Prion excretion in faeces of healthy and clinical scrapie infected sheep. Prions extracted from 8.3 mg of faeces were used as seed for Method 1 [10 rounds of sPMCA]. After 4 to 10 rounds of sPMCA (as indicated), products were digested with proteinase K and 10 μL applied to Western blots. PrP was detected with monoclonal antibodies SHA31 and P4; molecular weight markers are shown (M1, 20 and 30 kDa; M2, 19 and 28 kDa). Sheep were either in the preclinical (lanes 1 and 2 for animals 1236/09 and 1305/09 respectively) or clinical stages of disease progression (lanes 3-6 for animals 0320/09, 0324/09, 0470/09 and 0572/09 respectively) or were unexposed to the scrapie agent (lanes 7-16 for animals R185, R223, R233, R234, R297, R303, R328, R382, R413 and R421 respectively). Two analyses were carried out for each sample and representative analyses are shown. Cerebellum (2.5 μL of a 10% w/v homogenate) from a terminally affected sheep was analysed on each blot as a PrPSc control (C).