Thursday, June 6, 2013



Last updated on 6 June 2013 .

The FSA has published an update of BSE control breaches

The Food Standards Agency has investigated three incidents in which meat from cattle over 72 months of age has entered the food chain without the animals being tested for BSE. .

All of the incidents predate changes to the BSE testing rules that came in on 1 March 2013. Before then it was mandatory for all cattle slaughtered for human consumption and aged over 72 months to have a negative BSE test result before they entered the food supply. Since 1 March this has no longer been a requirement.

The health risk from eating the meat associated with any of these incidents is very low as it is extremely unlikely that any of the cattle involved had BSE. In addition, the parts of the animals most likely to contain BSE, the specified risk material, had been removed and destroyed.

Under the BSE regulations, as a precaution, the animal slaughtered immediately before the untested cattle and the two immediately after it are also stopped from entering the food supply. ..

First incident

In the first incident, a cow aged 72 months and 3 days was slaughtered on 23 July 2012 at J A Jewitt (Meat) Ltd, a combined abattoir and cutting plant in Co. Durham. The missed test was discovered in September during routine cross-checks of slaughter and BSE testing data.

The carcass slaughtered immediately before the untested animal was rejected for other reasons and was disposed of. The untested carcass and two associated carcasses were dispatched as part of a consignment of 52 sides to a meat processor. All the sides were then processed and mixed with other consignments of beef and dispatched to eight different food businesses as both fresh and frozen product. Much of the product was sold on and consumed. However, 21 cases of frozen meat associated with the untested animal were traced, detained and destroyed. ..

Second incident

In the second incident, a cow aged 77 months and 18 days was slaughtered on 11 September 2012 at Simply Halal (Banham), a combined abattoir and cutting plant in Norfolk. The missed test was discovered in November during routine cross-checks of slaughter and BSE testing data.

Meat from the untested carcass and three associated carcasses was sold to five separate food businesses. The local authorities for the food businesses that received the meat confirmed that it had all had been sold, in chilled form, and most likely consumed. ..

Third incident

In the third incident, the animal, aged 72 months and 193 days, was slaughtered on 29 November 2012, at Anglo Dutch Meats (Charing), a combined abattoir and cutting plant in Kent. A batch of 70 animals was processed that day. Of these, 41 required testing. Forty animals were tested and all found to be negative. The one remaining untested carcass went into the food supply.

The missed test was discovered in January following routine cross-checks of slaughter and BSE testing data. The untested carcass, together with the three associated carcasses, was sold to Alec Jarrett Ltd, a combined slaughterhouse and cutting plant in Bristol as part of a consignment of 108 sides. The meat was then cut at Alec Jarrett alongside a second consignment from Anglo Dutch Meats. Some of the cut meat was sold as chilled product to a number of businesses. The remaining frozen meat was voluntarily detained at the cold store and subsequently sent for disposal by Alec Jarrett Ltd. The breach was not the responsibility of Alec Jarrett Ltd. ..

Goats test positive for scrapie

Two goats that tested positive for scrapie entered the food supply following an error at the testing laboratory.

Scrapie is a disease found in sheep and goats and is similar to BSE. However, there is no known risk to humans from eating meat from scrapie infected animals. In addition, the parts of the animal most likely to contain infectivity were removed before entering the human food chain.

The two animals were slaughtered as part of a batch of 26 goats on 21 January 2013 at Melton Meat Ltd, a slaughterhouse in Leicestershire. This was part of the Compulsory Scrapie Flocks Scheme, which allows undiagnosed animals from flocks affected by scrapie to be monitored for the disease at slaughter.

The slaughterhouse took the required samples from all the goats slaughtered that day and received the test results from LGC Runcorn, an approved testing laboratory, on 22 January. On 23 January, the results identified two positive samples and those carcasses were destroyed. The remaining carcasses were immediately released for sale. However, on 25 January LGC notified the FSA that an error had occurred at the laboratory and the wrong carcasses were identified as positive. The two positive carcasses were sold direct to two private customers from Melton Meat Ltd’s on site shop. These were cash sales and it was not possible to identify the customers and retrieve the meat.

LGC has carried out their its internal investigation regarding the reasons for the error at its laboratory. Melton Meat Ltd was not responsible for the positive animals entering the food chain.


Euro Quality Lambs Ltd is recalling its lambs’ brains, which have entered the food chain without being inspected properly. The Food Standards Agency is asking all local authority enforcement officers to ensure that the product is withdrawn from sale and destroyed. The Agency has issued a Food Alert for Action.

