Chronic wasting disease (CWD) is a fatal prion disease affecting cervids that is endemic in North America and also present in Asia and Europe. It is one of the only spongiform encephalopathy that is environmentally transmitted. CWD prions (PrPCWD) are released in the environment either through carcasses or through biological fluids such as feces or saliva. It has been reported that soils play a major role in horizontal CWD transmission, acting as an environmental reservoir of infectivity. Indeed soil mineral and organic components can both bind prions.
Upper horizons of the soil are rich in soil organic matter, which is defined as all biologically derived matter. Little is known about the role of soil organic matter in CWD prions conservation and infectivity in soil. Here, the interaction of humic acid, a major soil organic matter component, with CWD prions is investigated. CWD-infected brain homogenates have been incubated with humic acids at different concentrations to mimic different soil types. The fate of prions PrPCWD was then examined with Western blots.