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"While injecting clay-bound prions into experimental animals has shown that they remain infectious, more environmentally relevant exposure routes need to be examined," says Pedersen. Experiments examining oral infectivity are under way. The researchers also plan to determine how long prions remain infectious in soils.

This is the crux of the matter. If clay bound prions can be effectively removed from the food chain by adsorption onto clay minerals, then certain soil types will make preferred pastureage for domestic animals should the CWD be shown to be capable of interspecies infection.

It might be possible, through the use of soil amendments to help keep those prions bound by pH controls, although having to boil them and use detergent to separate them sounds like the prions are in a fairly stable arrangement.

I hope they also study what mechanisms, if any release the prions in the digestive tract of the animal, whether it be enzyme action, stomach acids, or a combination (or other factors).

Scrapie has been rumored to remain in the soil for a long time and be capable of infecting sheep later.

My Dad has a couple of old vet med books. A few from the turn of the last century. The preferred way of dealing with scrapie was to cull the herd and let the grazing land lay fallow for a period of time. It was stated that you could use lime to raise the pH and "kill" the "infective agent", but that would also make the ground unsuitable for grazing until the pH was lowered.

I even think that there was some discussion of a similar disease in cattle in one of those books. When the BSE scare happened, both my grandfathers (now deceased) were not that surprised about it.