Volume 18, Number 1—January 2012 Dispatch
Oral Transmission of L-type Bovine Spongiform Encephalopathy in Primate Model
Nadine Mestre-Francés , Simon Nicot, Sylvie Rouland, Anne-Gaëlle Biacabe, Isabelle Quadrio, Armand Perret-Liaudet, Thierry Baron, and Jean-Michel Verdier Author affiliations: Institut National de la Santé et de la Recherche Médicale (INSERM) U710, Montpellier, France (N. Mestre-Francés, S. Rouland, J.-M. Verdier); Université Montpellier 2, Montpellier (N. Mestre-Francés, S. Rouland, J.-M. Verdier); École Pratique des Hautes Etudes, Paris, France (N. Mestre-Francés, S. Rouland, J.-M. Verdier); Agence Nationale de Sécurité Sanitaire, Lyon, France (S. Nicot, A.-G. Biacabe, T. Baron); Hopitaux Civils de Lyon, Lyon, France (I. Quadrio, A. Perret-Liaudet); Université Lyon 1, Lyon (I. Quadrio, A. Perret-Liaudet); INSERM U1028, Lyon (I. Quadrio, A. Perret-Liaudet); Centre National de la Recherche Scientifique, Lyon (I. Quadrio, A. Perret-Liaudet)
Abstract
We report transmission of atypical L-type bovine spongiform encephalopathy to mouse lemurs after oral or intracerebral inoculation with infected bovine brain tissue. After neurologic symptoms appeared, transmissibility of the disease by both inoculation routes was confirmed by detection of disease-associated prion protein in samples of brain tissue.
SNIP...
The Study A total of 12 mouse lemurs of both sexes (Center for Breeding and Experimental Conditioning of Animal Models, University Montpellier 2, Montpellier, France) were maintained in animal Biosafety Level 3 facilities, according to requirements of the French ethics committee (authorization CE-LR-0810). Young and adult lemurs were fed (8 animals) or IC inoculated (4 animals) with 5 or 50 mg of L-BSE–infected brain tissue (10% homogenate in 5% glucose) (Table). The isolate for the L-BSE agent (02–2528) was derived from cattle in France (11). When progression of prion disease was evident, the lemurs were euthanized and their brains were isolated. Brains were processed for Western blot analysis with SHa31 monoclonal antibody against PrP for PrPres detection, as described in mice (11); for histologic examination by using hematoxylin and eosin staining; and for disease-associated prion protein (PrPd) immunochemical detection by using the paraffin-embedded tissue blot method or immunohistochemical analysis with monoclonal antibody 3F4 against PrP.
Beginning ≈3 months before the terminal stage of the disease (19–22 months after inoculation), neurologic symptoms developed in the 4 mouse lemurs that received IC inoculations (Table). In all 4 animals, initial clinical signs and symptoms were blindness, thigmotaxic behavior, and poor appearance of the fur. Appetite and general fitness were maintained; anxiety and aggressiveness were not observed. Next, locomotion became slower, followed by incoordination and loss of balance in the last month of life. Ipsilateral circling behavior was reported, indicating unilateral degeneration of the striatum. This behavior stopped 15 days after onset, suggesting damage to the contralateral striatum. Disequilibrium, with frequent falls, became more noticeable. At the terminal stage of the disease, the animals were prostrate.
One orally inoculated lemur, which was fed 5 mg of infected brain and euthanized 27 months later, had signs and symptoms of disease similar to those in IC-inoculated animals, except for the ipsilateral circling behavior. In 2 lemurs fed 50 mg and 2 others fed 5 mg of L-BSE–infected brain, clinical signs and symptoms of prion disease developed just a few weeks before the animals were euthanized (18 and 32 months and 33 and 34 months after inoculation, respectively). Disease was characterized by progressive prostration, loss of appetite, and poor appearance of the fur, without incoordination or disequilibrium. The 3 remaining lemurs were orally inoculated at 2 years of age and were still alive and healthy 28 months after inoculation (Table).
