Friday, February 19, 2010

Creutzfeldt-Jakob disease (CJD) biannual update (2010/1)

Emerging infections/CJD

Creutzfeldt-Jakob disease (CJD) biannual update (2010/1)

This six-monthly report provides an update on reports of incidents of potential iatrogenic (healthcareacquired) exposure to CJD via surgery, and on the National Anonymous Tonsil Archive. Data are correct as of 26 January 2010.

For numbers of CJD case reports, readers should consult data provided by the national CJD Surveillance Unit (NCJDSU), Edinburgh [1]. The latest yearly analysis of vCJD reports (onsets and deaths) is also available from the NCJDSU website [2].

Reports of incidents of potential iatrogenic exposure to CJD via surgery:

2000 to 31 December 2009

Since the previous update report [3], 19 surgical incidents were reported – between 1 July and 31 December 2009 – bringing the total number reported since 2000 to 407 (table 1). A surgical incident occurs when a patient undergoes surgery but is only identified as having CJD or being at risk of CJD at a later date. This means that the ACDP TSE Working Group infection control guidelines would not have been followed. The surgery carried out on an index patient with, or at risk of CJD, may result in contamination of the instruments with abnormal prion protein. Table 1 shows the number of CJD surgical incidents reported to the CJD Incidents Panel from January 2000 to 31st December 2009 by the diagnosis of the index patient. Information about the CJD Incidents Panel can be found on the HPA website [4].

Table 1. Closed CJD Surgical Incidents (n=407) reported to the CJD Incidents Panel, by diagnosis of index patient: 1 January 2000 to 30 June 2009

Incident type 2000 2001 2002 2003 2004 2005 2006 2007 2008 First half 2009 Total

1. Sporadic (possible, probable or definite) 7 19 22 24 16 18 31 17 21 11 186(46%)

2. vCJD (possible, probable or definite) 6 14 22 5 4 1 2 – 1 1 56(14%)

3. Familial including 'at risk' familial – 2 2 7 1 3 7 – 2 2 26(6%)

4. 'At risk' vCJD blood component recipient – – – – 4 10 6 1 – – 21(5%)

5. 'At risk' - vCJD plasma product recipient – 1 2 – 10 18 9 8 6 8 62(15%)

6. 'At risk' - other – – 2 2 1 2 4 – – 1 12(3%)

7. CJD type unclear/ CJD unlikely 1 1 4 1 1 2 – – – 10(2%)

8. Not CJD 2 1 4 7 7 1 1 – 3 – 26(6%)

9.Other – – 1 1 1 2 1 – – – 6(1%)

10. No longer considered 'at-risk' – – 1 – – – – 1 – – 2(0%)

Total 16 38 56 50 45 56 63 27 33 23 407(100%)

Investigation of surgical incidents may result in advice to remove surgical instruments from clinical use (to quarantine, destroy, or donate for research). Such advice is generally only given for instruments considered to be potentially contaminated with the CJD agent that have not undergone a certain number of cycles of use and decontamination since their use on an index patient. Hospitals are asked to consider sending any instruments to be permanently removed from use to the Surgical Instrument Store (held by the Health Protection Agency, Porton Down) for research. Since 2000, there have been 46 incidents in which instruments were permanently removed from use.

The Panel may advise contacting and informing some patients of their possible exposure to CJD in a surgical incident. Such advice is generally only given for patients who have definitely been exposed to potentially contaminated instruments which have been used on risk tissues in certain index patients. The Panel may advise that some of these patients should be considered „at-risk of CJD for public health purposes' and asked to take certain precautions (ie, not to donate blood or other tissues and to inform their medical and dental carers prior to any invasive procedures) in order to reduce the risk of transmitting the CJD agent further. Since 2000, 22 incidents have given rise to such advice. There are currently nine incidents in which 77 patients have been categorised as „at-risk' by the Panel, according to the current risk assessment. Seven of these patients died before notification. A total of 31 patients are currently notified of their „at-risk' status. Notifications are pending for another 31 patients. Three patients have not been notified due to local, clinical decisions.

