A Quantitative Assessment of the Amount of Prion Diverted to Category 1
Materials and Wastewater During Processing
Amie Adkin1,*, Neil Donaldson1, Louise Kelly1,2Article first published
online: 24 DEC 2012
DOI: 10.1111/j.1539-6924.2012.01922.x
© 2012 Society for Risk Analysis
Keywords:Abattoir;bovine spongiform encephalopathy;QRA;scrapie;TSE
In this article the development and parameterization of a quantitative
assessment is described that estimates the amount of TSE infectivity that is
present in a whole animal carcass (bovine spongiform encephalopathy [BSE] for
cattle and classical/atypical scrapie for sheep and lambs) and the amounts that
subsequently fall to the floor during processing at facilities that handle
specified risk material (SRM). BSE in cattle was found to contain the most oral
doses, with a mean of 9864 BO ID50s (310, 38840) in a whole carcass compared to
a mean of 1851 OO ID50s (600, 4070) and 614 OO ID50s (155, 1509) for a sheep
infected with classical and atypical scrapie, respectively. Lambs contained the
least infectivity with a mean of 251 OO ID50s (83, 548) for classical scrapie
and 1 OO ID50s (0.2, 2) for atypical scrapie. The highest amounts of infectivity
falling to the floor and entering the drains from slaughtering a whole carcass
at SRM facilities were found to be from cattle infected with BSE at rendering
and large incineration facilities with 7.4 BO ID50s (0.1, 29), intermediate
plants and small incinerators with a mean of 4.5 BO ID50s (0.1, 18), and
collection centers, 3.6 BO ID50s (0.1, 14). The lowest amounts entering drains
are from lambs infected with classical and atypical scrapie at intermediate
plants and atypical scrapie at collection centers with a mean of 3 × 10−7 OO
ID50s (2 × 10−8, 1 × 10−6) per carcass. The results of this model provide key
inputs for the model in the companion paper published here.
it would have been interesting if CWD would have been included in this
study. ...tss
Saturday, December 15, 2012
Bovine spongiform encephalopathy: the effect of oral exposure dose on
attack rate and incubation period in cattle -- an update 5 December 2012
Detection of Protease-Resistant Prion Protein in Water from a CWD-Endemic
Area
65
Tracy A. Nichols*1,2, Bruce Pulford1, Christy Wyckoff1,2, Crystal
Meyerett1, Brady Michel1, Kevin Gertig3, Jean E. Jewell4, Glenn C. Telling5 and
M.D. Zabel1 1Department of Microbiology, Immunology and Pathology, College of
Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort
Collins, CO 80523, USA 2National Wildlife Research Center, Wildlife Services,
United States Department of Agriculture, Fort Collins, Colorado, 80521, USA
3Fort Collins Water and Treatment Operations, Fort Collins, Colorado, 80521, USA
4 Department of Veterinary Sciences, Wyoming State Veterinary Laboratory,
University of Wyoming, Laramie, Wyoming, 82070, USA 5Department of Microbiology,
Immunology, Molecular Genetics and Neurology, Sanders Brown Center on Aging,
University of Kentucky, Lexington, Kentucky, 40536, USA * Corresponding author-
tracy.a.nichols@aphis.usda.gov
Chronic wasting disease (CWD) is the only known transmissible spongiform
encephalopathy affecting free-ranging wildlife. Experimental and epidemiological
data indicate that CWD can be transmitted horizontally and via blood and saliva,
although the exact mode of natural transmission remains unknown. Substantial
evidence suggests that prions can persist in the environment, implicating it as
a potential prion reservoir and transmission vehicle. CWD- positive animals can
contribute to environmental prion load via biological materials including
saliva, blood, urine and feces, shedding several times their body weight in
possibly infectious excreta in their lifetime, as well as through decomposing
carcasses. Sensitivity limitations of conventional assays hamper evaluation of
environmental prion loads in water. Here we show the ability of serial protein
misfolding cyclic amplification (sPMCA) to amplify minute amounts of CWD prions
in spiked water samples at a 1:1 x106 , and protease-resistant prions in
environmental and municipal-processing water samples from a CWD endemic area.
Detection of CWD prions correlated with increased total organic carbon in water
runoff from melting winter snowpack. These data suggest prolonged persistence
and accumulation of prions in the environment that may promote CWD transmission.
snip...