Figure 1
Figure 1. Western blot analysis of protease-resistant prion protein in the brain (thalamus/hypothalamus) and spleen of mouse lemurs inoculated with a cattle-derived L-type bovine spongiform encephalopathy (BSE) isolate by oral and intracerebral routes...
PrPres was readily detected by Western blot analysis in brain extracts (thalamus/hypothalamus region) from 8 of the 9 animals examined (Table), although at lower levels in the lemur that was euthanized earlier (i.e., 18 months after inoculation). Western blot analyses showed uniform PrPres molecular profiles, irrespective of the route or dose of inoculation, with a low apparent molecular mass (≈19 kDa, similar to the PrPres in the original cattle brain) (Figure 1). However, the PrPres profile in mouse lemurs was characterized by a higher proportion of di- and monoglycosylated species (>95% of the total signal) than in the inoculum of the agent of bovine L-BSE (≈80%). In addition, PrPres was detected by Western blot in the spleens of 3 (1 IC inoculated and 2 fed with 5 mg of cattle brain) of the 9 animals examined (Figure 1).
Figure 2
Figure 2. Histopathologic and disease-associated prion protein (PrPd) immunodetection in the brain of 2 mouse lemurs after intracerebral (5 mg) or oral (50 mg) inoculation with a cattle-derived L-type bovine spongiform encephalopathy isolate....
Histopathologic analysis showed severe spongiform changes in the brains of the 4 IC-inoculated mouse lemurs (Figure 2, panel A). The brains displayed a pattern of vacuolation characterized by intense spongiosis with many confluent vacuoles in the basal telencephalon (septum, striatum, caudate putamen nuclei), midbrain (thalamus, hypothalamus), mesencephalon (colliculi), and in some parts of the brainstem (tegmental ventral area, raphe nuclei). Lesions in the cortex and hippocampus were less severe than in the subcortical areas. Cerebellum showed occasional small-size vacuoles. Among the 5 orally inoculated animals, 2 (1 fed 5 mg, the other fed 50 mg) showed histopathologic features similar to those observed in IC-inoculated animals. In the other 3 orally inoculated animals, spongiosis was characterized by fewer vacuoles and was restricted to the striatum (Figure 2, panel B), thalamus, colliculi, and brainstem.
Distribution of PrPd in the brain was assessed by paraffin-embedded tissue blot (Figure 2, panels C and D) or immunohistochemical analysis with 3F4 antibody (Figure 2, panels E and F). Results for IC-inoculated animals showed that PrPd strongly accumulated in a dense synaptic pattern associated with nonamyloid plaques in the striatum, several thalamic nuclei (Figure 2, panel E), the external cortex of the colliculi, and the tegmental area. Other areas that were slightly less affected (e.g., neocortex and hippocampus) showed few coarse granules and synaptic deposits. The cortical molecular layer and the corpus callosum were devoid of PrPd (Figure 2, panel C). In orally inoculated animals, PrPd was strongly accumulated in the striatum and thalamus (Figure 2, panel D) but weakly accumulated in the cortex. Immunohistochemical analysis showed synaptic deposits (Figure 2, panel F), and some focal deposits were evident in animals that survived longer. No plaques were detected in orally inoculated animals.
Conclusions We demonstrated that the agent of L-BSE can be transmitted by the oral route from cattle to mouse lemurs. As expected, orally inoculated animals survived longer than IC-inoculated animals. Orally inoculated lemurs had less severe clinical signs and symptoms, with no evidence of motor dysfunction. It was previously suggested that the agent of L-BSE might be involved in the foodborne transmission of a prion disease in mink (11,12), a species in which several outbreaks of transmissible mink encephalopathy had been identified, notably in the United States (13).
Our study clearly confirms, experimentally, the potential risk for interspecies oral transmission of the agent of L-BSE. In our model, this risk appears higher than that for the agent of classical BSE, which could only be transmitted to mouse lemurs after a first passage in macaques (14). We report oral transmission of the L-BSE agent in young and adult primates. Transmission by the IC route has also been reported in young macaques (6,7). A previous study of L-BSE in transgenic mice expressing human PrP suggested an absence of any transmission barrier between cattle and humans for this particular strain of the agent of BSE, in contrast to findings for the agent of classical BSE (9). Thus, it is imperative to maintain measures that prevent the entry of tissues from cattle possibly infected with the agent of L-BSE into the food chain.
