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Title: A REVIEW OF SCRAPIE AND BOVINE SPONGIFORM ENCEPHALOPATHY (BSE).

Author
item Cutlip, Randall

Submitted to: Sheep Symposium Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 3/4/1995
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Scrapie and BSE are members of a group of diseases called the transmissible spongiform encephalopathies (TSE's) or prion diseases. Diseases of this group are characterized clinically by progressive dementia and motor neuron dysfunctions and histologically by degenerative lesions in the brain. Most now believe that the causal agent is the abnormal form of a normal protein called the prion protein which is both infectious and inherited. TSE's are unique among diseases because no immune or inflammatory responses are induced in the host and there is no antemortem test. Scrapie, the prototype of the spongiform encephalopathies, was recognized some 250 years ago in the British Isles and Europe. It was introduced into the United States in 1947 and by 1990 had been diagnosed in 540 flocks in all but nine states. It is most common in black face breeds. During the last ten years the official diagnosis of scrapie has risen about 30%. Whether this is real or perceived is unclear because of incentives put in place to encourage owners to report suspected cases. BSE was diagnosed first in Great Britain in 1985 and reported in 1986. Epidemiological evidence indicated that the cause was a contaminant in protein supplement, probably resulting from a change in the rendering process that resulted in incomplete inactivation of the prion protein in affected sheep carcasses and offal. However, there is a possibility that the agent came from cattle harboring low levels of the agent that was released with the changes in rendering practices. A 1988 ban on feeding ruminant products back to ruminants is showing promise of controlling the outbreak.