Introduction
Materials and methods
Experimental site design
Burial of TSE-spiked bovine heads and bolus
Sampling procedures and infectivity assays
Detection of PrPSc within filter extracts
Results
Survival of 301V in buried cattle heads
Clay | Sand | ||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Year | 1 | 2 | 3 | 4 | 5 | SC | 1 | 2 | 3 | 4 | 5 | SC | |||||||||||||
N | IP | N | IP | N | IP | N | IP | N | IP | N | IP | N | IP | N | IP | N | IP | N | IP | N | IP | N | IP | ||
Samples taken from within the heads | |||||||||||||||||||||||||
In head
| A |
4/4
|
149
|
4/4
|
165
|
3/4
|
201
|
4/4
|
167
|
4/4
|
173
|
1/4
|
181
| 0/4 |
4/4
|
137
|
2/4
|
237
|
4/4
|
180
| |||||
B |
4/4
|
155
|
4/4
|
134
|
2/4
|
193
|
2/4
|
174
|
1/4
|
175
|
4/4
|
153
|
4/4
|
130
|
4/4
|
130
|
4/4
|
149
|
4/4
|
173
| |||||
C |
4/4
|
162
|
4/4
|
151
|
4/4
|
165
|
4/4
|
184
|
1/4
|
328
|
4/4
|
158
|
4/4
|
130
|
3/4
|
180
|
4/4
|
179
|
4/4
|
168
| |||||
D |
3/4
|
222
|
3/3
|
144
|
4/4
|
214
|
4/4
|
207
|
4/4
|
205
|
4/4
|
161
|
4/4
|
130
| 0/4 |
4/4
|
202
|
4/4
|
165
| ||||||
E |
2/4
|
186
|
2/4
|
185
| 0/4 |
4/4
|
198
|
4/4
|
186
|
4/4
|
143
|
3/4
|
268
|
3/4
|
156
|
4/4
|
151
|
3/4
|
201
| ||||||
F |
2/4
|
234
|
4/4
|
140
|
1/4
|
315
|
2/4
|
205
|
3/4
|
226
|
3/3
|
160
|
2/4
|
235
|
4/4
|
152
|
4/4
|
153
|
4/4
|
159
|
Clay | Sand | ||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Depth (cm) | N | IP | N | IP | N | IP | N | IP | N | IP | N | IP | N | IP | N | IP | N | IP | N | IP | N | IP | N | IP | |
Samples taken from the soil around the heads | |||||||||||||||||||||||||
N | 40 | 0/3 | 0/4 | ||||||||||||||||||||||
50 | 0/4 | 0/4 | 0/4 | 0/4 |
1/4
|
210
| 0/4 | 0/1 | 0/4 | 0/4 | 0/4 | ||||||||||||||
60 | 0/4 | 0/4 |
1/4
|
251
|
4/4
|
237
|
3/4
|
296
| 0/4 |
1/4
|
359
| 0/6 | 0/4 | 0/4 | 0/4 | 0/4 | |||||||||
70 | 0/4 | 0/4 |
3/4
|
237
| 0/4 | 0/4 | 0/4 | 0/5 | 0/4 |
1/4
|
236
| 0/4 | |||||||||||||
80 | 0/4 | 0/4 | |||||||||||||||||||||||
E | 40 | 0/4 | |||||||||||||||||||||||
50 | 0/3 | 0/4 |
1/4
|
H
| 0/4 | 0/4 | 0/4 | 0/5 | 0/4 | 0/4 | 0/4 | ||||||||||||||
60 | 0/4 |
1/4
|
307
|
3/4
|
H
|
2/2
|
181
