Final answer:
Variant CJD (vCJD) typically affects younger individuals and has a slower progression compared to sporadic CJD (sCJD), which affects older individuals and leads to death more rapidly, usually within a year of diagnosis.
Step-by-step explanation:
Variants of Creutzfeldt-Jakob Disease (CJD) manifest with different ages of onset and courses of disease. Variant CJD (vCJD) is linked to consumption of products from cows affected by bovine spongiform encephalopathy (BSE), while sporadic CJD (sCJD) often has no identifiable cause and occurs more spontaneously. vCJD affects younger individuals, typically in their late 20s, and has a longer duration from onset of symptoms to death, which can range from a few years to over a decade. In contrast, sCJD usually strikes later in life, around the age of 60, and progresses more rapidly, with most patients dying within a year of diagnosis. Both conditions are associated with prion proteins, but the means of transmission and disease progression distinguish vCJD from sCJD. Prions, infectious proteins responsible for these diseases, lead to brain degeneration that can be confirmed through brain autopsies revealing sponge-like lesions.