Chronic wasting disease (CWD) is an emerging prion disease affecting cervids including deer, elk, and moose. It has an expanding geographical range in both North America and Europe. CWD is detrimental to the cervid population with the incidence that can exceed 50% in free-ranging deer and a poorly defined zoonotic potential including humans. Soil is likely to serve as a significant environmental reservoir for CWD prions released from secretions/excreta of infected animals and decomposed CWD carcasses. CWD can persist in the environment and environmental transmission of CWD has been observed. Transitional metals, especially manganese and copper, can bind prions and were found to impact prion properties, e.g., prion conversion capacity. However, the effects of copper and manganese on the persistence of CWD prions in the environment are unclear. In this study, we investigated whether copper and/or manganese could alter prion resistance to environmental degradation. A rodent prion (hamster-adapted transmissible mink encephalopathy, HY TME) or natural elk CWD prion isolates were incubated with CuCl2 or MnCl2 at 0.05, 0.5, or 5 mM (final concentration) for 1 week or 1 month at both room and elevated (40°C) temperatures. All treated samples were subjected to proteinase K (PK) digestion to assess the relative resistance of PrPSc to degradation. It was observed that both HY TME and CWD PrPSc became less resistant to PK digestion when incubated with CuCl2 depending on metal concentration and incubation conditions, whereas the ones incubated with MnCl2 were less or not impacted regarding PK resistance. The results indicate a decreased stability of PrPSc when associated with copper. These PrPSc-metal mixtures will be subjected to simulated weathering conditions such as repeated cycles of drying and wetting to further elucidate the effects of copper and manganese on prion persistence in the environment. Prion infectivity will also be evaluated.

Effects of transitional metals on the persistence of chronic wasting disease prions in the environment

ACS Fall 2021

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