Friday, January 15, 2016

TEXAS PARKS & WILDLIFE CWD Ante-Mortem Testing Symposium Texas Disposal Systems Events Pavilion January 12, 2016

CWD Ante-Mortem Testing Symposium Texas Disposal Systems Events Pavilion January 12, 2016

 

TEXAS PARKS & WILDLIFE

 

CWD Ante-Mortem Testing Symposium Texas Disposal Systems Events Pavilion January 12, 2016

 

9:00 - 9:15 Welcome - Carter Smith and Dr. Andy Schwartz

 

Morning Session - Dr. T.R. Lansford (Moderator)

 

9:15 -10:00 Dr. Mike Miller - Distribution and Progression of Prion Accumulation in Deer and Elk

 

10:00 - 10:45 Dr. Nathan Shotts - Retropharyngeal Lymph Node Biopsy Technique

 

10:00 - 10:45 Break

 

11:00 - 11:45 Dr. Mike Miller - Detecting Prion Accumulation in Deer and Elk via Tonsil or Rectal Mucosa Biopsy

 

11:45 - 12:30 Dr. Nicholas Haley - Live Animal Test Developments for CWO

 

12:30 - 1:30 Lunch

 

Afternoon Session - Clayton Wolf (Moderator)

 

 1:30 - 2:15 Dr. Tracy Nichols - Rectal and Tonsil Biopsy as Ante-mortem Assay and Experimental Assays

 

 2:15 - 3:30 Dr. Randy Pritchard - Regulatory Impacts and Challenges

 

 3:30 - 3:45 Break

 

 3:45 - 5:30 Panel Discussion - Mary Luedeker (Moderator) - How do we use these tests?

 

Lead in with modeling comparing detection probabilities between post-mortem and ante-mortem testing strategies (Dr. Dan Baca).

 


 


 

Disease in Deer and Elk

 

Chris Siepker1, Nicholas Haley1, W. David Walter2, Matteo Manca3, Laura Hoon-Hanks4, Ryan Monello5, Jenny Powers5, Justin Greenlee6 , Bruce Thomsen7 , Aaron Lehmkuhl7, Gordon Mitchell8, Tracy Nichols9,Byron Caughey3, Edward Hoover4, and Juergen Richt1.

 

1. Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan KS USA 2. United States G e o l o g i c a l Survey, P e n n s y l v a n i a Cooperative Fish and Wildlife Research Unit, University Park PA USA 3. TSE/Prion Biochemistry Section, Rocky Mountain Laboratories, National Institutes of Health, Hamilton, MT USA 3. Department of MIP, Colorado State University, Fort Collins CO USA 4. National Park Service, Wildlife Health Branch, Fort Collins CO USA 5. Virus and Prion Research Unit, National Animal Disease Center, ARS, USDA, Ames IA USA 6. USDA, APHIS, VS, STAS, National Veterinary Service Laboratories, Ames IA USA 7. National and OIE Reference Laboratory for Scrapie and CWD, Canadian Food Inspection Agency, Ottawa ON Canada 8. National Wildlife Research Center Wildlife Services, APHIS, USDA, Fort Collins CO USA

 

Chronic wasting disease (CWD) is an e f f i c i e n t l y t r a n smi t t e d s p o n g i f o r m encephalopathy of cervids (e.g. deer, elk, and moose), and is the only known prion disease affecting both free-ranging wildlife and captive animals. The antemortem detection of CWD and other prion diseases has proven difficult, due in part to difficulties in identifying an appropriate peripheral tissue specimen and complications with conventional test sensitivity. At present, biopsies of the recto-

 

Prion2015 Program Guide 22

 

anal mucosal-associated lymphoid tissues (RAMALT) have shown promising sensitivity and are not impractical to collect in live animals. Nasal brush collections have likewise proven both sensitive and practical for identification of prion infections in humans. In this study, we evaluated both RAMALT and nasal brush collections by real time quaking-induced conversion (RT-QuIC), and compared our findings to RAMALT immu n o h i s t o c h emi s t r y a s we l l a s conventional postmortem evaluation of obex and retropharyngeal lymph node tissues from over 700 captive and free-ranging deer and elk in areas with endemic CWD. We correlated our results with various clinical findings, including pathological stage of infection as determined by obex scoring, PrP genotype, age, and sex. While the sensitivity of RAMALT RT-QuIC analyses exceeded that of RAMALT IHC (69-80% vs. >44%) and nasal brush collections (15-30%), the sensitivity of both biopsy and nasal brush analyses were dependent primarily on clinical stage of disease, although PrP genotype was also an important predictor of sample positivity. Our findings further demonstrate the potential and limitations of antemortem sample analyses by RT-QuIC in the identification and management of prion diseases.

 

==================

 

P200 Clinical Stage of Infection is Critical in the Antemortem Diagnosis of Chronic Wasting Disease in Deer and Elk.

 

Chris Siepker1, Nicholas Haley1, W. David Walter2, Laura Hoon-Hanks7, Ryan Monello3, Jenny Powers3, Bruce Thomsen4, Justin Greenlee4, Aaron Lehmkuhl4, Gordon Mitchell5, Tracy Nichols6, Edward Hoover7, Juergen Richt1

 

1Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan, KS, USA, 2United States G e o l o g i c a l Survey, P e n n s y l v a n i a Cooperative Fish & Wildlife Research Unit, Pennsylvania State University, University Park, PA 16802, USA, 3National Park Service, Wildlife Health Branch, Fort Collins, CO, USA, 4USDA, APHIS, VS, STAS, National Veterinary Service Laboratories, Ames, IA, USA, 5National and OIE Reference Laboratory for Scrapie and CWD Ottawa Laboratory Fallowfield Canadian Food Inspection Agency, Ottawa, ON, Canada, 6National Wildlife Research Center Wildlife Services APHIS, USDA, Fort Collins, CO, USA, 7Department of MIP, Colorado State University, Fort Collins, CO, USA

 

Chronic wasting disease (CWD) is an e f f i c i e n t l y t r a n smi t t e d s p o n g i f o r m encephalopathy of cervids (e.g. deer, elk, and moose), and is the only known prion disease affecting both free-ranging wildlife and captive animals. The antemortem detection of CWD and other prion diseases has proven difficult, due in part to difficulties in identifying an appropriate peripheral tissue specimen and complications with conventional test sensitivity. At present, biopsies of the rectoanal mucosal-associated lymphoid tissues (RAMALT) have shown promising sensitivity and are not impractical to collect in live animals. Nasal brush collections have likewise proven both sensitive and practical for identification of prion infections in humans. In this study, we evaluated both RAMALT and nasal brush collections by real time quaking-induced conversion (RT-QuIC), and compared our findings to RAMALT immu n o h i s t o c h emi s t r y a s we l l a s conventional postmortem evaluation of obex and retropharyngeal lymph node tissues from over 700 captive and free-ranging deer and elk in areas with endemic CWD. We correlated our results with various clinical findings, including pathological stage of infection as determined by obex scoring, PrP genotype, age, and sex. While the sensitivity of RAMALT RT-QuIC analyses exceeded that of RAMALT IHC (69-80% vs. >44%) and nasal brush collections (15-30%), the sensitivity of both biopsy and nasal brush analyses were dependent primarily on clinical stage of disease, although PrP genotype was also an important predictor of sample positivity. Our findings further demonstrate the potential and limitations of antemortem sample analyses by RT-QuIC in the identification and management of prion diseases.

 


 


 

Research Project: Mitigating the Risk of Transmission and Environmental Contamination of Transmissible Spongiform Encephalopathies Location: Animal Diseases Research

 

2015 Annual Report

 

1a.Objectives (from AD-416): Objective 1: Determine whether goats are a transmission reservoir for ovine scrapie by developing and validating diagnostic methods for detecting goat scrapie. Determine the genetic predisposition and transmission route(s) of goat scrapie.

 

Subobjective 1.1: Improve eradication efforts by developing improved methods for antemortem scrapie diagnosis.

 

Subobjective 1.2: Determine if placenta and milk from goats are potential sources of scrapie to sheep.

 

Objective 2: Develop methods to mitigate infectivity of soil-associated prions by screening soil microbes for potential candidates for bioremediation.

 

1b.Approach (from AD-416): Scrapie is a complex and rare disorder affecting outbred farm animals held under a wide variety of husbandry conditions and exposed to an agent for which the transmissible and pathogenic events remain largely unknown. The work described in the research plan is an extension of the previous highly productive studies by this research group, addressing the need for implementation of federal regulations based on the best available science, often in the face of relatively small sample numbers in the natural host. The work includes development of specific management and diagnostic tools and is presented as an integrated series of research objectives. This approach was selected over a hypothesis based approach. After consulting Glass and Hall, the group determined that the work presented in the following plan was best represented by goal statements rather than hypotheses because the work increases the density of data necessary for progress and for support of current and proposed federal regulations. This project addresses only scrapie, the TSE of sheep and goats. Chronic wasting disease (CWD) is the TSE of North America cervids (deer and elk). ***No live animal work with CWD is included in this project plan since CWD is not endemic in Washington State, the disease appears to be highly communicable, the modes of transmission are unknown, and we do not have suitable biocontainment facilities to conduct CWD studies in large animals.

 

3.Progress Report: The National Scrapie Eradication program in the U.S. is conducted by the state and federal animal disease health regulatory agencies, with research support by ARS and several land grant universities, in a joint endeavor with the sheep and goat industries. The comprehensive program of animal identification, surveillance and genetic selection has resulted in a decrease of scrapie prevalence by 88%. As prevalence falls, remaining potential sources of infection will be monitored. The transmissible spongiform encephalopathies (TSE) project at the Animal Disease Research Unit, Pullman, Washington, includes an integrated examination of modes of transmission (both intraspecies and interspecies), diagnostic test development and refinement, and delineation of species-specific and genetically controlled differences in pathogenesis. In FY15, progress was reported in each of these research areas.

 

Objective 1: Transmission of scrapie by placenta, blood and milk. Exposure of the newborn lamb or kid to infectious prions shed by the postparturient ewe/doe is probably the most efficient route of transmission in the field. Our earlier work demonstrated the role of fetal genotype on transmission by the ovine placenta. In this Fiscal Year (FY), we completed a study demonstrating that the caprine placenta, while containing sparse amounts of detectable PrP-Sc, is infectious to lambs and kids by oral exposure. Experimental oral exposure of lambs and kids to milk from infected does during the first 2 to 3 days of life was performed last year and the recipient animals are monitored for evidence of disease. With an incubation period of 24-36 months, the study is expected to yield useful information in FY16. These studies of experimental disease are complemented by ongoing observations on transmission in our mixed herd of infected goats and sheep.

 

Objective 2: Diagnosis and genetics of the TSEs in ruminant animals: Gold standard testing of scrapie is performed by immunohistochemistry of formalin fixed tissues, using lymphoid tissue to detect early disease and brain tissue to detect advanced disease. Antemortem tissue based testing requires expertise in the field and in the laboratory. We are completing a study examining the effects of host and biopsy handling on lymphoid follicle frequency and detection of PrP-Sc. Similarly, immunohistochemistry has been applied to determine the effects of these factors on the frequency of observing two major cell types known to accumulate PrPSc in lymphoid tissues—namely, macrophages and follicular dendritic cells. These studies will be completed in FY16 and will provide information on any needed refinements in the antemortem testing of sheep and goats, with possible application to the evolving program of live animal testing of captive deer and elk.

 

Genetic variation among animals within each species affects disease resistance and incubation time: We have previously reported the effect of genotype on diagnostic accuracy in white tailed deer. We have now completed a study examining the role of a prion gene polymorphism at residue 127 in goats on incubation time (reported in accomplishments) and in FY16 will perform studies on diagnostic accuracy of the current testing modes in goats with this genotype.

 

Polymorphisms at additional sites (146 and 222) have been reported to be associated with reduced susceptibility to caprine scrapie. Goat kids were exposed to scrapie by the oral route on day 1 of life and are being monitored. Goats with the potentially resistant allele have remained clinically normal for more than 7 years after oral challenge; control goats lacking this allele developed disease at 2-3 years of age. We will continue to monitor the 222K goats for their natural lifespan and will perform extensive necropsy examinations upon termination to determine whether these animals are a benefit to the industry or represent a long lived source of prions in goat herds. The polymorphism at residue 222, while potentially conferring resistance to scrapie, also presents a diagnostic challenge. Residue 222 is included in the epitope recognized by the monoclonal antibody used in gold standard diagnostic testing in the U.S. We have reported the effect of this polymorphism on test sensitivity (reported in accomplishments). We have previously reported that this polymorphism is rare in U.S. goats, but in the current work, we presented some alternatives to testing should this genotype be selected by breeders in the future.

 

Examination of the prion distribution in fixed tissues is the basis for diagnostic testing. In addition, the distribution and intensity of the immunohistochemical staining are also useful indirect measures of disease progression. We have reported this effect in our studies of genetics and diagnosis of chronic wasting disease in white tailed deer. We have now extended those studies to include Rocky Mountain elk, which have a unique prion distribution pattern. We continue to work with state and federal agencies monitoring the effects of genotype on prion disease captive and free-ranging Rocky Mountain elk, as components of species-specific control programs.

 

While antemortem and postmortem tissue-based testing is sensitive and specific, collection of tissues is inconvenient and testing is expensive. Development of a blood based test might alleviate those problems. We are conducting a systematic examination of prion-bearing cell types in sheep and goats and have reported that all three major types of peripheral blood mononuclear cells—B lymphocytes, T lymphocytes, and monocytes, can harbor prions and are thus reasonable targets on which to base development of a diagnostic platform for use during preclinical infection. We have recently reported that relatively small amounts of blood contain infectious prions and continue to examine methods for more sensitive and specific detection of PrP-Sc in circulating cells.

 

Objective 3: Introduction of disease by novel routes: While direct contact with prion-bearing tissues remains the most likely source of infection in sheep and goats, the introduction of disease through fomites or through contact with other species has not been ruled out. We originally intended to examine the role of soil or premise contamination with prions after removal of infected sheep. However, the success of the eradication program at reducing scrapie prevalence to nearly undetectable levels over a relatively short amount of time suggests that environmental routes are not highly efficient. ***However, prevalence of chronic wasting disease in farmed and free-ranging cervids continues to climb and as the disease is discovered in an increasing number of states and provinces, the threat of transmission to sheep remains under investigation. In conjunction with the Canadian Food Inspection Agency, we are completing a study delineating methods for discriminating between a TSE of ovine and cervid origin in sheep, using both conventional in vitro prion characterization methods and in vivo studies with a panel of transgenic mice. The study will be concluded in FY16; preliminary findings show differences in incubation time and molecular folding patterns that may be useful in determining the origin of TSEs of sheep in the CWD endemic zones.

 

In a continued effort to reduce research dependence on bioassay, work continued on the creation of cultured cell lines with robust permissiveness to natural isolates of prions. Work continued on the immortalization of caprine microglia cell lines with different prion genotypes of interest. Studies also continued in the optimization of the scrapie permissiveness of a caprine prion protein-transfected rabbit kidney epithelial cell line. Factors associated with cellular permissiveness to infection were also determined in a study that compared the transcriptomes of clones from an immortalized ovine microglia cell line but that differ greatly in permissiveness to natural source isolates (i.e., hindbrain) of classical scrapie prions.

