals usually die in one to two days after the first symp- 

 toms appear. 



Course and Prognosis. — The course is rapid, the patients 

 dying within twenty-four to thirty-six hours. The prognosis 

 is bad; nearly every case dies. 



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