Tuesday, March 5, 2013

FSA notified of BSE control breaches again and again 5 March 2013

Thursday, January 17, 2013

FSA notified of two breaches of BSE testing regulations 14 January 2013


Due to an oversight, four breaches of BSE controls in British beef identified last year were not publicised immediately on the Agency’s website in the normal manner.


The Agency has been notified that meat has entered the food supply from a cow aged over 72 months that had not been tested for BSE. A negative BSE test result is mandatory for cattle slaughtered for human consumption at over 72 months of age.


The Agency has been notified that meat from a cow that did not have the required BSE test has entered the food supply. The 62 month old cow had been slaughtered on farm for welfare reasons.

Friday, November 30, 2012


Thursday, September 6, 2012

UK Breaches of BSE controls in consignments of beef 2011 communications missing four reports

Wednesday, December 21, 2011

Potential mad cows that entered food supply without being tested for BSE 2011: UK END OF YEAR REVIEW

Monday, November 14, 2011

Bullock aged over 72 months enters food supply without being tested for BSE

Monday, June 3, 2013

Unsuccessful oral transmission of scrapie from British sheep to cattle

Sunday, June 2, 2013

Characterisation of an Unusual TSE in a Goat by Transmission in Knock-in Transgenic Mice

Thursday, May 30, 2013

World Organization for Animal Health (OIE) has upgraded the United States' risk classification for mad cow disease to "negligible" from "controlled", and risk further exposing the globe to the TSE prion mad cow type disease U.S. gets top mad-cow rating from international group and risk further exposing the globe to the TSE prion mad cow type disease

Tuesday, May 21, 2013

Canada, USA, Bad feed, mad cows: Why we know three BSE cases had a common origin and why the SSS policy is in full force $$$

Friday, May 10, 2013

Evidence of effective scrapie transmission via colostrum and milk in sheep

Tuesday, April 30, 2013

Transmission of classical scrapie via goat milk

Veterinary Record2013;172:455 doi:10.1136/vr.f2613

Monday, May 6, 2013

Warning of mad cow disease threat to blood transfusions

Thursday, April 4, 2013

Variably protease-sensitive prionopathy in the UK: a retrospective review 1991–2008

Brain (2013) 136 (4): 1102-1115. doi: 10.1093/brain/aws366

*** The discovery of previously unrecognized prion diseases in both humans and animals (i.e., Nor98 in small ruminants) demonstrates that the range of prion diseases might be wider than expected and raises crucial questions about the epidemiology and strain properties of these new forms. We are investigating this latter issue by molecular and biological comparison of VPSPr, GSS and Nor98.


OR-10: Variably protease-sensitive prionopathy is transmissible in bank voles

Romolo Nonno,1 Michele Di Bari,1 Laura Pirisinu,1 Claudia D’Agostino,1 Stefano Marcon,1 Geraldina Riccardi,1 Gabriele Vaccari,1 Piero Parchi,2 Wenquan Zou,3 Pierluigi Gambetti,3 Umberto Agrimi1 1Istituto Superiore di Sanit√†; Rome, Italy; 2Dipartimento di Scienze Neurologiche, Universit√† di Bologna; Bologna, Italy; 3Case Western Reserve University; Cleveland, OH USA

Background. Variably protease-sensitive prionopathy (VPSPr) is a recently described “sporadic”neurodegenerative disease involving prion protein aggregation, which has clinical similarities with non-Alzheimer dementias, such as fronto-temporal dementia. Currently, 30 cases of VPSPr have been reported in Europe and USA, of which 19 cases were homozygous for valine at codon 129 of the prion protein (VV), 8 were MV and 3 were MM. A distinctive feature of VPSPr is the electrophoretic pattern of PrPSc after digestion with proteinase K (PK). After PK-treatment, PrP from VPSPr forms a ladder-like electrophoretic pattern similar to that described in GSS cases. The clinical and pathological features of VPSPr raised the question of the correct classification of VPSPr among prion diseases or other forms of neurodegenerative disorders. Here we report preliminary data on the transmissibility and pathological features of VPSPr cases in bank voles.

Materials and Methods. Seven VPSPr cases were inoculated in two genetic lines of bank voles, carrying either methionine or isoleucine at codon 109 of the prion protein (named BvM109 and BvI109, respectively). Among the VPSPr cases selected, 2 were VV at PrP codon 129, 3 were MV and 2 were MM. Clinical diagnosis in voles was confirmed by brain pathological assessment and western blot for PK-resistant PrPSc (PrPres) with mAbs SAF32, SAF84, 12B2 and 9A2.

