October 19, 2009
Greetings,
An update of sorts on atypical BSE and other TSE in North America, reported, and or, not reported. Please remember, the _typical_ U.K. c-BSE, the l-BSE (BASE), and the h-BSE have all been documented in North America, along with the typical scrapie's, and atypical Nor-98 Scrapie, and to date, 2 different strains of CWD, and also TME. please remember, all these TSE in different species have been rendered and feed to food producing animals for humans and animals in North America (absolutely no idea of TSE in cats and dogs see reference on that), and that the trading of these TSEs via animals and products via the USA and Canada has been so immense over the years, decades, that it was like swapping spit between two lovers. also, please remember, in my opinion (I will show the facts to prove this), Canada is Looking to find TSE in cattle, and the USA has done just the opposite, the look NOT to find and report. The SSS policy has been in full force in the USA for some time. also, there will be some additional information on Transmission studies. Also, what about any human TSE there from, and the surveillance there of ???
With that said, I present you with these facts as follows. There is new data mixed up with old data, so don't miss any of it. ...kind regards, terry
Wednesday, February 11, 2009
Atypical BSE North America Update February 2009 Both of the BSE cases ascertained in the US native-born cattle were atypical cases (H-type), which contributed to the initial ambiguity of the diagnosis. 174, 185 In Canada, there have been 2 atypical BSE cases in addition to the 14 cases of the classic UK strain of BSE2: one was the H-type, and the other was of the L-type.198
snip...end
source : Enhanced Abstract Journal of the American Veterinary Medical Association January 1, 2009, Vol. 234, No. 1, Pages 59-72 Bovine spongiform encephalopathy Jane L. Harman, DVM, PhD; Christopher J. Silva, PhD
http://avmajournals.avma.org/doi/ref/10.2460/javma.234.1.59
October 2009
O.11.3
Infectivity in skeletal muscle of BASE-infected cattle
Silvia Suardi1, Chiara Vimercati1, Fabio Moda1, Ruggerone Margherita1, Ilaria Campagnani1, Guerino Lombardi2, Daniela Gelmetti2, Martin H. Groschup3, Anne Buschmann3, Cristina Casalone4, Maria Caramelli4, Salvatore Monaco5, Gianluigi Zanusso5, Fabrizio Tagliavini1 1Carlo Besta” Neurological Institute,Italy; 2IZS Brescia, Italy; 33FLI Insel Riems, D, Germany; 4CEA-IZS Torino, Italy; 5University of Verona, Italy
Background: BASE is an atypical form of bovine spongiform encephalopathy caused by a prion strain distinct from that of BSE. Upon experimental transmission to cattle, BASE induces a previously unrecognized disease phenotype marked by mental dullness and progressive atrophy of hind limb musculature. Whether affected muscles contain infectivity is unknown. This is a critical issue since the BASE strain is readily transmissible to a variety of hosts including primates, suggesting that humans may be susceptible.
Objectives: To investigate the distribution of infectivity in peripheral tissues of cattle experimentally infected with BASE. Methods: Groups of Tg mice expressing bovine PrP (Tgbov XV, n= 7-15/group) were inoculated both i.c. and i.p. with 10% homogenates of a variety of tissues including brain, spleen, cervical lymph node, kidney and skeletal muscle (m. longissimus dorsi) from cattle intracerebrally infected with BASE. No PrPres was detectable in the peripheral tissues used for inoculation either by immunohistochemistry or Western blot.
Results: Mice inoculated with BASE-brain homogenates showed clinical signs of disease with incubation and survival times of 175±15 and 207±12 days. Five out of seven mice challenged with skeletal muscle developed a similar neurological disorder, with incubation and survival times of 380±11 and 410±12 days. At present (700 days after inoculation) mice challenged with the other peripheral tissues are still healthy. The neuropathological phenotype and PrPres type of the affected mice inoculated either with brain or muscle were indistinguishable and matched those of Tgbov XV mice infected with natural BASE.
Discussion: Our data indicate that the skeletal muscle of cattle experimentally infected with BASE contains significant amount of infectivity, at variance with BSE-affected cattle, raising the issue of intraspecies transmission and the potential risk for humans. Experiments are in progress to assess the presence of infectivity in skeletal muscles of natural BASE.
P.4.23
Transmission of atypical BSE in humanized mouse models
Liuting Qing1, Wenquan Zou1, Cristina Casalone2, Martin Groschup3, Miroslaw Polak4, Maria Caramelli2, Pierluigi Gambetti1, Juergen Richt5, Qingzhong Kong1 1Case Western Reserve University, USA; 2Instituto Zooprofilattico Sperimentale, Italy; 3Friedrich-Loeffler-Institut, Germany; 4National Veterinary Research Institute, Poland; 5Kansas State University (Previously at USDA National Animal Disease Center), USA
Background: Classical BSE is a world-wide prion disease in cattle, and the classical BSE strain (BSE-C) has led to over 200 cases of clinical human infection (variant CJD). Atypical BSE cases have been discovered in three continents since 2004; they include the L-type (also named BASE), the H-type, and the first reported case of naturally occurring BSE with mutated bovine PRNP (termed BSE-M). The public health risks posed by atypical BSE were largely undefined.
Objectives: To investigate these atypical BSE types in terms of their transmissibility and phenotypes in humanized mice.
Methods: Transgenic mice expressing human PrP were inoculated with several classical (C-type) and atypical (L-, H-, or Mtype) BSE isolates, and the transmission rate, incubation time, characteristics and distribution of PrPSc, symptoms, and histopathology were or will be examined and compared.
Results: Sixty percent of BASE-inoculated humanized mice became infected with minimal spongiosis and an average incubation time of 20-22 months, whereas only one of the C-type BSE-inoculated mice developed prion disease after more than 2 years. Protease-resistant PrPSc in BASE-infected humanized Tg mouse brains was biochemically different from bovine BASE or sCJD. PrPSc was also detected in the spleen of 22% of BASE-infected humanized mice, but not in those infected with sCJD. Secondary transmission of BASE in the humanized mice led to a small reduction in incubation time. The atypical BSE-H strain is also transmissible with distinct phenotypes in the humanized mice, but no BSE-M transmission has been observed so far.
Discussion: Our results demonstrate that BASE is more virulent than classical BSE, has a lymphotropic phenotype, and displays a modest transmission barrier in our humanized mice. BSE-H is also transmissible in our humanized Tg mice. The possibility of more than two atypical BSE strains will be discussed. Supported by NINDS NS052319, NIA AG14359, and NIH AI 77774.
P.5.3
Differences in the expression levels of selected genes in the brain tissue of cattle naturally infected with classical and atypical BSE.
Magdalena Larska1, Miroslaw P. Polak1, Jan F. Zmudzinski1, Juan M. Torres2 1National Veterinary Institute, Poland; 2CISA/INIA
Background: Recently cases of BSE in older cattle named BSE type L and type H were distinguished on the basis of atypical glycoprofiles of PrPres. The nature of those strains is still not fully understood but it is suspected that the atypical BSE cases are sporadic. Hitherto most BSE cases were studied in respect to the features of PrPSc. Here we propose gene expression profiling as a method to characterize and distinguish BSE strains.
