title: Detection of PrPCWD in feces from naturally exposed Rocky Mountain elk (Cervus elaphus nelsoni) using protein misfolding cyclic amplification.
abstract: Chronic wasting disease (CWD) is a transmissible spongiform encephalopathy affecting captive and free-ranging cervids. Currently, tests for CWD in live animals involve relatively invasive procedures to collect lymphoid tissue biopsies and examine them for CWD-associated, protease-resistant cervid prion protein (PrP(CWD)) detected by immunohistochemistry (IHC). We adapted an ultrasensitive prion detection system, protein misfolding cyclic amplification (PMCA), to detect PrP(CWD) in Rocky Mountain elk (Cervus elaphus nelsoni) feces. Our PMCA reproducibly detected a 1.2 × 10(7) dilution of PrP(CWD) (a 10% infected brain homogenate diluted 1.2 × 10(6)-fold into 10% fecal homogenates), equivalent to approximately 100 pg of PrP(CWD)/g of feces. We developed a semiquantitative scoring system based on the first PMCA round at which PrP(CWD) was detected and fit a nonlinear regression curve to our serial dilutions to correlate PMCA scores with known PrP(CWD) concentrations. We used this PMCA scoring system to detect PrP(CWD) and estimate its concentration in feces from free-ranging elk from Rocky Mountain National Park, Colorado. We compared our results to PrP(CWD) IHC of rectoanal mucosa-associated lymphoid tissue and obex from the same animals. The PMCA successfully detected PrP(CWD) in feces from elk that were positive by IHC, with estimated prion loads from 100 to 5,000 pg PrP(CWD)/g of feces. These data show for the first time PrP(CWD) in feces from naturally exposed free-ranging elk and demonstrate the potential of PMCA as a new, noninvasive CWD diagnostic tool to complement IHC.
authors.affiliation: Department of Microbiology, Immunology and Pathology, Prion Research Program, Colorado State University, 1619 Campus Delivery, Fort Collins, Colorado 80523, USA.
authors.forename: Bruce
authors.initials: B
authors.lastname: Pulford
authors.forename: Terry R
authors.initials: TR
authors.lastname: Spraker
authors.forename: A Christy
authors.initials: AC
authors.lastname: Wyckoff
authors.forename: Crystal
authors.initials: C
authors.lastname: Meyerett
authors.forename: Heather
authors.initials: H
authors.lastname: Bender
authors.forename: Adam
authors.initials: A
authors.lastname: Ferguson
authors.forename: Brittney
authors.initials: B
authors.lastname: Wyatt
authors.forename: Krista
authors.initials: K
authors.lastname: Lockwood
authors.forename: Jenny
authors.initials: J
authors.lastname: Powers
authors.forename: Glenn C
authors.initials: GC
authors.lastname: Telling
authors.forename: Margaret A
authors.initials: MA
authors.lastname: Wild
authors.forename: Mark D
authors.initials: MD
authors.lastname: Zabel
mesh_terms: D000818:Animals; D000835:Animals, Wild; D003670:Deer; D005243:Feces / Q000737:chemistry*; D005260:Female; D007150:Immunohistochemistry / Q000662:veterinary; D008221:Lymphoid Tissue / Q000737:chemistry; D008297:Male; D018620:PrPSc Proteins / Q000032:analysis*; D034081:Wasting Disease, Chronic / Q000175:diagnosis*
chemical_list: D018620:PrPSc Proteins