Environmental Sources of Scrapie Prions

Abstract

Ovine scrapie and cervine chronic wasting disease show considerable horizontal transmission. Here we report that a scrapie-affected sheep farm has a widespread environmental contamination with prions. Prions were amplified by protein-misfolding cyclic amplification (sPMCA) from seven of nine environmental swab samples taken, including those from metal, plastic, and wooden surfaces. Sheep had been removed from the areas from which the swabs were taken up to 20 days prior to sampling, indicating that prions persist for at least that long. These data implicate inanimate objects as environmental reservoirs for prion infectivity that are likely to contribute to facile disease transmission.

Deer density and disease prevalence influence transmission of chronic wasting disease in white‐tailed deer

“…If infectious contacts are driven by contaminated environments, more information is required regarding the likely sources of concentrated prion contamination (e.g., mineral licks, scrapes, bait sites). Sampling the environment for prions (Maddison et al 2010), especially across a range of densities of infected deer, could help determine the availability and importance of environmental sources of prions to CWD transmission. In general, we believe the role of environmental transmission in wild deer populations is a critical area of needed research to determine the future dynamics of CWD epidemics (Wasserberg et al 2009, Almberg et al 2011).…”

Influence of landscape factors and management decisions on spatial and temporal patterns of the transmission of chronic wasting disease in white-tailed deer

“…Prions in urine, faecal material or from an infected carcass can enter the environment and remain infectious for long periods Haley et al, 2009;Saunders et al, 2012). Prions bind strongly to various types of soil and resist removal by water or various solvents (Leita et al, 2006;Saunders et al, 2008) so though possibly long-lasting, there is little subsequent migration or leaching through the soil (Jacobson et al, 2010;Maddison et al, 2010). Prions may interact with various components of soil including clay, sand and organic components (Ma et al, 2007;Maddison et al, 2010;Saunders et al, 2010).…”

“…Prions bind strongly to various types of soil and resist removal by water or various solvents (Leita et al, 2006;Saunders et al, 2008) so though possibly long-lasting, there is little subsequent migration or leaching through the soil (Jacobson et al, 2010;Maddison et al, 2010). Prions may interact with various components of soil including clay, sand and organic components (Ma et al, 2007;Maddison et al, 2010;Saunders et al, 2010). In vitro and laboratory assays have indicated that prions bound to clays may have greater infectivity (Johnson et al, 2006) while field studies by Walter et al (2011) showed an association between CWD in mule deer and a higher percentage of clay soils within the deer's home range.…”

Protein Misfolding Cyclic Amplification of Prions

“…The prion agent is able to withstand harsh environmental conditions and remain infectious 16,17 . However, the amount of PrP Sc in the environment is too small to be detected using conventional techniques such WB.…”

“…The prion protein has two distinct isoforms, the non-infectious host-encoded protein (PrP . This technique has proven to effectively recapitulate the species and strain specificity of PrP Sc conversion from PrP C , to emulate prion strain interference, and to amplify very low levels of PrP Sc from infected tissues, fluids, and environmental samples 6,7,16,23 . This paper details the PMCA protocol, including recommendations for minimizing contamination, generating consistent results, and quantifying those results.…”