Prion incubation times.

Incubation times are given for prion transmissions following intra-cerebral inoculation and are displayed as the mean ± sem given in days with the number of animals per group given in parentheses. RML and Me7 represent two distinct strains of mouse-passaged scrapie and mouse BSE and MRC2 represent two different preparations of mouse passaged BSE. For all prion strains, all groups of mice were inoculated with 1% brain homogenate made from the same stock of 10% brain homogenate. All RML/scrapie and mouse passaged BSE transmissions were carried out in a conventional animal facility and ME7 and MRC2 transmissions were carried out in a specific-pathogen-free facility. Where data were normally distributed groups were analysed statistically using a t-test. Where one or both of the groups did not pass a normality test, a non-parametric Mann-Whitney test was used. ns denotes not significant (P>0.05).