Results. To date, 2 VPSPr cases (1 MV and 1 MM) gave positive transmission in BvM109. Overall, 3 voles were positive with survival time between 290 and 588 d post inoculation (d.p.i.). All positive voles accumulated PrPres in the form of the typical PrP27–30, which was indistinguishable to that previously observed in BvM109 inoculated with sCJDMM1 cases.

In BvI109, 3 VPSPr cases (2 VV and 1 MM) showed positive transmission until now. Overall, 5 voles were positive with survival time between 281 and 596 d.p.i.. In contrast to what observed in BvM109, all BvI109 showed a GSS-like PrPSc electrophoretic pattern, characterized by low molecular weight PrPres. These PrPres fragments were positive with mAb 9A2 and 12B2, while being negative with SAF32 and SAF84, suggesting that they are cleaved at both the C-terminus and the N-terminus. Second passages are in progress from these first successful transmissions.

Conclusions. Preliminary results from transmission studies in bank voles strongly support the notion that VPSPr is a transmissible prion disease. Interestingly, VPSPr undergoes divergent evolution in the two genetic lines of voles, with sCJD-like features in BvM109 and GSS-like properties in BvI109.

The discovery of previously unrecognized prion diseases in both humans and animals (i.e., Nor98 in small ruminants) demonstrates that the range of prion diseases might be wider than expected and raises crucial questions about the epidemiology and strain properties of these new forms. We are investigating this latter issue by molecular and biological comparison of VPSPr, GSS and Nor98.

Wednesday, March 28, 2012


Sunday, March 31, 2013

Creutzfeldt Jakob Disease CJD worlds youngest documented victim, 11 years old, shall we pray

Volume 33, Issue 3, Article first published online: 20 JAN 2013

Special Lecture

Human prion diseases: Molecular, cellular and population biology

Mark W. Head

National CJD Research & Surveillance Unit, Centre for Clinical Brain Sciences, School of Clinical Sciences,

The University of Edinburgh, Edinburgh, UK


Potential future zoonoses

Scrapie is endemic in many countries around the world, yet there is no evidence to suggest that it is pathogenic for humans. The intense investigations of ruminant TSEs that followed the BSE epidemic have resulted in the identification of several distinct animal prion diseases, atypical or Nor98 scrapie in sheep and H-type and L-type BSE in cattle.32 Moreover, BSE is experimentally transmissible to sheep and there are concerns that if BSE were to have infected the national flock in the UK its presence might be masked by endemic scrapie, but it might retain its pathogenicity for humans.33,34 Another concern, particularly for the North American countries, is the spread of chronic wasting disease in farmed and free-ranging deer and elk.35 There is no known epidemiological link between any of these animal prion diseases and human disease, but there are active efforts to try to quantify strain-related species barriers between the diseases known to be a risk (BSE/ vCJD), those thought not to represent a risk (scrapie) and those for which data is lacking (atypical scrapie, H- and L-type BSE and BSE in sheep).36 In assessing whether or not human prion diseases might have an animal origin, it is important to have a proper understanding of the clinicopathological heterogeneity of the sporadic human prion diseases, because it is against this backdrop that any new acquired forms of the disease will be seen and from which it will need to be distinguished.

Sporadic CJD and variably protease-sensitive prionopathy

Sporadic CJD is the most commonly occurring human prion disease; it occurs world-wide and it has long been known to be clinically and pathologically heterogeneous. The molecular basis for this heterogeneity is currently thought to reside in a combination of the PRNP codon 129 polymorphic status of the patient (MM, MV, or VV) and the type (type 1 or type 2) of the protease-resistant component of PrPSc determined by protease K digestion and Western blotting (termed PrPres).37,38 The original sCJD sub-classification system of Parchi et al. that recognized six sCJD subtypes (MM1/MV1, MM2c, MM2t, MV2,VV2 and VV1) has had to be modified to accommodate the growing number of cases recognized to contain both type 1 and type 2 PrPres in different or sometimes the same regions of the brain.39,40 Moreover, intensive surveillance and investigation of forms of human prion disease that lack PRNP mutation and known risk factors has identified another sporadic human prion disease, termed protease-sensitive prionopathy (VPSPr).41While intensively investigated, the etiology and diversity of the sporadic human prion diseases remain poorly understood.