 

4.Accomplishments 1. The placenta of goats with scrapie is infectious to goat kids and lambs. The placenta of sheep is a highly infectious source of scrapie prions and is well known to play a major role in natural transmission. Goats, too, are a natural host of classical scrapie and are frequently raised with sheep, but the potential routes of natural transmission from goats to sheep have not been studied. ARS researchers at the Animal Disease Research Unit in Pullman, Washington, have now demonstrated that the placenta shed from a goat, despite its relatively sparse accumulation of the disease-associated form of the prion protein, is infectious to newborn lambs and goat kids by oral exposure. This accomplishment provides a scientific basis for regulatory and veterinary consideration as to the possible modes of transmission risk of scrapie from goats to sheep.

 

2. Prions were detected in small volume blood samples obtained from sheep with preclinical scrapie. Initial studies that demonstrated the potential for developing a blood-based live animal diagnostic test for classical scrapie in sheep were based on blood sample volumes many times more than routinely used in the practice of veterinary medicine. ARS researchers at the Animal Disease Research Unit in Pullman, Washington, have now demonstrated that infectious prions can be detected from much smaller blood sample volumes, even during preclinical infection. This study supports further development of a safe and highly efficient blood-based diagnostic test for preclinical scrapie infection in sheep. It demonstrates the utility of using the small blood sample volumes already routinely collected for diagnostic purposes.

 

3. A prion gene polymorphism that prolongs scrapie incubation in goats. Scrapie eradication in sheep is based in part on strong genetic resistance to classical scrapie infection. However, knowledge regarding the implications of differing genotypes in goats is incomplete. ARS researchers at the Animal Disease Research Unit in Pullman, Washington, have now demonstrated that the appearance of clinical signs associated with scrapie can be significantly delayed in goats with a prion gene polymorphism at codon 127. This accomplishment helps explain why goats with this polymorphism may be underrepresented in surveys of scrapie infected goat herds. Additionally, this accomplishment suggests that scrapie eradication programs might need to include longer trace-back histories when investigating scrapie-exposed goats of this genotype.

 

4. A prion gene polymorphism that reduces the sensitivity of some diagnostic tests for caprine scrapie. Gold standard diagnostic testing for caprine scrapie is performed by monoclonal antibody immunohistochemistry. While this assay is highly specific, the sensitivity of the assay is limited by the use of a single monoclonal antibody directed to a variable portion of the prion molecule. ARS researchers at the Animal Disease Research Unit in Pullman, Washington, have confirmed that the monoclonal antibody currently used for testing in the U.S. fails to detect prions in goats homozygous for a prion polymorphism at codon 222. The study was performed by developing a digital image segmentation and analysis algorithm to objectively measure spatially diverse PrPSc accumulation profiles in the hindbrain of goats with naturally acquired classical scrapie. Comparisons were also made under the standardized conditions and reagents currently utilized by regulatory agencies. This accomplishment provides the scientific basis for modification of the assay should this prion genotype become more prevalent in the U.S. goat herd.

 

***5. Delineation of the progression of abnormal prion accumulation in the brain of elk with chronic wasting disease. Diagnostic testing for the transmissible spongiform encephalophathies (TSE) of elk is performed by examination of a single section of brain, using a monoclonal antibody that detects the abnormal prion protein. Collaborative research including scientists from the Colorado State University Diagnostic Laboratory, the U.S. Department of Agriculture Animal Health Inspection Service, the Canadian Food Inspection Agency, and the ARS Animal Disease Research Unit in Pullman, Washington, has demonstrated that the abnormal prion in this section of brain has a unique and relatively consistent pattern of accumulation as disease progresses. The study complements the earlier work performed by ARS and others on the effect of prion genotype on disease progression in elk and in white tailed deer. The scoring system described in these studies may be useful for estimating prion distribution throughout the infected animal and potentially for estimating the duration of infection, facilitating epidemiologic studies in infected herds.

 

Review Publications Schneider, D.A., Madsen-Bouterse, S.A., Zhuang, D., Truscott, T.C., Dassanayake, R.P., O'Rourke, K.I. 2015. The placenta shed from goats with classical scrapie is infectious to goat kids and lambs. Journal of General Virology. doi: 10.1099/vir.0.000151.

 

 Munoz-Gutierrez, J.F., Schneider, D.A., Baszler, T.V., Dinkel, K.D., Greenlee, J.J., Nicholson, E.M., Stanton, J.J. 2015. hTERT-immortalized ovine microglia propagate natural scrapie isolates. Virus Research. 198:35-43.

 

Dassanayake, R.P., White, S.N., Madsen-Bouterse, S.A., Schneider, D.A., O'Rourke, K.I. 2015. Role of PRNP S127 allele in experimental goat infection with classical caprine scrapie. Animal Genetics. doi: 10.1111/age.12291.

 

Dassanayake, R.P., Truscott, T.C., Zhuang, D., Schneider, D.A., Madsen-Bouterse, S.A., Young, A.J., Stanton, J.B., Davis, W.C., O’Rourke, K.I. 2015. Classical natural ovine scrapie prions are detected in practical volumes of blood by lamb and transgenic mouse bioassay. Journal of Veterinary Science. 16(2):179-186.

 

Madsen-Bouterse, S.A., Schneider, D.A., Dassanayake, R.P., Truscott, T.C., Zhuang, D., Kumpula-Mcwhirter, N., O'Rourke, K.I. 2015. PRNP variants in goats reduce sensitivity of detection of PrPSc by immunoassay. Journal of Veterinary Diagnostic Investigation. 27(3):332-343.

 

Spraker, T.R., Gidlewski, T., Powers, J.G., Nichols, T., Balachandran, .A., Cummins, B., Wild, M.A., Vercauteren, K., O'Rourke, K. 2015. Progressive accumulation of the abnormal conformer of the prion protein and spongiform encephalopathy in the obex of nonsymptomatic and symptomatic Rocky Mountain elk (Cervus elaphus nelsoni) with chronic wasting disease. Journal of Veterinary Diagnostic Investigation. doi: 10.117/1040638715593368.

 


 

 Research Project: TRANSMISSION, DIFFERENTIATION, AND PATHOBIOLOGY OF TRANSMISSIBLE SPONGIFORM ENCEPHALOPATHIES Title: Antemortem detection of chronic wasting disease prions in nasal brush collections and rectal biopsies from white-tailed deer by real time quaking-induced conversion

 

Authors

 

item Haley, Nicholas - item Siepker, Chris - item Walter, W. David - item Thomsen, Bruce - item Greenlee, Justin item Lehmkuhl, Aaron - item Richt, Jürgen -

 

Submitted to: Journal of Clinical Microbiology Publication Type: Peer Reviewed Journal Publication Acceptance Date: November 27, 2015 Publication Date: N/A

 

Interpretive Summary: Chronic Wasting Disease (CWD), a fatal neurodegenerative disease that occurs in farmed and wild cervids (deer and elk) of North America, is a transmissible spongiform encephalopathy (TSE). TSEs are caused by infectious proteins called prions that are resistant to various methods of decontamination and environmental degradation. Early diagnosis of CWD in wild and captive herds would be very helpful to controlling the spread of CWD, for which there are not yet any preventative or treatment measures available. The purpose of this study was to test a laboratory method of prion detection (real-time Quaking Induced Conversion; RT-QuIC) that has the potential to detect very low levels of infectious prions in samples collected from live animals against the gold standard diagnostic where abnormal prion in tissues is stained on a microscope slide. This study reports that RT-QuIC detects more cases of CWD than standard methods, but also can identify a small number of animals without CWD as being positive. In the case of CWD, where it is likely that large numbers of animals within a herd may be positive, misidentifying a negative as a positive may have less of an impact than in the case of other prion diseases such as bovine spongiform encephalopathy considering that this test allows testing much larger numbers of samples with a faster turn around time than traditional methods. This information could have an impact on regulatory and wildlife officials developing plans to reduce or eliminate CWD and cervid farmers that want to ensure that their herd remains CWD-free. Technical Abstract: Chronic wasting disease (CWD), a transmissible spongiform encephalopathy of cervids, was first documented nearly fifty years ago in Colorado and Wyoming and has since spread to cervids in 23 states, 2 Canadian provinces, and the Republic of Korea. The increasing expansion of this disease makes the development of sensitive diagnostic assays and antemortem sampling techniques crucial for the mitigation of spread; this is especially true in cases of relocation/reintroduction of farmed or free-ranging deer and elk, or surveillance studies in private or protected herds where depopulation may be contraindicated. This study sought to evaluate the sensitivity of the real-time quaking-induced conversion (RT-QuIC) assay in samples collected antemortem. Antemortem findings were then compared to results from ante- and postmortem samples evaluated using the current gold standard diagnostic assay, immunohistochemistry (IHC). Recto-anal mucosal associated lymphoid tissue (RAMALT) biopsies and nasal brush collections from three separate herds of farmed white-tailed deer (n=409) were evaluated, along with standard postmortem microscopic analysis of brainstem at the level of the obex and retropharyngeal lymph nodes. We hypothesized the sensitivity of RT-QuIC would be comparable to IHC in antemortem tissues, and would correlate with both genotype and stage of clinical disease. ***Our results showed that RAMALT testing by RT-QuIC had the highest sensitivity (69.8%) when compared to postmortem testing. This data suggests that RT-QuIC, like IHC, is a fairly sensitive assay for detection of CWD prions in rectal biopsies and other antemortem samples, and with further investigation has potential for large scale and rapid automated testing for CWD diagnosis.

 


 

Research Project: Transmission, Differentiation, and Pathobiology of Transmissible Spongiform Encephalopathies 2015 Annual Report

 

1a.Objectives (from AD-416): 1. Investigate the pathobiology of atypical transmissible spongiform encephalopathies (TSEs) in natural hosts. A. Investigate the pathobiology of atypical scrapie. B. Investigate the pathobiology of atypical bovine spongiform encephalopathy (BSE). 2. Investigate the horizontal transmission of TSEs. A. Assess the horizontal transmission of sheep scrapie in the absence of lambing. B. Determine routes of transmission in chronic wasting disease (CWD) infected premises. C. Assess oral transmission of CWD in reindeer. 3. Investigate determinants of CWD persistence. A. Determine CWD host range using natural routes of transmission. B. Investigate the pathobiology of CWD.

 

1b.Approach (from AD-416): The studies will focus on three animal transmissible spongiform encephalopathy (TSE) agents found in the United States: bovine spongiform encephalopathy (BSE); scrapie of sheep and goats; and chronic wasting disease (CWD) of deer, elk, and moose. The research will address sites of accumulation, routes of infection, environmental persistence, and ante mortem diagnostics with an emphasis on controlled conditions and natural routes of infection. Techniques used will include clinical exams, histopathology, immunohistochemistry and biochemical analysis of proteins. The enhanced knowledge gained from this work will help mitigate the potential for unrecognized epidemic expansions of these diseases in populations of animals that could either directly or indirectly affect food animals.

 

3.Progress Report: Research efforts directed toward meeting objective 1 of our project plan include work in previous years starting with the inoculation of animals for studies designed to address the pathobiology of atypical scrapie, atypical bovine spongiform encephalopathy (BSE), as well as a genetic version of BSE. Post-mortem examination of the animals inoculated with atypical scrapie has been initiated and laboratory analysis of the tissues is ongoing. Atypical BSE animals have developed disease and evaluation of the samples is currently underway. Animals inoculated with a genetic version of BSE have developed disease with a manuscript reporting these results was published (2012), and additional laboratory comparisons of genetic BSE to atypical and classical BSE are ongoing. In addition, we have investigated the possibility that atypical scrapie was present earlier than previously detected in the national flock by analyzing archived field isolates using methods that were unavailable at the time of original diagnosis. Sample quality was sufficiently degraded that modern methods, beyond those applied to the tissues at the time the tissues were archived, were not suitable for evaluation. In research pertaining to objective 2, "Investigate the horizontal transmission of TSEs", we have initiated a study to determine if cohousing non-lambing scrapie inoculated sheep is sufficient to transmit scrapie to neonatal lambs. At this time, scrapie free ewes have lambed in the presence of scrapie inoculated animals and the lambs are cohoused with these inoculated animals.

 

4.Accomplishments 1. Changes in retinal function in cattle can be used to identify different types of bovine spongiform encephalopathy (BSE). BSE belongs to a group of fatal, transmissible protein misfolding diseases known as transmissible spongiform encephalopathies (TSEs). Like other protein misfolding diseases including Parkinson's disease and Alzheimer's disease, TSEs are generally not diagnosed until the onset of disease after the appearance of unequivocal clinical signs. As such, identification of the earliest clinical signs of disease may facilitate diagnosis. The retina is the most accessible part of the central nervous system. ARS scientist in Ames IA described antemortem changes in retinal function and thickness that are detectable in BSE inoculated animals up to 11 months prior to the appearance of any other signs of clinical disease. Differences in the severity of these clinical signs reflect the amount of PrPSc accumulation in the retina and the resulting inflammatory response of the tissue. These results are the earliest reported clinical signs associated with TSE infection and provide a basis for understanding the pathology and evaluating therapeutic interventions. Further, this work shows that High-type BSE and classical BSE can be differentiated by eye examination alone, the first time BSE strains have been differentiable in a live animal.

 

2. Sheep genetics influences the susceptibility of sheep to scrapie. Sheep scrapie is a transmissible spongiform encephalopathy that can be transmitted between affected animals resulting in significant economic losses in affected flocks. The prion protein gene (PRNP) profoundly influences the susceptibility of sheep to the scrapie agent and the tissue levels and distribution of PrPSc in affected sheep. In this study, sheep of 3 different prion genetic types (denoted VRQ/VRQ, VRQ/ARR and ARQ/ARR) were inoculated and subsequently euthanized upon onset of disease. Disease aspects were uniform across genotypes and consistent with manifestations of classical scrapie. Mean survival time differences were associated with the genetic type such that VRQ/VRQ sheep survived 18 months, whereas VRQ/ARR and ARQ/ARR sheep survived 60 and 56 months, respectively. Microscopic evaluation revealed similar accumulations in central nervous system tissues regardless of host genetic type. PrPSc in lymphoid tissue was consistently abundant in VRQ/VRQ, present but confined to tonsil or retropharyngeal lymph node in 4/5 VRQ/ARR, and totally absent in ARQ/ARR sheep. The results of this study demonstrate the susceptibility of sheep with the ARQ/ARR genotype to scrapie by the intracranial inoculation route with PrPSc accumulation in CNS tissues, but prolonged incubation times and lack of PrPSc in lymphoid tissue. These results are important for science based policy with regard to testing of sheep for scrapie where some live animal testing is conducted using lymphoid tissues which would not detect scrapie in some specific genetic types which could limit the national scrapie eradication program.

 

Review Publications Greenlee J.J. 2014. The prion diseases of animals. In: McManus, L.M., Mitchell, R.N., editors. Pathobiology of Human Disease. San Diego: Elsevier. p. 1124-1133.

 

 Greenlee, J.J., Kunkle, R.A., Richt, J.A., Nicholson, E.M., Hamir, A.N. 2014. Lack of prion accumulation in lymphoid tissues of PRNP ARQ/ARR sheep intracranially inoculated with the agent of scrapie. PLoS One. 9(9):e108029.

 

Greenlee, J.J., West Greenlee, M.,H. 2015. The transmissible spongiform encephalopathies of livestock. ILAR Journal. 56(1):7-25.

 

Munoz-Gutierrez, J.F., Schneider, D.A., Baszler, T.V., Dinkel, K.D., Greenlee, J.J., Nicholson, E.M., Stanton, J.J. 2015. hTERT-immortalized ovine microglia propagate natural scrapie isolates. Virus Research. 198:35-43.

 

Nicholson, E.M. 2015. Detection of the disease-associated form of the prion protein in biological samples. Bioanalysis. 7(2):253-261.

