TABLE 1.
Timeline of exposure of animals to a scrapie-positive farm environment, sample collection, and scrapie status
| Animala (PrP genotypeb) | Age at exposurec | Days postexposure at lactation | Days postlactation to clinical scrapied | Clinical statuse | PrPSc detection at postmortemf | PrPSc detection in milk (positive tests/total tests)g |
|---|---|---|---|---|---|---|
| 1349/08 (VRQ/VRQ) | Not exposed | NAh,i | NA | Negative | Negative | 0/20 |
| K489 (VRQ/VRQ) | Not exposed | NAi | NA | Negative | NA (still alive) | 0/18 |
| 0618/06 (VRQ/VRQ) | Not exposed | NAi | NA | Negative | Negative | 0/20 |
| 1348/08 (VRQ/VRQ) | Not exposed | NAi | NA | Negative | Negative | 0/20 |
| 0695/07 (VRQ/VRQ) | Birth | 666-680 | 0 | Positive | Positive | 3/3 |
| 0334/07 (VRQ/VRQ) | Birth | 661-666 | 0 | Positive | Positive | 3/3 |
| 0335/07 (VRQ/VRQ) | Birth | 666-674 | 0 | Positive | Positive | 3/3 |
| 0350/07 (VRQ/VRQ) | Birth | 663-676 | 0 | Positive | Positive | 3/3 |
| 0333/07 (VRQ/VRQ) | Birth | 667-675 | 0 | Positive | Positive | 3/3 |
| 0142/07 (VRQ/VRQ) | Birth | 665-673 | 0 | Positive | Positive | 3/3 |
| 0326/07 (VRQ/VRQ) | Birth | 670-676 | 0 | Positive | Positive | 2/3 |
| 0199/07 (VRQ/VRQ) | Birth | 664 | 0 | Positive | Positive | 2/3 |
| 0692/07 (ARQ/VRQ) | ∼480 days | 1,003 | >450 | Negative | Positive | 2/3 |
| 0480/07 (ARQ/VRQ) | ∼480 days | 1,003 | >355 | Negative | Positive | 3/3 |
| 0349/07 (ARQ/VRQ) | ∼480 days | 1,003 | >348 | Negative | Positive | 3/3 |
| 0822/07 (ARQ/VRQ) | Birth | 760 | >564 | Negative | Negative | 2/3 |
| 2295 (AHQ/VRQ) | ∼120 days | 1,376 | >621 | Negative | Negative | 3/3 |
| 3148 (ARR/VRQ) | Birth | 1,288 | >621 | Negative | NA (still alive) | 2/3 |
| 1514 (ARR/VRQ) | Unknown | 597 | >621 | Negative | NA (still alive) | 2/3 |
| 1518 (ARR/VRQ) | Unknown | 597 | >621 | Negative | NA (still alive) | 1/3 |
| 1244 (ARR/VRQ) | Birth | 1,130 | >621 | Negative | NA (still alive) | 3/3 |
All animal procedures were performed under Home Office (United Kingdom) and local ethical review committee approval and compliance with the Animal (Scientific Procedures) Act of 1986.
Amino acid residues at positions 136, 154, and 171 of the PRNP gene.
Introduction into a scrapie-affected flock.
Days postlactation to postmortem or as of 12 December 2008 for animals that were still alive at the time this paper was written.
Clinical disease usually included head tremors and pruritus with associated wool loss and nervousness. The indicated clinical status was applicable throughout lactation to either postmortem or as of 12 December 2008 for animals that were still alive at the time this paper was written.
PrPSc was analyzed by IHC, Western blot analysis, or enzyme-linked immunosorbent assay. All animals with a positive result contained PrPSc within both brain and lymphatic tissues.
sPMCA was used for PrPSc detection and the results are tallied within this column. Replica analysis of a single milk sample from each animal was carried out. For animals 0695/07, 0334/07, 0335/07, 0350/07, 0333/07, 0142/07, and 0326/07, multiple milk samples were collected during the lactation period indicated and multiple samples from an individual animal were pooled before analysis.
NA, not applicable.
Nonexposed animals were 750 to 1,110 days old at lactation and where applicable were 1,200 to 1,650 days old at postmortem.