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Rose Sydlowski Nicole Sheimo

Rose Sydlowski Nicole Sheimo. What is CWD?. Transmissible spongiform encephalopathy Occurs in white-tail deer, mule deer, and elk 100% fatal. TSE’s. Prions: “infectious proteins” (probably) Abnormal form of a normal cell protein found in CNS and lymphoid tissues

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Rose Sydlowski Nicole Sheimo

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  1. Rose Sydlowski Nicole Sheimo

  2. What is CWD? • Transmissible spongiform encephalopathy • Occurs in white-tail deer, mule deer, and elk • 100% fatal

  3. TSE’s • Prions: “infectious proteins” (probably) • Abnormal form of a normal cell protein found in CNS and lymphoid tissues • Self-replicating: causes conformational change in normal proteins, converting them to prions • Neurodegenerative: spongiform change in cerebrum, neuronal degeneration, accumulation of abnormal protein

  4. Other TSE’s • Scrapie: 1st reported mid-1700’s, never found in other species • BSE: 1st case probably occurred 1985, only TSE known to affect both humans and animals • CJD: human TSE, vCJD = human “mad cow” • Transmissible mink encephalopathy

  5. Clinical Signs of CWD • Adult animal • Decreased appetite • Poor body condition • Tremors, stumbling, ataxia • Difficulty swallowing • Increased thirst, PU • Excessive salivation, drooling • Incubation: months to years • Signs persist days to months (up to 1 yr)

  6. Transmission • Not fully understood, may be lateral transmission: • urine, feces, saliva • Increased population density • Captivity (contact with wild) • Feeding • VERY resistant in environment

  7. Diagnosis • Histopathology Spongiform lesions in brain • Immunohistochemistry detects CWD protein in brain and lymphoid tissue

  8. Diagnosis • IHC: parasympatheticnucleus in obex

  9. Diagnosis • IHC on brainstem neurons: • CWD protein stains darkly • Vacuolization of neurons

  10. CWD has been known to exist • since 1967– • mule deer in Colorado • Small endemic area recognized • in wild herds: • Northeast Colorado • Southeast Wyoming • Southwest Nebraska Why do we care about it now??

  11. IT’S EPI TIME!!! • CWD is spreading: • New areas of CO and NE • Has since been found (wild or captive) in SD, KS, OK, MT, MN, NM, and…. • WISCONSIN!! (White-tail, 2002)

  12. EPI TIME • Prevalence • Wild herds: limited data • < 1-15% mule deer • < 1% elk • Captive herds: higher prevalence • 23-90%, depending on herd

  13. Control • Challenging: • No treatment • No vaccine • Long incubation period • No reliable antemortem test • Persistent in environment • Transmission = ?

  14. Control • Captive herds: • Depopulate or quarantine • Environmental contamination? • Wild herds: • Surveillance • Containment, eradicate? • Limit movement of animals • Ban supplemental feeding • Population reduction (?)

  15. What about Michigan? • Discovery of CWD in Wisconsin threat to Michigan! • Goal: Keep CWD out!!! • 1.8 million wild deer and elk • 900-1000 privately-owned facilities (~25000 animals)

  16. What about Michigan? • If introduced into MI, CWD would negatively impact: • Animal health: wild and captive • Economics: • Quarantines and restrictions on MI cervids • Public health fears-- hunting

  17. Michigan’s Plan • Importation of cervids: Banned • Supplemental feeding: Banned in UP (and LP) • Increased surveillance • Education: Hunters, Farmers, Residents • Response Plan: plans for containment and eradication

  18. Surveillance • MI was conducting surveillance before CWD found in WI: • 1998: DNR tested 459 deer from NE LP, all (-) • “Targeted” surveillance: tested deer with suspicious symptoms, all (-)

  19. Surveillance • DNR and MDA: New plans include “targeted” and “active” testing • ~6000 wild deer over the next 3 years • ~50 deer per county • ~50 elk per year • Additional testing of captive cervids

  20. Surveillance • IHC testing of tissues will be performed by the Diagnostic Center for Population and Animal Health

  21. Transmissible– to people?

  22. Suggestions for Hunters • No evidence that people can contract CWD by eating infected animals • CDC: risk is “extremely small, if it exists at all” • In CWD areas: very low % of animals are infected

  23. Suggestions for Hunters • Don’t consume meat from infected or ill animals • Don’t consume nervous system or lymphatic tissues; minimize contact • Wear gloves when field dressing, wash hands • Bone out meat • Have head tested

  24. References CWD Alliance: www.cwd-info.org Michigan DNR: www.michigan.gov/dnr Minnesota DNR: www.dnr.state.mn.us/mammals/deer/cwd.html Dr. Matti Kiupel And special thanks to our model, Kevin Kristick!

  25. Questions?

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