 

West Greenlee, M.H., Smith, J.D., Platt, E.M., Juarez, J.R., Timms, L.L, Greenlee, J.J. 2015. Changes in retinal function and morphology are early clinical signs of disease in cattle with bovine spongiform encephalopathy. PLoS ONE. 10(3):e0119431.

 

Comoy, E.E., Mikol, J., Luccantoni-Freire, S., Correia, E., Lescoutra-Etchegaray, N., Durand, V., Dehen, C., Andreoletti, O., Casalone, C., Richt, J.A., Greenlee, J.J., Baron, T., Benestad, S., Brown, P., Deslys, J. 2015. Transmission of scrapie prions to primate after an extended silent incubation period. Scientific Reports. 5:11573.

 


 

DOI: 10.7589/2014-12-284 Journal of Wildlife Diseases, 51(4), 2015, pp. 801–810 # Wildlife Disease Association 2015

 

AGE AND REPEATED BIOPSY INFLUENCE ANTEMORTEM PRPCWD TESTING IN MULE DEER (ODOCOILEUS HEMIONUS) IN COLORADO, USA

 

Chris Geremia,1,6,7 Jennifer A. Hoeting,2 Lisa L. Wolfe,3 Nathan L. Galloway,4 Michael F. Antolin,4 Terry R. Spraker,5 Michael W. Miller,3 and N. Thompson Hobbs1

 

1 Natural Resource Ecology Laboratory, Graduate Degree Program in Ecology, 1499 Campus Delivery, Colorado State University, Fort Collins, Colorado, 80523, USA 2 Department of Statistics, 1877 Campus Delivery, Colorado State University, Fort Collins, Colorado 80523, USA 3 Colorado Division of Parks andWildlife,Wildlife Health Program, 4330 Laporte Avenue, Fort Collins, Colorado 80521,USA 4 Department of Biology, 1878 Campus Delivery, Colorado State University, Fort Collins, Colorado 80523, USA 5 Colorado State Diagnostics Laboratory, College of Veterinary Medicine, Colorado State University, Fort Collins, Colorado 80523, USA 6 Current address: Yellowstone Center for Resources, P.O. Box 168, Yellowstone National Park, Mammoth Hot Springs, Wyoming 82190, USA 7 Corresponding author (email: chris_geremia@nps.gov)

 

ABSTRACT: Biopsy of rectal mucosa–associated lymphoid tissue provides a useful, but imperfect, live-animal test for chronic wasting disease (CWD) in mule deer (Odocoileus hemionus). It is difficult and expensive to complete these tests on free-ranging animals, and wildlife health managers will benefit from methods that can accommodate test results of varying quality. To this end, we developed a hierarchical Bayesian model to estimate the probability that an individual is infected based on test results. Our model was estimated with the use of data on 210 adult female mule deer repeatedly tested during 2010214. The ability to identify infected individuals correctly declined with age and may have been influenced by repeated biopsy. Fewer isolated lymphoid follicles (where PrPCWD accumulates) were obtained in biopsies of older deer and the proportion of follicles showing PrPCWD was reduced. A deer’s genotype in the prion gene (PRNP) also influenced detection. At least five follicles were needed in a biopsy to assure a 95%accurate test in PRNP genotype 225SS deer.

 

Key words: Bayesian, capture–mark–recapture, chronic wasting disease, mule deer, prion, test sensitivity.

 

snip...

 

DISCUSSION

 

Reliably detecting prion infection inmule deer requires some consideration of sample quality. Our findings resemble earlier work suggesting examination of at least nine lymphoid follicles in a tonsil biopsy might be necessary to determine CWD status in mule deer accurately (Wolfe et al. 2002).We found that examining five follicles in a rectal biopsy of 225SS mule deer, regardless of age, should ensure 95% probability of an accurate test; negative results were less conclusive for deer genotypes including phenylalanine (225SF, 225FF). Importantly, examining fewer follicles providedmeaningful, but less certain information about the disease status of the individual. For example, fewer than five follicles were observed in 13 of 31 (42%) tests on animals that were confirmed PrPCWD negative postmortem. These less-conclusive live tests ensured 61% probability of the correct result when one follicle was obtained, and increased to 82% with two follicles, 91% with three, and 94% with four. Likewise, we encountered four apparent false-negative results in 225SS deer. In each case, we could not ensure a 95% accurate test based on deer

 

FIGURE 5. Sum of positive and negative lymphoid follicles detected in rectal-anal mucosa tissue by age in known chronic wasting disease positive female mule deer (Odocoileus hemionus) that were annually captured and tested for chronic wasting disease in north-central Colorado, USA during 2010–14. FIGURE 6. Probabilities of a false-negative test by age for total lymphoid follicles (positive and negative combined) obtained in a rectal-anal mucosa tissue biopsy estimated from a Bayesian model fit to data on female mule deer (Odocoileus hemionus) that were annually captured and tested for chronic wasting disease (CWD) in north-central Colorado, USA during 2010–14. Horizontal lines at 0.01 and 0.05 correspond to 0.99 and 0.95 probability of detecting CWD when animal is CWD positive, respectively.

 

GEREMIA ET AL.—AGE AND CWD TESTING OF LIVE ANIMALS 807

 

age and numbers of follicles in biopsies.

 

Rarely have individual animals infected with prion disease been repeatedly tested after a positive test. Instead, infected animals have generally been presumed to remain positive if retested because postmortem exams have confirmed their infection status (e.g.,Wolfe et al. 2007; Gona´ lez et al. 2008). This belief appears well-founded based on evidence that prion diseases are progressive and that the proportion of positive lymphoid follicles increases over the course of infection (e.g., Fox et al. 2006). Given this well-established pattern, we were surprised that nearly half of the follow-up biopsies collected fromdeer that had already yielded a positive biopsy were negative.

 

Repeated biopsy of the rectal mucosa may have given rise to these false-negative tests. Isolated lymphoid follicles show dynamic properties, including de novo formation in adult animals (Lorenz et al. 2003). Gut-associated lymphoid tissue serves a variety of mucosal barrier defense functions, and isolated lymphoid follicles have been suggested to play a role in mucosal repair (Sipos et al. 2010). If the damage resulting from a biopsy stimulated new isolated lymphoid follicles to form in adjacent rectal mucosa, then the follicles available for subsequent sampling would be a mix of newer and older follicles. Because new follicles (#12 mo old) would not have the same opportunity for prion accumulation as older follicles, their presence in nearby spans of mucosa could dilute or supplant the IHC-positive follicle pool in subsequent samples even as PrPCWD accumulation progressed unabated in static lymphoid structures that remain undisturbed. This phenomenon could explain the static or declining proportion of positive follicles observed in biopsies from some infected individuals that were repeatedly sampled (Fig. 4) as well as the pattern of increasing follicle counts in repeatedly sampled individuals in the face of aging (Fig. 3). If isolated lymphoid follicle formation occurs in response to rectal mucosa biopsy, then repeated sampling could lower the likelihood of detecting infected animals, particularly in individuals genetically inclined toward more gradual disease progression. Alternatively, we implicitly assumed no laboratory errors occurred in the processing of biopsy samples. However, because three of the four false-negative cases came from the same year’s IHC accession, we cannot preclude the possibility of a systematic error somewhere in the course of testing.

 

The decline in the proportion of isolated lymphoid follicles showing PrPCWD in older deer did not appear to be solely the result of repeated testing and associated disruption of tissue structure. Among eight deer that were biopsy positive on first testing, the proportion of follicles showing PrPCWD in 122-yr-old deer was 100% (n52), whereas proportions ranged from 27% to 100% (mean of proportions 63%) in $3-yr-old deer (n56). We speculate that the higher proportion of positive follicles in young mule deer may result from greater activity in the immature lymphatic system or greater exposure because of close association with an infected dam or contaminated environment. Regardless of whether the foregoing observations were an artifact of small sample size, in the absence of repeated biopsy, age appeared to decrease ability to detect infection because fewer isolated lymphoid follicles were obtained in biopsies of older deer.

 

Every test sample is not the same; each individual exhibits unique variation, and the technique for estimating CWD infection that we developed here can account for some of these complications. Disease status becomes a probabilistic statement conditioned on the current test result, previous disease status, and infection and test sensitivity probabilities. Therefore, uncertainty in sampling becomes incorporated into the placement of individuals into discrete disease categories. This step forward allows us to make explicit probabilistic statements

 

808 JOURNAL OF WILDLIFE DISEASES, VOL. 51, NO. 4, OCTOBER 2015

 

about whether an individual is infected and the chance that a test result is correct. With CWD, rather than conclude that an individual is not infected based on a test with few follicles or decide that the test was inconclusive, we can now state the probability that an individual is truly infected.

 

Consequently, we can make conclusions that “a 90% chance exists that this deer is not infected, based on the results.” Surveillance and containment programs for CWD benefit from an ability to diagnose animals correctly with the use of antemortem tests. Our model can easily be applied to surveillance on mule deer, facilitating use of all available samples regardless of total follicle counts. Probabilistic estimates of the infection status of each tested individual could then be used to provide 95% credible intervals of population prevalence that account for differences in test quality. Our model is robust to differences in population prevalence except when prevalence is low (e.g., ,0.02%), because the detection and infection parameters become inestimable.

 

When planning surveillance in areas where disease may not occur, we recommend assuming values for the test detection parameters to allow for estimation of population prevalence. Our approach also has application to CWD screening for transport of wild or captive deer or targeted culling efforts. Individuals could be identified that require additional testing to confirm disease status with desired levels of certainty, although our approach cannot account for misdiagnosing deer in early stages of infection when PrPCWD is undetectable (Wolfe et al. 2002, 2007). In light of our findings, further attention to the potential for repeated sampling to lower the probability of detecting infection via rectal mucosa biopsy appears warranted before such approaches are substituted for more conventional surveillance that relies on samples collected postmortem.

 


 

 CHRONIC WASTING DISEASE CWD TSE PRION AKA MAD COW TYPE DISEASE

 

Friday, January 01, 2016

 

Bayesian Modeling of Prion Disease Dynamics in Mule Deer Using Population Monitoring and Capture-Recapture Data

 

Chris Geremia, Michael W. Miller, Jennifer A. Hoeting, Michael F. Antolin, N. Thompson Hobbs PLOS x Published: October 28, 2015 DOI: 10.1371/journal.pone.0140687

 

Abstract

 

Epidemics of chronic wasting disease (CWD) of North American Cervidae have potential to harm ecosystems and economies. We studied a migratory population of mule deer (Odocoileus hemionus) affected by CWD for at least three decades using a Bayesian framework to integrate matrix population and disease models with long-term monitoring data and detailed process-level studies. We hypothesized CWD prevalence would be stable or increase between two observation periods during the late 1990s and after 2010, with higher CWD prevalence making deer population decline more likely. The weight of evidence suggested a reduction in the CWD outbreak over time, perhaps in response to intervening harvest-mediated population reductions. Disease effects on deer population growth under current conditions were subtle with a 72% chance that CWD depressed population growth. With CWD, we forecasted a growth rate near one and largely stable deer population. Disease effects appear to be moderated by timing of infection, prolonged disease course, and locally variable infection. Long-term outcomes will depend heavily on whether current conditions hold and high prevalence remains a localized phenomenon.

 

Discussion

 

The protracted time-scale of the CWD outbreak is much longer than the timespan of our research, which limits our ability to identify the true explanation of our findings. Nonetheless, our research suggests that, at least for the foreseeable future (e.g., decades), mule deer populations sharing the overall survival and infection probabilities estimated from our analyses may persist but likely will not thrive where CWD becomes established as an endemic infectious disease.

 


 

‘’Nonetheless, our research suggests that, at least for the foreseeable future (e.g., decades), mule deer populations sharing the overall survival and infection probabilities estimated from our analyses may persist but likely will not thrive where CWD becomes established as an endemic infectious disease. ‘’

 

*** Bayesian Modeling of Prion Disease Dynamics in Mule Deer Using Population Monitoring and Capture-Recapture Data

 

‘’Mountain lions prey selectively on CWD infected deer [33] and CWD could result in an abundance of vulnerable prey, thereby enhancing mountain lion survival and reproduction [20].’’

 

please see ;

 

‘’preliminary results suggesting that bobcats (Lynx rufus) may be susceptible to white-tailed deer (Odocoileus virginianus) chronic wasting disease agent.’’

 

references on Feline Spongiform Encephalopathy FSE toward the bottom, see ;

 

Assessing Transmissible Spongiform Encephalopathy Species Barriers with an In Vitro Prion Protein Conversion Assay

 

Tuesday, December 15, 2015

 

Chronic Wasting Disease will cause a Wyoming deer herd to go virtually extinct in 41 years, a five-year study predicts

 

Study: Chronic Wasting Disease kills 19% of deer herd annually

 


 

Research Project: TRANSMISSION, DIFFERENTIATION, AND PATHOBIOLOGY OF TRANSMISSIBLE SPONGIFORM ENCEPHALOPATHIES

 

***Title: Transmission of chronic wasting disease to sentinel reindeer (Rangifer tarandus tarandus)

 

Authors

 

item Moore, S - item Kunkle, Robert item Nicholson, Eric item Richt, Juergen item Hamir, Amirali item Waters, Wade item Greenlee, Justin

 

Submitted to: American College of Veterinary Pathologists Meeting Publication Type: Abstract Only Publication Acceptance Date: August 12, 2015 Publication Date: N/A

 

Technical Abstract:

 

Chronic wasting disease (CWD) is a naturally-occurring, fatal neurodegenerative disease of North American cervids. Reindeer (Rangifer tarandus tarandus) are susceptible to CWD following oral challenge, but CWD has not been reported in free-ranging caribou (Rangifer tarandus caribou) or farmed reindeer. Potential contact between CWD-affected cervids and Rangifer species that are free-ranging or co-housed on farms presents a potential risk of CWD transmission. The aims of this study were to 1) investigate the transmission of CWD from white-tailed deer (Odocoileus virginianus; CWD-wtd), mule deer (Odocoileus hemionus; CWD-md), or elk (Cervus elaphus nelsoni; CWD-elk) to reindeer via the intracranial route, and 2) to assess for direct and indirect horizontal transmission to non-inoculated sentinels. Three groups of 5 reindeer fawns were challenged intracranially with CWD-wtd, CWD-md, or CWD-elk. Two years after challenge of inoculated reindeer, non-inoculated control reindeer were introduced into the same pen as the CWD-wtd inoculated reindeer (n=4) or into a pen adjacent to the CWD-md inoculated reindeer (n=2). Reindeer were allowed to develop clinical disease. At death/euthanasia a complete necropsy examination was performed, including immunohistochemical testing of tissues for disease-associated CWD prion protein (PrP-CWD). Intracranially challenged reindeer developed clinical disease from 21 months post-inoculation (MPI). PrP-CWD was detected in 5/6 sentinel reindeer although only 2/6 developed clinical disease during the study period (<57 div="" mpi="">

 

***We have shown that reindeer are susceptible to CWD from various cervid sources and can transmit CWD to naive reindeer both directly and indirectly.

 

Last Modified: 12/3/2015

 


 

***PrP-CWD was detected in 5/6 sentinel reindeer although only 2/6 developed clinical disease during the study period (<57 div="" mpi="">

 

***We have shown that reindeer are susceptible to CWD from various cervid sources and can transmit CWD to naive reindeer both directly and indirectly.

