Friday, October 4, 2013

If a man eat of the fish..

ProMed has carried a report that could be rather ominous.  If the prion that can give deer Chronic Wasting Disease (CWD) can be transmitted by something as common as alfalfa, what does that suggest about pathways to other animals such as cows, humans, or even fish fed on animal protein?   In Shakespeare's Hamlet, the prince muses, "A man may fish with the worm that hath eat of a king, and eat of the fish that hath fed of that worm."

Date: Fri 27 Sep 2013
Source: OASIS (Online Abstract Submission and Invitation System), The Wildlife Society Annual Conference, Milwaukee, Wisconsin [edited]

Uptake of prions into plants
Session title: Current science of chronic wasting disease: what have we learned in the last 5 years?
Author: Christopher Johnson, US Geological Survey, Madison, WI

Chronic wasting disease (CWD) and scrapie-infected animals shed infectious prions during both the preclinical and clinical phases of disease. Contamination of environments with prions released from animals or from infected carcasses appears to contribute to the transmission of these diseases.

Previous work has suggested that soil may serve as an environmental disease reservoir. Vegetation is ubiquitous in CWD-contaminated environments and plants are known to absorb a variety of substances from soil, ranging from nutrients to contaminants.

The uptake of proteins from soil into plants has been documented for many years and we have been investigating the uptake of prions into plants in vitro. Using laser scanning confocal microscopy, we observed root uptake of fluorescently-tagged, abnormal prion protein in the model plant thale cress or mouse-eared cress (_Arabidopsis thaliana_), as well as the crop plants alfalfa (_Medicago sativa_), barley (_Hordeum vulgare_), and tomato _(Solanum lycopersicum_). Using serial protein misfolding cyclic amplification, a sensitive biochemical prion detection method, we have found evidence of prions in aerial tissues from these species, as well as maize (_Zea mays_). Both stems and leaves of _A. thaliana_ grown in culture media containing prions are infectious when injected into mice and oral bioassays are underway for _A. thaliana_ and other plants. Our results suggest that prions are taken up by plants and that contaminated plants may represent a previously unrecognized risk of human, domestic species, and wildlife exposure to CWD and scrapie agents.

Communicated by:
Terry S Singeltary Sr

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