The Panel has revised its advice on endoscopy and anterior eye patients. This has led to patients being denotified in 2006 and 2009. This resulted in reclassification of 38 patients from the „at-risk' category; 32 in anterior eye surgery, two in invasive endoscopy.

Table 2. Panel advice to inform patients that they are ‘at-risk' of CJD/vCJD: 1 January 2000 to 30 June 2009

Diagnosis of index patient Procedure on index patient Number of Incidents Alive 'at-risk' Died before notification Total Notified Not notified Total

Sporadic CJD Brain biopsy 2 20 1* 21 2 28

vCJD Appendectomy 1 – 2* 2 – 2

Endoscopy and GI surgery 2† 3 1 ** 4 1 5

'At risk' vCJD Endoscopy and GI surgery 4 8 30** 38 4 42

Total – 9 31 34 65 7 77

*Local decision not to notify.

† The index patient in one of these incidents was a haemophiliac plasma product recipient with evidence of vCJD infection.

** Notification pending.

National anonymous tonsil archive for studies of detectable abnormal prion protein

The National Anonymous Tonsil Archive (NATA) continues to receive approximately 250 tonsil pairs per week (figure 1). The archive had received a total of 81,604 tonsil pairs up to the end of December 2009 from hospitals in England and Scotland. A further 3,000 tonsil pairs have been received from the Medical Research Council Prion Unit at the Institute for Neurology, National Hospital for Neurology and Neurosurgery. Therefore the total number of tonsil pairs in the archive was 84,604. The number of collection forms that were completed but no tonsil tissue collected was 2,395 (1,565 due to patient objection and 830 due to clinical pathology being requested).

Out of the 100 NHS Hospital Trusts that perform over 200 tonsillectomies per year in England, 91 have been recruited and are currently sending tonsil pairs to NATA on a regular basis. There are 120 hospitals sites within these trusts taking part in NATA. At present, approximately 50,000 tonsillectomies are performed annually in England. Figure 2 shows the number of tonsil pairs received from each Strategic Health Authority.

Figure 1. Number of tonsil pairs collected for NATA quarterly: Q1 2004 – Q4 2009

Just over 5,000 tonsillectomies are performed in Scotland each year. The project in Scotland, where there are 14 hospitals that each carry out more than 200 tonsillectomies per year, is being coordinated by Health Protection Scotland. All fourteen of these hospitals have been recruited and are collecting tonsils for NATA. The tonsil tissue is being transported to the Health Protection Agency in Colindale for inclusion in the archive. Figure 3 shows all hospitals in England and Scotland currently recruited in the study.

Figure 2. Tonsils pairs collected by Strategic Health Authority, January 2004 - December 2009

Figure 3. NHS Trusts and Scottish Hospitals currently collecting and sending tonsil tissue to the archive December 2009

Testing of homogenates of the tonsil tissue from the archive began at the end of January 2007. Two enzyme immunoassays (EIAs) are being used for the initial screening of the homogenates for the presence of abnormal prion protein. These EIAs allow the identification of any tonsils that need to be investigated further by the more specific tests of Western blotting (WB) and immunohistochemistry (IHC) [5].


1. The National Creutzfeldt-Jakob Disease Surveillance Unit, The University of Edinburgh. CJD statistics. Available at:

2.The National Creutzfeldt-Jakob Disease Surveillance Unit, The University of Edinburgh. Incidence of variant Creutzfeldt-Jakob Disease Onsets and Deaths in the UK January 1994 - December 2006. Edinburgh: NCJDSU, 2 February 2007. Available at:

3. HPA. Biannual CJD update (2009/1). Health Protection Report [serial online] 2009; 3(27): Emerging Infections/CJD. Available at:

4. HPA. CJD Incidents Panel [online]. London: HPA, 2010. Available at:

5. Spongiform Encephalopathy Advisory Committee. Combining evidence from tissue surveys to estimate the prevalence of subclinical vCJD. London: SEAC, 2008. Available at:

Health Protection Report Vol 4 No. 7 - 19 February 2010

Iatrogenic CJD knows NO age group, TSE knows no boundaries. I propose as with Aguzzi, Asante, Collinge, Caughey, Deslys, Dormont, Gibbs, Gajdusek, Ironside, Manuelidis, Marsh, et al and many more, that the world of TSE Transmissible ...