There is also a potentially important practical corollary to the idea of prion-like spread, which may affect future stem cell therapies for neurodegenerative diseases. Presumably therapeutic stem cell-derived neurons would be equally susceptible to “infection” (with misfolded protein aggregates) as the patient’s own cells, unless steps were taken to prevent this,55 the most obvious of which would be to prevent expression of the gene product that can be converted to a pathological prion-like isoform.The suggestion that a prion-like mechanism of spread of molecular pathology underlies diseases as diverse as Alzheimer’s disease and Parkinson’s disease has led some researchers to explore whether the molecular pathology of these diseases is transmissible in an experimental setting56–58 and to suggest that perhaps some cases of these more common neurodegenerative illnesses might, like CJD, be acquired.58,59


MOLECULAR BASIS OF HUMAN PRION DISEASES Molecular strain typing Molecular strain typing in the form of classifying the mobility and glycoform ratio of protease-resistant prion protein byWestern blotting is a remarkably useful adjunct to neuropathological assessment during the post-mortem diagnosis of human prion diseases (Fig. 1). The glycoform ratio difference between vCJD and all forms of sCJD is a remarkably robust phenomenon, although the mechanism underlying it remains obscure. All cases of vCJD examined show type 2B PrPres, irrespective of brain region assayed and the PrPres type is also found in lymphoreticular tissues, albeit with presumably tissue-specific minor modification of mobility and an accentuation of the glycoform ratio. Similarly sCJD cases are characterized by a narrow range of glycoform ratios, distinct from vCJD, and the presence of either type 1 or type 2 PrPres (type 1A and type 2A).The PrPres types found in the brain in iCJD and kuru resemble those found in sCJD (type 1A and type 2A), from which they were presumably derived. Individual cases of gCJD, GSS and FFI usually have type 1 or type 2 PrPres, but with a glycoform ratio in which the non-glycosylated component is under-represented (which we have termed A/B). However, this is not always true and a broad spectrum of glycoform ratios can be found in genetic prion diseases. Moreover, some cases of GSS are characterized by an approximately 8 kDa (N- and C-terminally truncated) PrPres fragment, and some cases of FFI have little detectable PrPres at all. Despite the diagnostic utility, a simple one-to-one correspondence between PrPres type and disease phenotype (and by implication to agent strain) seems unlikely in principle and is complicated by the facts. First, the choice of analyzing only that fraction of PrPSc which survives a particular concentration of protease may seem arbitrary. Second, the interpretation of a molecular population variable, such as glycosylation site occupancy, as conforming to two or three discrete types, could be seen as simplistic. Lastly, protease digestion may be considered to be a somewhat blunt instrument to distinguish secondary and higherorder conformational differences in PrPSc. Even when genotype (mutations and polymorphisms) is taken into account, three major types (1, 2, 8 kDa) and three wild-type genotypes (MM,MV and VV) provide insufficient molecular variation to account for all the phenotypic variations observed. For example, two forms of sCJD share methione homozygosity and type 2A PrPres but one form closely resembles FFI (without the causative mutation) and the other is CJD-like.8 Two more substantial problems, which may point toward a more subtle and perhaps informative approach to PrPSc analysis, are discussed below. The co-occurrence of PrPres types 1 and 2 Once controversial, the idea that PrPSc in individual cases might be composed of mixtures (or different types co-occurring) is now well recognized and accepted.40,70 There are probably two phenomena at play here. One is the finding of different predominant types in individual samples from different parts of the brain or more rarely approximately equal amounts of type 1A and type 2A in the same sCJD brain samples.The other is the observation made using antibodies that specifically recognize type 1 or type 2 PrPres, that a minority type always accompanies a majority type in sCJD and vCJD, albeit at sub-detectable levels when conventional antibodies are used.71–75 The former issue is more tractable and a consensus is beginning to emerge that when multiple brain sampling and sensitive co-detection is performed on cohorts of sCJD cases, a plateau is reached at between 30–40% of cases showing co-occurrence. Our own data examining four regions (temporal cortex, parietal cortex, occipital cortex and thalamus) instead of frontal cortex only, shows a rise in detected co-occurrence from 3% to 24% of cases.76 Interestingly, only very rarely did this re-analysis involve a change in the predominant type found in the brain overall. Parchi et al. have offered a revised version of their 1999 sporadic CJD classification system that adds mixed type to the original “pure” types and have shown that the most common of these 12 sCJD subtypes can be recognized on histological grounds, without reference to biochemical analysis.39,40,77 It will be interesting to see in the fullness of time whether this additional complexity reflects a more refined series of discrete clinicopathological phenotypes or whether it is indicative of a spectrum of phenotypes depending on the spacio-temporal accumulation of PrPSc types set against the patient genotype.78