Objectives: The aim of the study was to compare the activities of some factors which are known to play a role in TSE’s pathogenesis in order to distinguish the differences/similarities between all BSE types. Methods: 10 % homogenate of brain stem tissue collected from obex region of medulla oblongata from 20 naturally infected BSE cows (8 assigned as classical BSE, other 8 and 4 infected with atypical BSE L type and H type respectively) was used in the study. As negative control animals we’ve used 8 animals in the age between 2.5 and 13 years. The genes were relatively quantified using SYBR Green real time RT-PCR. Raw data of Ct values was transformed into normalized relative quantities using Qbase Plus®.
Results and Discussion: In most of the tested genes significant differences in the expression levels between the brain stem of healthy cattle and animals infected with different BSE types were observed. In c-type BSE in comparison to healthy and atypical BSE the overexpression of the gene of bcl-2, caspase 3, 14-3-3 and tylosine kinase Fyn was significant. Simultaneously in atypical BSEs type-L and type-H the levels of prion protein, Bax and LPR gene was elevated in comparison to c-BSE. Additionally L-BSE was characterized by the overexpression of STI1 and SOD genes compared to the other of BSE types. The downregulation of the gene encoding NCAM1 was observed in all BSE types in comparison to healthy cows. Different gene expression profiles of bovine brains infected with classical and atypical BSE indicates possible different pathogenesis or source of the disease.
O.10.1
Transmission of uncommon forms of bovine prions to transgenic mice expressing human PrP: questions and progress
Vincent Béringue, Hubert Laude INRA, UR 892, Virologie Immunologie Moléculaires, France
The active, large-scale testing of livestock nervous tissues for the presence of protease-resistant prion protein (PrPres) has led to the recognition of 2 uncommon PrPres molecular signatures, termed H-type and L-type BSE. Their experimental transmission to various transgenic and inbred mouse lines unambiguously demonstrated the infectious nature of such cases and the existence of distinct prion strains in cattle. Like the classical BSE agent, H- and L-type (or BASE) prions can propagate in heterologous species. In addition L-type prions acquire molecular and neuropathologic phenotypic traits undistinguishable from BSE or BSE-related agents upon transmission to transgenic mice expressing ovine PrP (VRQ allele) or wild-type mice. An understanding of the transmission properties of these newly recognized prions when confronted with human PrP sequence was therefore needed. Toward this end, we inoculated mice expressing human PrP Met129 with several field isolates. Unlike classical BSE agent, L-type prions appeared to propagate in these mice with no obvious transmission barrier. In contrast, we repeatedly failed to infect them with Htype prions. Ongoing investigations aim to extend the knowledge on these uncommon strains: are these agents able to colonize lymphoid tissue, a potential key factor for successful transmission by peripheral route; is there any relationship between these assumedly sporadic forms of TSE in cattle and some sporadic forms of human CJD are among the issues that need to be addressed for a careful assessment of the risk for cattle-to-human transmission of H- and L-type prions.
O.4.3
Spread of BSE prions in cynomolgus monkeys (Macaca fascicularis) after oral transmission
Edgar Holznagel1, Walter Schulz-Schaeffer2, Barbara Yutzy1, Gerhard Hunsmann3, Johannes Loewer1 1Paul-Ehrlich-Institut, Federal Institute for Sera and Vaccines, Germany; 2Department of Neuropathology, Georg-August University, Göttingen, Germany, 3Department of Virology and Immunology, German Primate Centre, Göttingen, Germany
Background: BSE-infected cynomolgus monkeys represent a relevant animal model to study the pathogenesis of variant Creutzfeldt-Jacob disease (vCJD).
Objectives: To study the spread of BSE prions during the asymptomatic phase of infection in a simian animal model.
Methods: Orally BSE-dosed macaques (n=10) were sacrificed at defined time points during the incubation period and 7 orally BSE-dosed macaques were sacrificed after the onset of clinical signs. Neuronal and non-neuronal tissues were tested for the presence of proteinase-K-resistant prion protein (PrPres) by western immunoblot and by paraffin-embedded tissue (PET) blot technique.
Results: In clinically diseased macaques (5 years p.i. + 6 mo.), PrPres deposits were widely spread in neuronal tissues (including the peripheral sympathetic and parasympathetic nervous system) and in lymphoid tissues including tonsils. In asymptomatic disease carriers, PrPres deposits could be detected in intestinal lymph nodes as early as 1 year p.i., but CNS tissues were negative until 3 – 4 years p.i. Lumbal/sacral segments of the spinal cord and medulla oblongata were PrPres positive as early as 4.1 years p.i., whereas sympathetic trunk and all thoracic/cervical segments of the spinal cord were still negative for PrPres. However, tonsil samples were negative in all asymptomatic cases.
Discussion: There is evidence for an early spread of BSE to the CNS via autonomic fibres of the splanchnic and vagus nerves indicating that trans-synaptical spread may be a time-limiting factor for neuroinvasion. Tonsils were predominantly negative during the main part of the incubation period indicating that epidemiological vCJD screening results based on the detection of PrPres in tonsil biopsies may mostly tend to underestimate the prevalence of vCJD among humans.
O.4.4
PrPSc distribution pattern in cattle experimentally challenged with H-type and L-type atypical BSE
Anne Buschmann1, Ute Ziegler1, Leila McIntyre2, Markus Keller1, Ron Rogers3, Bob Hills3, Martin H. Groschup1 1Friedrich-Loeffler-Institut, INEID, Germany; 2Faculty of Veterinary Medicine, University of Calgary, Canada; 3Health Canada, Ottawa, Canada
Background: After the detection of two novel BSE forms designated H-type and L-type BSE, the question of the pathogenesis and the agent distribution in cattle affected with these forms was fully open. From initial studies, it was already known that the PrPSc distribution in L-type BSE affected cattle differed from that known for classical BSE (C-type) where the obex region always displays the highest PrPSc concentrations. In contrast in L-type BSE cases, the thalamus and frontal cortex regions showed the highest levels of the pathological prion protein, while the obex region was only weakly involved. No information was available on the distribution pattern in H-type BSE.
Objectives: To analyse the PrPSc and infectivity distribution in cattle experimentally challenged with H-type and L-type BSE.
Methods: We analysed CNS and peripheral tissue samples collected from cattle that were intracranially challenged with Htype (five animals) and L-type (six animals) using a commercial BSE rapid test (IDEXX HerdChek), immunohistochemistry (IHC) and a highly sensitive Western blot protocol including a phosphotungstic acid precipitation of PrPSc (PTA-WB). Samples collected during the preclinical and the clinical stages of the disease were examined. For the detection of BSE infectivity, selected samples were also inoculated into highly sensitive Tgbov XV mice overexpressing bovine prion protein (PrPC).
Results: Analysis of a collection of fifty samples from the peripheral nervous, lymphoreticular, digestive, reproductive, respiratory and musculo-skeletal systems by PTA-WB, IDEXXHerdChek BSE EIA and IHC revealed a general restriction of the PrPSc accumulation to the central nervous system.