 

Tuesday, September 29, 2015

 

*** Transmission of chronic wasting disease to sentinel reindeer (Rangifer tarandus tarandus) can transmit CWD to naive reindeer both directly and indirectly

 

Research Project: TRANSMISSION, DIFFERENTIATION, AND PATHOBIOLOGY OF TRANSMISSIBLE SPONGIFORM ENCEPHALOPATHIES

 


 

*** Infectious agent of sheep scrapie may persist in the environment for at least 16 years ***

 

Gudmundur Georgsson1, Sigurdur Sigurdarson2 and Paul Brown3

 


 

*** Spraker suggested an interesting explanation for the occurrence of CWD. The deer pens at the Foot Hills Campus were built some 30-40 years ago by a Dr. Bob Davis. At or abut that time, allegedly, some scrapie work was conducted at this site. When deer were introduced to the pens they occupied ground that had previously been occupied by sheep.

 


 

PL1

 

Using in vitro prion replication for high sensitive detection of prions and prionlike proteins and for understanding mechanisms of transmission.

 

Claudio Soto

 

Mitchell Center for Alzheimer's diseases and related Brain disorders, Department of Neurology, University of Texas Medical School at Houston.

 

Prion and prion-like proteins are misfolded protein aggregates with the ability to selfpropagate to spread disease between cells, organs and in some cases across individuals. I n T r a n s m i s s i b l e s p o n g i f o r m encephalopathies (TSEs), prions are mostly composed by a misfolded form of the prion protein (PrPSc), which propagates by transmitting its misfolding to the normal prion protein (PrPC). The availability of a procedure to replicate prions in the laboratory may be important to study the mechanism of prion and prion-like spreading and to develop high sensitive detection of small quantities of misfolded proteins in biological fluids, tissues and environmental samples. Protein Misfolding Cyclic Amplification (PMCA) is a simple, fast and efficient methodology to mimic prion replication in the test tube. PMCA is a platform technology that may enable amplification of any prion-like misfolded protein aggregating through a seeding/nucleation process. In TSEs, PMCA is able to detect the equivalent of one single molecule of infectious PrPSc and propagate prions that maintain high infectivity, strain properties and species specificity. Using PMCA we have been able to detect PrPSc in blood and urine of experimentally infected animals and humans affected by vCJD with high sensitivity and specificity. Recently, we have expanded the principles of PMCA to amplify amyloid-beta (Aβ) and alphasynuclein (α-syn) aggregates implicated in Alzheimer's and Parkinson's diseases, respectively. Experiments are ongoing to study the utility of this technology to detect Aβ and α-syn aggregates in samples of CSF and blood from patients affected by these diseases.

 

=========================

 

***Recently, we have been using PMCA to study the role of environmental prion contamination on the horizontal spreading of TSEs. These experiments have focused on the study of the interaction of prions with plants and environmentally relevant surfaces. Our results show that plants (both leaves and roots) bind tightly to prions present in brain extracts and excreta (urine and feces) and retain even small quantities of PrPSc for long periods of time. Strikingly, ingestion of prioncontaminated leaves and roots produced disease with a 100% attack rate and an incubation period not substantially longer than feeding animals directly with scrapie brain homogenate. Furthermore, plants can uptake prions from contaminated soil and transport them to different parts of the plant tissue (stem and leaves). Similarly, prions bind tightly to a variety of environmentally relevant surfaces, including stones, wood, metals, plastic, glass, cement, etc. Prion contaminated surfaces efficiently transmit prion disease when these materials were directly injected into the brain of animals and strikingly when the contaminated surfaces were just placed in the animal cage. These findings demonstrate that environmental materials can efficiently bind infectious prions and act as carriers of infectivity, suggesting that they may play an important role in the horizontal transmission of the disease.

 

========================

 

Since its invention 13 years ago, PMCA has helped to answer fundamental questions of prion propagation and has broad applications in research areas including the food industry, blood bank safety and human and veterinary disease diagnosis.

 


 

see ;

 


 


 


 


 


 

Wednesday, December 16, 2015

 

Objects in contact with classical scrapie sheep act as a reservoir for scrapie transmission

 

Objects in contact with classical scrapie sheep act as a reservoir for scrapie transmission

 

Timm Konold1*, Stephen A. C. Hawkins2, Lisa C. Thurston3, Ben C. Maddison4, Kevin C. Gough5, Anthony Duarte1 and Hugh A. Simmons1

 

1 Animal Sciences Unit, Animal and Plant Health Agency Weybridge, Addlestone, UK, 2 Pathology Department, Animal and Plant Health Agency Weybridge, Addlestone, UK, 3 Surveillance and Laboratory Services, Animal and Plant Health Agency Penrith, Penrith, UK, 4 ADAS UK, School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington, UK, 5 School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington, UK

 

Classical scrapie is an environmentally transmissible prion disease of sheep and goats. Prions can persist and remain potentially infectious in the environment for many years and thus pose a risk of infecting animals after re-stocking. In vitro studies using serial protein misfolding cyclic amplification (sPMCA) have suggested that objects on a scrapie affected sheep farm could contribute to disease transmission. This in vivo study aimed to determine the role of field furniture (water troughs, feeding troughs, fencing, and other objects that sheep may rub against) used by a scrapie-infected sheep flock as a vector for disease transmission to scrapie-free lambs with the prion protein genotype VRQ/VRQ, which is associated with high susceptibility to classical scrapie. When the field furniture was placed in clean accommodation, sheep became infected when exposed to either a water trough (four out of five) or to objects used for rubbing (four out of seven). This field furniture had been used by the scrapie-infected flock 8 weeks earlier and had previously been shown to harbor scrapie prions by sPMCA. Sheep also became infected (20 out of 23) through exposure to contaminated field furniture placed within pasture not used by scrapie-infected sheep for 40 months, even though swabs from this furniture tested negative by PMCA. This infection rate decreased (1 out of 12) on the same paddock after replacement with clean field furniture. Twelve grazing sheep exposed to field furniture not in contact with scrapie-infected sheep for 18 months remained scrapie free. The findings of this study highlight the role of field furniture used by scrapie-infected sheep to act as a reservoir for disease re-introduction although infectivity declines considerably if the field furniture has not been in contact with scrapie-infected sheep for several months. PMCA may not be as sensitive as VRQ/VRQ sheep to test for environmental contamination.

 

snip...

 

Discussion

 

Classical scrapie is an environmentally transmissible disease because it has been reported in naïve, supposedly previously unexposed sheep placed in pastures formerly occupied by scrapie-infected sheep (4, 19, 20). Although the vector for disease transmission is not known, soil is likely to be an important reservoir for prions (2) where – based on studies in rodents – prions can adhere to minerals as a biologically active form (21) and remain infectious for more than 2 years (22). Similarly, chronic wasting disease (CWD) has re-occurred in mule deer housed in paddocks used by infected deer 2 years earlier, which was assumed to be through foraging and soil consumption (23).

 

Our study suggested that the risk of acquiring scrapie infection was greater through exposure to contaminated wooden, plastic, and metal surfaces via water or food troughs, fencing, and hurdles than through grazing. Drinking from a water trough used by the scrapie flock was sufficient to cause infection in sheep in a clean building. Exposure to fences and other objects used for rubbing also led to infection, which supported the hypothesis that skin may be a vector for disease transmission (9). The risk of these objects to cause infection was further demonstrated when 87% of 23 sheep presented with PrPSc in lymphoid tissue after grazing on one of the paddocks, which contained metal hurdles, a metal lamb creep and a water trough in contact with the scrapie flock up to 8 weeks earlier, whereas no infection had been demonstrated previously in sheep grazing on this paddock, when equipped with new fencing and field furniture. When the contaminated furniture and fencing were removed, the infection rate dropped significantly to 8% of 12 sheep, with soil of the paddock as the most likely source of infection caused by shedding of prions from the scrapie-infected sheep in this paddock up to a week earlier.

 

This study also indicated that the level of contamination of field furniture sufficient to cause infection was dependent on two factors: stage of incubation period and time of last use by scrapie-infected sheep. Drinking from a water trough that had been used by scrapie sheep in the predominantly pre-clinical phase did not appear to cause infection, whereas infection was shown in sheep drinking from the water trough used by scrapie sheep in the later stage of the disease. It is possible that contamination occurred through shedding of prions in saliva, which may have contaminated the surface of the water trough and subsequently the water when it was refilled. Contamination appeared to be sufficient to cause infection only if the trough was in contact with sheep that included clinical cases. Indeed, there is an increased risk of bodily fluid infectivity with disease progression in scrapie (24) and CWD (25) based on PrPSc detection by sPMCA. Although ultraviolet light and heat under natural conditions do not inactivate prions (26), furniture in contact with the scrapie flock, which was assumed to be sufficiently contaminated to cause infection, did not act as vector for disease if not used for 18 months, which suggest that the weathering process alone was sufficient to inactivate prions.

 

PrPSc detection by sPMCA is increasingly used as a surrogate for infectivity measurements by bioassay in sheep or mice. In this reported study, however, the levels of PrPSc present in the environment were below the limit of detection of the sPMCA method, yet were still sufficient to cause infection of in-contact animals. In the present study, the outdoor objects were removed from the infected flock 8 weeks prior to sampling and were positive by sPMCA at very low levels (2 out of 37 reactions). As this sPMCA assay also yielded 2 positive reactions out of 139 in samples from the scrapie-free farm, the sPMCA assay could not detect PrPSc on any of the objects above the background of the assay. False positive reactions with sPMCA at a low frequency associated with de novo formation of infectious prions have been reported (27, 28). This is in contrast to our previous study where we demonstrated that outdoor objects that had been in contact with the scrapie-infected flock up to 20 days prior to sampling harbored PrPSc that was detectable by sPMCA analysis [4 out of 15 reactions (12)] and was significantly more positive by the assay compared to analogous samples from the scrapie-free farm. This discrepancy could be due to the use of a different sPMCA substrate between the studies that may alter the efficiency of amplification of the environmental PrPSc. In addition, the present study had a longer timeframe between the objects being in contact with the infected flock and sampling, which may affect the levels of extractable PrPSc. Alternatively, there may be potentially patchy contamination of this furniture with PrPSc, which may have been missed by swabbing. The failure of sPMCA to detect CWD-associated PrP in saliva from clinically affected deer despite confirmation of infectivity in saliva-inoculated transgenic mice was associated with as yet unidentified inhibitors in saliva (29), and it is possible that the sensitivity of sPMCA is affected by other substances in the tested material. In addition, sampling of amplifiable PrPSc and subsequent detection by sPMCA may be more difficult from furniture exposed to weather, which is supported by the observation that PrPSc was detected by sPMCA more frequently in indoor than outdoor furniture (12). A recent experimental study has demonstrated that repeated cycles of drying and wetting of prion-contaminated soil, equivalent to what is expected under natural weathering conditions, could reduce PMCA amplification efficiency and extend the incubation period in hamsters inoculated with soil samples (30). This seems to apply also to this study even though the reduction in infectivity was more dramatic in the sPMCA assays than in the sheep model. Sheep were not kept until clinical end-point, which would have enabled us to compare incubation periods, but the lack of infection in sheep exposed to furniture that had not been in contact with scrapie sheep for a longer time period supports the hypothesis that prion degradation and subsequent loss of infectivity occurs even under natural conditions.

 

In conclusion, the results in the current study indicate that removal of furniture that had been in contact with scrapie-infected animals should be recommended, particularly since cleaning and decontamination may not effectively remove scrapie infectivity (31), even though infectivity declines considerably if the pasture and the field furniture have not been in contact with scrapie-infected sheep for several months. As sPMCA failed to detect PrPSc in furniture that was subjected to weathering, even though exposure led to infection in sheep, this method may not always be reliable in predicting the risk of scrapie infection through environmental contamination. These results suggest that the VRQ/VRQ sheep model may be more sensitive than sPMCA for the detection of environmentally associated scrapie, and suggest that extremely low levels of scrapie contamination are able to cause infection in susceptible sheep genotypes.

 

Keywords: classical scrapie, prion, transmissible spongiform encephalopathy, sheep, field furniture, reservoir, serial protein misfolding cyclic amplification

 


 

Wednesday, December 16, 2015

 

*** Objects in contact with classical scrapie sheep act as a reservoir for scrapie transmission ***

 


 

Circulation of prions within dust on a scrapie affected farm

 

Kevin C Gough1, Claire A Baker2, Hugh A Simmons3, Steve A Hawkins3 and Ben C Maddison2*

 

Abstract

 

Prion diseases are fatal neurological disorders that affect humans and animals. Scrapie of sheep/goats and Chronic Wasting Disease (CWD) of deer/elk are contagious prion diseases where environmental reservoirs have a direct link to the transmission of disease. Using protein misfolding cyclic amplification we demonstrate that scrapie PrPSc can be detected within circulating dusts that are present on a farm that is naturally contaminated with sheep scrapie. The presence of infectious scrapie within airborne dusts may represent a possible route of infection and illustrates the difficulties that may be associated with the effective decontamination of such scrapie affected premises.

 

snip...

 

Discussion

 

We present biochemical data illustrating the airborne movement of scrapie containing material within a contaminated farm environment. We were able to detect scrapie PrPSc within extracts from dusts collected over a 70 day period, in the absence of any sheep activity. We were also able to detect scrapie PrPSc within dusts collected within pasture at 30 m but not at 60 m distance away from the scrapie contaminated buildings, suggesting that the chance of contamination of pasture by scrapie contaminated dusts decreases with distance from contaminated farm buildings. PrPSc amplification by sPMCA has been shown to correlate with infectivity and amplified products have been shown to be infectious [14,15]. These experiments illustrate the potential for low dose scrapie infectivity to be present within such samples. We estimate low ng levels of scrapie positive brain equivalent were deposited per m2 over 70 days, in a barn previously occupied by sheep affected with scrapie. This movement of dusts and the accumulation of low levels of scrapie infectivity within this environment may in part explain previous observations where despite stringent pen decontamination regimens healthy lambs still became scrapie infected after apparent exposure from their environment alone [16]. The presence of sPMCA seeding activity and by inference, infectious prions within dusts, and their potential for airborne dissemination is highly novel and may have implications for the spread of scrapie within infected premises. The low level circulation and accumulation of scrapie prion containing dust material within the farm environment will likely impede the efficient decontamination of such scrapie contaminated buildings unless all possible reservoirs of dust are removed. Scrapie containing dusts could possibly infect animals during feeding and drinking, and respiratory and conjunctival routes may also be involved. It has been demonstrated that scrapie can be efficiently transmitted via the nasal route in sheep [17], as is also the case for CWD in both murine models and in white tailed deer [18-20].

 

The sources of dust borne prions are unknown but it seems reasonable to assume that faecal, urine, skin, parturient material and saliva-derived prions may contribute to this mobile environmental reservoir of infectivity. This work highlights a possible transmission route for scrapie within the farm environment, and this is likely to be paralleled in CWD which shows strong similarities with scrapie in terms of prion dissemination and disease transmission. The data indicate that the presence of scrapie prions in dust is likely to make the control of these diseases a considerable challenge.

 


 

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

 

snip...

 

In the USA, under the Food and Drug Administration’s BSE Feed Regulation (21 CFR 589.2000) most material (exceptions include milk, tallow, and gelatin) from deer and elk is prohibited for use in feed for ruminant animals. With regards to feed for non-ruminant animals, under FDA law, CWD positive deer may not be used for any animal feed or feed ingredients. For elk and deer considered at high risk for CWD, the FDA recommends that these animals do not enter the animal feed system. However, this recommendation is guidance and not a requirement by law.

 

Animals considered at high risk for CWD include:

 

1) animals from areas declared to be endemic for CWD and/or to be CWD eradication zones and

 

2) deer and elk that at some time during the 60-month period prior to slaughter were in a captive herd that contained a CWD-positive animal.

 

Therefore, in the USA, materials from cervids other than CWD positive animals may be used in animal feed and feed ingredients for non-ruminants.

