Chronic wasting disease detection in the lymph nodes of free-ranging cervids by real time quaking-induced conversion

Chronic wasting disease detection in the lymph nodes of free-ranging cervids by real time quaking-induced conversion" (2014). Abstract 23 Chronic wasting disease (CWD), a transmissible spongiform encephalopathy of deer, elk 24 and moose, is the only prion disease affecting free-ranging animals. First identified in northern 25 Colorado and southern Wyoming in 1967, new epidemic foci of the disease have since been 2 identified in 20 additional states, as well as two Canadian provinces and the Republic of South 27 Korea. Identification of CWD-affected animals currently requires post-mortem analysis of brain 28 or lymphoid tissues using immunohistochemistry (IHC) or an enzyme linked immunosorbent 29 assay (ELISA), with no practical way to evaluate potential strain types or investigate the 30 epidemiology of existing or novel foci of disease. Using a standardized real time quaking-31 induced conversion (RT-QuIC) assay, a seeded amplification assay employing recombinant 32 prion protein as a conversion substrate and Thioflavin T (ThT) as an amyloid-binding 33 fluorophore, we blindly analyzed 1243 retropharyngeal lymph node samples from white-tailed 34 deer, mule deer and moose, collected in the field from current or historic CWD-endemic areas. 35 RT-QuIC results were then compared with those obtained by conventional IHC and ELISA, and 36 amplification metrics using ThT and Thioflavin S examined in relation to clinical history of the 37 sampled deer. The results indicate that RT-QuIC is useful in both for identifying CWD-infected 38 animals and facilitating epidemiologic studies in CWD endemic and non-endemic areas.