Discussion: Our results on the PrPSc distribution in peripheral tissues of cattle affected with H-type and L-type BSE are generally in accordance with what has been known for C-type BSE. Bioassays are ongoing in highly sensitive transgenic mice in order to reveal infectivity.
http://www.prion2009.com/sites/default/files/Prion2009_Book_of_Abstracts.pdf
Research Project: GENETIC AND BIOLOGICAL DETERMINANTS OF RESPIRATORY DISEASE SUSCEPTIBILITY Location: Animal Health Systems Research
Title: Association of a bovine prion gene haplotype with atypical BSE
Author
Clawson, Michael
Submitted to: Meeting Abstract Publication Type: Abstract Publication Acceptance Date: December 2, 2008 Publication Date: January 1, 2009 Citation: Clawson, M.L. 2009. Association of a bovine prion gene haplotype with atypical BSE [abstract]. Plant and Animal Genomes XVII Conference. Abstract No. W091. Available:
http://www.intl-pag.org/17/abstracts/
Technical Abstract: Transmissible spongiform encephalopathies (TSEs), also known as prion diseases, are a class of fatal neurodegenerative disorders that occur in humans, ruminants, cats, and mink. Three distinct TSEs afflict cattle: classical bovine spongiform encephalopathy (BSE), atypical H-type BSE, and atypical L-type BSE. Classical BSE was identified in the 1980s and is acquired by cattle through the consumption of feed contaminated with the infectious prion agent. Atypical BSEs have only recently been recognized as distinct cattle prion diseases and are extremely rare. The full extent of genetic susceptibilities to atypical BSEs is unknown; however, one atypical H-type case identified in the United States (2006) was most likely caused by a genetic mutation in the prion gene, E211K. We have identified an association of a bovine prion DNA haplotype with atypical BSE that is independent of E211K. The haplotype spans a portion of the prion gene that includes part of intron 2, the entire coding region of exon 3, and part of the three prime untranslated region of exon 3 (13 kb). Despite the low frequency of this haplotype among general cattle populations, it was present in a majority of H- and L-type atypical BSE cases from Canada, France, and the United States. This result indicates that there is a genetic component to atypical BSE susceptibility in addition to E211K.
http://www.ars.usda.gov/research/publications/publications.htm?SEQ_NO_115=234699
I ask Professor Kong ;
Thursday, December 04, 2008 3:37 PM Subject: RE: re--Chronic Wating Disease (CWD) and Bovine Spongiform Encephalopathies (BSE): Public Health Risk Assessment
''IS the h-BSE more virulent than typical BSE as well, or the same as cBSE, or less virulent than cBSE? just curious.....''
Professor Kong reply ;
.....snip
''As to the H-BSE, we do not have sufficient data to say one way or another, but we have found that H-BSE can infect humans. I hope we could publish these data once the study is complete.
Thanks for your interest.''
Best regards,
Qingzhong Kong, PhD Associate Professor Department of Pathology Case Western Reserve University Cleveland, OH 44106 USA
END...TSS
I look forward to further transmission studies, and a true ENHANCED BSE/atypical BSE surveillance program put forth testing all cattle for human and animal consumption for 5 years. a surveillance program that uses the most sensitive TSE testing, and has the personnel that knows how to use them, and can be trusted. I look forward to a stringent mad cow feed ban being put forth, and then strictly enforced. we need a forced, not voluntary feed ban, an enhanced feed ban at that, especially excluding blood. we need some sort of animal traceability. no more excuses about privacy. if somebody is putting out a product that is killing folks and or has the potential to kill you, then everybody needs to know who they are, and where that product came from. same with hospitals, i think medical incidents in all states should be recorded, and made public, when it comes to something like a potential accidental transmission exposure event. so if someone is out there looking at a place to go have surgery done, if you have several hospitals having these type 'accidental exposure events', than you can go some place else. it only makes sense. somewhere along the road, the consumer lost control, and just had to take whatever they were given, and then charged these astronomical prices. some where along the line the consumer just lost interest, especially on a long incubating disease such as mad cow disease i.e. Transmissible Spongiform Encephalopathy. like i said before, there is much more to the mad cow story than bovines and eating a hamburger, we must start focusing on all TSE in all species. ...TSS
Month Number of Tests
Feb 2009 -- 1,891
Jan 2009 -- 4,620
http://www.aphis.usda.gov/newsroom/hot_issues/bse/surveillance/ongoing_surv_results.shtml
P02.35
Molecular Features of the Protease-resistant Prion Protein (PrPres) in H-type BSE
Biacabe, A-G1; Jacobs, JG2; Gavier-Widén, D3; Vulin, J1; Langeveld, JPM2; Baron, TGM1 1AFSSA, France; 2CIDC-Lelystad, Netherlands; 3SVA, Sweden
Western blot analyses of PrPres accumulating in the brain of BSE-infected cattle have demonstrated 3 different molecular phenotypes regarding to the apparent molecular masses and glycoform ratios of PrPres bands. We initially described isolates (H-type BSE) essentially characterized by higher PrPres molecular mass and decreased levels of the diglycosylated PrPres band, in contrast to the classical type of BSE. This type is also distinct from another BSE phenotype named L-type BSE, or also BASE (for Bovine Amyloid Spongiform Encephalopathy), mainly characterized by a low representation of the diglycosylated PrPres band as well as a lower PrPres molecular mass. Retrospective molecular studies in France of all available BSE cases older than 8 years old and of part of the other cases identified since the beginning of the exhaustive surveillance of the disease in 20001 allowed to identify 7 H-type BSE cases, among 594 BSE cases that could be classified as classical, L- or H-type BSE. By Western blot analysis of H-type PrPres, we described a remarkable specific feature with antibodies raised against the C-terminal region of PrP that demonstrated the existence of a more C-terminal cleaved form of PrPres (named PrPres#2 ), in addition to the usual PrPres form (PrPres #1). In the unglycosylated form, PrPres #2 migrates at about 14 kDa, compared to 20 kDa for PrPres #1. The proportion of the PrPres#2 in cattle seems to by higher compared to the PrPres#1. Furthermore another PK–resistant fragment at about 7 kDa was detected by some more N-terminal antibodies and presumed to be the result of cleavages of both N- and C-terminal parts of PrP. These singular features were maintained after transmission of the disease to C57Bl/6 mice. The identification of these two additional PrPres fragments (PrPres #2 and 7kDa band) reminds features reported respectively in sporadic Creutzfeldt-Jakob disease and in Gerstmann-Sträussler-Scheinker (GSS) syndrome in humans.
http://www.neuroprion.com/pdf_docs/conferences/prion2007/abstract_book.pdf
Atypical BSE North America Update February 2009
http://bse-atypical.blogspot.com/2009/02/atypical-bse-north-america-update.html
http://bse-atypical.blogspot.com/2009/06/l-type-bse-h-type-bse-c-type-bse-ibnc.html
Detection of Pathologic Prion Protein in the Olfactory Bulb of Natural and Experimental Bovine Spongiform Encephalopathy Affected Cattle in Great Britain
Y. H. LEE, M. M. SIMMONS, S. A. C. HAWKINS, Y. I. SPENCER, P. WEBB, M. J. STACK, AND G. A. H. WELLS National Veterinary Research and Quarantine Service, Anyang, Republic of Korea (YHL); and Veterinary Laboratories Agency, Addlestone, Surrey, United Kingdom (MMS, SACH, YIS, PW, MJS, GAHW)
Abstract.
To investigate the relative involvement of the olfactory region in classical bovine spongiform encephalopathy (BSE), immunohistochemical labeling of prion protein scrapie (PrPSc) was scored in the brainstem, frontal cerebral cortex, and olfactory bulb of cattle with natural and experimental clinical cases of BSE in Great Britain. The intensity of immunolabeling was greatest in the brainstem, but PrPSc was also detected in the olfactory bulb and the cerebral cortex. A diffuse, nonparticulate labeling, possibly due to abundance of cellular PrP, was consistently observed in the olfactory glomeruli of the cases and negative controls. Involvement of the olfactory bulb in BSE and other naturally occurring TSEs of animals raises speculation as to an olfactory portal of infection or a route of excretion of the prion agent.
