%0 Journal Article %A Henderson, Davin M. %A Davenport, Kristen A. %A Haley, Nicholas J. %A Denkers, Nathaniel D. %A Mathiason, Candace K. %A Hoover, Edward A. %T Quantitative assessment of prion infectivity in tissues and body fluids by real-time quaking-induced conversion %D 2015 %J Journal of General Virology, %V 96 %N 1 %P 210-219 %@ 1465-2099 %R https://doi.org/10.1099/vir.0.069906-0 %I Microbiology Society, %X Prions are amyloid-forming proteins that cause transmissible spongiform encephalopathies through a process involving the templated conversion of the normal cellular prion protein (PrPC) to a pathogenic misfolded conformation. Templated conversion has been modelled in several in vitro assays, including serial protein misfolding amplification, amyloid seeding and real-time quaking-induced conversion (RT-QuIC). As RT-QuIC measures formation of amyloid fibrils in real-time, it can be used to estimate the rate of seeded conversion. Here, we used samples from deer infected with chronic wasting disease (CWD) in RT-QuIC to show that serial dilution of prion seed was linearly related to the rate of amyloid formation over a range of 10−3 to 10−8 µg. We then used an amyloid formation rate standard curve derived from a bioassayed reference sample (CWD+ brain homogenate) to estimate the prion seed concentration and infectivity in tissues, body fluids and excreta. Using these methods, we estimated that urine and saliva from CWD-infected deer both contained 1–5 LD50 per 10 ml. Thus, over the 1–2 year course of an infection, a substantial environmental reservoir of CWD prion contamination accumulates. %U https://www.microbiologyresearch.org/content/journal/jgv/10.1099/vir.0.069906-0