Detectable levels of PrP^Sc on Western blots do not correlate with the levels of infectivity.

<p>10% brain homogenates from an uninfected brain (lane 2) time-course samples week 3, 6, 9, 12, 15, 18, 21 (lane 3–9), and the terminal sample (lane 10) were digested with proteinase K at 60°C for 10 minutes and assessed by Western blot. The observed signal does not correspond with the levels of infectivity found in corresponding bioassays for the week 12–21 post-exposure time-points.</p

Comparison of the cull dates for the mice challenged via the gingival margin.

<p>Panel A; Frequency distribution plots show the presence of a normally distributed population with a mean incubation period of around 250 days plus a small number of animals with significantly shorter incubations ranging from 140–188 days. Panel B; when these two groups are compared they show distinct means and distribution and are considered as distinct populations (p<0.001).</p