The data presented here demonstrate that sPMCA can detect low levels of
PrPCWD in the environment, corroborate previous biological and experimental data
suggesting long term persistence of prions in the environment2,3 and imply that
PrPCWD accumulation over time may contribute to transmission of CWD in areas
where it has been endemic for decades. This work demonstrates the utility of
sPMCA to evaluate other environmental water sources for PrPCWD, including
smaller bodies of water such as vernal pools and wallows, where large numbers of
cervids congregate and into which prions from infected animals may be shed and
concentrated to infectious levels.
snip...end...full text at ;
PLoS ONE. 2008; 3(8): e2969.
Prion Infected Meat-and-Bone Meal Is Still Infectious after Biodiesel
Production
The epidemic of bovine spongiform encephalopathy (BSE) has led to a
world-wide drop in the market for beef by-products, such as Meat-and-Bone Meal
(MBM), a fat-containing but mainly proteinaceaous product traditionally used as
an animal feed supplement. While normal rendering is insufficient, the
production of biodiesel from MBM has been suggested to destroy infectivity from
transmissible spongiform encephalopathies (TSEs). In addition to producing fuel,
this method simultaneously generates a nutritious solid residue. In our study we
produced biodiesel from MBM under defined conditions using a modified form of
alkaline methanolysis. We evaluated the presence of prion in the three resulting
phases of the biodiesel reaction (Biodiesel, Glycerol and Solid Residue) in
vitro and in vivo. Analysis of the reaction products from 263K scrapie infected
MBM led to no detectable immunoreactivity by Western Blot. Importantly, and in
contrast to the biochemical results the solid MBM residue from the reaction
retained infectivity when tested in an animal bioassay. Histochemical analysis
of hamster brains inoculated with the solid residue showed typical spongiform
degeneration and vacuolation. Re-inoculation of these brains into a new cohort
of hamsters led to onset of clinical scrapie symptoms within 75 days, suggesting
that the specific infectivity of the prion protein was not changed during the
biodiesel process. The biodiesel reaction cannot be considered a viable prion
decontamination method for MBM, although we observed increased survival time of
hamsters and reduced infectivity greater than 6 log orders in the solid MBM
residue. Furthermore, results from our study compare for the first time prion
detection by Western Blot versus an infectivity bioassay for analysis of
biodiesel reaction products. We could show that biochemical analysis alone is
insufficient for detection of prion infectivity after a biodiesel process.
New studies on the heat resistance of hamster-adapted scrapie agent:
Threshold survival after ashing at 600°C suggests an inorganic template of
replication
Abstract
One-gram samples from a pool of crude brain tissue from hamsters infected
with the 263K strain of hamster-adapted scrapie agent were placed in covered
quartz-glass crucibles and exposed for either 5 or 15 min to dry heat at
temperatures ranging from 150°C to 1,000°C. Residual infectivity in the treated
samples was assayed by the intracerebral inoculation of dilution series into
healthy weanling hamsters, which were observed for 10 months; disease
transmissions were verified by Western blot testing for proteinase-resistant
protein in brains from clinically positive hamsters. Unheated control tissue
contained 9.9 log10LD50/g tissue; after exposure to 150°C, titers equaled or
exceeded 6 log10LD50/g, and after exposure to 300°C, titers equaled or exceeded
4 log10LD50/g. Exposure to 600°C completely ashed the brain samples, which, when
reconstituted with saline to their original weights, transmitted disease to 5 of
35 inoculated hamsters. No transmissions occurred after exposure to
1,000°C.
see full text:
Friday, December 14, 2012
Susceptibility of domestic cats to chronic wasting disease
Friday, December 14, 2012
Susceptibility Chronic Wasting Disease (CWD) in wild cervids to Humans 2005
- December 14, 2012
Friday, December 14, 2012
DEFRA U.K. What is the risk of Chronic Wasting Disease CWD being introduced
into Great Britain? A Qualitative Risk Assessment October 2012
Tuesday, December 18, 2012
A Growing Threat How deer breeding could put public trust wildlife at risk
Wednesday, March 28, 2012
VARIABLY PROTEASE-SENSITVE PRIONOPATHY IS TRANSMISSIBLE, price of prion
poker goes up again $
Tuesday, December 18, 2012
Bioassay Studies Support the Potential for Iatrogenic Transmission of
Variant Creutzfeldt Jakob Disease through Dental Procedures
Wednesday, May 16, 2012
Alzheimer’s disease and Transmissible Spongiform Encephalopathy prion
disease, Iatrogenic, what if ?
Proposal ID: 29403
RIP MOM 12/14/97 confirmed hvCJD...TSS December 25, 2012
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