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Degradation and detection of prions in the environment
Prions in the environment are of concern due to their unique characteristics distinguishing them from conventional pathogens and the nature of prion diseases as incurable and ultimately fatal, and the longevity of prion persistence in the environment. Knowledge of environmental degradation and inactivation and quantification of prion abundance and infectivity is of significance for the management of prion disease transmission. To date, most studies of the environmental degradation and inactivation of prions are conducted under conditions that are not environmentally-relevant or occur on unbound prions. In the environment, prions are likely to be associated with soils, as they have been shown to bind strongly to soils. Although very limited studies have reported prion detection in environmental samples, no studies have quantified the recovery of prions from environmental samples. In this dissertation study, simulated natural processes including repeated cycles of drying and wetting and freezing and thawing, were investigated for prion degradation and inactivation. Rodent prion models (HY TME and DY TME) as well as elk CWD prions were exposed to these processes in both an unbound and soil-associated form. Significant reduction in prion abundance and prion conversion capacity was observed after exposure to 10 cycles of repeated drying and wetting, and 500 cycles of repeated freezing and thawing, results that were dependent on prion strain and soil type. A reduction in infectivity was also observed after exposure to 10 cycles of wetting and drying. Additionally, quantitative measurements of HY TME and elk CWD, recovered from foam swabs and wood, an environmentally-relevant surface, were investigated. The maximum recovery of HY TME and elk CWD was approximate 69% ± 7% and 55% ± 10%, respectively. Recovery reduced significantly as drying time on the swab increased. Prion recovery from wood surface was inefficient probably due to strong attachment of prions to the surface. These studies provide the first evidence of the possibility of natural prion clearance in the environment and fundamental information on prion recovery from surfaces, which is useful for control of prion diseases in the environment.
Civil engineering|Environmental engineering
Yuan, Qi, "Degradation and detection of prions in the environment" (2014). ETD collection for University of Nebraska - Lincoln. AAI3667001.