Key words: BSE; olfactory bulb; olfactory glomeruli; PrPSc; PrPC.
snip...
Only two cases of atypical BSE have been reported from GB; both were H type and were diagnosed on molecular characterization.10 Detailed neuropathologic description of atypical BSE is limited to the L type, originally named bovine amyloidotic spongiform encephalopathy (BASE).3
snip...
In BASE, in addition to PrP-amyloid plaques in the olfactory bulb, the highest levels of PrPSc were recovered from the thalamus and olfactory regions.2 Also, in both captive and free-ranging mule deer with chronic wasting disease, the olfactory cortex has been found to be among the most severely affected areas of the brain.8 Such patterns may be solely a reflection of selective vulnerability of certain neuroanatomic loci and, in end-stage disease, a reflection of phenotype, but equally, they arouse speculation as to possible olfactory portals of infection or excretion of agent. In human transmissible spongiform encephalopathies (TSEs), PrPSc immunolabeling has been reported in the olfactory tract of a variant Creutzfeldt-Jakob disease patient, and in sporadic Creutzfeldt-Jakob disease (sCJD), selective deposition of PrPSc in olfactory glomeruli, olfactory tracts, and olfactory cortex is recorded.6 In the latter study, PrPSc was also reported in the cilia of olfactory receptor neurons and basal cells of the olfactory epithelium but not in the respiratory epithelium. Detection of PrPSc in an olfactory mucosa biopsy, performed 45 days after disease onset in a sCJD patient, led to the suggestion that the involvement of olfactory epithelium might be an early event in sCJD.6
snip...
The present study demonstrates that, in clinical cases, involvement of the olfactory lobe is a consistent phenotypic feature of classic BSE but, in contrast to BASE,3 it is not preferentially affected compared with the cerebral cortex or brainstem. In studies of the pathogenesis of classical BSE after oral exposure, infectivity has not been demonstrated in nasal mucosa,11 but it has been shown, albeit at low titer, in this tissue in clinical cases of scrapie of sheep and goats.5 The detection of PrPSc in olfactory bulb in this study and indeed in other TSEs in terminal disease suggests that olfactory pathways cannot be excluded as a secondary or ancillary route of infection.
http://www.vetpathology.org/cgi/content/abstract/46/1/59
http://www.vetpathology.org/cgi/reprint/46/1/59
???$$$???
Research Project: Study of Atypical Bse Location: Virus and Prion Diseases of Livestock
Project Number: 3625-32000-086-05 Project Type: Specific Cooperative Agreement
Start Date: Sep 15, 2004 End Date: Sep 14, 2009
Objective: The objective of this cooperative research project with Dr. Maria Caramelli from the Italian BSE Reference Laboratory in Turin, Italy, is to conduct comparative studies with the U.S. bovine spongiform encephalopathy (BSE) isolate and the atypical BSE isolates identified in Italy. The studies will cover the following areas: 1. Evaluation of present diagnostics tools used in the U.S. for the detection of atypical BSE cases. 2. Molecular comparison of the U.S. BSE isolate and other typical BSE isolates with atypical BSE cases. 3. Studies on transmissibility and tissue distribution of atypical BSE isolates in cattle and other species.
Approach: This project will be done as a Specific Cooperative Agreement with the Italian BSE Reference Laboratory, Istituto Zooprofilattico Sperimentale del Piemonte, in Turin, Italy. It is essential for the U.S. BSE surveillance program to analyze the effectiveness of the U.S diagnostic tools for detection of atypical cases of BSE. Molecular comparisons of the U.S. BSE isolate with atypical BSE isolates will provide further characterization of the U.S. BSE isolate. Transmission studies are already underway using brain homogenates from atypical BSE cases into mice, cattle and sheep. It will be critical to see whether the atypical BSE isolates behave similarly to typical BSE isolates in terms of transmissibility and disease pathogenesis. If transmission occurs, tissue distribution comparisons will be made between cattle infected with the atypical BSE isolate and the U.S. BSE isolate. Differences in tissue distribution could require new regulations regarding specific risk material (SRM) removal.
http://www.ars.usda.gov/research/projects/projects.htm?ACCN_NO=408490
???$$$???
2009 UPDATE ON ALABAMA AND TEXAS MAD COWS 2005 and 2006
http://bse-atypical.blogspot.com/2006/08/bse-atypical-texas-and-alabama-update.html
P.4.25
Human susceptibility to atypical scrapie
Chris Plinston, Rona Barron, Nora Hunter The Roslin Institute and R(D)SVS, University of Edinburgh, UK
Background: Isolates of classical sheep scrapie are thought to pose little risk to humans as there have been no documented links between presence of sheep scrapie and the development of human TSE disease. However, the link between BSE and the development of vCJD in humans proves that a risk does exist from ruminant TSE disease, and therefore all new ruminant TSEs may potentially be transmissible to humans. Due to increased sensitivity of TSE diagnostic assay systems, a new TSE of sheep termed ‘atypical scrapie’ has been identified. This disease has been difficult to identify, and is found mainly in sheep which are previously thought to have a genetic makeup that made them resistant to scrapie. It is unclear whether this is a new TSE of sheep, an old disease which has only been identified through increased surveillance, or if it represents the phenotype of classical scrapie in so called ‘resistant’ sheep PrP genotypes.
Objectives: The objective of the study is to assess relative transmissibility of atypical scrapie isolates to humans and the associated risk to the population.
Methods: In order to determine whether atypical scrapie poses a risk to human health we have transmitted isolates from three different sheep PrP genotypes to our gene targeted transgenic mice which express human PrP with the M129V polymorphism known to be important in human susceptibility to disease. Mice of all three PrP genotypes have been inoculated intracerebrally with atypical scrapie isolates.
Discussion: In order to prevent the emergence of a new human TSE, we need to be able to assess the risk to humans from new emerging TSEs in livestock. The study of atypical scrapie infection in these transgenic lines could therefore provide important information on the host range and disease characteristics associated with such isolates. Preventative measures could then be put in place before this disease gives rise to another human disease variant and an underlying level of infection in the population.
P.5.21
Parallels between different forms of sheep scrapie and types of Creutzfeldt-Jakob disease (CJD)
Wiebke M. Wemheuer1, Sylvie L. Benestad2, Arne Wrede1, Wilhelm E. Wemheuer3, Tatjana Pfander1, Bjørn Bratberg2, Bertram Brenig3,Walter J. Schulz-Schaeffer1 1University Medical Center Goettingen, Germany; 2Institute of Veterinary Medicine Oslo, Norway; 3Institute of Veterinary Medicine Goettingen, Germany
Background: Scrapie in sheep and goats is often regarded as the archetype of prion diseases. In 1998, a new form of scrapie – atypical/Nor98 scrapie – was described that differed from classical scrapie in terms of epidemiology, Western blot profile, the distribution of pathological prion protein (PrPSc) in the body and its stability against proteinase K. In a similar way, distinct disease types exist in sporadic Creutzfeldt-Jakob disease (CJD). They differ with regard to their clinical outcome, Western blot profile and PrPSc deposition pattern in the central nervous system (CNS).