Saturday, January 16, 2010

Evidence For CJD TSE Transmission Via Endoscopes 1-24-3 re-Singeltary to Bramble et al

Monday, July 20, 2009

Pre-surgical risk assessment for variant Creutzfeldt-Jakob disease (vCJD) risk in neurosurgery and eye surgery units

[2] UK: SEAC position statement on dentistry Date: Sat 30 Jun 2007 Source: Position Statement vCJD and Dentistry, Spongiform Encephalopathy Advisory Committee (SEAC) Update, June 2007 [edited]

Position Statement vCJD and Dentistry ------------------------------------- Issue ----- 1. The Department of Health (DH) asked SEAC to advise on the findings of preliminary research aimed at informing estimates of the risk of variant Creutzfeldt-Jakob Disease (vCJD) transmission via dentistry.

Background ---------- 2. Prions are more resistant than other types of infectious agents to the conventional cleaning and sterilization practices used to decontaminate dental instruments (1). Appreciable quantities of residual material may remain adherent to the surface after normal cleaning and sterilization (2). Therefore, if dental tissues are both infectious and susceptible to infection, the dental instruments are a potential mechanism for the secondary transmission of vCJD. Dentistry could be a particularly significant route of transmission for the population as a whole, due to the large number of routine procedures undertaken and also because dental patients have a normal life expectancy.

This is in contrast with other transmission routes, such as blood transfusion and neurosurgery, where procedures are often carried out in response to some life-threatening condition. Additionally, the ubiquity of dental procedures and the lack of central records on dental procedures means that should such transmission occur, then it would be difficult to detect and control.

3. No cases of vCJD transmission arising from dental procedures have been reported to date (3). Previous DH risk assessments (4,5) have focused on 2 possible mechanisms for the transfer of vCJD infectivity via dental instruments; accidental abrasion of the lingual tonsil and endodontic procedures that involve contact with dental pulp. In considering these assessments, SEAC agreed that the risk of transmission via accidental abrasion of the lingual tonsil appears very low. However, the risk of transmission via endodontic procedures may be higher and give rise to a self sustaining vCJD epidemic under circumstances where (i) dental pulp is infective, (ii) transmission via endodontic instruments is efficient and (iii) a large proportion of vCJD infections remain in a subclinical carrier state (SEAC 91, February 2006). In light of this, SEAC advised that restricting endodontic files and reamers to single use be considered (6). SEAC recommended reassessment of these issues as new data emerge.

New research ------------ 4. Preliminary, unpublished results of research from the Health Protection Agency, aimed at addressing some of the uncertainties in the risk assessments, were reviewed by SEAC (SEAC 97, May 2007). The prion agent used in these studies is closely related to the vCJD agent. This research, using a mouse model, shows that following inoculation of mouse-adapted bovine spongiform encephalopathy (BSE) directly into the gut, infectivity subsequently becomes widespread in tissues of the oral cavity, including dental pulp, salivary glands and gingiva, during the preclinical as well as clinical stage of disease.

5. It is not known how closely the level and distribution of infectivity in the oral cavity of infected mice reflects those of humans infected with vCJD, as there are no comparable data from oral tissues, in particular dental pulp and gingiva, from human subclinical or clinical vCJD cases (7). Although no abnormal prion protein was found in a study of human dental tissues, including dental pulp, salivary glands and gingiva from vCJD cases, the relationship between levels of infectivity and abnormal prion protein is unclear (8). Infectivity studies underway using the mouse model and oral tissues that are presently available from human vCJD cases will provide some comparable data. On the basis of what is currently known, there is no reason to suppose that the mouse is not a good model for humans in respect to the distribution of infectivity in oral tissues. Furthermore, the new data are consistent with published results from experiments using a hamster scrapie model (9).

