250 DISEASES OF THE BRAIN 



fever point to the condition. In rare cases in which the tumor 

 leads to a deformity of the cranium the diagnosis is easier. 

 The cHnical symptoms of chronic hydrocephalus, chronic 

 meningo-encephalitis, abscess, and parasites of the brain so 

 closely resemble those of tumor in many cases that an accu- 

 rate diagnosis becomes impossible. 



Treatment. — ^Treatment for brain tumor in animals is rarely 

 of avail. In man they are occasionally removed siu-gically. 



GID. CffiNUROSIS. 



Definition. — Gid is a chronic parasitic disease of sheep and 

 cattle, due to the presence of the Coenurus cerebralis in the 

 brain and very rarely in the spinal cord. 



Natural History. — Coenurus cerebralis is the cyst form of 

 the tapeworm Taenia coenurus. The adidt worm is harbored 

 by dogs, principally shepherd and butchers' dogs. Occasion- 

 ally wolves and foxes are hosts. The infestation of sheep and 

 cattle takes place by their ingesting the eggs or proglottides 

 which are voided with the feces. The shell of the egg is 

 dissolved in the abomasum allowing the six-hooked embryo 

 to escape. The embryos perforate the bowel wall and prob- 

 ably through the bloodvessels reach the brain and spinal 

 cord where they produce a hemorrhagic leptomeningitis and 

 in some instances a pm'ulent infection. They ultimately 

 develop into cysts from the size of a pigeon's to a hen's egg. 

 The cyst produces atrophy of the brain tissue surrounding it 

 and also of the overlying skull. 



Occurrence. — While gid is common in sonie districts abroad 

 it is a comparatively rare disease in the United States, 

 although isolated outbreaks have occurred ipi various parts of 

 this country. Sheep are much more commonly infested than 

 cattle, in which it is a very rare disease. Young sheep are 

 more susceptible than aged ones. 



Symptoms in Sheep. — ^From a clinical standpoint, and due 

 to the development of the parasite in the brain, three stages 

 of the disorder may be determined : (a) The stage of acute 

 cerebral inflammation, (&) the stage of latency due to the 

 gradual growth of the cyst, and (c) the stage of gid, the cyst 

 being completely developed. 



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