Relationship between clinical signs and postmortem test status in cattle experimentally infected with the bovine spongiform encephalopathy agent

Table 1 Grouping of animals according to source study, experimental treatments, postmortem diagnosis, the total number of assessments (examinations and observations) and the number (%) clinically diagnosed on the basis of selected criteria prior to cull

Group (N animals)	Postmortem BSE diagnosis	Total examinations	Total observations	Number (%) of cattle with a clinical diagnosis of BSE
Study 1 (oral challenge)
Controls, not dosed (93)	Negative	982	8 473	0 (0)
100 g BSE brainstem (25)	Positive	318	2 338	17 (68)
1 g BSE brainstem (5)	Positive	96	923	3 (60)
100 g BSE brainstem (74)	Negative	365	2 139	11 (15)
1 g BSE brainstem (94)	Negative	1 076	9 205	10 (11)
Study 2 (intracerebral inoculation)
Group 1: Control (10)	Negative	193	2 556	0 (0)
Group 2: Tissue without expected infectivity (240)	Negative	5 290	59 310	15 (6)*
Group 3: Tissue with expected infectivity (53)	Negative	1 204	12 526	3 (6)*
Group 4: Tissue with confirmed infectivity (22)	Positive	110	1 051	17 (77)
Total		9 634	98 521

Study 1: cattle culled at pre-determined time points post dosing.
Study 2: cattle culled upon development of BSE or at 7 years post inoculation; see Methods for groupings.
* Clinical suspects despite negative postmortem BSE diagnoses were: in group 2 (n = 15) inoculated with pooled kidney (collected at 18 mpi), mesenteric lymph node (18 mpi), bone marrow (36 mpi), buffy coat (18 mpi), buffy coat (26 mpi; n = 2), CNS and spinal cord C2-3 & T10-11 (18 mpi; n = 2), cervical/popliteal lymph nodes (26 mpi), peripheral nerve (26 mpi), pooled liver (32 mpi), salivary gland (18 mpi), skin (18 mpi), spleen (18 mpi) and urine (18 mpi) [16], and
in group 3 (n = 3) inoculated with distal ileum (collected at 26 mpi), tonsil (6 mpi) and caudal medulla/spinal cord (26 mpi).

ISSN: 1746-6148