NR AXPF
AU Johnson,C.J.; Pedersen,J.A.; Chappell,R.; McKenzie,D.; Aiken,J.M.
TI Oral Transmission of Prion Disease Is Enhanced by Binding to Soil Particles
QU International Conference - Prion 2007 (26.-28.9.2007) Edinburgh International Conference Centre, Edinburgh, Scotland, UK - Book of Abstracts: Epidemiology, Risk Assessment and Transmission P04.71
IA http://www.prion2007.com/pdf/Prion Book of Abstracts.pdf
PT Konferenz-Poster
AB A long-unanswered question in prion biology is how certain transmissible spongiform encephalopathies (TSEs), such as sheep scrapie and cervid chronic wasting disease, spread from animal to animal. Anecdotal evidence and controlled field experiments have suggested the presence of an environmental TSE reservoir. We, and others, have speculated that soil may harbor TSE agent in the environment and allow its transfer to naive hosts. TSE infectivity can persist in soil for years, and we previously demonstrated that the disease-associated form of the prion protein binds to soil particles and that prions adsorbed to the common soil mineral montmorillonite (Mte) retain infectivity following intracerebral inoculation. We assessed the oral infectivity of Mte- and soil-bound prions and found that prions bound to Mte are orally bioavailable and that, unexpectedly, binding to Mte significantly enhances disease penetrance and reduces incubation period relative to unbound agent. Cox proportional hazards modelling revealed that across the doses of TSE agent tested, Mte increased the effective infectious titer by a factor of 680 relative to unbound agent. Oral exposure to Mte-associated prions led to TSE development in experimental animals even at doses too low to produce clinical symptoms in the absence of the mineral. We tested the oral infectivity of prions bound to three whole soils differing in texture, mineralogy and organic carbon content, and found soil-bound prions to be orally infectious. Two of the three soils increased oral transmission of disease, and the infectivity of agent bound to the third soil was equivalent to that of unbound agent. Enhanced infectivity of soilbound prions may explain the environmental transmission of some TSEs despite the presumably low levels shed into the environment.
AD C. Johnson, J. Pedersen, R. Chappell, D. McKenzie, J. Aiken, University of Wisconsin - Madison, USA
SP englisch
PO Schottland