Objectives: The comparison of PrPSc deposits in sheep scrapie and human sporadic CJD. Methods: Tissues of the CNS of sheep with classical scrapie, sheep with atypical/Nor98 scrapie and 20 patients with sporadic CJD were examined using the sensitive Paraffin Embedded Tissue (PET) blot method. The results were compared with those obtained by immunohistochemistry. With the objective of gaining information on the protein conformation, the PrPSc of classical and atypical/Nor98 sheep scrapie and sporadic CJD was tested for its stability against denaturation with guanidine hydrochloride (GdnHCl) using a Membrane Adsorption Assay.
Results: The PrPSc of atypical/Nor98 scrapie cases and of CJD prion type 1 patients exhibits a mainly reticular/synaptic deposition pattern in the brain and is relatively sensitive to denaturation with GdnHCl. In contrast classical scrapie cases and CJD prion type 2 patients have a more complex PrPSc deposition pattern in common that consists of larger PrPSc aggregates and the PrPSc itself is comparatively stable against denaturation.
Discussion: The similarity between CJD types and scrapie types indicates that at least two comparable forms of the misfolded prion protein exist beyond species barriers and can elicit prion diseases. It seems therefore reasonable to classify classical and atypical/Nor98 scrapie – in analogy to the existing CJD types – as different scrapie types.
P.4.31
Prion infectivity in milk from ARQ/ARQ sheep experimentally infected with Scrapie and MAEDI-VISNA virus
Ciriaco Ligios1, Maria Giovanna Cancedda1, Antonello Carta2, Cinzia Santucciu1 Caterina Maestrale1, Francesca Demontis1, Sonia Attene1, Maria Giovanna Tilocca1, Cristiana Patta1, Massimo Basagni5, Paola Melis1, James C. De- Martini3, Christina Sigurdson4 1Istituto Zooprofilattico Sperimentale della Sardegna, Italy; 2Research Unit: Genetics and Biotechnology, DIRPA, AGRIS Sardinia, Italy; 3Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO, USA; 4Department of Pathology, School of Medicine, University of California San Diego, USA; 5Prion Diagnostica Rho, Italy
Background: Scrapie in sheep is characterized by the deposition of misfolded and aggregated prion protein (PrPSc) in the central nervous system (CNS) and within the lymphoreticular system (LRS). PrPSc was shown to accumulate in organs beyond the CNS and the LRS when lymphofollicular or granulomatous inflammation was also present. Objectives: Our aim was to determine whether ectopic PrPSc accumulation in the inflamed mammary gland of sheep with scrapie results in infectious prion secretion into the milk.
Methods: We fed approximately 1.1 - 2.1 L of milk from sheep with lymphofollicular mastitis and clinical scrapie to each of 8 ARQ/ARQ lambs derived from scrapie-free flocks. The milk donor sheep had been previously inoculated with Maedi-Visna virus (MVV) intratracheally and intravenously and scrapie brain homogenate orally. In addition, 3 ARQ/ARQ lambs were fed approximately 1.4 – 1.7 L of milk from ARQ/ARQ sheep that had been experimentally infected with only scrapie. Additional control ARQ/ARQ lambs were inoculated with scrapie brain homogenate only, or with milk from uninfected sheep.
Results: Two lambs which had received milk from sheep with mastitis and scrapie developed clinical signs of scrapie at 677 and 745 days post-inoculation. One additional clinically healthy lamb from this group, which was sacrificed for a cause unrelated to scrapie, was found to have PrPSc in brain and tonsil. The control lambs and those which received milk from sheep affected only with scrapie are, to date, clinically healthy.
Discussion: This is the first evidence of clinical scrapie in sheep fed milk from scrapie sick sheep. The experiment is ongoing, however these preliminary results indicate that milk and/or colostrum from ARQ/ARQ sheep with clinical scrapie and lymphofollicular mastitis could contribute to scrapie transmission.
P.4.50
Successful oral transmission of classical scrapie to ARR/ARQ sheep
Sarah Jo Moore1, Hugh Simmons1, Timm Konold1, Glenda Dexter1, Steve Ryder2 1Veterinary Laboratories Agency, 2Home Office Animals (Scientific Procedures) Inspectorate
Background: Scrapie susceptibility in sheep is strongly influenced by allelic variation in the gene which encodes the prion protein. As part of the National Scrapie Plan (NSP) for Great Britain ram genotyping and selective breeding has been used to increase the number of sheep in the national flock that are genetically resistant to classical scrapie. According to the NSP, ARR/ARQ sheep are considered ‘genetically resistant’ to scrapie, although four field cases have been detected since 2002.
Objective: To investigate the susceptibility and pathogenesis of classical scrapie in ARR/ARQ sheep.
Methods: TSE-free lambs were dosed orally with 5g of pooled brain from scrapie clinical suspects. Timed-culls were performed at 12 and 24 months post-inoculation (mpi) then six monthly thereafter. All sheep underwent a detailed clinical examination before culling. At post-mortem 41 tissues were sampled from all major body systems. Detection of disease-associated prion protein (PrPd) in central nervous system tissues was done by immunohistochemistry (IHC), Western blot and Bio-rad elisa. All other tissues were examined by IHC only.
Results: PrPd was first detected in the LRS at 24 mpi, in the central nervous system (CNS) at 36 mpi, and in the peripheral nervous system (PNS) at 66 mpi. Throughout the time course PrPd accumulation in LRS tissues was more restricted and less severe than in CNS and PNS tissues. The first confirmed clinical case occurred at 72 mpi.
Discussion: We have shown that ARR/ARQ sheep can be infected with classical scrapie via the oral route.The pathogenesis of scrapie in ARR/ARQ sheep appears to be different to that in sheep of susceptible genotypes. While VRQ/VRQ clinical suspects have extensive LRS involvement only one LRS tissue was positive in the ARR/ARQ clinical suspect. This could suggest that infectivity had travelled to the CNS via a nongastrointestinal route. ARR/ARQ sheep may act as ‘silent carriers’ of disease. However, PrPd accumulation in the gut-associated lymphoid tissues was mild and restricted so non-faecal routes may be more important in lateral transmission from this genotype. The tissue distribution of PrPd accumulation in this study suggest that currently available ‘live tests’ for preclinical diagnosis – third eyelid and/or rectoanal mucosa-associated lymphoid tissue (RAMALT) biopsy – may be unrewarding in sheep of this genotype.
http://www.prion2009.com/sites/default/files/Prion2009_Book_of_Abstracts.pdf
Wednesday, July 1, 2009
Nor98 scrapie identified in the United States J Vet Diagn Invest 21:454-463 (2009)
http://nor-98.blogspot.com/2009/07/nor98-scrapie-identified-in-united.html
P03.141
Aspects of the Cerebellar Neuropathology in Nor98
Gavier-Widén, D1; Benestad, SL2; Ottander, L1; Westergren, E1 1National Veterinary Insitute, Sweden; 2National Veterinary Institute,
Norway Nor98 is a prion disease of old sheep and goats. This atypical form of scrapie was first described in Norway in 1998. Several features of Nor98 were shown to be different from classical scrapie including the distribution of disease associated prion protein (PrPd) accumulation in the brain. The cerebellum is generally the most affected brain area in Nor98. The study here presented aimed at adding information on the neuropathology in the cerebellum of Nor98 naturally affected sheep of various genotypes in Sweden and Norway. A panel of histochemical and immunohistochemical (IHC) stainings such as IHC for PrPd, synaptophysin, glial fibrillary acidic protein, amyloid, and cell markers for phagocytic cells were conducted. The type of histological lesions and tissue reactions were evaluated. The types of PrPd deposition were characterized. The cerebellar cortex was regularly affected, even though there was a variation in the severity of the lesions from case to case. Neuropil vacuolation was more marked in the molecular layer, but affected also the granular cell layer. There was a loss of granule cells. Punctate deposition of PrPd was characteristic. It was morphologically and in distribution identical with that of synaptophysin, suggesting that PrPd accumulates in the synaptic structures. PrPd was also observed in the granule cell layer and in the white matter. The pathology features of Nor98 in the cerebellum of the affected sheep showed similarities with those of sporadic Creutzfeldt-Jakob disease in humans.
