Paper Topic:

Mad Cow Disease

Mad Cow Disease

Mad Cow Disease

Table of Contents

Introduction

Origins of the BSE epidemic

A More Deep Insight

Epidemiology Issues

Conclusions

References

Introduction

Mad Cow Disease , or Bovine Spongiform Encephalopathy (BSE , is the cattle form of a family of progressive brain diseases . These diseases include scrapie in sheep , Creutzfeldt-Jakob disease (CJD ) in humans , and chronic wasting disease (CWD ) in deer and elk . They are also known as either "prion diseases " because of the association of a misfolded cellular prion protein in pathogenesis or "transmissible

spongiform encephalopathies (TSEs ) because of the spongelike nature of the damaged brain tissue [1]

The recent discovery of two BSE-infected cows , in Canada and in the United States , has dramatically increased concern in North America among meat producers and consumers alike over the extent to which BSE poses a threat to humans as well as to domestic and wild animals . The European BSE epidemic of the late-1980s seems to have been initiated a decade earlier in the United Kingdom by changes in the production of meat and bone meal (MBM ) from rendered livestock , which led to contamination of MBM with the BSE infectious agent . Furthermore , the fact that UK farmers fed this rendered MBM to younger animals and that this MBM was distributed to many countries may have contributed to the ensuing BSE epidemic in the United Kingdom and internationally [2]

Despite extensive knowledge about the spread of BSE through contaminated MBM , the source of BSE in Europe remains "an unsolved mystery " [2] . It has been proposed that BSE could be derived from a cross-species infection , perhaps through contamination of MBM by scrapie-infected sheep tissues . Alternatively , BSE may have been an endemic disease in cattle that went unnoticed because of its low level of horizontal transmission . Lastly , BSE might have originated by "spontaneous misfolding of the normal cellular prion protein into the disease-associated abnormal isoform [3] , which is postulated to be the infectious agent or "prion " This review summarizes the evolution of the bovine and human epidemics , gives some deep insight into problem speculates on their future development , and summarizes some of the outstanding issues

Origins of the BSE epidemic

Although the first case of BSE was identified in the United Kingdom in 1986 , it is likely that some cases occurred earlier than this but were not detected and that the origin of the epidemic probably dates back to the 1970s . [2] What caused the first case of BSE , why the epidemic started in the United Kingdom , and why it started when it did are questions that are unresolved and may remain so . What is clearer however , is that the epidemic was caused by the practice of feeding cattle the waste parts of other cattle , which were not used for human consumption , in the form of meat and bone meal (MBM ) after the bovine material had been rendered [4] . Rendering is the process whereby the waste parts of cattle are heated to separate out the fat and protein , so that the latter can be incorporated...

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