Prion Stability and Infectivity in the Environment

Abstract

The biology of normal prion protein and the property of infectivity observed in abnormal folding conformations remain thinly characterized. However, enough is known to understand that prion proteins stretch traditional views of proteins in biological systems. Numerous investigators are resolving details of the novel mechanism of infectivity, which appears to feature a protein-only, homologous replication of misfolded isoforms. Many other features of prion biology are equally extraordinary. This review focuses on the status of infectious prions in various natural and man-made environments. The picture that emerges is that prion proteins are durable under extreme conditions of environmental exposure that are uncommon in biological phenomena, and this durability offers the potential for environmental reservoirs of persistent infectivity lasting for years. A recurrent theme in prion research is a propensity for these proteins to bind to mineral and metal surfaces, and several investigators have provided evidence that the normal cellular functions of prion protein may include metalloprotein interactions. This structural propensity for binding to mineral and metal ions offers the hypothesis that prion polypeptides are intrinsically predisposed to non-physiological folding conformations that would account for their environmental durability and persistent infectivity. Similarly, the avidity of binding and potency of prion infectivity from environmental sources also offers a recent hypothesis that prion polypeptides bound to soil minerals are actually more infectious than studies with purified polypeptides would predict. Since certain of the prion diseases have a history of epidemics in economically important animal species and have the potential to transmit to humans, urgency is attached to understanding the environmental transmission of prion diseases and the development of protocols for their containment and inactivation.

The Prion-Like Properties of Amyloid-β Assemblies: Implications for Alzheimer's Disease

“…Although PrP prions vary in their stability (Tzaban et al 2002;Choi et al 2010;Zou et al 2010;Gambetti et al 2011), a notable characteristic of infectious prions is that some of them are quite durable, even under harsh environmental conditions (Appel et al 2001;Wiggins 2009). The ability of these prions to retain their pathogenic properties contributes to their infectivity, including rare instances of infection in neurosurgical patients exposed to PrP prion -contaminated surgical instruments that had been sterilized via conventional methods (Brown et al 2012;Thomas et al 2013).…”

Stable limit cycles and the paradox of enrichment in a model of chronic wasting disease

“…and elk (Cervus elaphus), scrapies in goats and sheep, ''mad cow disease'' in cattle, and similar transmissible spongiform encephalopathies in other species (Williams et al 2002, Miller et al 2004, Georgsson et al 2006, Johnson et al 2007, Seidel et al 2007, Saunders et al 2008, Wiggins 2009). Prions can bind to soil organic matter and montmorillonite clays, which stabilize them against thermal degradation and decomposition by soil microbes (Johnson et al 2007, Seidel et al 2007, Wiggins 2009). When thus stabilized, prions can remain infective for more than a decade, well within the reproductive age of ungulates (Georgsson et al 2006, Wiggins 2009).…”

“…Prions can bind to soil organic matter and montmorillonite clays, which stabilize them against thermal degradation and decomposition by soil microbes (Johnson et al 2007, Seidel et al 2007, Wiggins 2009). When thus stabilized, prions can remain infective for more than a decade, well within the reproductive age of ungulates (Georgsson et al 2006, Wiggins 2009). Prions are transmitted to susceptible animals mainly through ingestion of soil rather than direct transmission from infected animals (Miller et al 2004, Georgsson et al 2006, Johnson et al 2007, Seidel et al 2007, Saunders et al 2008, Wiggins 2009).…”

“…When thus stabilized, prions can remain infective for more than a decade, well within the reproductive age of ungulates (Georgsson et al 2006, Wiggins 2009). Prions are transmitted to susceptible animals mainly through ingestion of soil rather than direct transmission from infected animals (Miller et al 2004, Georgsson et al 2006, Johnson et al 2007, Seidel et al 2007, Saunders et al 2008, Wiggins 2009). The long-term stability of prions in soils and the virtual lack of transmission from infected animals are unique features of prion diseases compared to most others.…”

Prions in the environment

“…14 Recently, Wiggens examined prion stability and infectivity in the environment. 15 In contrast, this article will comprehensively review the pertinent literature addressing prion occurrence and fate in the environment, with a specific focus on prion interactions with soil. Potential avenues for environmental mitigation of prion infectivity will be considered.…”