6. A 2nd set of experiments using the same mouse model showed that non-invasive and transient contact between gingival tissue and fine dental files contaminated with mouse-adapted BSE brain homogenate transmits infection very efficiently. It is not known how efficient gingival transmission would be if dental files were contaminated with infectious oral tissues and then subsequently cleaned and sterilized, a situation which would more closely model human dental practice. Further studies using the mouse model that would be more representative of the human situation, comparing oral tissues with a range of doses of infectivity, cleaned and sterilized files and the kind of tissue contact with instruments that occurs during dentistry, should be considered.

7. SEAC considered that the experiments appear well designed and the conclusions justified and reliable, while recognizing that the research is incomplete and confirmatory experiments have yet to be completed. It is recommended that the research be completed, submitted for peer-review and widely disseminated as soon as possible so others can consider the implications. Nevertheless, these preliminary data increase the possibility that some oral tissues of humans infected with vCJD may potentially become infective during the preclinical stage of the disease. In addition, they increase the possibility that infection could potentially be transmitted not only via accidental abrasion of the lingual tonsil or endodontic procedures but a variety of routine dental procedures.

Implications for transmission risks ----------------------------------- 8. The new findings help refine assumptions made about the level of infectivity of dental pulp and the stage of incubation period when it becomes infective in the risk assessment of vCJD transmission from the reuse of endodontic files and reamers (10). For example, if one patient in 10 000 were to be carrying infection (equivalent to about 6000 people across the UK, the best current estimate (11), the data suggest that in the worst case scenario envisaged in the risk assessment, reuse of endodontic files and reamers might lead to up to 150 new infections per annum. It is not known how many of those infected would go on to develop clinical vCJD. In addition, transmission via the reuse of endodontic files and reamers could be sufficiently efficient to cause a self-sustaining vCJD epidemic arising via this route.

9. These results increase the importance of obtaining reliable estimates of vCJD infection prevalence. Data that will soon be available from the National Anonymous Tonsil Archive may help refine this assessment and provide evidence of the existence and extent of subclinical vCJD infection in tonsillectomy patients. Further data, such as from post mortem tissue or blood donations, will be required to assess prevalence in the general UK population (12).

10. Recent guidance issued by DH to dentists to ensure that endodontic files and reamers are treated as single use (13) is welcomed and should, as long as it is effectively and quickly implemented, prevent transmission and a self-sustaining epidemic arising via this route. However, the extent and monitoring of compliance with this guidance in private and National Health Service dental practice is unclear.

11. The new research also suggests that dental procedures involving contact with other oral tissues, including gingiva, may also be capable of transmitting vCJD. In the absence of a detailed risk assessment examining the potential for transmission via all dental procedures, it is not possible to come to firm conclusions about the implications of these findings for transmission of vCJD. However, given the potential for transmission by this route, serious consideration should be given to assessing the options for reducing transmission risks, such as improving decontamination procedures and practice or the implementation of single use instruments.

12. The size of the potential risk from interactions between the dental and other routes of secondary transmission, such as blood transfusion and hospital surgery, to increase the likelihood of a self-sustaining epidemic is unclear.

13. It is likely to be difficult to distinguish clinical vCJD cases arising from dietary exposure to BSE from secondary transmissions via dental procedures, should they arise, as a large proportion of the population is likely both to have consumed contaminated meat and undergone dentistry.

However, an analysis of dental procedures by patient age may provide an indication of the age group in which infections, if they occur, would be most likely to be observed. Should the incidence of clinical vCJD cases in this age group increase significantly, this may provide an indication that secondary transmission via dentistry is occurring. Investigation of the dental work for these cases may provide supporting data. There is no clear evidence, to date, based on surveillance or investigations of clinical vCJD cases, that any vCJD cases have been caused by dental procedures, but this possibility cannot be excluded.

Conclusions ----------- 14. Preliminary research findings suggest that the potential risk of transmission of vCJD via dental procedures may be greater than previously anticipated. Although this research is incomplete, uses an animal model exposed to relatively high doses of infectivity, and there are no data from infectivity studies on human oral tissues, these findings suggest an increased possibility that vCJD may be relatively efficiently transmitted via a range of dental procedures. Ongoing infectivity studies using human oral tissues and the other studies suggested here will enable more precise assessment of the risks of vCJD transmission through dental procedures.

