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CJD BLOOD SCREENING, DONORS, AND SILENT CARRIERS House of Commons Written Answers 16 May 2013

Posted May 19 2013 10:15pm

Mr Mike Hancock: To ask the Secretary of State for Health (1) when screening for vCJD will be available to families who have been affected by it; [155371]

(2) when he proposes that a vCJD blood screening test will be implemented to screen all UK blood donors. [155374]

Anna Soubry: At present, there are no validated blood screening tests for variant Creutzfeldt-Jakob disease. The Department, together with the United Kingdom blood services, continues to monitor scientific research and development in this area.

Mr Mike Hancock: To ask the Secretary of State for Health (1) how many silent carriers of vCJD there are in the UK; and how many of those could be potential blood donors; [155372]

16 May 2013 : Column 365W

(2) what his latest estimate is of the number of people in the UK who may be unknowing carriers of vCJD. [155373]

Anna Soubry: A recent study of stored tissue samples, published in the Health Protection Report in August 2012, found abnormal prion protein in 16 appendices out of 32,441 samples. This suggests a prevalence of about one in 2,000, which remains statistically consistent with results from an earlier appendix survey.

This estimate measures the prevalence of abnormal prion protein in appendix tissues within the population covered. We cannot know for certain whether this is a good indicator of risk in relation to potential blood-borne routes of infection, such that blood taken from donors with abnormal prion protein in appendix tissue would transmit prion infection. However, risk assessments, prepared for the independent scientific Advisory Committee on Dangerous Pathogens (ACDP), are based on the presumption that this could occur. In February 2013, ACDP agreed and published an updated variant Creutzfeldt-Jakob disease (vCJD) and blood components risk assessment, which takes into account the recent prevalence study data. A copy of this document has been placed in the Library, and is publicly available on the Department's website.

The prevalence of infective blood donors remains unknown. Not all individuals in the study would be of an age eligible to donate blood, nor is it clear whether presence of abnormal prion protein in tissues such as the appendix indicates that the blood of such a donor would transmit vCJD. Precautionary measures are assessed in the context of the fundamental uncertainties about prevalence.

Summary results of the second national survey of abnormal prion prevalence in archived appendix specimens

In April 2008, the Spongiform Encephalopathy Advisory Committee (SEAC) considered available prevalence data for variant Creutzfeldt-Jakob Disease (vCJD) in the British population and advised that a second appendix survey, using the same approach as a previous appendix tissue survey [1] on samples from the 1941 to 1985 birth cohort, be undertaken to further refine the estimate for the prevalence of subclinical infection [2].The second unlinked anonymous survey of the prevalence of abnormal prion protein in archived appendix tissues has now been completed and this summary provides an update to the interim results published in September 2011 [3,4].

The survey examined appendices by immunohistochemistry from operations conducted between 2000 and 2012 and collected from 41 hospitals throughout England. Abnormal prion accumulation was detected within the follicular dendritic cells of 16 appendices out of 32,441 suitable samples examined. None of the positive appendices have come from the 176 known vCJD cases in the UK. In line with the interim findings, the final overall prevalence estimate, 493 per million (95% Confidence Interval (CI): 282 to 801 per million), remained statistically consistent with results from the earlier appendix survey (237 per million, 95%CI 49 to 692 per million) which examined samples from operations performed between 1995 and 1999 [1]. The prevalence estimates by birth cohort were 733 per million (95% CI: 269 to 1596 per million) in those born between 1941 and 1960 and 412 per million (95% CI: 198 to 758 per million) in those born between 1961 and 1985: these results were also in line with the interim findings [3,4].

The survey was conducted by a collaboration of the HPA, the Department of Neurodegenerative Diseases at the UCL Institute of Neurology, the Animal Health and Veterinary Laboratories Agency, the National Creutzfeldt-Jakob Disease Research and Surveillance Unit, the Histopathology Department of Derriford Hospital in Plymouth, and the MRC Prion Unit.

The final survey results have been considered by the Transmissible Spongiform Encephalopathies Risk Assessment Sub-Group of the Advisory Committee on Dangerous Pathogens, the successor to SEAC [5]. In summary, the estimated prevalence range largely overlaps that from the first survey, but is narrower with a higher central estimate (around 1 in 2000 compared with around 1 in 4000). The new survey also demonstrates the presence of prion protein across a wider birth cohort than previously.

The hypothesis that the prevalence of abnormal prions found in both appendix surveys to date is linked to the epidemic of BSE in cattle in Britain can be tested directly by studying further appendix samples archived prior to the BSE outbreak and samples from those born in 1996 or later by which time measures had been put in place to protect the food chain [5].


1. Hilton DA, Ghani AC, Conyers L, Edwards P, McCardle L, Ritchie D, et al. Prevalence of lymphoreticular prion protein accumulation in UK tissue samples . J Pathol 2004; 203: 733-9.

2. Spongiform Encephalopathy Advisory Committee (SEAC). Position Statement. Prevalence of subclinical variant Creutzfeldt-Jakob Disease infections. August 2008. SEAC position statement .

3. HPA. Interim data from the current national survey of abnormal prion prevalence in archived appendix specimens. September 2011. Health Protection Report 5(36). Available at: .

4. HPA. Creutzfeldt-Jakob disease (CJD) biannual update (2012/1). February 2012. Health Protection Report 6(6). Available at:

5. Advisory Committee on Dangerous Pathogens (ACDP) TSE Risk Assessment Subgroup. Position Statement on occurrence of vCJD and prevalence of infection in the UK population. July 2012. Available at: .

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From: Terry S. Singeltary Sr.

Sent: Tuesday, March 19, 2013 2:46 PM


Cc: ; ;

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Tuesday, December 25, 2012


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Wednesday, June 13, 2012


*** 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 Sanità; Rome, Italy; 2Dipartimento di Scienze Neurologiche, Università 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


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

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