End-point titration of a brain homogenate (posterior brainstem- 12.5% weight/volume homogenate) in Tg338 mice.

The donor ewe was born and bred in the Langlade Flock. This ewe was at the terminal stage of Scrapie at the moment of culling. Each mouse was intracerebrally inoculated with 20 µl of homogenate. Mice were considered positive when abnormal PrP deposition was detected in brain. Incubation periods are presented as mean+/−SD except for that dilution with which less than 20% of mice were found positive. In that case (*) incubation times of the positive mice are individually presented.