Soil-bound Prions That Cause CWD Remain Infectious

University of Wisconsin-Madison via ScienceDaily ^ | April 14, 2006 | NA

[martin_fierro]

[Smokin' Joe]

"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.

[neverdem]

http://www.plos.org

I've noticed this website just recently. Does anyone have any feedback with respect to their political orientation?

Has any one read about F. O. Bastian and his Spiroplasma hypothesis for TSEs at PubMed? Enter Bastian FO, and spiroplasma into PubMed

[BJungNan]

What about blowing dust from a construction site? Does it contain dangerous prions?

[neverdem]

Life in the Green Lane (hybrids)

Nuggets of Death

FReepmail me if you want on or off my health and science ping list.

[Smokin' Joe]

I cannot say with certainty. There are lots of nasty critters that could be in topsoil, but for prions to be present, I would expect that the land would have had to have been grazing land, and that it had been retired from such use due to scrapie in sheep flocks, or BSE in cattle.

Documented BSE in cattle herds here is extremely rare.

In the event that the land had been used to graze sheep, and that there was scrapie known in the flock, it is possible that prions are present in the topsoil, but I would expect the construction company has removed the topsoil where any prions would be likely to be, and the blowing dust is the (generally lighter colored) mineral soil base below. The topsoil is often conserved for reapplication after landscaping when construction is complete, or may be used at another jobsite.

That, I would expect, would not be heavily contaminated (if at all), even if all other conditions had been met, simply because of the relative lack of orgaincs present (which generally accounts for the lighter color).

Note, too, that some mineral soils are deposited in environments which were swampy, and will be dark colored (usually blue-gray) as well. If there are light yellow brown or rusty colored nodules in the soil (ranging from marble sized to sometimes several feet across) usually the minerals limonite or hematite--AKA 'bog iron') and the soil is gray to blue gray in color, it usually indicates a swampy origin.

Overall, I'd figure the odds were against contamination by prions from dust blowing off the site. (Although that can be one heck of a nuisance).

[Smokin' Joe]

I just read the abstracts (all I have access to). "...99% nucleotide sequence homology" sounds like a pretty solid match to me, especially as it was only obtained with TSE infected brain tissue, and from humans, deer, and sheep, but absent in normal age matched brain tissue.

It appears the author may be on to something.

In another abstract, it is postulated that the Spiroplasma bacterium and the prion (if I am reading it correctly) act as the two components of a binary infection mechanism, with the one getting the other into the cell to cause infection.

[Smokin' Joe]

More here: Spiroplasma & Transmissible Spongiform Encephalopathies, discusses Spiroplasma as the cause of TSEs.

[Iris7]

Most interesting link. The "prion" hypothesis has never appealed to me.

If you have a ping list please add me to it.

[BJungNan]

Thanks hardly seems appropriate after such a thoughtful and informative reply. Thanks very much. Much appreciate the information.

[Smokin' Joe]

Spiroplasma web page-Ohio State

Spiroplasmas, not Prions, are Likely Cause of TSEs

CJD Diagnostic and Research Center

Deer Farmer.com (several articles in sidebar)

Articles on Chronic Wasting Disease in Wisconsin Deer

[Smokin' Joe]

You are most welcome. Apparently, there is an alternative hypothesis to the origins of CWD and other TSEs, but the likleyhood of the infectious agent in that instance being present in blowing dust from a construction site would be about the same, for the same reasons.

[Smokin' Joe]

I do not have a ping list, but there are more links in my post above.

The more I read about Spiroplasma, the more likely it seems to be a causative agent. I would like to see more inquiry (which takes funding) along those lines.

And just for the record, I am a geologist, and do not have any interest in the allocation of research funding beyond wanting to be able to go deer hunting without any reservations.

[Watery Tart]

Them doggone hybrids...

[Iris7]

I liked this piece from your second link:

"My way of saying it is that a protein (the prion) cannot acquire the characateristics of an infectious agent, because no evolution can be involved in its disease causing properties. The DNA for prions belongs to the host. Hosts cannot evolve their own diseases, beyond chance point mutations. So-called prion diseases are way too complex for that. They show strain variations in addition to complex pathology. A variety of random mutations would not continually improve the pathology. When the host holds the DNA, selection works for the host and against the disease. This means that the assumed cause of the problem, which was livestock carcasses being fed back to livestock, could not have caused the disease to adapt and become the problem that it has, if prions were the disease-causing agent."

This is so well put. Mr. Novak is crystal clear.

To be clear about myself I am only a curious untrained amateur in this field. (And in many others.) What is so remarkable about the universe is that it is comprehensible to any degree whatever. And is so darned interesting!


http://nov55.com/spr.html

[Iowa Granny]

I'm going to bookmark this thread. You've got an interesting discussion going and I hope it continues.

[GOPJ]

Thanks for the ping.

[redgolum]

Similar to scrapie (sp?) in sheep.

What is odd to me is that this hasn't been talked about before.

[redgolum]

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.