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ARS Home » Midwest Area » Ames, Iowa » National Animal Disease Center » Infectious Bacterial Diseases Research » Research » Publications at this Location » Publication #102588
Title: DIAGNOSIS OF CHRONIC WASTING DISEASE OF DEER AND ELK

Author
item WILLIAMS, E - UNIV.OF WY,LARAMIE, WY.
item MILLER, M - CO.DIV.WILD.FT.COLLINS,CO
item SPRAKER, T - CO.ST.UNIV.,FT.COLLINS,CO
item SIGURDSON, C - CO.ST.UNIV.,FT.COLLINS,CO
item JENNY, A - USDA,APHIS,NVSL,AMES, IA.
item Miller, Janice

Submitted to: Wildlife Disease Association Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 8/10/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Chronic wasting disease (CWD) is a spongiform encephalopathy of deer (Odocoileus hemionus, O. Virginianus) and elk (Cervus elaphus nelsoni) in limited areas of Wyoming and Colorado and in privately owned elk in several western states and provinces. Diagnosis of CWD is by histopathology for spongiform encephalopathy and immunohistochemistry (IHC) for evidence of accumulation of PrPres, a marker of prion diseases. Western blots for PrPres and negative stain electron microscopy for scrapie associated fibrils are used as ancillary tests. Currently, diagnosis of CWD is based on examination of the brain, at a minimum to include the medulla oblongata at the obex. Sections of brain are treated with formic acid before embedding for inactivation of the CWD agent. Formic acid treatment and hydrated autoclaving are used for antigen retrieval prior to IHC. Both polyclonal and monoclonal antibodies against PrPres have been used as primary antibodies. Surveillance of hunter harvested free-ranging cervids (n=4,287) in the CWD endemic area relies on IHC for estimation of prevalence. Of deer diagnosed with preclinical or subclinical CWD (n=132), 57% had both spongiform encephalopathy and accumulation of PrPres in the brain detected by IHC; the remainder of deer were only positive by IHC. The earliest site of accumulation of PrPres was the lateral aspect of the parasympathetic vagal nucleus in the medulla oblongata. Immunohistochemistry for PrPres is essential for confirmation of CWD in clinically affected animals and for estimation of CWD prevalence in the endemic area.