NR AOVA
AU Konold,T.; Ryder,S.J.; Sach,A.; Hawkins,S.A.C.
TI Description of Early Clinical Signs in Cattle Orally Infected with the BSE Agent
QU International Conference - Prion diseases: from basic research to intervention concepts - TSE-Forum, 08.10.-10.10.2003, Gasteig, München - Poster session - DG-01
PT Konferenz-Poster
AB
The clinical picture of BSE in naturally infected cattle, which are presented as clinical suspects, has been documented in several publications but the early clinical signs have not been described.
We summarise the clinical signs suggestive of BSE in Holstein-Friesian steers that were orally inoculated with 100 g of brainstem of naturally infected BSE cases and culled at set time-points throughout the incubation period.
All steers were monitored clinically at regular intervals. According to the regularity and severity of presented clinical signs the animals were grouped into 4 categories: status 0 (no apparent signs of BSE), status I (possible signs of BSE), status II (probable signs of BSE) and status III (definite signs of BSE).
15 out of 89 inoculated steers displayed signs suggestive of BSE prior to cull, which were subsequently confirmed by immunohistochemistry. 7 steers displayed possible signs, 3 steers displayed probable signs and 5 steers definite signs of BSE. 60 steers did not display any apparent signs of BSE and were also not confirmed by immunohistochemistry.
Abnormalities or changes in behaviour and activity were the dominant clinical signs seen in all animals with early signs of BSE (status I or II at time of cull), which were in particular evident when the animal was stressed. These consisted of agitated behaviour in a crush, apprehension/ fear entering a crush, moving away from the pen or crossing drains characterised by freezing and trembling episodes and startle reactions to auditory or visual stimuli. One steer each presented with mild hind limb ataxia and weight loss in addition to these behavioural changes.
In addition, 14 steers displayed similar clinical signs suggestive of early BSE, 11 with possible signs and 3 with probable signs, that were not confirmed by immunohistochemistry. Studies on neurophysiologic evoked responses are required to evaluate if these signs are accompanied by dysfunction of the sensory pathways in the brainstem.
AD T. Konold, S.J. Ryder, S.A.C. Hawkins, VLA Weybridge, UK; A. Sach, ADAS Drayton, UK; 4 VLA Weybridge, UK
SP englisch
PO Deutschland