Dr Mestre-Francés is an assistant professor at the École Pratique des Hautes Études. Her research focuses on neurodegenerative diseases (Alzheimer disease, prion diseases) in the nonhuman primate model Microcebus murinus.
EFSA Journal 2011 The European Response to BSE: A Success Story
This is an interesting editorial about the Mad Cow Disease debacle, and it's ramifications that will continue to play out for decades to come ; Monday, October 10, 2011 EFSA Journal 2011 The European Response to BSE: A Success Story
snip...
EFSA and the European Centre for Disease Prevention and Control (ECDC) recently delivered a scientific opinion on any possible epidemiological or molecular association between TSEs in animals and humans (EFSA Panel on Biological Hazards (BIOHAZ) and ECDC, 2011). This opinion confirmed Classical BSE prions as the only TSE agents demonstrated to be zoonotic so far but the possibility that a small proportion of human cases so far classified as "sporadic" CJD are of zoonotic origin could not be excluded. Moreover, transmission experiments to non-human primates suggest that some TSE agents in addition to Classical BSE prions in cattle (namely L-type Atypical BSE, Classical BSE in sheep, transmissible mink encephalopathy (TME) and chronic wasting disease (CWD) agents) might have zoonotic potential.
snip...
see follow-up here about North America BSE Mad Cow TSE prion risk factors, and the ever emerging strains of Transmissible Spongiform Encephalopathy in many species here in the USA, including humans ;
Wednesday, June 15, 2011
Galveston, Texas - Isle port moves through thousands of heifers headed to Russia, none from Texas, Alabama, or Washington, due to BSE risk factor
MAD COW DISEASE, TEXAS STYLE
Wednesday, March 31, 2010
Atypical BSE in Cattle
To date the OIE/WAHO assumes that the human and animal health standards set out in the BSE chapter for classical BSE (C-Type) applies to all forms of BSE which include the H-type and L-type atypical forms. This assumption is scientifically not completely justified and accumulating evidence suggests that this may in fact not be the case. Molecular characterization and the spatial distribution pattern of histopathologic lesions and immunohistochemistry (IHC) signals are used to identify and characterize atypical BSE. Both the L-type and H-type atypical cases display significant differences in the conformation and spatial accumulation of the disease associated prion protein (PrPSc) in brains of afflicted cattle. Transmission studies in bovine transgenic and wild type mouse models support that the atypical BSE types might be unique strains because they have different incubation times and lesion profiles when compared to C-type BSE. When L-type BSE was inoculated into ovine transgenic mice and Syrian hamster the resulting molecular fingerprint had changed, either in the first or a subsequent passage, from L-type into C-type BSE. In addition, non-human primates are specifically susceptible for atypical BSE as demonstrated by an approximately 50% shortened incubation time for L-type BSE as compared to C-type. Considering the current scientific information available, it cannot be assumed that these different BSE types pose the same human health risks as C-type BSE or that these risks are mitigated by the same protective measures.
This study will contribute to a correct definition of specified risk material (SRM) in atypical BSE. The incumbent of this position will develop new and transfer existing, ultra-sensitive methods for the detection of atypical BSE in tissue of experimentally infected cattle.
Thursday, August 12, 2010
Seven main threats for the future linked to prions
First threat
The TSE road map defining the evolution of European policy for protection against prion diseases is based on a certain numbers of hypotheses some of which may turn out to be erroneous. In particular, a form of BSE (called atypical Bovine Spongiform Encephalopathy), recently identified by systematic testing in aged cattle without clinical signs, may be the origin of classical BSE and thus potentially constitute a reservoir, which may be impossible to eradicate if a sporadic origin is confirmed.
***Also, a link is suspected between atypical BSE and some apparently sporadic cases of Creutzfeldt-Jakob disease in humans. These atypical BSE cases constitute an unforeseen first threat that could sharply modify the European approach to prion diseases.
