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The History of Chronic Wasting Disease

The History of Chronic Wasting Disease

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The History of Chronic Wasting Disease

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  1. The History of Chronic Wasting Disease Dr. Trent Bollinger, CCWHC One World, One Health Symposium Sept. 29, 2004

  2. Spongiform encephalopathies • CWD is classified as a TSEs similar to scrapie, Creutzfeldt-Jakob disease (CJD), kuru, transmissible mink encephalopathy, bovine spongiform encephalopathy (BSE)

  3. PrPSc PrPC Prusiner, S. B. 1999. An introduction to prion biology and diseases. Pages 1-66 in S. B. Prusiner, editor. Prion Biology and Diseases. Cold Springs Harbor Laboratory Press, Cold Springs Harbor, New York.

  4. Prion: protein infectious agent Composed of PrPSc

  5. Two ways in which spongiform encephalopathies develop PrPSc 2) PrPSc transmitted to new host +/- Protein X PrPC PrPSc PrPC PrPSc PrPSc • Spontaneous • conversion PrPSc PrPC PrPSc PrPSc +/- Protein X PrPC PrPSc +/- Protein X

  6. PrPSc PrPSc PrPc “ Species barrier” + X Species/Individual A slow + Species/Individual B fast + Species/Individual C

  7. Sheep Natural Scrapie 13 months Mice 1st passage 6 m Mice 2nd passage 4 m Mice 3rd passage 4.5 m Mice 4th passage 5 m Mice 5th passage PrPSc moPrPC + moPrPSc moPrPSc moPrPC + moPrPSc

  8. X Mule deer -CWD hamsters 4 -6 m 17 - 21 months 8 m 5 m Ferrets CWD Ferrets CWD Types of species susceptible to a prion isolate can be altered by transmission of prions to other species Bartz, et al, 1998

  9. Raymond et al, 2000 The EMBO Journal Vol 19 (17) p.4425

  10. Raymond et al, 2000 The EMBO Journal Vol 19 (17) p.4425

  11. Methods of transmission • Direct inoculation • Experimental exposure • Iatrogenic exposure of humans to CJD • Vaccine for louping ill in sheep contaminated with scrapie prion • Ingestion • Experimental exposure • BSE: sheep scrapie to cattle and then cattle to cattle • Kuru in humans • vCJD in humans • Direct animal to animal spread • Scrapie in sheep • CWD in deer and elk

  12. Chronic wasting disease • Disease of mule deer, black-tailed deer, white-tailed deer and elk

  13. History of CWD • First recognized as a clinical entity in the late 1960s in captive mule deer and elk in Colorado and Wyoming; confirmed as a TSE in late 1970s

  14. Estimated overall prevalence in endemic areas of Colorado and Wyoming is 4.9% in mule deer, 2.1 % in white-tailed deer and 0.5% in elk. Miller et al, 2000