Variably protease-sensitive prionopathy The phenotypic complexity of the sporadic forms of human prion disease has increased with the report of a new sporadic human prion disease, termed variably proteasesensitive prionopathy (VPSPr) that is distinct from previously recognized sub-types of sCJD.41,79 There are no mutations in the open reading frame of PRNP. The patients have no known risk factors for the disease, but the disease is most common in theVV genotype, as opposed to sCJD, which is most common in the MM genotype. The neuropathology involves medium-sized vacuolation and characteristic microplaques. Durations of illness can be very long and this coupled with symptoms that do not conform well to CJD have prompted speculation that the condition may be under-ascertained. The most interesting aspect of the disease from a biochemical perspective is that although PrPSc is abundantly present in the brain, PrPres is difficult to detect because of its sensitivity to proteolysis and because what remains after proteinase K (PK) digestion is both C- and N-terminally cleaved by PK digestion and seen as a faint 8 kDa band on Western blots (Fig. 2). The degree of protease resistance is reported to reflect the codon 129 genotype, withVV being least resistant andMM being most resistant, despite having the same 8 kDa PrPres fragment predominating.79We have identified two cases of VPSPr prospectively in the UK80,81 and recently completed a retrospective review for such cases confirming many of the original observations by Gambetti and colleagues.41,79 Our work has shown that some areas of the VPSPr brain contain PrPres similar in appearance to that found in sCJD and conversely that some cases of sCJD have a very minor PrPres band similar to the 8 kDa PrPres band that typifies VPSPr.82


The biochemical basis of the strain phenomenon The results of transmission of individual samples from single examples of the six different Parchi et al.39 sCJD subtypes (MM1/MV1, VV1, MM2c, MV2, VV2) into humanized transgenic mice suggest the existence of four distinct sCJD agents, termed M1, M2, V1 and V2, and a fifth strain corresponding to MM2t or sporadic fatal insomnia.99,100 Interestingly, when we performed formally analogous experiments in the cell-free PMCA reaction, similar results were obtained: The PrPres type of the seed was conserved in the PMCA product and the efficiency of conversion appeared to be determined by compatibility at codon 129 of PRNP.101 The behavior of the seeds from heterozygous patients were particularly interesting, in that MV1 sCJD seeds selectively amplified in MM substrate producing type 1 PrPres and MV2 sCJD seeds selectively amplified in VV substrate producing type 2 PrPres (Fig. 6). These results reinforce the association between methionine at codon 129 and the production of type 1 PrPres and valine at codon 129 and the production of type 2 PrPres.

EMERGING RISKS Zoonotic disease BSE is the only animal prion strain with demonstrated pathogenicity for humans.While it is tempting to suggest that scrapie might represent the animal reservoir that results in some cases of sCJD, there is no epidemiological evidence to support this hypothesis. The pathogenicity of new or newly described animal prion diseases for humans is unclear and this is particularly true for H- and L-type BSE, atypical scrapie and for chronic wasting disease (CWD), all of which are probably consumed. Human susceptibility has been modeled by attempted transmission to (humanized) transgenic mice with sometimes conflicting results, depending on the transgenic model used and depending upon whether central or peripheral tissues are examined.102–106 We have attempted to establish whether PMCA can model the molecular component of these hypothetical cross-species transmission events.107 The existing data correspond well with the established facts. First, PrPSc in vCJD brain samples amplifies most efficiently in humanized mouse MM substrate, less efficiently in MV substrate and not at all in VV. Cattle BSE PrPres is less efficient than vCJD, but shows the same substrate genotypic preference. Sheep scrapie fails to amplify detectably in any of the three substrates; however, sheep BSE PrPres does amplify, again with a codon 129 preference for methionine (Fig. 7). We are currently extending this approach to encompass atypical scrapie, H- and L-type BSE and CWD using human rather than humanized PMCA substrates.

