Infections of the brain caused by the protozoan toxoplasma gondii that primarily arise in individuals with immunologic deficiency syndromes (see also aids-related opportunistic infections). The infection may involve the brain diffusely or form discrete abscesses. Clinical manifestations include seizures, altered mentation, headache, focal neurologic deficits, and intracranial hypertension. (From Joynt, Clinical Neurology, 1998, Ch27, pp41-3)