Second threat
snip...
Price of PRION TSE aka MAD COW POKER GOES UP $$$
Saturday, December 3, 2011
Isolation of Prion with BSE Properties from Farmed Goat Volume 17, Number 12—December 2011
Saturday, June 25, 2011
Transmissibility of BSE-L and Cattle-Adapted TME Prion Strain to Cynomolgus Macaque
"BSE-L in North America may have existed for decades"
Over the next 8-10 weeks, approximately 40% of all the adult mink on the farm died from TME.
snip...
The rancher was a ''dead stock'' feeder using mostly (>95%) downer or dead dairy cattle...
2010-2011
When L-type BSE was inoculated into ovine transgenic mice and Syrian hamster the resulting molecular fingerprint had changed, either in the first or a subsequent passage, from L-type into C-type BSE. In addition, non-human primates are specifically susceptible for atypical BSE as demonstrated by an approximately 50% shortened incubation time for L-type BSE as compared to C-type. Considering the current scientific information available, it cannot be assumed that these different BSE types pose the same human health risks as C-type BSE or that these risks are mitigated by the same protective measures. This study will contribute to a correct definition of specified risk material (SRM) in atypical BSE. The incumbent of this position will develop new and transfer existing, ultra-sensitive methods for the detection of atypical BSE in tissue of experimentally infected cattle.
Wednesday, July 28, 2010
Atypical prion proteins and IBNC in cattle DEFRA project code SE1796 FOIA Final report
Tuesday, November 02, 2010
BSE - ATYPICAL LESION DISTRIBUTION (RBSE 92-21367) statutory (obex only) diagnostic criteria CVL 1992
When L-type BSE was inoculated into ovine transgenic mice and Syrian hamster the resulting molecular fingerprint had changed, either in the first or a subsequent passage, from L-type into C-type BSE. In addition, non-human primates are specifically susceptible for atypical BSE as demonstrated by an approximately 50% shortened incubation time for L-type BSE as compared to C-type. Considering the current scientific information available, it cannot be assumed that these different BSE types pose the same human health risks as C-type BSE or that these risks are mitigated by the same protective measures. This study will contribute to a correct definition of specified risk material (SRM) in atypical BSE. The incumbent of this position will develop new and transfer existing, ultra-sensitive methods for the detection of atypical BSE in tissue of experimentally infected cattle. http://www.prionetcanada.ca/detail.aspx?menu=5&dt=293380&app=93&cat1=387&tp=20&lk=no&cat2
Tuesday, July 14, 2009 U.S.
Emergency Bovine Spongiform Encephalopathy Response Plan Summary and BSE Red Book Date: February 14, 2000 at 8:56 am PST WHERE did we go wrong $$$
SEE FULL TEXT OF ALL THIS HERE ;
2009 UPDATE ON ALABAMA AND TEXAS MAD COWS 2005 and 2006
Thursday, June 23, 2011
Experimental H-type bovine spongiform encephalopathy characterized by plaques and glial- and stellate-type prion protein deposits
LET'S take a closer look at this new prionpathy or prionopathy, and then let's look at the g-h-BSEalabama mad cow. This new prionopathy in humans? the genetic makeup is IDENTICAL to the g-h-BSEalabama mad cow, the only _documented_ mad cow in the world to date like this, ......wait, it get's better. this new prionpathy is killing young and old humans, with LONG DURATION from onset of symptoms to death, and the symptoms are very similar to nvCJD victims, OH, and the plaques are very similar in some cases too, bbbut, it's not related to the g-h-BSEalabama cow, WAIT NOW, it gets even better, the new human prionpathy that they claim is a genetic TSE, has no relation to any gene mutation in that family. daaa, ya think it could be related to that mad cow with the same genetic make-up ??? there were literally tons and tons of banned mad cow protein in Alabama in commerce, and none of it transmitted to cows, and the cows to humans there from ??? r i g h t $$$ ALABAMA MAD COW g-h-BSEalabama In this study, we identified a novel mutation in the bovine prion protein gene (Prnp), called E211K, of a confirmed BSE positive cow from Alabama, United States of America. This mutation is identical to the E200K pathogenic mutation found in humans with a genetic form of CJD. This finding represents the first report of a confirmed case of BSE with a potential pathogenic mutation within the bovine Prnp gene. We hypothesize that the bovine Prnp E211K mutation most likely has caused BSE in "the approximately 10-year-old cow" carrying the E221K mutation.