15. Guidance was issued to dentists earlier this year [2007] recommending that endodontic files and reamers be treated as single use, which, provided this policy is adhered to, will remove any risk of a self-sustaining epidemic arising from reuse of these instruments. To minimize risk, it is critical that appropriate management and audit is in place, both for NHS and private dentistry.

16. It is also critical that a detailed and comprehensive assessment of the risks of all dental procedures be conducted as a matter of urgency. While taking into account the continuing scientific uncertainties, this will allow a more thorough consideration of the possible public health implications of vCJD transmission via dentistry and the identification of possible additional precautionary risk reduction measures. The assessment will require continued updating as more evidence becomes available on the transmissibility of vCJD by dental routes, and on the prevalence of infection within the population. A DH proposal to convene an expert group that includes dental professionals to expedite such an assessment is welcomed. Given the potential for transmission via dentistry, consideration should be given to the urgent assessment of new decontamination technologies which, if proven robust and effective, could significantly reduce transmission risks.

References ---------- (1) Smith et al. (2003) Prions and the oral cavity. J. Dent. Res. 82, 769-775. (2) Smith et al. (2005) Residual protein levels on reprocessed dental instruments. J. Hosp. Infect. 61, 237-241. (3) Everington et al. (2007) Dental treatment and risk of variant CJD - a case control study. Brit. Den. J. 202, 1-3. (4) Department of Health. (2003) Risk assessment for vCJD and dentistry. (5) Department of Health (2006) Dentistry and vCJD: the implications of a carrier-state for a self-sustaining epidemic. Unpublished. (6) SEAC (2006) Position statement on vCJD and endodontic dentistry . (7) Head et al. (2003) Investigation of PrPres in dental tissues in variant CJD. Br. Dent. J. 195, 339-343. (8) SEAC 90 reserved business minutes. (9) Ingrosso et al. (1999) Transmission of the 263K scrapie strain by the dental route. J. Gen. Virol. 80, 3043-3047. (10) Department of Health (2006) Dentistry and vCJD: the implications of a carrier-state for a self-sustaining epidemic. Unpublished. (11) Clarke & Ghani (2005) Projections of future course of the primary vCJD epidemic in the UK: inclusion of subclinical infection and the possibility of wider genetic susceptibility R. J. Soc. Interface. 2, 19-31. (12) SEAC Epidemiology Subgroup (2006) position statement of the vCJD epidemic . (13) DH (2007) Precautionary advice given to dentists on re-use of instruments .

-- Communicated by Terry S. Singletary, Sr.


Monday, December 31, 2007

Risk Assessment of Transmission of Sporadic Creutzfeldt-Jakob Disease in Endodontic Practice in Absence of Adequate Prion Inactivation

Subject: CJD: update for dental staff Date: November 12, 2006 at 3:25 pm PST

1: Dent Update. 2006 Oct;33(8):454-6, 458-60.

CJD: update for dental staff.

Friday, July 24, 2009

UW Hospital and Clinics Addresses Creutzfeldt-Jakob Disease Risk


Pre-surgical risk assessment for variant Creutzfeldt-Jakob disease (vCJD) risk in neurosurgery and eye surgery units

Hospitals should already be using a questionnaire in Annex J of the ACDP TSE Working Group Infection Control guidance to find out whether any patients who are about to undergo any surgery or endoscopy may be at increased risk of being infected with CJD. If a patient is found to have an increased risk of CJD prior to their surgery or endoscopy then special infection control precautions may need to be taken.

Annex J of the TSE Infection Control guidance has recently been revised, and now advises that patients who are due to have high risk surgery [1] or neuro-endoscopy should be asked an additional question: whether they have received transfusions of blood or blood components from 80 or more donors since 1980. This is because these patients may have an increased risk of being infected with variant CJD (vCJD).

On 16 July 2009 the HPA wrote to the chief executives of NHS trusts asking them to ensure that the guidance is implemented. Detailed information and tools for implementing the guidance can be downloaded from the links below.