 

The amount of animal PAP that is of deer and/or elk origin imported from the USA to GB can not be determined, however, as it is not specified in TRACES. It may constitute a small percentage of the 8412 kilos of non-fish origin processed animal proteins that were imported from US into GB in 2011.

 

Overall, therefore, it is considered there is a __greater than negligible risk___ that (nonruminant) animal feed and pet food containing deer and/or elk protein is imported into GB.

 

There is uncertainty associated with this estimate given the lack of data on the amount of deer and/or elk protein possibly being imported in these products.

 

snip...

 

36% in 2007 (Almberg et al., 2011). In such areas, population declines of deer of up to 30 to 50% have been observed (Almberg et al., 2011). In areas of Colorado, the prevalence can be as high as 30% (EFSA, 2011). The clinical signs of CWD in affected adults are weight loss and behavioural changes that can span weeks or months (Williams, 2005). In addition, signs might include excessive salivation, behavioural alterations including a fixed stare and changes in interaction with other animals in the herd, and an altered stance (Williams, 2005). These signs are indistinguishable from cervids experimentally infected with bovine spongiform encephalopathy (BSE). Given this, if CWD was to be introduced into countries with BSE such as GB, for example, infected deer populations would need to be tested to differentiate if they were infected with CWD or BSE to minimise the risk of BSE entering the human food-chain via affected venison.

 

snip...

 

The rate of transmission of CWD has been reported to be as high as 30% and can approach 100% among captive animals in endemic areas (Safar et al., 2008).

 

snip...

 

In summary, in endemic areas, there is a medium probability that the soil and surrounding environment is contaminated with CWD prions and in a bioavailable form. In rural areas where CWD has not been reported and deer are present, there is a greater than negligible risk the soil is contaminated with CWD prion.

 

snip...

 

In summary, given the volume of tourists, hunters and servicemen moving between GB and North America, the probability of at least one person travelling to/from a CWD affected area and, in doing so, contaminating their clothing, footwear and/or equipment prior to arriving in GB is greater than negligible. For deer hunters, specifically, the risk is likely to be greater given the increased contact with deer and their environment. However, there is significant uncertainty associated with these estimates.

 

snip...

 

Therefore, it is considered that farmed and park deer may have a higher probability of exposure to CWD transferred to the environment than wild deer given the restricted habitat range and higher frequency of contact with tourists and returning GB residents.

 

snip...

 


 

Saturday, January 31, 2015

 

European red deer (Cervus elaphus elaphus) are susceptible to Bovine Spongiform Encephalopathy BSE by Oral Alimentary route

 


 

I strenuously once again urge the FDA and its industry constituents, to make it MANDATORY that all ruminant feed be banned to all ruminants, and this should include all cervids as soon as possible for the following reasons...

 

======

 

In the USA, under the Food and Drug Administrations BSE Feed Regulation (21 CFR 589.2000) most material (exceptions include milk, tallow, and gelatin) from deer and elk is prohibited for use in feed for ruminant animals. With regards to feed for non-ruminant animals, under FDA law, CWD positive deer may not be used for any animal feed or feed ingredients. For elk and deer considered at high risk for CWD, the FDA recommends that these animals do not enter the animal feed system.

 

***However, this recommendation is guidance and not a requirement by law.

 

======

 

31 Jan 2015 at 20:14 GMT

 

*** Ruminant feed ban for cervids in the United States? ***

 

31 Jan 2015 at 20:14 GMT

 


 

Research Project: TRANSMISSION, DIFFERENTIATION, AND PATHOBIOLOGY OF TRANSMISSIBLE SPONGIFORM ENCEPHALOPATHIES

 

Title: Scrapie transmits to white-tailed deer by the oral route and has a molecular profile similar to chronic wasting disease

 

Authors

 

item Greenlee, Justin item Moore, S - item Smith, Jodi - item Kunkle, Robert item West Greenlee, M -

 

Submitted to: American College of Veterinary Pathologists Meeting Publication Type: Abstract Only Publication Acceptance Date: August 12, 2015 Publication Date: N/A Technical Abstract: The purpose of this work was to determine susceptibility of white-tailed deer (WTD) to the agent of sheep scrapie and to compare the resultant PrPSc to that of the original inoculum and chronic wasting disease (CWD). We inoculated WTD by a natural route of exposure (concurrent oral and intranasal (IN); n=5) with a US scrapie isolate. All scrapie-inoculated deer had evidence of PrPSc accumulation. PrPSc was detected in lymphoid tissues at preclinical time points, and deer necropsied after 28 months post-inoculation had clinical signs, spongiform encephalopathy, and widespread distribution of PrPSc in neural and lymphoid tissues. Western blotting (WB) revealed PrPSc with 2 distinct molecular profiles. WB on cerebral cortex had a profile similar to the original scrapie inoculum, whereas WB of brainstem, cerebellum, or lymph nodes revealed PrPSc with a higher profile resembling CWD. Homogenates with the 2 distinct profiles from WTD with clinical scrapie were further passaged to mice expressing cervid prion protein and intranasally to sheep and WTD. In cervidized mice, the two inocula have distinct incubation times. Sheep inoculated intranasally with WTD derived scrapie developed disease, but only after inoculation with the inoculum that had a scrapie-like profile. The WTD study is ongoing, but deer in both inoculation groups are positive for PrPSc by rectal mucosal biopsy. In summary, this work demonstrates that WTD are susceptible to the agent of scrapie, two distinct molecular profiles of PrPSc are present in the tissues of affected deer, and inoculum of either profile readily passes to deer.

 


 


 

White-tailed Deer are Susceptible to Scrapie by Natural Route of Infection

 

Jodi D. Smith, Justin J. Greenlee, and Robert A. Kunkle; Virus and Prion Research Unit, National Animal Disease Center, USDA-ARS

 

Interspecies transmission studies afford the opportunity to better understand the potential host range and origins of prion diseases. Previous experiments demonstrated that white-tailed deer are susceptible to sheep-derived scrapie by intracranial inoculation. The purpose of this study was to determine susceptibility of white-tailed deer to scrapie after a natural route of exposure. Deer (n=5) were inoculated by concurrent oral (30 ml) and intranasal (1 ml) instillation of a 10% (wt/vol) brain homogenate derived from a sheep clinically affected with scrapie. Non-inoculated deer were maintained as negative controls. All deer were observed daily for clinical signs. Deer were euthanized and necropsied when neurologic disease was evident, and tissues were examined for abnormal prion protein (PrPSc) by immunohistochemistry (IHC) and western blot (WB). One animal was euthanized 15 months post-inoculation (MPI) due to an injury. At that time, examination of obex and lymphoid tissues by IHC was positive, but WB of obex and colliculus were negative. Remaining deer developed clinical signs of wasting and mental depression and were necropsied from 28 to 33 MPI. Tissues from these deer were positive for scrapie by IHC and WB. Tissues with PrPSc immunoreactivity included brain, tonsil, retropharyngeal and mesenteric lymph nodes, hemal node, Peyer’s patches, and spleen. This work demonstrates for the first time that white-tailed deer are susceptible to sheep scrapie by potential natural routes of inoculation. In-depth analysis of tissues will be done to determine similarities between scrapie in deer after intracranial and oral/intranasal inoculation and chronic wasting disease resulting from similar routes of inoculation.

 

see full text ;

 


 

PO-039: A comparison of scrapie and chronic wasting disease in white-tailed deer

 

Justin Greenlee, Jodi Smith, Eric Nicholson US Dept. Agriculture; Agricultural Research Service, National Animal Disease Center; Ames, IA USA

 


 

White-tailed deer are susceptible to the agent of sheep scrapie by intracerebral inoculation

 

snip...

 

It is unlikely that CWD will be eradicated from free-ranging cervids, and the disease is likely to continue to spread geographically [10]. However, the potential that white-tailed deer may be susceptible to sheep scrapie by a natural route presents an additional confounding factor to halting the spread of CWD. This leads to the additional speculations that

 

1) infected deer could serve as a reservoir to infect sheep with scrapie offering challenges to scrapie eradication efforts and

 

2) CWD spread need not remain geographically confined to current endemic areas, but could occur anywhere that sheep with scrapie and susceptible cervids cohabitate.

 

This work demonstrates for the first time that white-tailed deer are susceptible to sheep scrapie by intracerebral inoculation with a high attack rate and that the disease that results has similarities to CWD. These experiments will be repeated with a more natural route of inoculation to determine the likelihood of the potential transmission of sheep scrapie to white-tailed deer. If scrapie were to occur in white-tailed deer, results of this study indicate that it would be detected as a TSE, but may be difficult to differentiate from CWD without in-depth biochemical analysis.

 


 


 

2012

 

PO-039: A comparison of scrapie and chronic wasting disease in white-tailed deer

 

Justin Greenlee, Jodi Smith, Eric Nicholson US Dept. Agriculture; Agricultural Research Service, National Animal Disease Center; Ames, IA USA

 

snip...

 

The results of this study suggest that there are many similarities in the manifestation of CWD and scrapie in WTD after IC inoculation including early and widespread presence of PrPSc in lymphoid tissues, clinical signs of depression and weight loss progressing to wasting, and an incubation time of 21-23 months. Moreover, western blots (WB) done on brain material from the obex region have a molecular profile similar to CWD and distinct from tissues of the cerebrum or the scrapie inoculum. However, results of microscopic and IHC examination indicate that there are differences between the lesions expected in CWD and those that occur in deer with scrapie: amyloid plaques were not noted in any sections of brain examined from these deer and the pattern of immunoreactivity by IHC was diffuse rather than plaque-like.

 

*** After a natural route of exposure, 100% of WTD were susceptible to scrapie.

 

Deer developed clinical signs of wasting and mental depression and were necropsied from 28 to 33 months PI. Tissues from these deer were positive for PrPSc by IHC and WB. Similar to IC inoculated deer, samples from these deer exhibited two different molecular profiles: samples from obex resembled CWD whereas those from cerebrum were similar to the original scrapie inoculum. On further examination by WB using a panel of antibodies, the tissues from deer with scrapie exhibit properties differing from tissues either from sheep with scrapie or WTD with CWD. Samples from WTD with CWD or sheep with scrapie are strongly immunoreactive when probed with mAb P4, however, samples from WTD with scrapie are only weakly immunoreactive. In contrast, when probed with mAb’s 6H4 or SAF 84, samples from sheep with scrapie and WTD with CWD are weakly immunoreactive and samples from WTD with scrapie are strongly positive. This work demonstrates that WTD are highly susceptible to sheep scrapie, but on first passage, scrapie in WTD is differentiable from CWD.

 


 

2011

 

*** After a natural route of exposure, 100% of white-tailed deer were susceptible to scrapie.

 


 

White-tailed Deer are Susceptible to Scrapie by Natural Route of Infection

 

Jodi D. Smith, Justin J. Greenlee, and Robert A. Kunkle; Virus and Prion Research Unit, National Animal Disease Center, USDA-ARS

 

Interspecies transmission studies afford the opportunity to better understand the potential host range and origins of prion diseases. Previous experiments demonstrated that white-tailed deer are susceptible to sheep-derived scrapie by intracranial inoculation. The purpose of this study was to determine susceptibility of white-tailed deer to scrapie after a natural route of exposure. Deer (n=5) were inoculated by concurrent oral (30 ml) and intranasal (1 ml) instillation of a 10% (wt/vol) brain homogenate derived from a sheep clinically affected with scrapie. Non-inoculated deer were maintained as negative controls. All deer were observed daily for clinical signs. Deer were euthanized and necropsied when neurologic disease was evident, and tissues were examined for abnormal prion protein (PrPSc) by immunohistochemistry (IHC) and western blot (WB). One animal was euthanized 15 months post-inoculation (MPI) due to an injury. At that time, examination of obex and lymphoid tissues by IHC was positive, but WB of obex and colliculus were negative. Remaining deer developed clinical signs of wasting and mental depression and were necropsied from 28 to 33 MPI. Tissues from these deer were positive for scrapie by IHC and WB. Tissues with PrPSc immunoreactivity included brain, tonsil, retropharyngeal and mesenteric lymph nodes, hemal node, Peyer’s patches, and spleen. This work demonstrates for the first time that white-tailed deer are susceptible to sheep scrapie by potential natural routes of inoculation. In-depth analysis of tissues will be done to determine similarities between scrapie in deer after intracranial and oral/intranasal inoculation and chronic wasting disease resulting from similar routes of inoculation.

 

see full text ;

 


 

PL1

 

Using in vitro prion replication for high sensitive detection of prions and prionlike proteins and for understanding mechanisms of transmission.

 

Claudio Soto

 

Mitchell Center for Alzheimer's diseases and related Brain disorders, Department of Neurology, University of Texas Medical School at Houston.

 

Prion and prion-like proteins are misfolded protein aggregates with the ability to selfpropagate to spread disease between cells, organs and in some cases across individuals. I n T r a n s m i s s i b l e s p o n g i f o r m encephalopathies (TSEs), prions are mostly composed by a misfolded form of the prion protein (PrPSc), which propagates by transmitting its misfolding to the normal prion protein (PrPC). The availability of a procedure to replicate prions in the laboratory may be important to study the mechanism of prion and prion-like spreading and to develop high sensitive detection of small quantities of misfolded proteins in biological fluids, tissues and environmental samples. Protein Misfolding Cyclic Amplification (PMCA) is a simple, fast and efficient methodology to mimic prion replication in the test tube. PMCA is a platform technology that may enable amplification of any prion-like misfolded protein aggregating through a seeding/nucleation process. In TSEs, PMCA is able to detect the equivalent of one single molecule of infectious PrPSc and propagate prions that maintain high infectivity, strain properties and species specificity. Using PMCA we have been able to detect PrPSc in blood and urine of experimentally infected animals and humans affected by vCJD with high sensitivity and specificity. Recently, we have expanded the principles of PMCA to amplify amyloid-beta (Aβ) and alphasynuclein (α-syn) aggregates implicated in Alzheimer's and Parkinson's diseases, respectively. Experiments are ongoing to study the utility of this technology to detect Aβ and α-syn aggregates in samples of CSF and blood from patients affected by these diseases.

 

=========================

 

***Recently, we have been using PMCA to study the role of environmental prion contamination on the horizontal spreading of TSEs. These experiments have focused on the study of the interaction of prions with plants and environmentally relevant surfaces. Our results show that plants (both leaves and roots) bind tightly to prions present in brain extracts and excreta (urine and feces) and retain even small quantities of PrPSc for long periods of time. Strikingly, ingestion of prioncontaminated leaves and roots produced disease with a 100% attack rate and an incubation period not substantially longer than feeding animals directly with scrapie brain homogenate. Furthermore, plants can uptake prions from contaminated soil and transport them to different parts of the plant tissue (stem and leaves). Similarly, prions bind tightly to a variety of environmentally relevant surfaces, including stones, wood, metals, plastic, glass, cement, etc. Prion contaminated surfaces efficiently transmit prion disease when these materials were directly injected into the brain of animals and strikingly when the contaminated surfaces were just placed in the animal cage. These findings demonstrate that environmental materials can efficiently bind infectious prions and act as carriers of infectivity, suggesting that they may play an important role in the horizontal transmission of the disease.

 

========================

 

Since its invention 13 years ago, PMCA has helped to answer fundamental questions of prion propagation and has broad applications in research areas including the food industry, blood bank safety and human and veterinary disease diagnosis.