***The pathology features of Nor98 in the cerebellum of the affected sheep showed similarities with those of sporadic Creutzfeldt-Jakob disease in humans.
http://www.prion2007.com/pdf/Prion%20Book%20of%20Abstracts.pdf
PR-26
NOR98 SHOWS MOLECULAR FEATURES REMINISCENT OF GSS
R. Nonno1, E. Esposito1, G. Vaccari1, E. Bandino2, M. Conte1, B. Chiappini1, S. Marcon1, M. Di Bari1, S.L. Benestad3, U. Agrimi1 1 Istituto Superiore di Sanità, Department of Food Safety and Veterinary Public Health, Rome, Italy (
[email protected]); 2 Istituto Zooprofilattico della Sardegna, Sassari, Italy; 3 National Veterinary Institute, Department of Pathology, Oslo, Norway
Molecular variants of PrPSc are being increasingly investigated in sheep scrapie and are generally referred to as "atypical" scrapie, as opposed to "classical scrapie". Among the atypical group, Nor98 seems to be the best identified. We studied the molecular properties of Italian and Norwegian Nor98 samples by WB analysis of brain homogenates, either untreated, digested with different concentrations of proteinase K, or subjected to enzymatic deglycosylation. The identity of PrP fragments was inferred by means of antibodies spanning the full PrP sequence. We found that undigested brain homogenates contain a Nor98-specific PrP fragment migrating at 11 kDa (PrP11), truncated at both the C-terminus and the N-terminus, and not N-glycosylated. After mild PK digestion, Nor98 displayed full-length PrP (FL-PrP) and N-glycosylated C-terminal fragments (CTF), along with increased levels of PrP11. Proteinase K digestion curves (0,006-6,4 mg/ml) showed that FL-PrP and CTF are mainly digested above 0,01 mg/ml, while PrP11 is not entirely digested even at the highest concentrations, similarly to PrP27-30 associated with classical scrapie. Above 0,2 mg/ml PK, most Nor98 samples showed only PrP11 and a fragment of 17 kDa with the same properties of PrP11, that was tentatively identified as a dimer of PrP11. Detergent solubility studies showed that PrP11 is insoluble in 2% sodium laurylsorcosine and is mainly produced from detergentsoluble, full-length PrPSc. Furthermore, among Italian scrapie isolates, we found that a sample with molecular and pathological properties consistent with Nor98 showed plaque-like deposits of PrPSc in the thalamus when the brain was analysed by PrPSc immunohistochemistry. Taken together, our results show that the distinctive pathological feature of Nor98 is a PrP fragment spanning amino acids ~ 90-155. This fragment is produced by successive N-terminal and C-terminal cleavages from a full-length and largely detergent-soluble PrPSc, is produced in vivo and is extremely resistant to PK digestion.
*** Intriguingly, these conclusions suggest that some pathological features of Nor98 are reminiscent of Gerstmann-Sträussler-Scheinker disease.
119
http://www.neuroprion.com/pdf_docs/conferences/prion2006/abstract_book.pdf
A newly identified type of scrapie agent can naturally infect sheep with resistant PrP genotypes
Annick Le Dur*,?, Vincent Béringue*,?, Olivier Andréoletti?, Fabienne Reine*, Thanh Lan Laï*, Thierry Baron§, Bjørn Bratberg¶, Jean-Luc Vilotte?, Pierre Sarradin**, Sylvie L. Benestad¶, and Hubert Laude*,?? +Author Affiliations
*Virologie Immunologie Moléculaires and ?Génétique Biochimique et Cytogénétique, Institut National de la Recherche Agronomique, 78350 Jouy-en-Josas, France; ?Unité Mixte de Recherche, Institut National de la Recherche Agronomique-Ecole Nationale Vétérinaire de Toulouse, Interactions Hôte Agent Pathogène, 31066 Toulouse, France; §Agence Française de Sécurité Sanitaire des Aliments, Unité Agents Transmissibles Non Conventionnels, 69364 Lyon, France; **Pathologie Infectieuse et Immunologie, Institut National de la Recherche Agronomique, 37380 Nouzilly, France; and ¶Department of Pathology, National Veterinary Institute, 0033 Oslo, Norway
Edited by Stanley B. Prusiner, University of California, San Francisco, CA (received for review March 21, 2005)
Abstract Scrapie in small ruminants belongs to transmissible spongiform encephalopathies (TSEs), or prion diseases, a family of fatal neurodegenerative disorders that affect humans and animals and can transmit within and between species by ingestion or inoculation. Conversion of the host-encoded prion protein (PrP), normal cellular PrP (PrPc), into a misfolded form, abnormal PrP (PrPSc), plays a key role in TSE transmission and pathogenesis. The intensified surveillance of scrapie in the European Union, together with the improvement of PrPSc detection techniques, has led to the discovery of a growing number of so-called atypical scrapie cases. These include clinical Nor98 cases first identified in Norwegian sheep on the basis of unusual pathological and PrPSc molecular features and "cases" that produced discordant responses in the rapid tests currently applied to the large-scale random screening of slaughtered or fallen animals. Worryingly, a substantial proportion of such cases involved sheep with PrP genotypes known until now to confer natural resistance to conventional scrapie. Here we report that both Nor98 and discordant cases, including three sheep homozygous for the resistant PrPARR allele (A136R154R171), efficiently transmitted the disease to transgenic mice expressing ovine PrP, and that they shared unique biological and biochemical features upon propagation in mice. These observations support the view that a truly infectious TSE agent, unrecognized until recently, infects sheep and goat flocks and may have important implications in terms of scrapie control and public health.
http://www.pnas.org/content/102/44/16031.abstract
Monday, December 1, 2008
When Atypical Scrapie cross species barriers
Authors
Andreoletti O., Herva M. H., Cassard H., Espinosa J. C., Lacroux C., Simon S., Padilla D., Benestad S. L., Lantier F., Schelcher F., Grassi J., Torres, J. M., UMR INRA ENVT 1225, Ecole Nationale Veterinaire de Toulouse.France; ICISA-INlA, Madrid, Spain; CEA, IBiTec-5, DSV, CEA/Saclay, Gif sur Yvette cedex, France; National Veterinary Institute, Postboks 750 Sentrum, 0106 Oslo, Norway, INRA IASP, Centre INRA de Tours, 3738O Nouzilly, France.
Content
Atypical scrapie is a TSE occurring in small ruminants and harbouring peculiar clinical, epidemiological and biochemical properties. Currently this form of disease is identified in a large number of countries. In this study we report the transmission of an atypical scrapie isolate through different species barriers as modeled by transgenic mice (Tg) expressing different species PRP sequence.
