Human Prion Disease

Evidence supporting the relationship of vCJD to the BSE epidemic includes the geographic and temporal relationship with the BSE epidemic accompanied by atypical clinicopathologic features. In contrast to sporadic CJD, the variant disease is heralded by sensory or psychiatric disturbances rather than dementia or motor abnormalities. Cerebellar signs and symptoms are often prominent. Patients are usually younger, under 50 years of age, and the clinical course is more protracted, with a median duration of 13 months (range 7-38 months). In addition to spongiform change, the histopathologic hallmark is the ¨florid plaque¨ (arrowhead). The highest concentration of these plaques occurs in the occipital lobe and cerebellum, whereas the most intense spongiform degeneration occurs in the basal ganglia and thalamus. Another notable feature of vCJD is the accumulation of protease-resistant PrP in the form of numerous mature, PAS reactive, PrP amyloid plaques, accompanied by frequent PAS-negative primitive plaque-like deposits. Immunohistochemical techniques are available to identify prion protein.