 


 

see ;

 


 


 


 


 


 

98 | Veterinary Record | January 24, 2015

 

EDITORIAL

 

Scrapie: a particularly persistent pathogen

 

Cristina Acín

 

Resistant prions in the environment have been the sword of Damocles for scrapie control and eradication. Attempts to establish which physical and chemical agents could be applied to inactivate or moderate scrapie infectivity were initiated in the 1960s and 1970s,with the first study of this type focusing on the effect of heat treatment in reducing prion infectivity (Hunter and Millson 1964). Nowadays, most of the chemical procedures that aim to inactivate the prion protein are based on the method developed by Kimberlin and collaborators (1983). This procedure consists of treatment with 20,000 parts per million free chlorine solution, for a minimum of one hour, of all surfaces that need to be sterilised (in laboratories, lambing pens, slaughterhouses, and so on). Despite this, veterinarians and farmers may still ask a range of questions, such as ‘Is there an official procedure published somewhere?’ and ‘Is there an international organisation which recommends and defines the exact method of scrapie decontamination that must be applied?’

 

From a European perspective, it is difficult to find a treatment that could be applied, especially in relation to the disinfection of surfaces in lambing pens of affected flocks. A 999/2001 EU regulation on controlling spongiform encephalopathies (European Parliament and Council 2001) did not specify a particular decontamination measure to be used when an outbreak of scrapie is diagnosed. There is only a brief recommendation in Annex VII concerning the control and eradication of transmissible spongiform encephalopathies (TSE s).

 

Chapter B of the regulation explains the measures that must be applied if new caprine animals are to be introduced to a holding where a scrapie outbreak has previously been diagnosed. In that case, the statement indicates that caprine animals can be introduced ‘provided that a cleaning and disinfection of all animal housing on the premises has been carried out following destocking’.

 

Issues around cleaning and disinfection are common in prion prevention recommendations, but relevant authorities, veterinarians and farmers may have difficulties in finding the specific protocol which applies. The European Food and Safety Authority (EFSA ) published a detailed report about the efficacy of certain biocides, such as sodium hydroxide, sodium hypochlorite, guanidine and even a formulation of copper or iron metal ions in combination with hydrogen peroxide, against prions (EFSA 2009). The report was based on scientific evidence (Fichet and others 2004, Lemmer and others 2004, Gao and others 2006, Solassol and others 2006) but unfortunately the decontamination measures were not assessed under outbreak conditions.

 

The EFSA Panel on Biological Hazards recently published its conclusions on the scrapie situation in the EU after 10 years of monitoring and control of the disease in sheep and goats (EFSA 2014), and one of the most interesting findings was the Icelandic experience regarding the effect of disinfection in scrapie control. The Icelandic plan consisted of: culling scrapie-affected sheep or the whole flock in newly diagnosed outbreaks; deep cleaning and disinfection of stables, sheds, barns and equipment with high pressure washing followed by cleaning with 500 parts per million of hypochlorite; drying and treatment with 300 ppm of iodophor; and restocking was not permitted for at least two years. Even when all of these measures were implemented, scrapie recurred on several farms, indicating that the infectious agent survived for years in the environment, even as many as 16 years after restocking (Georgsson and others 2006).

 

In the rest of the countries considered in the EFSA (2014) report, recommendations for disinfection measures were not specifically defined at the government level. In the report, the only recommendation that is made for sheep is repopulation with sheep with scrapie-resistant genotypes. This reduces the risk of scrapie recurrence but it is difficult to know its effect on the infection.

 

Until the EFSA was established (in May 2003), scientific opinions about TSE s were provided by the Scientific Steering Committee (SSC) of the EC, whose advice regarding inactivation procedures focused on treating animal waste at high temperatures (150°C for three hours) and high pressure alkaline hydrolysis (SSC 2003). At the same time, the TSE Risk Management Subgroup of the Advisory Committee on Dangerous Pathogens (ACDP) in the UK published guidance on safe working and the prevention of TSE infection. Annex C of the ACDP report established that sodium hypochlorite was considered to be effective, but only if 20,000 ppm of available chlorine was present for at least one hour, which has practical limitations such as the release of chlorine gas, corrosion, incompatibility with formaldehyde, alcohols and acids, rapid inactivation of its active chemicals and the stability of dilutions (ACDP 2009).

 

In an international context, the World Organisation for Animal Health (OIE) does not recommend a specific disinfection protocol for prion agents in its Terrestrial Code or Manual. Chapter 4.13 of the Terrestrial Code, General recommendations on disinfection and disinsection (OIE 2014), focuses on foot-and-mouth disease virus, mycobacteria and Bacillus anthracis, but not on prion disinfection. Nevertheless, the last update published by the OIE on bovine spongiform encephalopathy (OIE 2012) indicates that few effective decontamination techniques are available to inactivate the agent on surfaces, and recommends the removal of all organic material and the use of sodium hydroxide, or a sodium hypochlorite solution containing 2 per cent available chlorine, for more than one hour at 20ºC.

 

The World Health Organization outlines guidelines for the control of TSE s, and also emphasises the importance of mechanically cleaning surfaces before disinfection with sodium hydroxide or sodium hypochlorite for one hour (WHO 1999).

 

Finally, the relevant agencies in both Canada and the USA suggest that the best treatments for surfaces potentially contaminated with prions are sodium hydroxide or sodium hypochlorite at 20,000 ppm. This is a 2 per cent solution, while most commercial household bleaches contain 5.25 per cent sodium hypochlorite. It is therefore recommended to dilute one part 5.25 per cent bleach with 1.5 parts water (CDC 2009, Canadian Food Inspection Agency 2013).

 

So what should we do about disinfection against prions? First, it is suggested that a single protocol be created by international authorities to homogenise inactivation procedures and enable their application in all scrapie-affected countries. Sodium hypochlorite with 20,000 ppm of available chlorine seems to be the procedure used in most countries, as noted in a paper summarised on p 99 of this issue of Veterinary Record (Hawkins and others 2015). But are we totally sure of its effectiveness as a preventive measure in a scrapie outbreak? Would an in-depth study of the recurrence of scrapie disease be needed?

 

What we can conclude is that, if we want to fight prion diseases, and specifically classical scrapie, we must focus on the accuracy of diagnosis, monitoring and surveillance; appropriate animal identification and control of movements; and, in the end, have homogeneous and suitable protocols to decontaminate and disinfect lambing barns, sheds and equipment available to veterinarians and farmers. Finally, further investigations into the resistance of prion proteins in the diversity of environmental surfaces are required.

 

References

 

snip...

 

98 | Veterinary Record | January 24, 2015

 


 

Persistence of ovine scrapie infectivity in a farm environment following cleaning and decontamination

 

Steve A. C. Hawkins, MIBiol, Pathology Department1, Hugh A. Simmons, BVSc MRCVS, MBA, MA Animal Services Unit1, Kevin C. Gough, BSc, PhD2 and Ben C. Maddison, BSc, PhD3 + Author Affiliations

 

1Animal and Plant Health Agency, Woodham Lane, New Haw, Addlestone, Surrey KT15 3NB, UK 2School of Veterinary Medicine and Science, The University of Nottingham, Sutton Bonington, Loughborough, Leicestershire LE12 5RD, UK 3ADAS UK, School of Veterinary Medicine and Science, The University of Nottingham, Sutton Bonington, Loughborough, Leicestershire LE12 5RD, UK E-mail for correspondence: ben.maddison@adas.co.uk Abstract Scrapie of sheep/goats and chronic wasting disease of deer/elk are contagious prion diseases where environmental reservoirs are directly implicated in the transmission of disease. In this study, the effectiveness of recommended scrapie farm decontamination regimens was evaluated by a sheep bioassay using buildings naturally contaminated with scrapie. Pens within a farm building were treated with either 20,000 parts per million free chorine solution for one hour or were treated with the same but were followed by painting and full re-galvanisation or replacement of metalwork within the pen. Scrapie susceptible lambs of the PRNP genotype VRQ/VRQ were reared within these pens and their scrapie status was monitored by recto-anal mucosa-associated lymphoid tissue. All animals became infected over an 18-month period, even in the pen that had been subject to the most stringent decontamination process. These data suggest that recommended current guidelines for the decontamination of farm buildings following outbreaks of scrapie do little to reduce the titre of infectious scrapie material and that environmental recontamination could also be an issue associated with these premises.

 

SNIP...

 

Discussion

 

Thorough pressure washing of a pen had no effect on the amount of bioavailable scrapie infectivity (pen B). The routine removal of prions from surfaces within a laboratory setting is treatment for a minimum of one hour with 20,000 ppm free chlorine, a method originally based on the use of brain macerates from infected rodents to evaluate the effectiveness of decontamination (Kimberlin and others 1983). Further studies have also investigated the effectiveness of hypochlorite disinfection of metal surfaces to simulate the decontamination of surgical devices within a hospital setting. Such treatments with hypochlorite solution were able to reduce infectivity by 5.5 logs to lower than the sensitivity of the bioassay used (Lemmer and others 2004). Analogous treatment of the pen surfaces did not effectively remove the levels of scrapie infectivity over that of the control pens, indicating that this method of decontamination is not effective within a farm setting. This may be due to the high level of biological matrix that is present upon surfaces within the farm environment, which may reduce the amount of free chlorine available to inactivate any infectious prion. Remarkably 1/5 sheep introduced into pen D had also became scrapie positive within nine months, with all animals in this pen being RAMALT positive by 18 months of age. Pen D was no further away from the control pen (pen A) than any of the other pens within this barn. Localised hot spots of infectivity may be present within scrapie-contaminated environments, but it is unlikely that pen D area had an amount of scrapie contamination that was significantly different than the other areas within this building. Similarly, there were no differences in how the biosecurity of pen D was maintained, or how this pen was ventilated compared with the other pens. This observation, perhaps, indicates the slower kinetics of disease uptake within this pen and is consistent with a more thorough prion removal and recontamination. These observations may also account for the presence of inadvertent scrapie cases within other studies, where despite stringent biosecurity, control animals have become scrapie positive during challenge studies using barns that also housed scrapie-affected animals (Ryder and others 2009). The bioassay data indicate that the exposure of the sheep to a farm environment after decontamination efforts thought to be effective in removing scrapie is sufficient for the animals to become infected with scrapie. The main exposure routes within this scenario are likely to be via the oral route, during feeding and drinking, and respiratory and conjunctival routes. It has been demonstrated that scrapie infectivity can be efficiently transmitted via the nasal route in sheep (Hamir and others 2008), as is the case for CWD in both murine models and in white-tailed deer (Denkers and others 2010, 2013). Recently, it has also been demonstrated that CWD prions presented as dust when bound to the soil mineral montmorillonite can be infectious via the nasal route (Nichols and others 2013). When considering pens C and D, the actual source of the infectious agent in the pens is not known, it is possible that biologically relevant levels of prion survive on surfaces during the decontamination regimen (pen C). With the use of galvanising and painting (pen D) covering and sealing the surface of the pen, it is possible that scrapie material recontaminated the pens by the movement of infectious prions contained within dusts originating from other parts of the barn that were not decontaminated or from other areas of the farm.

 

Given that scrapie prions are widespread on the surfaces of affected farms (Maddison and others 2010a), irrespective of the source of the infectious prions in the pens, this study clearly highlights the difficulties that are faced with the effective removal of environmentally associated scrapie infectivity. This is likely to be paralleled in CWD which shows strong similarities to scrapie in terms of both the dissemination of prions into the environment and the facile mode of disease transmission. These data further contribute to the understanding that prion diseases can be highly transmissible between susceptible individuals not just by direct contact but through highly stable environmental reservoirs that are refractory to decontamination.

 

The presence of these environmentally associated prions in farm buildings make the control of these diseases a considerable challenge, especially in animal species such as goats where there is lack of genetic resistance to scrapie and, therefore, no scope to re-stock farms with animals that are resistant to scrapie.

 

Scrapie Sheep Goats Transmissible spongiform encephalopathies (TSE) Accepted October 12, 2014. Published Online First 31 October 2014

 


 

Monday, November 3, 2014

 

Persistence of ovine scrapie infectivity in a farm environment following cleaning and decontamination

 


 

PPo3-22:

 

Detection of Environmentally Associated PrPSc on a Farm with Endemic Scrapie

 

Ben C. Maddison,1 Claire A. Baker,1 Helen C. Rees,1 Linda A. Terry,2 Leigh Thorne,2 Susan J. Belworthy2 and Kevin C. Gough3 1ADAS-UK LTD; Department of Biology; University of Leicester; Leicester, UK; 2Veterinary Laboratories Agency; Surry, KT UK; 3Department of Veterinary Medicine and Science; University of Nottingham; Sutton Bonington, Loughborough UK

 

Key words: scrapie, evironmental persistence, sPMCA

 

Ovine scrapie shows considerable horizontal transmission, yet the routes of transmission and specifically the role of fomites in transmission remain poorly defined. Here we present biochemical data demonstrating that on a scrapie-affected sheep farm, scrapie prion contamination is widespread. It was anticipated at the outset that if prions contaminate the environment that they would be there at extremely low levels, as such the most sensitive method available for the detection of PrPSc, serial Protein Misfolding Cyclic Amplification (sPMCA), was used in this study. We investigated the distribution of environmental scrapie prions by applying ovine sPMCA to samples taken from a range of surfaces that were accessible to animals and could be collected by use of a wetted foam swab. Prion was amplified by sPMCA from a number of these environmental swab samples including those taken from metal, plastic and wooden surfaces, both in the indoor and outdoor environment. At the time of sampling there had been no sheep contact with these areas for at least 20 days prior to sampling indicating that prions persist for at least this duration in the environment. These data implicate inanimate objects as environmental reservoirs of prion infectivity which are likely to contribute to disease transmission.

 


 

HIGHEST INFECTION RATE ON SEVERAL CWD CONFIRMED CAPTIVES

 

CHRONIC WASTING DISEASE CWD WISCONSIN Almond Deer (Buckhorn Flats) Farm Update DECEMBER 2011

 

The CWD infection rate was nearly 80%, the highest ever in a North American captive herd.

 

RECOMMENDATION: That the Board approve the purchase of 80 acres of land for $465,000 for the Statewide Wildlife Habitat Program in Portage County and approve the restrictions on public use of the site.

 

SUMMARY:

 


 

For Immediate Release Thursday, October 2, 2014

 

Dustin Vande Hoef 515/281-3375 or 515/326-1616 (cell) or Dustin.VandeHoef@IowaAgriculture.gov

 

*** TEST RESULTS FROM CAPTIVE DEER HERD WITH CHRONIC WASTING DISEASE RELEASED 79.8 percent of the deer tested positive for the disease

 

DES MOINES – The Iowa Department of Agriculture and Land Stewardship today announced that the test results from the depopulation of a quarantined captive deer herd in north-central Iowa showed that 284 of the 356 deer, or 79.8% of the herd, tested positive for Chronic Wasting Disease (CWD).

 


 

*** see history of this CWD blunder here ;

 


 

On June 5, 2013, DNR conducted a fence inspection, after gaining approval from surrounding landowners, and confirmed that the fenced had been cut or removed in at least four separate locations; that the fence had degraded and was failing to maintain the enclosure around the Quarantined Premises in at least one area; that at least three gates had been opened;and that deer tracks were visible in and around one of the open areas in the sand on both sides of the fence, evidencing movement of deer into the Quarantined Premises.

 


 

The overall incidence of clinical CWD in white-tailed deer was 82%

 

Species (cohort) CWD (cases/total) Incidence (%) Age at CWD death (mo)

 


 

”The occurrence of CWD must be viewed against the contest of the locations in which it occurred. It was an incidental and unwelcome complication of the respective wildlife research programmes. Despite it’s subsequent recognition as a new disease of cervids, therefore justifying direct investigation, no specific research funding was forthcoming. The USDA veiwed it as a wildlife problem and consequently not their province!” page 26.

 


 

Sunday, January 06, 2013

 

USDA TO PGC ONCE CAPTIVES ESCAPE

 

*** "it‘s no longer its business.”

 


 

CWD, spreading it around...

