Tuesday, December 25, 2012

A Quantitative Assessment of the Amount of Prion Diverted to Category 1 Materials and Wastewater During Processing

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

No comments:

Post a Comment