Saturday, August 14, 2010
BSE Case Associated with Prion Protein Gene Mutation (g-h-BSEalabama) and VPSPr PRIONPATHY (see mad cow feed in COMMERCE IN ALABAMA...TSS)
her healthy calf also carried the mutation (J. A. Richt and S. M. Hall PLoS Pathog. 4, e1000156; 2008).
This raises the possibility that the disease could occasionally be genetic in origin. Indeed, the report of the UK BSE Inquiry in 2000 suggested that the UK epidemic had most likely originated from such a mutation and argued against the scrapierelated assumption. Such rare potential pathogenic PRNP mutations could occur in countries at present considered to be free of BSE, such as Australia and New Zealand. So it is important to maintain strict surveillance for BSE in cattle, with rigorous enforcement of the ruminant feed ban (many countries still feed ruminant proteins to pigs). Removal of specified risk material, such as brain and spinal cord, from cattle at slaughter prevents infected material from entering the human food chain. Routine genetic screening of cattle for PRNP mutations, which is now available, could provide additional data on the risk to the public. Because the point mutation identified in the Alabama animals is identical to that responsible for the commonest type of familial (genetic) CJD in humans, it is possible that the resulting infective prion protein might cross the bovine-human species barrier more easily. Patients with vCJD continue to be identified. The fact that this is happening less often should not lead to relaxation of the controls necessary to prevent future outbreaks. Malcolm A. Ferguson-Smith Cambridge University Department of Veterinary Medicine, Madingley Road, Cambridge CB3 0ES, UK e-mail: maf12@cam.ac.uk Jürgen A. Richt College of Veterinary Medicine, Kansas State University, K224B Mosier Hall, Manhattan, Kansas 66506-5601, USA NATURE|Vol 457|26 February 2009
P.9.21 Molecular characterization of BSE in Canada
Jianmin Yang1, Sandor Dudas2, Catherine Graham2, Markus Czub3, Tim McAllister1, Stefanie Czub1 1Agriculture and Agri-Food Canada Research Centre, Canada; 2National and OIE BSE Reference Laboratory, Canada; 3University of Calgary, Canada
Background: Three BSE types (classical and two atypical) have been identified on the basis of molecular characteristics of the misfolded protein associated with the disease. To date, each of these three types have been detected in Canadian cattle.
Objectives: This study was conducted to further characterize the 16 Canadian BSE cases based on the biochemical properties of there associated PrPres.
Methods: Immuno-reactivity, molecular weight, glycoform profiles and relative proteinase K sensitivity of the PrPres from each of the 16 confirmed Canadian BSE cases was determined using modified Western blot analysis. Results: Fourteen of the 16 Canadian BSE cases were C type, 1 was H type and 1 was L type. The Canadian H and L-type BSE cases exhibited size shifts and changes in glycosylation similar to other atypical BSE cases. PK digestion under mild and stringent conditions revealed a reduced protease resistance of the atypical cases compared to the C-type cases. N terminal- specific antibodies bound to PrPres from H type but not from C or L type. The C-terminal-specific antibodies resulted in a shift in the glycoform profile and detected a fourth band in the Canadian H-type BSE.
Discussion: The C, L and H type BSE cases in Canada exhibit molecular characteristics similar to those described for classical and atypical BSE cases from Europe and Japan. This supports the theory that the importation of BSE contaminated feedstuff is the source of C-type BSE in Canada. *** It also suggests a similar cause or source for atypical BSE in these countries.
