Table 3.
Summary of mouse bioassays of central core soil samples taken from lysimeters with buried boluses of 301V brain homogenate
| Depth (cm) | Number of samples tested | Number of TSE-positive mice/number inoculated | |
|---|---|---|---|
| Clay core | Sandy core | ||
| 10 | 1 | 0/4 | 0/4 |
| 20 | 1 | 0/4 | 0/4 |
| 30 | 1 | 2/4 | 0/4 |
| 40 | 1 | 4/4 | 0/4 |
| 50 | 5 | 20/20 | 20/20 |
| 60 | 3 | 1/12 | 6/12 |
| 70 | 1 | 0/4 | 0/4 |
| 80 | 1 | 0/4 | 1/4 |
| 90 | 1 | 0/4 | 0/4 |
| 100 | 1 | 0/4 | 0/4 |
| 110 | 1 | 0/4 | 0/4 |
| 120 | 1 | 0/4 | 0/4 |
Samples were taken after burial for 48 months. Each sample was inoculated into four mice, and results are presented as the number of TSE-positive animals/total injected. Samples with any sign of infectivity are in bold. The bolus level was 50 cm