Nervous symptoms have been frequently associated with parasitic infections in animals and peoples. The protozoas, cestodes, nematodes sporadically or with some frequency migrate through and inhibit the central nervous system (cns). Parasites may be located in the meningeal spaces or may penetrate into the tissues of the brain and spinal cord. The pathological changes are influenced by the route of entry, and the size and mobility of the parasite. These changes fall into three categories hemorrhagic, degenerative, and proliferative. Apart from the purely mechanical damage that parasites may cause; there has been considerable speculation as to whether they may facilitate the entry of virus, bacterial and fungal infections.

83-93