Saturday, July 23, 2011
CATTLE HEADS WITH TONSILS, BEEF TONGUES, SPINAL CORD, SPECIFIED RISK MATERIALS (SRM's) AND PRIONS, AKA MAD COW DISEASE
Saturday, November 6, 2010
TAFS1 Position Paper on Position Paper on Relaxation of the Feed Ban in the EU
Berne, 2010 TAFS INTERNATIONAL FORUM FOR TRANSMISSIBLE ANIMAL DISEASES AND FOOD SAFETY a non-profit Swiss Foundation
Archive Number 20101206.4364 Published Date 06-DEC-2010 Subject PRO/AH/EDR>
Prion disease update 2010 (11) PRION DISEASE UPDATE 2010 (11)
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.
18.173 page 189
Experimental Challenge of Cattle with H-type and L-type Atypical BSE
A. Buschmann1, U. Ziegler1, M. Keller1, R. Rogers2, B. Hills3, M.H. Groschup1. 1Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany, 2Health Canada, Bureau of Microbial Hazards, Health Products & Food Branch, Ottawa, Canada, 3Health Canada, Transmissible Spongiform Encephalopathy Secretariat, Ottawa, Canada
Background: After the detection of two novel BSE forms designated H-type and L-type atypical BSE the question of the pathogenesis and the agent distribution of these two types in cattle was fully open. From initial studies of the brain pathology, it was already known that the anatomical distribution of L-type BSE differs from that of the classical type where the obex region in the brainstem 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.
Methods:We performed intracranial inoculations of cattle (five and six per group) using 10%brainstemhomogenates of the two German H- and L-type atypical BSE isolates. The animals were inoculated under narcosis and then kept in a free-ranging stable under appropriate biosafety conditions.At least one animal per group was killed and sectioned in the preclinical stage and the remaining animals were kept until they developed clinical symptoms. The animals were examined for behavioural changes every four weeks throughout the experiment following a protocol that had been established during earlier BSE pathogenesis studies with classical BSE. Results and
Discussion: All animals of both groups developed clinical symptoms and had to be euthanized within 16 months. The clinical picture differed from that of classical BSE, as the earliest signs of illness were loss of body weight and depression. However, the animals later developed hind limb ataxia and hyperesthesia predominantly and the head. Analysis of brain samples from these animals confirmed the BSE infection and the atypical Western blot profile was maintained in all animals. Samples from these animals are now being examined in order to be able to describe the pathogenesis and agent distribution for these novel BSE types.
Conclusions: A pilot study using a commercially avaialble BSE rapid test ELISA revealed an essential restriction of PrPSc to the central nervous system for both atypical BSE forms. A much more detailed analysis for PrPSc and infectivity is still ongoing.
Saturday, November 19, 2011
Novel Prion Protein in BSE-affected Cattle, Switzerland
Wednesday, February 16, 2011
IN CONFIDENCE
SCRAPIE TRANSMISSION TO CHIMPANZEES
IN CONFIDENCE
Sunday, April 18, 2010
SCRAPIE AND ATYPICAL SCRAPIE TRANSMISSION STUDIES A REVIEW 2010
Monday, April 25, 2011
Experimental Oral Transmission of Atypical Scrapie to Sheep
Volume 17, Number 5-May 2011
Thursday, June 2, 2011
USDA scrapie report for April 2011 NEW ATYPICAL NOR-98 SCRAPIE CASES Pennsylvania AND California
Monday, June 20, 2011 2011
Annual Conference of the National Institute for Animal Agriculture ATYPICAL NOR-98 LIKE SCRAPIE UPDATE USA
Thursday, July 14, 2011
Histopathological Studies of "CH1641-Like" Scrapie Sources Versus Classical Scrapie and BSE Transmitted to Ovine Transgenic Mice (TgOvPrP4)
Wednesday, October 12, 2011
White-tailed deer are susceptible to the agent of sheep scrapie by intracerebral inoculation
2011 Monday, September 26, 2011
L-BSE BASE prion and atypical sporadic CJD
SEE RISE OF SPORADIC CJD YEAR TO YEAR ;
TSS
No comments:
Post a Comment
Note: Only a member of this blog may post a comment.