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The attack rate and phenotype of scrapie-like disease on transmission to cattle of fresh & rendered pools of scrapie. - SE1942

Description
The main aim of this research is to establish attack rate and dose response data of any scrapie-like agent which proved pathogenic for cattle after oral exposure to raw and rendered pools of sheep scrapie inoculum (of known titre by mouse assay). The study would furthermore determine the phenotypes of any infections established in cattle, for comparison with data on the BSE phenotype in cattle and, if appropriate on subsequent strain typing in mice. The attack rate data achieved would also be compared to that obtained in cattle for BSE (SE1918, SE1930). The potential occurrence of BSE presenting in sheep (as scrapie) as a result of food-borne exposure of domestic sheep populations to BSE via contaminated meat and bone meal has been considered and this study has the potential to identify this possibility in sheep which were likely to have been exposed to the agent via feed.

This study addresses policy concerns regarding deficits in our knowledge of the relationship between BSE and scrapie, the occurrence of BSE in sheep (presenting as scrapie) after oral exposure during the BSE epidemic and potential food safety hazards should this have occurred. In the absence of identifying the BSE agent, a further outcome of this study may identify the pathogenicity of sheep scrapie for cattle after oral exposure, before and after rendering of the inoculum. Not only could there be differences in pathogenicity, but possible changes in phenotype of disease after rendering might also become evident. The results will contribute to and underpin policy decisions on food safety.

This revision submitted 17 October 2002 includes:

- Changed objectives to reflect the different origin of the two inocula (unrendered and rendered), as required, following the 2001 identification of discrepancies between the nature of the unrendered inoculum used in this study and that described in the SE1942 roames submitted by GAH Wells and SAC Hawkins.

- Speciation testing of each inoculum by LGC and VLA (in progress) to address the questions raised by the IAH SBP speciation of 2001.

-Costs are submitted from 2002-2003 (Year 1 in this revision, although 5th year for this project) and are not increased from the last approved costs (VLA Costing Ref: CB1352) other than to cover Moredun’s clinical monitoring and VLA staff travel to Moredun.
Project Documents
• Final Report : Final Report   (317k)
Time-Scale and Cost
From: 1997

To: 2005

Cost: £3,140,743
Contractor / Funded Organisations
Veterinary Laboratories Agency
Keywords
Animal Health              
Cattle              
Pathogenesis              
Plants and Animals              
Rendering              
Scrapie              
Strain              
TSEs              
Fields of Study
Animal Health