Shedding and stability of CWD prion seeding activity in cervid feces

Abstract

CWD is an emergent prion disease that now affects cervid species on three continents. CWD is efficiently spread in wild and captive populations, likely through both direct animal contact and environmental contamination. Here, by longitudinally assaying in feces of CWD-exposed white-tailed deer by RT-QuIC, we demonstrate fecal shedding of prion seeding activity months before onset of clinical symptoms and continuing throughout the disease course. We also examine the impact of simulated environmental conditions such as repeated freeze-thaw cycles and desiccation on fecal prion seeding activity. We found that while multiple (n = 7) freeze-thaw cycles substantially decreased fecal seeding activity, desiccation had little to no effect on seeding activity. Finally, we examined whether RT-QuIC testing of landscape fecal deposits could distinguish two premises with substantial known CWD prevalence from one in which no CWD-infected animals had been detected. In the above pilot study, this distinction was possible. We conclude that fecal shedding of CWD prions occurs over much of the disease course, that environmental factors influence prion seeding activity, and that it is feasible to detect fecal prion contamination using RT-QuIC.

Large‐scale prion protein genotyping in Canadian caribou populations and potential impact on chronic wasting disease susceptibility

“…Climate change and industrial development have reduced the size of remaining caribou habitat leading to range retraction and increased contact between caribou and other cervids (especially white‐tailed deer) and predator species, either directly or indirectly (Bauduin, McIntire, St‐Laurent, & Cumming, 2018; Dawe & Boutin, 2016; Hebblewhite & Fortin, 2017; Hervieux et al., 2013; Leech et al, 2016; Tennant et al., 2020). Predators have been shown to pass prions in their faeces after consuming CWD‐infected cervids (Krumm, Conner, Hobbs, Hunter, & Miller, 2010; Nichols, Fischer, Spraker, Kong, & VerCauteren, 2015), and mountain lions preferentially prey on CWD‐infected deer (Krumm et al., 2010), which further increases the probability of prion dissemination.…”

Bioaccumulation of Pathogen Exposure in Top Predators

“…New advances in molecular technologies, including next-generation sequencing and sensitive serosurveillance, have afforded opportunities for detection of microparasites from freeranging wildlife [23][24][25][26]. Protocols permitting detection of pathogens in excreta have been perfected, allowing noninvasive sampling techniques that augment sample collection protocols that would otherwise be invasive, expensive, and potentially harmful to either animals or field personnel [27][28][29]. Furthermore, significant advances in bioinformatics approaches have accelerated pathogen genomic characterization that estimates time and place of transmission events based on phylodynamic and phylogeographic analyses [13,14,23,[30][31][32][33].…”

Cervid Prion Protein Polymorphisms: Role in Chronic Wasting Disease Pathogenesis

“…This is because PrP CWD disseminates throughout the body of the infected cervid. PrP CWD has been detected in the lymphatic system, salivary gland, intestinal tract, muscles, and blood, as well as urine, saliva, and feces, of infected cervids [ 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 ]. PrP CWD is released into the environment through bodily fluids and excreta and bind to soil and plants, remaining infectious even after decades [ 15 , 16 , 17 , 18 , 19 ].…”