Clinical Stage of Infection is Critical in the Antemortem Diagnosis of Chronic Wasting Disease in Deer and Elk
Chris Siepker1, Nicholas Haley1, W. David Walter2, Matteo Manca3, Laura Hoon-Hanks4, Ryan Monello5, Jenny Powers5, Justin Greenlee6 , Bruce Thomsen7 , Aaron Lehmkuhl7, Gordon Mitchell8, Tracy Nichols9,Byron Caughey3, Edward Hoover4, and Juergen Richt1.
1. Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan KS USA 2. United States G e o l o g i c a l Survey, P e n n s y l v a n i a Cooperative Fish and Wildlife Research Unit, University Park PA USA 3. TSE/Prion Biochemistry Section, Rocky Mountain Laboratories, National Institutes of Health, Hamilton, MT USA 3. Department of MIP, Colorado State University, Fort Collins CO USA 4. National Park Service, Wildlife Health Branch, Fort Collins CO USA 5. Virus and Prion Research Unit, National Animal Disease Center, ARS, USDA, Ames IA USA 6. USDA, APHIS, VS, STAS, National Veterinary Service Laboratories, Ames IA USA 7. National and OIE Reference Laboratory for Scrapie and CWD, Canadian Food Inspection Agency, Ottawa ON Canada 8. National Wildlife Research Center Wildlife Services, APHIS, USDA, Fort Collins CO USA
Chronic wasting disease (CWD) is an e f f i c i e n t l y t r a n s mi t t e d s p o n g i f o r m encephalopathy of cervids (e.g. deer, elk, and moose), and is the only known prion disease affecting both free-ranging wildlife and captive animals. The antemortem detection of CWD and other prion diseases has proven difficult, due in part to difficulties in identifying an appropriate peripheral tissue specimen and complications with conventional test sensitivity. At present, biopsies of the recto-
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anal mucosal-associated lymphoid tissues (RAMALT) have shown promising sensitivity and are not impractical to collect in live animals. Nasal brush collections have likewise proven both sensitive and practical for identification of prion infections in humans. In this study, we evaluated both RAMALT and nasal brush collections by real time quaking-induced conversion (RT-QuIC), and compared our findings to RAMALT immu n o h i s t o c h emi s t r y a s we l l a s conventional postmortem evaluation of obex and retropharyngeal lymph node tissues from over 700 captive and free-ranging deer and elk in areas with endemic CWD. We correlated our results with various clinical findings, including pathological stage of infection as determined by obex scoring, PrP genotype, age, and sex. While the sensitivity of RAMALT RT-QuIC analyses exceeded that of RAMALT IHC (69-80% vs. >44%) and nasal brush collections (15-30%), the sensitivity of both biopsy and nasal brush analyses were dependent primarily on clinical stage of disease, although PrP genotype was also an important predictor of sample positivity. Our findings further demonstrate the potential and limitations of antemortem sample analyses by RT-QuIC in the identification and management of prion diseases. https://prion2015.files.wordpress.com/2015/05/programguide1.pdf
see more CWD Diagnostic and sub-clinical infection ;http://chronic-wasting-disease.blogspot.com/2015/08/chronic-wasting-disease-cwd-tse-prion.html