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Soil clay content underlies prion infection odds.

David Walter W, Walsh DP, Farnsworth ML, Winkelman DL, Miller MW - Nat Commun (2011)

Bottom Line: Environmental factors-especially soil properties-have been suggested as potentially important in the transmission of infectious prion diseases.Because binding to montmorillonite (an aluminosilicate clay mineral) or clay-enriched soils had been shown to enhance experimental prion transmissibility, we hypothesized that prion transmission among mule deer might also be enhanced in ranges with relatively high soil clay content.Our findings suggest that soil clay content and related environmental properties deserve greater attention in assessing risks of prion disease outbreaks and prospects for their control in both natural and production settings.

View Article: PubMed Central - PubMed

Affiliation: United States Department of the Interior, United States Geological Survey, Colorado Cooperative Fish and Wildlife Research Unit, Fort Collins, Colorado 80523-1484, USA.

ABSTRACT
Environmental factors-especially soil properties-have been suggested as potentially important in the transmission of infectious prion diseases. Because binding to montmorillonite (an aluminosilicate clay mineral) or clay-enriched soils had been shown to enhance experimental prion transmissibility, we hypothesized that prion transmission among mule deer might also be enhanced in ranges with relatively high soil clay content. In this study, we report apparent influences of soil clay content on the odds of prion infection in free-ranging deer. Analysis of data from prion-infected deer herds in northern Colorado, USA, revealed that a 1% increase in the clay-sized particle content in soils within the approximate home range of an individual deer increased its odds of infection by up to 8.9%. Our findings suggest that soil clay content and related environmental properties deserve greater attention in assessing risks of prion disease outbreaks and prospects for their control in both natural and production settings.

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Related in: MedlinePlus

North American distribution of prion disease in deer.In some areas, prion disease foci in deer (Odocoileus spp.) in western North America33 overlap landscapes with soils that have cation exchange capacity (CEC)34 values (tan areas in inset) suggestive of a relative abundance of clay minerals (phyllosilicates) and/or organic matter. Game management units (GMUs) are administrative boundaries used in hunting management3047; prion-infected GMUs are shown in light grey on the continental map and in cross hatching on the inset.
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f2: North American distribution of prion disease in deer.In some areas, prion disease foci in deer (Odocoileus spp.) in western North America33 overlap landscapes with soils that have cation exchange capacity (CEC)34 values (tan areas in inset) suggestive of a relative abundance of clay minerals (phyllosilicates) and/or organic matter. Game management units (GMUs) are administrative boundaries used in hunting management3047; prion-infected GMUs are shown in light grey on the continental map and in cross hatching on the inset.

Mentions: Our findings support the notion that soil may have an important role in perpetuating epidemics of infectious prion diseases1234511121619202526, perhaps by serving as an environmental reservoir for prions. Other soil attributes may modulate prion bioavailability and infectivity in natural environments16192021222324252627, but soil clay content alone seems to offer a parsimonious improvement towards explaining spatial patterns of prion infection among mule deer inhabiting montane ranges of northern Colorado. Some chronic wasting disease foci in Colorado and elsewhere in western north America33 overlap areas where surface soils have a relatively high cation exchange capacity34 (Fig. 2). Such soils tend to have high clay content and/or high organic matter content35. The soils in our two study areas contain high proportions of phyllosilicate and quartz microparticles36 and relatively little organic matter37 and thus appear very similar in composition to other soils shown to enhance prion persistence25 or oral transmissibility20. Because soils with relatively high clay content relative to organic matter (for example, clay/organic matter ratio >1:1) may have a greater tendency to enhance prion transmission20, a ratio of percent clay to percent organic matter also might be useful for assessing landscape-level associations between soil characteristics and potential prion transmission risk in areas with higher organic matter content than encountered in our study areas.


Soil clay content underlies prion infection odds.

David Walter W, Walsh DP, Farnsworth ML, Winkelman DL, Miller MW - Nat Commun (2011)

North American distribution of prion disease in deer.In some areas, prion disease foci in deer (Odocoileus spp.) in western North America33 overlap landscapes with soils that have cation exchange capacity (CEC)34 values (tan areas in inset) suggestive of a relative abundance of clay minerals (phyllosilicates) and/or organic matter. Game management units (GMUs) are administrative boundaries used in hunting management3047; prion-infected GMUs are shown in light grey on the continental map and in cross hatching on the inset.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3105318&req=5

f2: North American distribution of prion disease in deer.In some areas, prion disease foci in deer (Odocoileus spp.) in western North America33 overlap landscapes with soils that have cation exchange capacity (CEC)34 values (tan areas in inset) suggestive of a relative abundance of clay minerals (phyllosilicates) and/or organic matter. Game management units (GMUs) are administrative boundaries used in hunting management3047; prion-infected GMUs are shown in light grey on the continental map and in cross hatching on the inset.
Mentions: Our findings support the notion that soil may have an important role in perpetuating epidemics of infectious prion diseases1234511121619202526, perhaps by serving as an environmental reservoir for prions. Other soil attributes may modulate prion bioavailability and infectivity in natural environments16192021222324252627, but soil clay content alone seems to offer a parsimonious improvement towards explaining spatial patterns of prion infection among mule deer inhabiting montane ranges of northern Colorado. Some chronic wasting disease foci in Colorado and elsewhere in western north America33 overlap areas where surface soils have a relatively high cation exchange capacity34 (Fig. 2). Such soils tend to have high clay content and/or high organic matter content35. The soils in our two study areas contain high proportions of phyllosilicate and quartz microparticles36 and relatively little organic matter37 and thus appear very similar in composition to other soils shown to enhance prion persistence25 or oral transmissibility20. Because soils with relatively high clay content relative to organic matter (for example, clay/organic matter ratio >1:1) may have a greater tendency to enhance prion transmission20, a ratio of percent clay to percent organic matter also might be useful for assessing landscape-level associations between soil characteristics and potential prion transmission risk in areas with higher organic matter content than encountered in our study areas.

Bottom Line: Environmental factors-especially soil properties-have been suggested as potentially important in the transmission of infectious prion diseases.Because binding to montmorillonite (an aluminosilicate clay mineral) or clay-enriched soils had been shown to enhance experimental prion transmissibility, we hypothesized that prion transmission among mule deer might also be enhanced in ranges with relatively high soil clay content.Our findings suggest that soil clay content and related environmental properties deserve greater attention in assessing risks of prion disease outbreaks and prospects for their control in both natural and production settings.

View Article: PubMed Central - PubMed

Affiliation: United States Department of the Interior, United States Geological Survey, Colorado Cooperative Fish and Wildlife Research Unit, Fort Collins, Colorado 80523-1484, USA.

ABSTRACT
Environmental factors-especially soil properties-have been suggested as potentially important in the transmission of infectious prion diseases. Because binding to montmorillonite (an aluminosilicate clay mineral) or clay-enriched soils had been shown to enhance experimental prion transmissibility, we hypothesized that prion transmission among mule deer might also be enhanced in ranges with relatively high soil clay content. In this study, we report apparent influences of soil clay content on the odds of prion infection in free-ranging deer. Analysis of data from prion-infected deer herds in northern Colorado, USA, revealed that a 1% increase in the clay-sized particle content in soils within the approximate home range of an individual deer increased its odds of infection by up to 8.9%. Our findings suggest that soil clay content and related environmental properties deserve greater attention in assessing risks of prion disease outbreaks and prospects for their control in both natural and production settings.

Show MeSH
Related in: MedlinePlus