| 0/4 | 0/4 | 0/4 | 0/4 | 0/4 | 0/4 | 0/4 | 0/4 | ||||||||||
70 | 0/3 | 0/4 |
3/4
|
239
|
4/4
|
188
| 0/4 | 0/7 |
1/3
|
H
| 0/4 | 0/4 | 0/4 | ||||||||||||
80 | 0/4 |
1/4
|
295
| ||||||||||||||||||||||
S | 40 | 0/4 | 0/4 | ||||||||||||||||||||||
50 | 0/3 | 0/8 | 0/4 | 0/4 | 0/4 | 0/4 | 0/4 | 0/4 | 0/4 | 0/4 | |||||||||||||||
60 | 0/4 |
1/4
|
230
| 0/4 |
1/4
|
355
| 0/4 | 0/4 |
1/3
|
218
| 0/6 | 0/4 | 0/4 | 0/4 | 0/4 | ||||||||||
70 | 0/4 | 0/4 |
2/4
|
223
|
1/4
|
321
| 0/4 | 0/4 | 0/4 | 0/4 | 0/4 | 0/4 | |||||||||||||
80 | 0/4 | 0/4 | |||||||||||||||||||||||
W | 40 | 0/4 | 0/4 | ||||||||||||||||||||||
50 | 0/3 | 0/4 | 0/4 |
4/4
|
283
| 0/4 | 0/4 | 0/4 | 0/4 | 0/4 |
1/4
|
295
| |||||||||||||
60 |
1/3
|
183
| 0/4 | 0/4 |
4/4
|
129
| 0/4 | 0/4 |
1/4
|
317
| 0/4 | 0/4 | 0/4 | 0/4 | 0/4 | ||||||||||
70 | 0/3 | 0/4 | 0/4 |
2/4
|
254
|
2/4
|
172
| 0/3 | 0/4 | 0/4 | 0/4 | 0/4 | |||||||||||||
80 | 0/4 | 0/4 | |||||||||||||||||||||||
Cen | 60 |
2/3
|
257
| ND |
4/4
|
267
|
4/4
|
169
|
2/3
|
252
| 0/4 | 0/4 | 0/4 | 0/4 | 0/4 |
1/4
|
204
| 0/4 | |||||||
70 |
1/4
|
218
|
1/4
|
H
|
4/4
|
190
| 0/4 | 0/4 | 0/4 | 0/4 | 0/4 | 0/4 | 0/4 |
1/4
|
267
| 0/4 | |||||||||
80 |
1/4
|
239
| 0/4 |
2/4
|
174
|
3/4
|
244
|
1/4
|
203
| 0/3 | 0/4 |
1/4
|
H
| 0/4 |
3/4
|
255
| |||||||||
100 | 0/4 |
2/4
|
288
|
Survival of 301V macerate in soils
Depth (cm) | 25 cm distance from central core | |||||||||
---|---|---|---|---|---|---|---|---|---|---|
Month: | 1 | 3 | 7 | 9 | 12 | 18 | 14 | 36 | 48 | |
40 | X | X | X | X | 0/4 | 0/4 | 0/4 | 0/4 | 0/4 | |
50 | 0/3# | 0/4 | 0/4 | 0/4 | 0/4 | 0/4 | 0/4 | 0/4 | 0/4 | |
60 | 0/4 | 0/4 | 0/4 | 0/4 |
1/4
| 0/4 | 0/4 | 0/4 | 0/4 | |
70 | 0/4 | 0/4 | 0/4 | 0/4 | 0/4 | 0/4 | 0/4 | 0/4 | 0/4 |
Depth (cm) | 50 cm distance from central core | |||||||||
---|---|---|---|---|---|---|---|---|---|---|
Month: | 1 | 3 | 7 | 9 | 12 | 18 | 14 | 36 | 48 | |
40 | X | X | X | X | X | X | X | X | X | |
50 | X | X | X | X | 0/4 | 0/4 | 0/4 | 0/4 | 0/4 | |
60 | 0/4 | 0/4 | 0/4 | 0/4 | 0/4 | 0/4 | 0/4 | 0/4 | 0/4 | |
70 | X | X | X | X | 0/4 | 0/4 | 0/4 | 0/4 | 0/4 |
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 |