 

for the game farm industry, and their constituents, to continue to believe that they are _NOT_, and or insinuate that they have _NEVER_ been part of the problem, will only continue to help spread cwd. the game farming industry, from the shooting pens, to the urine mills, the antler mills, the sperm mills, velvet mills, shooting pens, to large ranches, are not the only problem, but it is painfully obvious that they have been part of the problem for decades and decades, just spreading it around, as with transportation and or exportation and or importation of cervids from game farming industry, and have been proven to spread cwd. no one need to look any further than South Korea blunder ;

 

===========================================

 

spreading cwd around...

 

Between 1996 and 2002, chronic wasting disease was diagnosed in 39 herds of farmed elk in Saskatchewan in a single epidemic. All of these herds were depopulated as part of the Canadian Food Inspection Agency’s (CFIA) disease eradication program. Animals, primarily over 12 mo of age, were tested for the presence CWD prions following euthanasia. Twenty-one of the herds were linked through movements of live animals with latent CWD from a single infected source herd in Saskatchewan, 17 through movements of animals from 7 of the secondarily infected herds.

 

***The source herd is believed to have become infected via importation of animals from a game farm in South Dakota where CWD was subsequently diagnosed (7,4). A wide range in herd prevalence of CWD at the time of herd depopulation of these herds was observed. Within-herd transmission was observed on some farms, while the disease remained confined to the introduced animals on other farms.

 


 

spreading cwd around...

 

Friday, May 13, 2011

 

Chronic Wasting Disease (CWD) outbreaks and surveillance program in the Republic of Korea

 

Hyun-Joo Sohn, Yoon-Hee Lee, Min-jeong Kim, Eun-Im Yun, Hyo-Jin Kim, Won-Yong Lee, Dong-Seob Tark, In- Soo Cho, Foreign Animal Disease Research Division, National Veterinary Research and Quarantine Service, Republic of Korea

 

Chronic wasting disease (CWD) has been recognized as an important prion disease in native North America deer and Rocky mountain elks. The disease is a unique member of the transmissible spongiform encephalopathies (TSEs), which naturally affects only a few species. CWD had been limited to USA and Canada until 2000.

 

On 28 December 2000, information from the Canadian government showed that a total of 95 elk had been exported from farms with CWD to Korea. These consisted of 23 elk in 1994 originating from the so-called “source farm” in Canada, and 72 elk in 1997, which had been held in pre export quarantine at the “source farm”.Based on export information of CWD suspected elk from Canada to Korea, CWD surveillance program was initiated by the Ministry of Agriculture and Forestry (MAF) in 2001.

 

All elks imported in 1997 were traced back, however elks imported in 1994 were impossible to identify. CWD control measures included stamping out of all animals in the affected farm, and thorough cleaning and disinfection of the premises. In addition, nationwide clinical surveillance of Korean native cervids, and improved measures to ensure reporting of CWD suspect cases were implemented.

 

Total of 9 elks were found to be affected. CWD was designated as a notifiable disease under the Act for Prevention of Livestock Epidemics in 2002.

 

Additional CWD cases - 12 elks and 2 elks - were diagnosed in 2004 and 2005.

 

Since February of 2005, when slaughtered elks were found to be positive, all slaughtered cervid for human consumption at abattoirs were designated as target of the CWD surveillance program. Currently, CWD laboratory testing is only conducted by National Reference Laboratory on CWD, which is the Foreign Animal Disease Division (FADD) of National Veterinary Research and Quarantine Service (NVRQS).

 

In July 2010, one out of 3 elks from Farm 1 which were slaughtered for the human consumption was confirmed as positive. Consequently, all cervid – 54 elks, 41 Sika deer and 5 Albino deer – were culled and one elk was found to be positive. Epidemiological investigations were conducted by Veterinary Epidemiology Division (VED) of NVRQS in collaboration with provincial veterinary services.

 

Epidemiologically related farms were found as 3 farms and all cervid at these farms were culled and subjected to CWD diagnosis. Three elks and 5 crossbreeds (Red deer and Sika deer) were confirmed as positive at farm 2.

 

All cervids at Farm 3 and Farm 4 – 15 elks and 47 elks – were culled and confirmed as negative.

 

Further epidemiological investigations showed that these CWD outbreaks were linked to the importation of elks from Canada in 1994 based on circumstantial evidences.

 

In December 2010, one elk was confirmed as positive at Farm 5. Consequently, all cervid – 3 elks, 11 Manchurian Sika deer and 20 Sika deer – were culled and one Manchurian Sika deer and seven Sika deer were found to be positive. This is the first report of CWD in these sub-species of deer. Epidemiological investigations found that the owner of the Farm 2 in CWD outbreaks in July 2010 had co-owned the Farm 5.

 

In addition, it was newly revealed that one positive elk was introduced from Farm 6 of Jinju-si Gyeongsang Namdo. All cervid – 19 elks, 15 crossbreed (species unknown) and 64 Sika deer – of Farm 6 were culled, but all confirmed as negative.

 


 


 


 


 

New studies on the heat resistance of hamster-adapted scrapie agent: Threshold survival after ashing at 600°C suggests an inorganic template of replication

 

The infectious agents responsible for transmissible spongiform encephalopathy (TSE) are notoriously resistant to most physical and chemical methods used for inactivating pathogens, including heat. It has long been recognized, for example, that boiling is ineffective and that higher temperatures are most efficient when combined with steam under pressure (i.e., autoclaving). As a means of decontamination, dry heat is used only at the extremely high temperatures achieved during incineration, usually in excess of 600°C. It has been assumed, without proof, that incineration totally inactivates the agents of TSE, whether of human or animal origin.

 


 

Prion Infected Meat-and-Bone Meal Is Still Infectious after Biodiesel Production

 

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.

 


 

Detection of protease-resistant cervid prion protein in water from a CWD-endemic area

 

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.

 


 

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

 

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.

 


 

O.05: Transmission of prions to primates after extended silent incubation periods: Implications for BSE and scrapie risk assessment in human populations

 

Emmanuel Comoy, Jacqueline Mikol, Valerie Durand, Sophie Luccantoni, Evelyne Correia, Nathalie Lescoutra, Capucine Dehen, and Jean-Philippe Deslys Atomic Energy Commission; Fontenay-aux-Roses, France

 

Prion diseases (PD) are the unique neurodegenerative proteinopathies reputed to be transmissible under field conditions since decades. The transmission of Bovine Spongiform Encephalopathy (BSE) to humans evidenced that an animal PD might be zoonotic under appropriate conditions. Contrarily, in the absence of obvious (epidemiological or experimental) elements supporting a transmission or genetic predispositions, PD, like the other proteinopathies, are reputed to occur spontaneously (atpical animal prion strains, sporadic CJD summing 80% of human prion cases). Non-human primate models provided the first evidences supporting the transmissibiity of human prion strains and the zoonotic potential of BSE. Among them, cynomolgus macaques brought major information for BSE risk assessment for human health (Chen, 2014), according to their phylogenetic proximity to humans and extended lifetime. We used this model to assess the zoonotic potential of other animal PD from bovine, ovine and cervid origins even after very long silent incubation periods.

 

*** We recently observed the direct transmission of a natural classical scrapie isolate to macaque after a 10-year silent incubation period,

 

***with features similar to some reported for human cases of sporadic CJD, albeit requiring fourfold long incubation than BSE. Scrapie, as recently evoked in humanized mice (Cassard, 2014),

 

***is the third potentially zoonotic PD (with BSE and L-type BSE),

 

***thus questioning the origin of human sporadic cases. We will present an updated panorama of our different transmission studies and discuss the implications of such extended incubation periods on risk assessment of animal PD for human health.

 

===============

 

***thus questioning the origin of human sporadic cases***

 

===============

 


 

==========================================

 

***our findings suggest that possible transmission risk of H-type BSE to sheep and human. Bioassay will be required to determine whether the PMCA products are infectious to these animals.

 

==========================================

 

PRION 2015 CONFERENCE FT. COLLINS CWD RISK FACTORS TO HUMANS

 

*** LATE-BREAKING ABSTRACTS PRION 2015 CONFERENCE ***

 

O18

 

Zoonotic Potential of CWD Prions

 

Liuting Qing1, Ignazio Cali1,2, Jue Yuan1, Shenghai Huang3, Diane Kofskey1, Pierluigi Gambetti1, Wenquan Zou1, Qingzhong Kong1 1Case Western Reserve University, Cleveland, Ohio, USA, 2Second University of Naples, Naples, Italy, 3Encore Health Resources, Houston, Texas, USA

 

*** These results indicate that the CWD prion has the potential to infect human CNS and peripheral lymphoid tissues and that there might be asymptomatic human carriers of CWD infection.

 

==================

 

***These results indicate that the CWD prion has the potential to infect human CNS and peripheral lymphoid tissues and that there might be asymptomatic human carriers of CWD infection.***

 

==================

 

P.105: RT-QuIC models trans-species prion transmission

 

Kristen Davenport, Davin Henderson, Candace Mathiason, and Edward Hoover Prion Research Center; Colorado State University; Fort Collins, CO USA

 

Conversely, FSE maintained sufficient BSE characteristics to more efficiently convert bovine rPrP than feline rPrP. Additionally, human rPrP was competent for conversion by CWD and fCWD.

 

***This insinuates that, at the level of protein:protein interactions, the barrier preventing transmission of CWD to humans is less robust than previously estimated.

 

================

 

***This insinuates that, at the level of protein:protein interactions, the barrier preventing transmission of CWD to humans is less robust than previously estimated.***

 

================

 


 

*** These results would seem to suggest that CWD does indeed have zoonotic potential, at least as judged by the compatibility of CWD prions and their human PrPC target. Furthermore, extrapolation from this simple in vitro assay suggests that if zoonotic CWD occurred, it would most likely effect those of the PRNP codon 129-MM genotype and that the PrPres type would be similar to that found in the most common subtype of sCJD (MM1).***

 


 

*** The potential impact of prion diseases on human health was greatly magnified by the recognition that interspecies transfer of BSE to humans by beef ingestion resulted in vCJD. While changes in animal feed constituents and slaughter practices appear to have curtailed vCJD, there is concern that CWD of free-ranging deer and elk in the U.S. might also cross the species barrier. Thus, consuming venison could be a source of human prion disease. Whether BSE and CWD represent interspecies scrapie transfer or are newly arisen prion diseases is unknown. Therefore, the possibility of transmission of prion disease through other food animals cannot be ruled out. There is evidence that vCJD can be transmitted through blood transfusion. There is likely a pool of unknown size of asymptomatic individuals infected with vCJD, and there may be asymptomatic individuals infected with the CWD equivalent. These circumstances represent a potential threat to blood, blood products, and plasma supplies.

 


 

now, let’s see what the authors said about this casual link, personal communications years ago. see where it is stated NO STRONG evidence. so, does this mean there IS casual evidence ???? “Our conclusion stating that we found no strong evidence of CWD transmission to humans”

 

From: TSS (216-119-163-189.ipset45.wt.net)

 

Subject: CWD aka MAD DEER/ELK TO HUMANS ???

 

Date: September 30, 2002 at 7:06 am PST

 

From: "Belay, Ermias"

 

To: Cc: "Race, Richard (NIH)" ; ; "Belay, Ermias"

 

Sent: Monday, September 30, 2002 9:22 AM

 

Subject: RE: TO CDC AND NIH - PUB MED- 3 MORE DEATHS - CWD - YOUNG HUNTERS

 

Dear Sir/Madam,

 

In the Archives of Neurology you quoted (the abstract of which was attached to your email), we did not say CWD in humans will present like variant CJD. That assumption would be wrong. I encourage you to read the whole article and call me if you have questions or need more clarification (phone: 404-639-3091). Also, we do not claim that "no-one has ever been infected with prion disease from eating venison." Our conclusion stating that we found no strong evidence of CWD transmission to humans in the article you quoted or in any other forum is limited to the patients we investigated.

 

Ermias Belay, M.D. Centers for Disease Control and Prevention

 

-----Original Message-----

 

From: Sent: Sunday, September 29, 2002 10:15 AM

 

To: rr26k@nih.gov; rrace@niaid.nih.gov; ebb8@CDC.GOV

 

Subject: TO CDC AND NIH - PUB MED- 3 MORE DEATHS - CWD - YOUNG HUNTERS

 

Sunday, November 10, 2002 6:26 PM ......snip........end..............TSS

 

Thursday, April 03, 2008

 

A prion disease of cervids: Chronic wasting disease 2008 1: Vet Res. 2008 Apr 3;39(4):41 A prion disease of cervids: Chronic wasting disease Sigurdson CJ.

 

snip...

 

*** twenty-seven CJD patients who regularly consumed venison were reported to the Surveillance Center***,

 

snip... full text ;

 


 

CJD is so rare in people under age 30, one case in a billion (leaving out medical mishaps), that four cases under 30 is "very high," says Colorado neurologist Bosque. "Then, if you add these other two from Wisconsin [cases in the newspaper], six cases of CJD in people associated with venison is very, very high." Only now, with Mary Riley, there are at least seven, and possibly eight, with Steve, her dining companion. "It's not critical mass that matters," however, Belay says. "One case would do it for me." The chance that two people who know each other would both contact CJD, like the two Wisconsin sportsmen, is so unlikely, experts say, it would happen only once in 140 years.

 

Given the incubation period for TSEs in humans, it may require another generation to write the final chapter on CWD in Wisconsin. "Does chronic wasting disease pass into humans? We'll be able to answer that in 2022," says Race. Meanwhile, the state has become part of an immense experiment.

 


 

I urge everyone to watch this video closely...terry

 

*** you can see video here and interview with Jeff's Mom, and scientist telling you to test everything and potential risk factors for humans ***

 


 

*** These results would seem to suggest that CWD does indeed have zoonotic potential, at least as judged by the compatibility of CWD prions and their human PrPC target. Furthermore, extrapolation from this simple in vitro assay suggests that if zoonotic CWD occurred, it would most likely effect those of the PRNP codon 129-MM genotype and that the PrPres type would be similar to that found in the most common subtype of sCJD (MM1).***

 


 

***This information will have a scientific impact since it is the first study that demonstrates the transmission of scrapie to a non-human primate with a close genetic relationship to humans. This information is especially useful to regulatory officials and those involved with risk assessment of the potential transmission of animal prion diseases to humans.

 

***This observation strengthens the questioning of the harmlessness of scrapie to humans, at a time when protective measures for human and animal health are being dismantled and reduced as c-BSE is considered controlled and being eradicated. Our results underscore the importance of precautionary and protective measures and the necessity for long-term experimental transmission studies to assess the zoonotic potential of other animal prion strains.

 


 

Research Project: TRANSMISSION, DIFFERENTIATION, AND PATHOBIOLOGY OF TRANSMISSIBLE SPONGIFORM ENCEPHALOPATHIES

 

Title: Evaluation of the zoonotic potential of transmissible mink encephalopathy

 

Authors

 

item Comoy, Emmanuel - item Mikol, Jacqueline - item Ruchoux, Marie-Madeleine - item Durand, Valerie - item Luccantoni-Freire, Sophie - item Dehen, Capucine - item Correia, Evelyne - item Casalone, Cristina - item Richt, Juergen item Greenlee, Justin item Torres, Juan Maria - item Brown, Paul - item Deslys, Jean-Philippe -

 

Submitted to: Pathogens Publication Type: Peer Reviewed Journal Publication Acceptance Date: July 30, 2013 Publication Date: July 30, 2013 Citation: Comoy, E.E., Mikol, J., Ruchoux, M., Durand, V., Luccantoni-Freire, S., Dehen, C., Correia, E., Casalone, C., Richt, J.A., Greenlee, J.J., Torres, J.M., Brown, P., Deslys, J. 2013. Evaluation of the zoonotic potential of transmissible mink encephalopathy. Pathogens. 2:(3)520-532.

