Summary results of the second national survey of abnormal prion prevalence in archived appendix specimens August 2012
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].
References
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: http://www.hpa.org.uk/hpr/archives/2011/news3611.htm#cjd.
4. HPA. Creutzfeldt-Jakob disease (CJD) biannual update (2012/1). February
2012. Health Protection Report 6(6). Available at: http://www.hpa.org.uk/hpr/archives/2012/hpr0612.pdf.
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: http://www.dh.gov.uk/ab/ACDP/TSEguidance/DH_125868.
1 in 2,000 is huge.
considering this study was only looking at the appendix, was only using
immunohistochemistry, this study tells little, and may even be giving false
hope.
in my opinion, everyone in the U.K., back in the worse days of the mad cow
epidemic, that consumed beef, would have had to have been exposed to BSE, how many there from that
are sub-clinical, that is another question, one this study does not answer in
full.
TSS
Survey underlines need for minimizing secondary human exposure to prions
16 August 2012
Official publications
Tags: TSE, vCJD
Source: Health Protection Agenca/ ACDP
The Health Protection Agency of the UK has released its summary results of the second national survey of abnormal prion prevalence in archived appendix specimens. The Advisory Committee on Dangerous Pathogens (ACDP) TSE Risk Assessment Subgroup published a comment on the these results in a position paper.
The position paper concludes amongst other things that (highlighting by USP):
- While fundamental research into prion diseases continues, it is essential to ensure that consistent, long-term surveillance of the population continues. This should include development of methods to characterise the disease and if appropriate differentiate between strains.
- Despite the welcome fall in vCJD diagnoses, the indication of relatively widespread, albeit “silent”, vCJD infection necessitates continued attention to the risks of secondary, person-to-person transmission, and for applied research to support the development and implementation of risk management strategies.
Published Date: 2011-11-07 19:37:21
Subject: PRO/AH/EDR> Prion disease update 2011 (10) Archive Number:
20111107.3317
PRION DISEASE UPDATE 2011 (10)
Tuesday, October 05, 2010
Large-scale immunohistochemical examination for lymphoreticular prion
protein in tonsil specimens collected in Britain
05 Oct 2010 14:46
Friday, August 10, 2012
Incidents of Potential iatrogenic Creutzfeldt-Jakob disease (CJD) biannual
update (July 2012)
North America has NO surveillance system for iatrogenic CJD. a few mishaps
of late ;
Tuesday, July 31, 2012
11 patients may have been exposed to fatal disease Creutzfeldt-Jakob
Disease CJD Greenville Memorial Hospital
Thursday, August 02, 2012
CJD case in Saint John prompts letter to patients Canada CJD case in Saint
John prompts letter to patients
Wednesday, May 16, 2012
Alzheimer’s disease and Transmissible Spongiform Encephalopathy prion
disease, Iatrogenic, what if ?
Proposal ID: 29403
layperson
TSS
posted by Terry S. Singeltary Sr. at
10:14 AM
<< Home