ABSTRACT
On average, sporadic cases appear in the seventh decade, but
the range is wide, from late teenage years to the tenth decade.
Inherited cases tend to appear a bit earlier, mostly in the early
sixth decade. Iatrogenic cases appear anything from 1 to
30 years after the infectious event. Although most cases appear
subacutely, over weeks to months, fulminant onsets spanning
only a few days have been reported.