The donor isolate was collected in 1995 in a French commercial sheep flock. inoculation into AHQ/AHQ sheep induced a disease which had all neuro-pathological and biochemical characteristics of atypical scrapie. Transmitted into Transgenic mice expressing either ovine or PrPc, the isolate retained all the described characteristics of atypical scrapie.
Surprisingly the TSE agent characteristics were dramatically different v/hen passaged into Tg bovine mice. The recovered TSE agent had biological and biochemical characteristics similar to those of atypical BSE L in the same mouse model. Moreover, whereas no other TSE agent than BSE were shown to transmit into Tg porcine mice, atypical scrapie was able to develop into this model, albeit with low attack rate on first passage.
Furthermore, after adaptation in the porcine mouse model this prion showed similar biological and biochemical characteristics than BSE adapted to this porcine mouse model. Altogether these data indicate.
(i) the unsuspected potential abilities of atypical scrapie to cross species barriers
(ii) the possible capacity of this agent to acquire new characteristics when crossing species barrier
These findings raise some interrogation on the concept of TSE strain and on the origin of the diversity of the TSE agents and could have consequences on field TSE control measures.
http://www.neuroprion.org/resources/pdf_docs/conferences/prion2008/abstract-book-prion2008.pdf
NOR-98 ATYPICAL SCRAPIE 5 cases documented in USA in 5 different states USA 2007
http://nor-98.blogspot.com/2008/04/seac-spongiform-encephalopathy-advisory.html
Tuesday, June 3, 2008 SCRAPIE USA UPDATE JUNE 2008 NOR-98 REPORTED PA
http://nor-98.blogspot.com/2008/06/scrapie-usa-update-june-2008-nor-98.html
Monday, September 1, 2008
RE-FOIA OF DECLARATION OF EXTRAORDINARY EMERGENCY BECAUSE OF AN ATYPICAL T.S.E. (PRION DISEASE) OF FOREIGN ORIGIN IN THE UNITED STATES [No. 00-072-1] September 1, 2008
http://foiamadsheepmadrivervalley.blogspot.com/2008/09/re-foia-of-declaration-of-extraordinary.html
http://nor-98.blogspot.com/
http://scrapie-usa.blogspot.com/
O.11.2
Transmission of bovine-passaged TME prion strain to macaque
Emmanuel Comoy1, Juergen Richt2, Valérie Durand1, Sophie Freire1, Evelyne Correia1, Amir Hamir2, Marie- Madeleine Ruchoux1, Paul Brown1, Jean-Philippe Deslys1 1Atomic Energy Commission, France; 2National Animal Disease Center, USA
Background: The origin of Transmissible Mink Encephalopathy (TME) remains controversial, with historical evidence for either scrapie or BSE as the source of separate outbreaks. The case for BSE is supported by the experimental transmission of BSE from cattle to mink, whereas scrapie failed to transmit from sheep to mink. Transmission of TME from mink to cynomolgus macaque is inefficient, suggesting a low risk of TSE to human health. Because only typical and atypical BSE prion strains have been shown to be easily transmissible from non-primate to primate species, we have investigated transmissibility to monkeys of a cattle-passaged strain of TME.
Objectives: To compare the transmissibility of cattle-passaged TME prions to the transmissibility of other cattle-passaged prions.
Methods: Monkeys (cynomolgus macaques) were intra-cerebrally infected with classical BSE, atypical BSE strains (BASE and BSE H), and a cattle-passaged TME strain. Animals were regularly monitored for clinical signs, and extensive biochemical and immunohistochemical studies were performed on lymphoid and neural tissues of animals that have already died.
Results and discussion: The animal infected with the cattlepassaged TME strain developed neurological clinical signs after a very short incubation period of 20 months, with a clinical picture that is clearly different from that of BSE/vCJD-infected animals, but similar to that of BASE (the animal is still alive at the time of this writing but post-mortem histopathological and immunohistochemical analyses will provide a more complete characterization of the disease). This new transmission reinforces the notion of human vulnerability to prion diseases passaged through cattle, perhaps due to a low species barrier.
http://www.prion2009.com/sites/default/files/Prion2009_Book_of_Abstracts.pdf
Saturday, December 01, 2007
Phenotypic Similarity of Transmissible Mink Encephalopathy in Cattle and L-type Bovine Spongiform Encephalopathy in a Mouse Model
http://transmissible-mink-encephalopathy.blogspot.com/2007/12/phenotypic-similarity-of-transmissible.html
Tuesday, July 21, 2009
Transmissible mink encephalopathy - review of the etiology Folia Neuropathologica 2/2009
http://transmissible-mink-encephalopathy.blogspot.com/2009/07/transmissible-mink-encephalopathy.html
http://transmissible-mink-encephalopathy.blogspot.com/
O.4.5
Recent results on the transmission, detection, and pathogenesis of chronic wasting disease
Edward A. Hoover1, Nicholas J. Haley1, Candace K. Mathiason1, Nathanial D. Denkers1, Davis M. Seelig1, and Glenn C. Telling2 1Colorado State University, USA; 2University of Kentucky, Lexington, USA
Background: Chronic wasting disease (CWD) of cervids is distinguished by its high level of transmissibility. We have previously shown that body fluids and excretions contain infectious CWD prions. The precise means by which these prions may access, traffick and cause disease in cervids (or other species) remains to be elucidated. Here we present current results of studies employing cervid and cervidized mouse bioassays and serial protein misfolding cyclic amplification (sPMCA) to address these questions.
Objectives: We sought to determine: (1) which components of blood and saliva carry prion infectivity; (2) whether long term, very low level CWD infection undetectable by conventional assays may exist in cervids; (3) whether CWD can be transmitted via aerosol or minor oral lesions; and (4) potential alternate pathways of CWD prion entry and dissemination exist in vivo.
Methods: The studies described utilized cervid and cervid-PrPexpressing transgenic mouse bioassays, serial protein misfolding cyclic amplification (sPMCA), and high resolution immunostaining.
Results: We present data to demonstrate: (1) localization of infectious CWD prions chiefly to the circulating CD21-expressing B/DC cell fractions of blood; (2) very low level subclinical CWD infection in cervids detectable by sPMCA and bioassay; (3) CWD transmission by aerosol and minor oral epithelial lesions; and (4) evidence of villous autonomic neural uptake and dissemination of PrPCWD.
Discussion: These findings contribute insights into CWD prion transmission, trafficking, and dissemination. The results also help direct efforts toward ante-mortem detection of CWD in cervids and raise interesting questions regarding duration of sub-clinical prion infection in cervids or other species.
O.11.1
Prions in feces of asymptomatic deer
Gültekin Tamgüney1,2, Michael W. Miller3, Lisa L. Wolfe3, Tracey M. Sirochman3, David V. Glidden4, Christina Palmer 1, Azucena Lemus5, Stephen J. DeArmond5, Stanley B. Prusiner1,2 1Institute for Neurodegenerative Diseases, University of California, San Francisco, USA; 2Department of Neurology, University of California, San Francisco, USA; 3Colorado Division of Wildlife, Wildlife Research Center, Fort Collins, USA; 4Department of Epidemiology and Biostatistics, University of California, San Francisco, USA; 5Department of Pathology, University of California, San Francisco, USA
Background: Chronic wasting disease (CWD) of several species in the deer family and scrapie of sheep are infectious prion diseases that are transmitted naturally within affected host populations. Even though several potential sources of infectivity have been identified in secretions and excretions from symptomatic animals, the biological importance of these sources in sustaining epidemics remains unclear.
