Quote Originally Posted by Delkal View Post
The scary part about prion diseases is that it is impossible to sterilize an infected area. Even at the deer farms once it is in an area it is there forever. That dead carcass or even the dirt next a that pile of poop could be infectious for years. Its not going to ever go away and WILL spread........no matter what we do.

The much bigger question is can humans get it from eating the deer.

indeed, very scary. think plague in slow motion...

***> This is very likely to have parallels with control efforts for CWD in cervids.

Rapid recontamination of a farm building occurs after attempted prion removal

http://dx.doi.org/10.1136/vr.105054

Kevin Christopher Gough, BSc (Hons), PhD1, Claire Alison Baker, BSc (Hons)2, Steve Hawkins, MIBiol3, Hugh Simmons, BVSc, MRCVS, MBA, MA3, Timm Konold, DrMedVet, PhD, MRCVS3 and Ben Charles Maddison, BSc (Hons), PhD2

Abstract

The transmissible spongiform encephalopathy scrapie of sheep/goats and chronic wasting disease of cervids are associated with environmental reservoirs of infectivity.

Preventing environmental prions acting as a source of infectivity to healthy animals is of major concern to farms that have had outbreaks of scrapie and also to the health management of wild and farmed cervids.

Here, an efficient scrapie decontamination protocol was applied to a farm with high levels of environmental contamination with the scrapie agent.

Post-decontamination, no prion material was detected within samples taken from the farm buildings as determined using a sensitive in vitro replication assay (sPMCA).

A bioassay consisting of 25 newborn lambs of highly susceptible prion protein genotype VRQ/VRQ introduced into this decontaminated barn was carried out in addition to sampling and analysis of dust samples that were collected during the bioassay.

Twenty-four of the animals examined by immunohistochemical analysis of lymphatic tissues were scrapie-positive during the bioassay, samples of dust collected within the barn were positive by month 3.

The data illustrates the difficulty in decontaminating farm buildings from scrapie, and demonstrates the likely contribution of farm dust to the recontamination of these environments to levels that are capable of causing disease.

snip...

As in the authors' previous study,12 the decontamination of this sheep barn was not effective at removing scrapie infectivity, and despite the extra measures brought into this study (more effective chemical treatment and removal of sources of dust) the overall rates of disease transmission mirror previous results on this farm. With such apparently effective decontamination (assuming that at least some sPMCA seeding ability is coincident with infectivity), how was infectivity able to persist within the environment and where does infectivity reside? Dust samples were collected in both the bioassay barn and also a barn subject to the same decontamination regime within the same farm (but remaining unoccupied). Within both of these barns dust had accumulated for three months that was able to seed sPMCA, indicating the accumulation of scrapie-containing material that was independent of the presence of sheep that may have been incubating and possibly shedding low amounts of infectivity.

This study clearly demonstrates the difficulty in removing scrapie infectivity from the farm environment. Practical and effective prion decontamination methods are still urgently required for decontamination of scrapie infectivity from farms that have had cases of scrapie and this is particularly relevant for scrapiepositive goatherds, which currently have limited genetic resistance to scrapie within commercial breeds.24 This is very likely to have parallels with control efforts for CWD in cervids.

Acknowledgements The authors thank the APHA farm staff, Tony Duarte, Olly Roberts and Margaret Newlands for preparation of the sheep pens and animal husbandry during the study. The authors also thank the APHA pathology team for RAMALT and postmortem examination.

Funding This study was funded by DEFRA within project SE1865.

Competing interests None declared.

https://veterinaryrecord.bmj.com/con...vr.105054.long

Saturday, January 5, 2019

Rapid recontamination of a farm building occurs after attempted prion removal

https://prionprp.blogspot.com/2019/0...-building.html


kind regards, terry