If you have any queries about the implementation of the guidance, please contact the HPA Centre for Infections CJD Section at mhtml:%7B33B38F65-8D2E-434D-8F9B-8BDCD77D3066%7Dmid://00000260/! or on 020 8327 6074/6411.

Background information on this new pre-surgical assessment is contained in this Letter to chief executives - July 2009 (PDF, 73 KB) written to all hospitals in England.

The new version of Annex J of the TSE Infection Control Guidance contains new question for patients undergoing high risk surgery and neuro-endoscopy. These questions should be used to assess patients' CJD risk factors.

Clinicians carrying out the new pre-surgical assessment should read Pre-surgical assessment Information for healthcare staff - July 2009 (PDF, 163 KB) This vCJD Algorithm for per-surgical roles - July 2009 (PDF, 28 KB) shows suggested roles and responsibilities for infection control teams, surgical teams and blood transfusion specialists.

Information on patients' transfusion histories should be collected using the Highly transfused vCJD risk assessment form - July 2009 (Word Document, 328 KB) This form is also available as a vCJD risk assessment spreadsheet - July 2009 (Excel Spreadsheet, 2.7 MB). This may help calculate the number of blood donors to a patient. The form may be posted or emailed to the HPA Centre for Infections CJD Section mhtml:%7B33B38F65-8D2E-434D-8F9B-8BDCD77D3066%7Dmid://00000260/!

Blood transfusion laboratories may wish to use this draft Letter to other blood laboratories - July 2009 (Word Document, 31 KB) when collecting transfusion information from other hospitals.

Pre-surgical assessment teams and patients may wish to read this vCJD Information for presurgical patients - July 2009 (PDF, 29 KB) about this new pre-surgical assessment.

[1] High risk surgery is defined as surgery involving any of the following organs or tissues (high risk tissues): brain, spinal cord, cranial nerves (specifically the entire optic nerve and only the intercranial components of the other cranial nerves), cranial nerve ganglia, posterior eye (specifically the posterior hyaloid face, retina, retinal pigment epithelium, choroid, subretinal fluid, optic nerve) and pituitary gland.

Letter to chief executives - July 2009 (PDF, 73 KB) Added/updated: 16 July 2009

Pre-surgical assessment Information for healthcare staff - July 2009 (PDF, 163 KB) Added/updated: 16 July 2009

vCJD Algorithm for per-surgical roles - July 2009 (PDF, 28 KB) Added/updated: 16 July 2009

Highly transfused vCJD risk assessment form - July 2009 (Word Document, 328 KB) Added/updated: 16 July 2009

Letter to other blood laboratories - July 2009 (Word Document, 31 KB) Added/updated: 16 July 2009

vCJD Information for presurgical patients - July 2009 (PDF, 29 KB) Added/updated: 16 July 2009

vCJD risk assessment spreadsheet - July 2009 (Excel Spreadsheet, 2.7 MB) Added/updated: 16 July 2009

full text ;

see also ;

Friday, July 17, 2009

Revision to pre-surgical assessment of risk for vCJD in neurosurgery and eye surgery units Volume 3 No 28; 17 July 2009

Tuesday, August 12, 2008

Biosafety in Microbiological and Biomedical Laboratories Fifth Edition 2007 (occupational exposure to prion diseases)

Thursday, January 29, 2009

Medical Procedures and Risk for Sporadic Creutzfeldt-Jakob Disease, Japan, 1999-2008 (WARNING TO Neurosurgeons and Ophthalmologists) Volume 15, Number 2-February 2009 Research


Friday, July 24, 2009

UW Hospital and Clinics Addresses Creutzfeldt-Jakob Disease Risk

Sunday, January 17, 2010

CJD Following up: Patients never contracted brain disorder UW Hospital patients

Friday, February 05, 2010

New Variant Creutzfelt Jakob Disease case reports United States 2010 A Review


Sunday, February 14, 2010

[Docket No. FSIS-2006-0011] FSIS Harvard Risk Assessment of Bovine Spongiform Encephalopathy (BSE)

Friday, January 29, 2010

14th International Congress on Infectious Diseases H-type and L-type Atypical BSE January 2010 (special pre-congress edition)


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