Secondary infection

In the same way that animal reservoirs cannot be completely excluded as causes of individual sCJD cases, neither can other environmental sources, such as medical procedures. The known routes of iatrogenic CJD acquisition are historically growth hormone therapy, dura mater grafting, corneal grafting and certain highly specialized neurosurgical procedures. The secondary transmission of vCJD by blood transfusion and experimental evidence showing the efficiency of the transfusion of viable blood cells between scrapie and BSE-infected and naive sheep have prompted a reappraisal of transfusion-transmitted CJD, including consideration being given to the possibility of prion blood testing or filtration.25,26,108,109

Blood transfusion is the original and most extensively used cellular therapy, but we may be on the threshold of a new era of cellular therapies based on embryonic stem cell and induced pluripotent stem cell technologies. Although the potential for stem cell therapy-mediated prion transmission might be judged remote, this was also considered to be the case for transfusion transmission of CJD before 2004.



While the prospect of a major epidemic of vCJD in the UK and elsewhere seems to be receding, there remain a series of uncertainties surrounding the eventual numbers of individuals that will suffer from this devastating condition.The issues include the effects of genotype on susceptibility and the possible existence of substantial numbers of asymptomatic infected individuals that may pose risks of onward transmission. sCJD remains the most frequently occurring human prion disease and arguably the least well understood. Other idiopathic forms of human prion disease (such as VPSPr), characterized by protease-sensitive forms of the prion protein, also exist and their true prevalence may be hard to ascertain. The possible risks from newly described animal prion diseases and from emerging cellular therapies are currently poorly quantified. On a more theoretic level the prion hypothesis has provided a unifying conceptual framework for TSE research and provided a paradigm to interrogate the similarities and differences between the diverse neurodegenerative conditions involving prion-like mechanisms of molecular pathology.

SNIP...see more here ;

Tuesday, June 4, 2013


Thursday, February 21, 2013

National Prion Disease Pathology Surveillance Center Cases Examined January 16, 2013


Monday, January 14, 2013

Gambetti et al USA Prion Unit change another highly suspect USA mad cow victim to another fake name i.e. sporadic FFI at age 16 CJD Foundation goes along with this BSe

Monday, December 31, 2012

Creutzfeldt Jakob Disease and Human TSE Prion Disease in Washington State, 2006–2011-2012

Tuesday, December 25, 2012


Tuesday, June 26, 2012

Creutzfeldt Jakob Disease Human TSE report update North America, Canada, Mexico, and USDA PRION UNIT as of May 18, 2012

type determination pending Creutzfeldt Jakob Disease (tdpCJD), is on the rise in Canada and the USA

Wednesday, June 13, 2012


Monday, October 10, 2011

EFSA Journal 2011 The European Response to BSE: A Success Story


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.


Tuesday, May 28, 2013

Late-in-life surgery associated with Creutzfeldt-Jakob disease: a methodological outline for evidence-based guidance

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


Rural and Regional Affairs and Transport References Committee

The possible impacts and consequences for public health, trade and agriculture of the Government's decision to relax import restrictions on beef Final report June 2010

2.65 At its hearing on 14 May 2010, the committee heard evidence from Dr Alan Fahey who has recently submitted a thesis on the clinical neuropsychiatric, epidemiological and diagnostic features of Creutzfeldt-Jakob disease.48 Dr Fahey told the committee of his concerns regarding the lengthy incubation period for transmissible spongiform encephalopathies, the inadequacy of current tests and the limited nature of our current understanding of this group of diseases.49

2.66 Dr Fahey also told the committee that in the last two years a link has been established between forms of atypical CJD and atypical BSE. Dr Fahey said that: They now believe that those atypical BSEs overseas are in fact causing sporadic Creutzfeldt-Jakob disease. They were not sure if it was due to mad sheep disease or a different form. If you look in the textbooks it looks like this is just arising by itself. But in my research I have a summary of a document which states that there has never been any proof that sporadic Creutzfeldt-Jakob disease has arisen de novo-has arisen of itself. There is no proof of that. The recent research is that in fact it is due to atypical forms of mad cow disease which have been found across Europe, have been found in America and have been found in Asia. These atypical forms of mad cow disease typically have even longer incubation periods than the classical mad cow disease.50

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.

*** 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.

The chances of a person or domestic animal contracting CWD are “extremely remote,” Richards said. The possibility can’t be ruled out, however. “One could look at it like a game of chance,” he explained. “The odds (of infection) increase over time because of repeated exposure. That’s one of the downsides of having CWD in free-ranging herds: We’ve got this infectious agent out there that we can never say never to in terms of (infecting) people and domestic livestock.”


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