 

Interpretive Summary: Cases of bovine spongiform encephalopathy (BSE) or mad cow disease can be subclassified into at least 3 distinct disease forms with the predominate form known as classical BSE and the others collectively referred to as atypical BSE. Atypical BSE can be further subdivided into H-type and L-type cases that are distinct from classical BSE and from each other. Both of the atypical BSE subtypes are believed to occur spontaneously, whereas classical BSE is spread through feeding contaminated meat and bone meal to cattle. Transmissible mink encephalopathy (TME) is another prion disease that transmits to cattle and show similarities to L-type BSE when subjected to laboratory testing. The purpose of this study was to use non-human primates (cynomologous macaque) and transgenic mice expressing the human prion protein to determine if TME could represent a potential risk to human health. TME from two sources (cattle and raccoons) was able to infect non-human primates and transgenic mice after exposure by the intracranial route. This result suggest that humans may be able to replicate TME prions after an exposure that allows infectious material access to brain tissue. At this time, it is unknown whether non-human primates or transgenic mice would be susceptible to TME prions after oral exposure. The results obtained in these animal models were similar to those obtained for L-type BSE. Although rare, the existence of TME and that it transmits to cattle, non-human primates, and transgenic mice suggest that feed bans preventing the feeding of mammalian tissues to cattle should stay in place and that regular prion surveillance during the slaughter should remain in place. Parties with interest in the cattle and beef industries and regulatory officials responsible for safe feeding practices of cattle will be interested in this work. Technical Abstract: Successful transmission of Transmissible Mink Encephalopathy (TME) to cattle supports the bovine hypothesis to the still controversial origin of TME outbreaks. Human and primate susceptibility to classical Bovine Spongiform Encephalopathy (c-BSE) and the transmissibility of L-type BSE to macaques assume a low cattle-to-primate species barrier: we therefore evaluated the zoonotic potential of cattle-adapted TME. In less than two years, this strain induced in cynomolgus macaques a neurological disease similar to L-BSE and distinct from c-BSE. TME derived from another donor species (raccoon) induced a similar disease with shorter incubation periods.

 

*** L-BSE and cattle-adapted TME were also transmissible to transgenic mice expressing human PrP. Interestingly, secondary transmissions to transgenic mice expressing bovine PrP showed the maintenance of prion strain features for the three tested bovine prion strains (cattle TME, c-BSE and L-BSE) regardless of intermediate host.

 

*** Thus, TME is the third animal prion strain transmissible to both macaques and humanized transgenic mice, suggesting zoonotic potentials that should be considered in the risk analysis of animal prion diseases for human health.

 

*** Moreover, the similarities between TME and L-BSE are highly suggestive of a link between those strains, and of the presence of L-BSE decades prior to its identification in USA and Europe.

 


 

Research Project: TRANSMISSION, DIFFERENTIATION, AND PATHOBIOLOGY OF TRANSMISSIBLE SPONGIFORM ENCEPHALOPATHIES

 

Title: Scrapie transmits to white-tailed deer by the oral route and has a molecular profile similar to chronic wasting disease

 

Authors

 

item Greenlee, Justin item Moore, S - item Smith, Jodi - item Kunkle, Robert item West Greenlee, M -

 

Submitted to: American College of Veterinary Pathologists Meeting Publication Type: Abstract Only Publication Acceptance Date: August 12, 2015 Publication Date: N/A Technical Abstract: The purpose of this work was to determine susceptibility of white-tailed deer (WTD) to the agent of sheep scrapie and to compare the resultant PrPSc to that of the original inoculum and chronic wasting disease (CWD). We inoculated WTD by a natural route of exposure (concurrent oral and intranasal (IN); n=5) with a US scrapie isolate. All scrapie-inoculated deer had evidence of PrPSc accumulation. PrPSc was detected in lymphoid tissues at preclinical time points, and deer necropsied after 28 months post-inoculation had clinical signs, spongiform encephalopathy, and widespread distribution of PrPSc in neural and lymphoid tissues. Western blotting (WB) revealed PrPSc with 2 distinct molecular profiles. WB on cerebral cortex had a profile similar to the original scrapie inoculum, whereas WB of brainstem, cerebellum, or lymph nodes revealed PrPSc with a higher profile resembling CWD. Homogenates with the 2 distinct profiles from WTD with clinical scrapie were further passaged to mice expressing cervid prion protein and intranasally to sheep and WTD. In cervidized mice, the two inocula have distinct incubation times. Sheep inoculated intranasally with WTD derived scrapie developed disease, but only after inoculation with the inoculum that had a scrapie-like profile. The WTD study is ongoing, but deer in both inoculation groups are positive for PrPSc by rectal mucosal biopsy. In summary, this work demonstrates that WTD are susceptible to the agent of scrapie, two distinct molecular profiles of PrPSc are present in the tissues of affected deer, and inoculum of either profile readily passes to deer.

 


 


 

Monday, November 16, 2015

 

*** Docket No. APHIS-2007-0127 Scrapie in Sheep and Goats Terry Singeltary Sr. Submission ***

 


 


 

Saturday, December 12, 2015

 

*** CHRONIC WASTING DISEASE CWD TSE PRION REPORT DECEMBER 14, 2015

 


 

TEXAS CHRONIC WASTING DISEASE CWD TSE PRION

 

Tuesday, December 29, 2015

 

*** TEXAS MONTHLY CHRONIC WASTING DISEASE CWD JANUARY 2016 DEER BREEDERS STILL DON'T GET IT $

 

Chronic Wasting Unease

 

*** The emergence of a deadly disease has wildlife officials and deer breeders eyeing each other suspiciously. ***

 


 

Saturday, October 03, 2015

 

TEXAS CHRONIC WASTING DISEASE CWD TSE PRION GOD MUST NOT BE A TEXAN 2002 TO 2015

 


 

Monday, November 16, 2015

 

*** TEXAS PARKS AND WILDLIFE DEPARTMENT EXECUTIVE DIRECTOR ORDER NO. 015-006

 

*** Chronic Wasting Disease (CWD) immediate danger to the white-tailed deer and mule deer resources of Texas

 


 

Saturday, November 14, 2015

 

TEXAS CAPTIVE BREEDER CHRONIC WASTING DISEASE CWD 2 MORE SUSPECTS DECTECTED BRINGING NUMBER TO 7 DETECTED IN CAPTIVE BREEDER (if/when the last two are confirmed).

 


 

Thursday, November 05, 2015

 

*** TPW Commission Adopts Interim Deer Breeder Movement Rules

 


 

Friday, October 09, 2015

 

Texas TWA Chronic Wasting Disease TSE Prion Webinars and Meeting October 2015

 


 

Thursday, September 24, 2015

 

TEXAS Hunters Asked to Submit Samples for Chronic Wasting Disease CWD TSE Prion Testing

 

*** I cannot stress enough to all of you, for the sake of your family and mine, before putting anything in the freezer, have those deer tested for CWD. ...terry

 


 

***raw and uncut

 

Sunday, August 23, 2015

 

TAHC Chronic Wasting Disease CWD TSE Prion and how to put lipstick on a pig and take her to the dance in Texas

 


 

Friday, August 07, 2015

 

*** Texas CWD Captive, and then there were 4 ?

 


 

Thursday, August 06, 2015

 

*** WE HAVE LOST TEXAS TO CWD TASK FORCE CATERING TO INDUSTRY

 


 

Tuesday, July 21, 2015

 

*** Texas CWD Medina County Herd Investigation Update July 16, 2015 ***

 


 

Wednesday, July 01, 2015

 

*** TEXAS Chronic Wasting Disease Detected in Medina County Captive Deer

 


 

Wednesday, March 18, 2015

 

*** Chronic Wasting Disease CWD Confirmed Texas Trans Pecos March 18, 2015

 


 

Wednesday, March 25, 2015

 

*** Chronic Wasting Disease CWD Cases Confirmed In New Mexico 2013 and 2014 UPDATE 2015

 


 

Friday, August 14, 2015

 

*** Susceptibility of cattle to the agent of chronic wasting disease from elk after intracranial inoculation

 


 

Friday, August 14, 2015

 

Carcass Management During a Mass Animal Health Emergency Draft Programmatic Environmental Impact Statement—August 2015

 


 

Tuesday, September 22, 2015

 

*** Host Determinants of Prion Strain Diversity Independent of Prion Protein Genotype

 


 

Friday, August 28, 2015

 

*** Chronic Wasting Disease CWD TSE Prion Diagnostics and subclinical infection

 


 

*** Thursday, January 14, 2016

 

*** EMERGING ANIMAL DISEASES Actions Needed to Better Position USDA to Address Future Risks Report to the Chairman, Committee on Energy and Commerce, House of Representatives December 2015 GAO-16-132

 

*** GAO

 


 

 Saturday, December 12, 2015

 

CREUTZFELDT JAKOB DISEASE CJD TSE PRION REPORT DECEMBER 14, 2015

 


 

MOM

 

Thursday, December 24, 2015

 

Revisiting the Heidenhain Variant of Creutzfeldt-Jakob Disease: Evidence for Prion Type Variability Influencing Clinical Course and Laboratory Findings

 

Article type: Research Article

 


 

 

Evidence for human transmission of amyloid-β pathology and cerebral amyloid angiopathy

 


 

07 02:27 AM

 

Terry S. Singeltary Sr. said:

 

re-Evidence for human transmission of amyloid-? pathology and cerebral amyloid angiopathy

 

Nature 525, 247?250 (10 September 2015) doi:10.1038/nature15369 Received 26 April 2015 Accepted 14 August 2015 Published online 09 September 2015 Updated online 11 September 2015 Erratum (October, 2015)

 


 

I would kindly like to comment on the Nature Paper, the Lancet reply, and the newspaper articles.

 

***snip...see full text ;

 


 

Subject: 1992 IN CONFIDENCE TRANSMISSION OF ALZHEIMER TYPE PLAQUES TO PRIMATES POSSIBILITY ON A TRANSMISSIBLE PRION REMAINS OPEN

 

BSE101/1 0136

 

IN CONFIDENCE

 

CMO

 

From: . Dr J S Metiers DCMO

 

4 November 1992

 

TRANSMISSION OF ALZHEIMER TYPE PLAQUES TO PRIMATES

 

1. Thank you for showing me Diana Dunstan's letter. I am glad that MRC have recognised the public sensitivity of these findings and intend to report them in their proper context. 'This hopefully will avoid misunderstanding and possible distortion by the media to portray the results as having more greater significance than the findings so far justify.

 

2. Using a highly unusual route of transmission (intra-cerebral injection) the researchers have demonstrated the transmission of a pathological process from two cases one of severe Alzheimer's disease the other of Gerstmann-Straussler disease to marmosets. However they have not demonstrated the transmission of either clinical condition as the "animals were behaving normally when killed". As the report emphasises the unanswered question is whether the disease condition would have revealed itself if the marmosets had lived longer. They are planning further research to see if the conditions, as opposed to the partial pathological process, is transmissible.

 

what are the implications for public health?

 

3. The route 'of transmission is very specific and in the natural state of things highly unusual. However it could be argued that the results reveal a potential risk, in that brain tissue from these two patients has been shown to transmit a pathological process. Should therefore brain tissue from such cases be regarded as potentially infective? Pathologists, morticians, neuro surgeons and those assisting at neuro surgical procedures and others coming into contact with "raw" human brain tissue could in theory be at risk. However, on a priori grounds given the highly specific route of transmission in these experiments that risk must be negligible if the usual precautions for handling brain tissue are observed.

 

1

 

92/11.4/1.1

 

BSE101/1 0137

 

4. The other dimension to consider is the public reaction. To some extent the GSS case demonstrates little more than the transmission of BSE to a pig by intra-cerebral injection. If other prion diseases can be transmitted in this way it is little surprise that some pathological findings observed in GSS were also transmissible to a marmoset. But the transmission of features of Alzheimer's pathology is a different matter, given the much greater frequency of this disease and raises the unanswered question whether some cases are the result of a transmissible prion. The only tenable public line will be that "more research is required’’ before that hypothesis could be evaluated. The possibility on a transmissible prion remains open. In the meantime MRC needs carefully to consider the range and sequence of studies needed to follow through from the preliminary observations in these two cases. Not a particularly comfortable message, but until we know more about the causation of Alzheimer's disease the total reassurance is not practical.

 

J S METTERS Room 509 Richmond House Pager No: 081-884 3344 Callsign: DOH 832 llllYc!eS 2 92/11.4/1.2

 


 

>>> The only tenable public line will be that "more research is required’’ <<<

 

>>> possibility on a transmissible prion remains open<<<

 

O.K., so it’s about 23 years later, so somebody please tell me, when is "more research is required’’ enough time for evaluation ?

 

Self-Propagative Replication of Ab Oligomers Suggests Potential Transmissibility in Alzheimer Disease

 

Received July 24, 2014; Accepted September 16, 2014; Published November 3, 2014

 


 

*** Singeltary comment PLoS ***

 

Alzheimer’s disease and Transmissible Spongiform Encephalopathy prion disease, Iatrogenic, what if ?

 

Posted by flounder on 05 Nov 2014 at 21:27 GMT

 


 

Wednesday, January 13, 2016

 

ALS-Causing Mutations Significantly Perturb the Self-Assembly and Interaction with Nucleic Acid of the Intrinsically Disordered Prion-Like Domain of TDP-43

 

Research Article

 


 

Wednesday, January 13, 2016

 

An efficient procedure for removal and inactivation of alpha-synuclein assemblies from laboratory materials

 

***>>>An efficient procedure for removal and inactivation of alpha-synuclein assemblies from laboratory materials<<<***

 

***>>> This retrospective study, however, does not definitively exclude the possibility that a-synucleinopathy can transmit between humans. <<<***

 

An efficient procedure for removal and inactivation of alpha-synuclein assemblies from laboratory materials ???

 


 

Tuesday, December 1, 2015

 

Sorting Out Release, Uptake and Processing of Alpha-Synuclein During Prion-Like Spread of Pathology

 


 

Thursday, December 3, 2015

 

Transmission of Soluble and Insoluble α-Synuclein to Mice

 


 

Tuesday, September 1, 2015

 

Evidence for α-synuclein prions causing multiple system atrophy in humans with parkinsonism

 


 


 

Wednesday, September 2, 2015

 

Clinically Unsuspected Prion Disease Among Patients With Dementia Diagnoses in an Alzheimer’s Disease Database

 


 

Transmission of Creutzfeldt-Jakob disease to a chimpanzee by electrodes contaminated during neurosurgery.

 

Gibbs CJ Jr, Asher DM, Kobrine A, Amyx HL, Sulima MP, Gajdusek DC. Laboratory of Central Nervous System Studies, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892.

 

Stereotactic multicontact electrodes used to probe the cerebral cortex of a middle aged woman with progressive dementia were previously implicated in the accidental transmission of Creutzfeldt-Jakob disease (CJD) to two younger patients. The diagnoses of CJD have been confirmed for all three cases. More than two years after their last use in humans, after three cleanings and repeated sterilisation in ethanol and formaldehyde vapour, the electrodes were implanted in the cortex of a chimpanzee. Eighteen months later the animal became ill with CJD. This finding serves to re-emphasise the potential danger posed by reuse of instruments contaminated with the agents of spongiform encephalopathies, even after scrupulous attempts to clean them.

 


 

 

Terry S. Singeltary Sr.

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