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From: TSS ()
89th meeting on Thursday 22nd September 2005 In BSE in cattle there is early infection of the ileum and tonsils, followed by later infection of the CNS, dorsal root ganglia and trigeminal ganglia. Emerging Japanese data suggests that there may be infectivity in peripheral nerves in clinical BSE. http://www.seac.gov.uk/papers/tseroadmap05.pdf TSE Roadmap – Scientific Opinions Final Version 6 September 2005 Page 1.1.7. SSC Opinion on Chronic Wasting Disease and Tissues that might carry a risk for Human and Animal Feed Chains, 6-7 March 2003 Theoretical risk for prion transmission to humans consuming products of CWD affected cervids of all ages cannot be excluded. Similarly, transmission risk to domestic animals cannot be excluded4. Early and widespread involvement of tissues in CWD-infected animals does not allow definition of SRM list, nor to define age limits. Insufficient data to define exclusions or amendment of any SRM rule on the basis of relative genetic resistance to infection. Important to be certain that no risk of transmission of CWD from North America to EU through trade in live cervids or their products. No scientific data that CWD is present in countries outside North America (except single import to Korea). However further European surveillance necessary. 1.1.8. SSC Opinion on BSE Risk of Autonomic Nervous System, 6-7 March 2003 Infectivity found in vagus nerve and sympathetic mesenteric ganglia of experimental animals (mice/hamsters) and sheep infected with scrapie. Experimental data from cattle insufficient, but infectivity in these tissues has not been shown in cattle5 other than the inconsistent presence of disease-related PrP in the myenteric plexus (network of nerve fibres throughout muscle of digestive tract) of cattle during the Unclear whether scrapie models are applicable to pathogenesis of BSE. Cannot exclude possibility that other autonomic NS structures carry infectivity in BSEinfected Recommend collection of tissue samples appropriate to improving understanding role of PNS and particularly the autonomic NS, from field cases and cattle in 4 See also 1.1.2. Experimental Transmission of Chronic Wasting Disease Agent from Mule Deer to Cattle by Intracerebral Route, Hamir et al.2005, J Vet Diagn Invest 5 The Japanese Institute for Animal Health has detected Western Blot positives in peripheral nerves in a fallen bovine. Further results are expected in late 2005/early TSE Roadmap – Scientific Opinions Final Version 6 September 2005 Page 8 of 18 9 EC FAIR CT97 3308 Project 10 Refers to April 2004 SSC Opinion on oral exposure of humans to BSE agent: infective dose and species barrier. This refers to small amount of tissue that can contain an infective dose of BSE agent for cattle and sheep ( < 1 gram of homogenised brain tissue). 2005 data suggests 1mg is sufficient to infect calves. SNIP... TSE Roadmap – Scientific Opinions Final Version 6 September 2005 Page 9 of 18 2.3.2. Unpublished Data from VLA, 2005 Unpublished data from a pressure rendering study indicates that BSE infectivity can survive in tallow recovered by centrifugation and tallow recovered by solvent extraction. http://www.seac.gov.uk/papers/tseroadmap05-app3.pdf Appendix 4 – A Summary of Opinions from the Spongiform Encephalopathy Advisory Committee (SEAC) http://www.seac.gov.uk/papers/tseroadmap05-app4.pdf TSS
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