Objective/Methods: Feces from mule deer (Odocoileus hemionus) were periodically collected before and after oral inoculation with CWD prions until the deer developed clinical signs of CWD. Fecal samples were irradiated and intracerebrally inoculated into transgenic mice overexpressing cervid PrP. Results: We report that asymptomatic CWD-infected mule deer excrete CWD prions in their feces long before they develop clinical signs of prion disease. Intracerebral inoculation of irradiated deer feces into transgenic mice overexpressing cervid PrP revealed infectivity in 14 of 15 fecal samples collected from 5 deer at 7–11 months before the onset of neurological disease. Even though prion concentrations in deer feces were much lower than those in brain tissue from the same deer collected at the disease terminus, the estimated total infectious dose excreted in feces by an infected deer over the disease course may approximate the total contained in brain tissue.
Discussion: Fecal prion excretion over long periods of time by infected deer provides a likely natural mechanism that may explain the high incidence and efficient horizontal transmission of CWD within deer herds, as well as prion transmission among susceptible cervid species.
P.4.11
Detection of subclinical CWD infection in conventional test-negative deer long after oral exposure to urine and feces from CWD+ deer
Nicholas Haley1, Candace Mathiason1, Mark Zabel1, Glenn Telling2, Edward Hoover1 1Colorado State University, USA; 2University of Kentucky, USA
Background: Chronic wasting disease (CWD) of cervids is distinguished by its high level of transmissibility, wherein bodily fluids and excretions are thought to play an important role. Using cervid bioassay and established CWD detection methods, we have previously identified infectious prions in saliva and blood but not urine or feces of CWD+ donors. More recently, we were able to identify very low concentrations of CWD prions in urine of deer by cervid PrP transgenic (Tg[Cer- PrP]) mouse bioassay and serial protein misfolding cyclic amplification (sPMCA).
Objectives: In these experiments, we sought to investigate whether deer previously exposed orally to urine and feces from CWD+ deer, while conventional test-negative, may actually be harboring very low level CWD infection, not evident in the 19 month observation period in the previous studies. Methods: Brain and lymph nodes from conventional test-negative deer were reanalyzed for CWD prions by sPMCA and cervid transgenic mouse bioassay in parallel with appropriate tissue-matched positive and negative controls.
Results: PrPres was detected in tissues of exposed deer by both sPMCA and Tg[CerPrP] mouse bioassay; each assay revealed very low levels of CWD prions previously undetectable by western blot, ELISA, or IHC. D
iscussion: The finding of subclinical infection in deer orally exposed to urine and feces (1) suggests that a prolonged subclinical state can exist such that observation periods in excess of two years may be needed to detect CWD infection and (2) illustrates the sensitive and specific application of sPMCA in the diagnosis of low level prion infection.
P.4.27
Minor oral lesions facilitate CWD infection
Nathaniel Denkers1, Glenn Telling2, Edward Hoover1 1Colorado State University, USA; 2University of Kentucky, USA
Background: While the exact mechanisms of chronic wasting disease (CWD) prion transmission, entry, and trafficking remain incompletely elucidated, transmission by exposure of the oral and/or nasal mucous membranes seems certain. As part of foraging, cervids likely experience minor lesions in the oral mucous membranes; these could have impact on susceptibility to prion entry and subsequent infection.
Objectives: To explore this potential co-factor, we used cervid PrP transgenic mice to assess whether or not micro-abrasions to the tongue may enhance susceptibility to oral CWD infection.
Methods: Two sets of FVB mice transgenically expressing the normal cervid PrPC protein [Tg(cerPrP) mice], with or without abrasions on the lingual mucosa, were inoculated orally with 10ìl of a 10% w/v brain homogenate from either CWD-positive or negative deer. Abrasions were created by lightly scratching the dorsal lingual epithelium with a 30g needle. Cohorts were sacrificed at 1, 2, 12, 52, 78, and 104 weeks post inoculation (pi) or when signs of neurologic disease were observed. Tongue, lymphoid tissue, and the brain were assessed by western blotting and immunohistochemistry to detect the CWD abnormal prion protein (PrPCWD).
Results: Between 296 and 430 dpi, 8 of the 9 CWD-inoculated mice with lingual lesions developed clinical signs of neurologic dysfunction mandating euthanasia. The brains of all 8 mice were positive by western blot and immunohistochemistry for PrPCWD. Conversely, all mice without oral lesions remain asymptomatic at >450 dpi. No evidence of PrPCWD was detected in any Tg(cerPrP) mice examined at any of the preterminal time points.
Discussion: Micro-abrasions to the lingual surface substantially facilitate CWD transmission, suggesting a co-factor that may be significant in foraging cervids or other species. Earlier post-inoculation sampling intervals (1 and 4 hours) are in progress in an attempt to determine when and where PrPCWD might be detectable after oral mucosal exposure.
P.4.26
Aerosol and intranasal transmission of CWD
Nathaniel Denkers1, Glenn Telling2, Edward Hoover1 1Colorado State University, USA; 2University of Kentucky, USA
Background: Little is known regarding the potential risk posed by aerosolized prions. Chronic wasting disease (CWD) prions are present in saliva and urine of infected animals and it is clearly established that CWD is transmitted horizontally, almost surely by mucosal exposure. However, the potential transmissibility of CWD by aerosol or nasal routes is not known.
Objectives: The present study was therefore designed to determine whether CWD prions are transmissible by these routes of exposure using the cervid PrP transgenic mouse model of CWD infection.
Methods: FVB mice transgenically expressing the normal cervid PrPC protein [Tg(cerPrP) mice] were exposed to CWD prions by either nose-only exposure to an aerosol generated by nebulizing 0.5 ml of a 5% w/v CWD+ brain homogenate or 10ƒÊl of a 10% w/v CWD+ brain homogenate by dropwise instillation into the nostrils. Mice were monitored for signs of clinical disease for up to 755 days post inoculation (dpi). Nasal mucosa, vomeronasal organ, lymphoid tissue, and the brain were assessed for PrPCWD by western blotting and immunohistochemistry.
Results: Six of 7 aerosol-exposed Tg(cerPrP) mice developed clinical signs of neurologic dysfunction between 411 and 749 dpi mandating euthanasia. In all symptomatic mice CWD infection was confirmed by histopathologic lesions and detection of PrPCWD within the brain. Two of 9 IN-inoculated Tg(cerPrP) mice also developed TSE between 417 and 755 dpi, again confirmed by PrPCWD detection within the brain. No evidence of PrPCWD was detected in any Tg(cerPrP) mice examined at any of the pre-terminal time points.
Discussion: CWD is transmissible by aerosol as well as intranasal exposurePpotentially implicating exposure via the respiratory system in CWD and potentially other prion diseases. Studies examining very early post-inoculation sampling intervals (1 and 4 hours) are in progress in an attempt to determine initial prion targeting and entry portals.
SNIP...PLEASE SEE FULL TEXT ;
Monday, October 19, 2009
Atypical BSE, BSE, and other human and animal TSE in North America Update October 19, 2009
http://bse-atypical.blogspot.com/2009/10/atypical-bse-bse-and-other-human-and.html