Abstract. Cerebrospinal fluid (CSF) has been examined as a possible source for preclinical diagnosis of prion diseases
in hamsters and sheep. The present report describes the detection of chronic wasting disease (CWD) in the CSF of elk
and evaluates its usefulness as an antemortem test for CWD. The CSF from 6 captive and 31 free-ranging adult elk was
collected at necropsy and evaluated for the presence of the abnormal isoform of the prion protein that has been associated
with CWD (PrPCWD) via protein misfolding cyclic amplification. Additionally, the obex from each animal was examined by
immunohistochemistry (IHC). Four out of 6 captive animals were CWD-positive and euthanized due to signs of terminal
CWD. The remaining 2 were CWD negative. None of the 31 free-range animals showed overt signs of CWD, but 12 out of
31 tested positive for CWD by IHC. Protein misfolding cyclic amplification detected PrPCWD from 3 of the 4 captive animals
showing clinical signs of CWD and none of the nonclinical animals that were CWD positive by IHC. The data suggests that
CWD prions can be detected in the CSF of elk, but only relatively late in the course of the disease.
Key words: Cerebrospinal fluid; Cervus canadensis nelson; chronic wasting disease; protein misfolding cyclic
amplification; prion protein; Rocky Mountain elk.