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Prions: Proteins Gone Bad

Prions: Proteins Gone Bad. Karen Moody, PT, MS Creutzfeldt-Jakob Disease Surveillance Coordinator Texas Department of State Health Services Diseases in Nature – Ft Worth, TX June 2, 2009. Outline. The Medical Mystery Prions Human Prion Disease Animal Prion Disease BSE – Mad Cow Disease

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Prions: Proteins Gone Bad

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  1. Prions: Proteins Gone Bad Karen Moody, PT, MS Creutzfeldt-Jakob Disease Surveillance Coordinator Texas Department of State Health Services Diseases in Nature – Ft Worth, TX June 2, 2009

  2. Outline • The Medical Mystery • Prions • Human Prion Disease • Animal Prion Disease • BSE – Mad Cow Disease • Variant CJD • Texas CJD Cases • Reporting and Investigating • Infection Control • Resources

  3. Prion Disease - A Medical Mystery • 1700s • Scrapie – sheep • Fatal Familial Insomnia (FFI) • Gerstmann-Straussler-Scheinker • 1920s • Hans Gerhard Creutzfeldt and Alfons Maria Jakob

  4. Prion Disease – A Medical Mystery • 1950s • Kuru – Fore Tribe - New Guinea • 1980s • Bovine Spongiform Encephalopathy (BSE) • The Discovery of Prions – Stanley Prusiner • 1990s • Prions are transmissible from cattle to humans (variant CJD)

  5. Prions – Proteins Gone Bad • Not a bacterium or virus • Misfolded protein • Two stable conformations (PrPc vs. PrPsc) • No nucleic acid • Genetic mutations • Survive routine disinfection & sterilization procedures

  6. Human Prion Diseases • Sporadic • Sporadic CJD (sCJD) • Sporadic fatal insomnia • Acquired (Infectious) • Variant CJD (vCJD) • Iatrogenic CJD (iCJD) • Genetic • Fatal Familial Insomnia • Familial CJD (fCJD) • Gertsmann-Straussler-Scheinker

  7. Animal Prion Diseases • Chronic Wasting Disease (CWD) • Mule deer, White tailed deer, Moose and Elk • Bovine Spongiform Encephalopathy (BSE) • Cattle • Scrapie • Sheep

  8. Downloaded form http://www.cdc.gov

  9. Bovine Spongiform Encephalopathy (BSE or Mad Cow Disease) • 1985 – recognized progressive neurological disorder in two cattle • 1986 – examination of cow brain indicate spongiform changes • 1987 – meat-and-bone-meal feed • 1988 – Feed ban enacted in UK • 1993 – BSE epidemic in UK peaked with 1,000 cattle affected per week • 2007 – 184,500 cattle confirmed in 35,000 herds

  10. Cases of BSE in USA • 2003 – Washington • Holstein imported from Canada • 2005 – Texas • First endemic case of BSE in US • 2006 - Alabama • Euthanized and buried on farm (herd of origin not identified) • April 25, 2009 – FDA issued regulation barring high risk material use in animal feed in USA.

  11. vCJD • 1990 – CJD surveillance unit in UK • 1995 – Three CJD cases (ages 16, 19, 29) • 10 suspected CJD cases <50 years old • 1996 – Identified first human case • Distinctive clinical syndrome associated with plaque formation • vCJD prion strain unique to humans • Prion strain similar to BSE strain • Clinical and pathological characteristics different from sCJD

  12. Clinical and Pathological Characteristics of vCJD • Pathological characteristics • Amyloid plaques with spongiform degeneration • Clinical characteristics • Psychological / behavioral symptoms • Dysesthesias • Average age of patient – 28 years • Duration of illness – 12 to 14 months • No unique EEG findings • Positive pulvinar sign on MRI

  13. Sporadic CJD vs. Variant CJD

  14. Downloaded http://www.cdc.gov

  15. vCJD Worldwide • As of 2008 • 208 cases (4 related to blood transfusions) • Three cases identified in USA – likely exposure in UK • Do genetics play a role in susceptibility? • Polymorphic codon 129 PRNP gene • 100% of cases have been Methionine-Methionine • How many more cases might we see?

  16. Reporting and Investigating • CJD – reportable condition in Texas • CSF – elevated 14-3-3 protein and positive Tau protein = suspect case of CJD • Medical records – signs and symptoms • Arrange for autopsy (especially those suspected of having vCJD) • Under 55 years – suspect for vCJD

  17. CJD in Texas

  18. CJD Cases by Age and Gender

  19. iCJD and Infection Control • iCJD risk – contaminated surgical instruments & certain medical procedures • Incineration eliminates risk of infectivity • Special procedures - heat resistant surgical devices • Prions not transmissible by touching, kissing or bathing • Possible transmission – ingest or transplant contaminated neural tissue

  20. Resources • National Prion Disease Pathology Surveillance Center (NPDPSC) • Free CSF testing and autopsy arrangement • CJD Foundation • Family conference • Centers for Disease Control and Prevention (CDC) • Quarterly conference calls • World Health Organization (WHO)

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