Bioassay Studies Support the Potential for Iatrogenic Transmission of Variant Creutzfeldt Jakob Disease through Dental Procedures
Bioassay Studies Support the Potential for Iatrogenic Transmission of
Variant Creutzfeldt Jakob Disease through Dental Procedures
Elizabeth Kirby1#, Joanne Dickinson1#, Matthew Vassey1, Mike Dennis1, Mark
Cornwall1, Neil McLeod1, Andrew Smith2, Philip D. Marsh1,3, James T. Walker1, J.
Mark Sutton1*, Neil D. H. Raven1
1 Health Protection Agency - Porton Down, Salisbury, Wiltshire, United
Kingdom, 2 College of Medical, Veterinary & Life Sciences, Glasgow Dental
Hospital & School, University of Glasgow, Glasgow, United Kingdom, 3 Leeds
Dental Institute, Leeds, West Yorkshire, United Kingdom
Abstract
Background
Evidence is required to quantify the potential risks of transmission of
variant Creutzfeldt Jakob (vCJD) through dental procedures. Studies, using
animal models relevant to vCJD, were performed to address two questions.
Firstly, whether oral tissues could become infectious following dietary exposure
to BSE? Secondly, would a vCJD-contaminated dental instrument be able to
transmit disease to another patient?
Methods
BSE-301V was used as a clinically relevant model for vCJD. VM-mice were
challenged by injection of infected brain homogenate into the small intestine
(Q1) or by five minute contact between a deliberately-contaminated dental file
and the gingival margin (Q2). Ten tissues were collected from groups of
challenged mice at three or four weekly intervals, respectively. Each tissue was
pooled, homogenised and bioassayed in indicator mice.
Findings
Challenge via the small intestine gave a transmission rate of 100% (mean
incubation 157±17 days). Infectivity was found in both dental pulp and the
gingival margin within 3 weeks of challenge and was observed in all tissues
tested within the oral cavity before the appearance of clinical symptoms.
Following exposure to deliberately contaminated dental files, 97% of mice
developed clinical disease (mean incubation 234±33 days).
Interpretation
Infectivity was higher than expected, in a wider range of oral tissues,
than was allowed for in previous risk assessments. Disease was transmitted
following transient exposure of the gingiva to a contaminated dental file. These
observations provide evidence that dental procedures could be a route of
cross-infection for vCJD and support the enforcement of single-use for certain
dental instruments.
Citation: Kirby E, Dickinson J, Vassey M, Dennis M, Cornwall M, et al.
(2012) Bioassay Studies Support the Potential for Iatrogenic Transmission of
Variant Creutzfeldt Jakob Disease through Dental Procedures. PLoS ONE 7(11):
e49850. doi:10.1371/journal.pone.0049850
Editor: Noriyuki Nishida, Nagasaki University Graduate School of Biomedical
Sciences, Japan
Received: March 23, 2012; Accepted: October 15, 2012; Published: November
30, 2012
Copyright: © 2012 Kirby et al. This is an open-access article distributed
under the terms of the Creative Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in any medium, provided the
original author and source are credited.
Funding: The study was funded by the Department of Health (England),
contract number 007/0099. The funders had no role in study design, data
collection and analysis, decision to publish, or preparation of the
manuscript.
Competing interests: AS has received lecture fees and funding for a PhD
studentship from W&H Ltd, lecture fees from Steris Ltd and travel expenses
for attending a meeting from Schulke and Mayr. PM identified consultancy work
for Johnson and Johnson, UK and Unilever, UK. JMS identified consultancy work
for Advanced Sterilisation Products and funding for research involving TSO3,
CISA SpaA, BES Decon, BiotAK, and Genencor International. JMS also received
travel money to attend a meeting of the British Association for the Study of
Community Dentistry. This does not alter the authors' adherence to all the PLOS
ONE policies on sharing data and materials.
* E-mail: mark.sutton@hpa.org.uk
# These authors contributed equally to this work.
snip...
Implications for public health
Currently there is no evidence for vCJD transmission through either surgery
or dentistry. Transmission of vCJD by blood transfusion [5], [9] highlights that
any procedure contacting nervous or lymphoid tissue must also be considered a
risk given the wider tissue distribution of vCJD infectivity compared to
sporadic CJD [19]–[21]. The highly efficient transmission of BSE strain 301 V
infection through direct inoculation into the murine small intestine in this
study raises similar concerns for vCJD transmission through endoscopic
procedures in man.
The observations in the current study also provide theoretical grounds for
concern in respect to dental procedures. The levels of infectivity observed in
all oral tissues tested (most notably gingival margin with up to ~1000 ID per
mg) were higher than previously considered.
A further element of the study assessed residual protein contamination on a
range of dental instruments after routine cleaning and disinfection in general
dental practice in England [22]). The study showed a number of instrument types
and cleaning procedures where the upper interquartile range for residual protein
was in excess of 100 µg. This could equate to up to 100 ID per instrument in the
case of gingival tissue. Autoclaving has been shown to achieve only a 3-log
inactivation of various TSE agents [23] and an autoclave designed for the dental
market has been tested recently and shown to provide only a 100-fold reduction
in infectivity in the BSE301V/VM model used here (134°C, 18 minutes; Sutton et
al unpublished). A dental instrument soiled with infectious gingival tissue and
disinfected under this regimen would have an inadequate safety margin.
The gingival challenge was designed as a worse-case scenario in respect to
the infectious load on a dental instrument, but to be of limited invasiveness.
The procedure resulted in very high levels of transmission with short incubation
periods indicating that a much lower titre challenge material would also have
caused some transmission. Even if a relatively rare event, the large number of
dental interventions taking place in a younger age profile population (c.f.
surgical procedures) and a carrier population of unknown size means these risks
are not negligible. This would seem to be at odds with the absence of any
reported cases of clinical vCJD transmission linked to dental procedures. This
might be explained by a number of factors, including difficulties in linking
dental records to known vCJD patients [24], asymptomatic cases [5] and extended
incubation periods for patients exposed by blood transfusion (up to 7.8 years;
[25]). As a worse case study, the incubation periods described here would be
expected to be the most rapid giving rise to prion-disease symptoms in this
model, and as a novel low-dose, peripheral model of infection, the incubation
periods might be expected to be considerably longer than those observed for
blood transfusion cases. Given the difficulties in linking dental procedure case
histories to vCJD, such cases may not yet be evident.
Preliminary data from this study have already been provided to the UK
Department of Health as part of the revision of the dental risk assessment (http://www.dh.gov.uk/prod_consum_dh/groups/dh_digitalassets/dh/en/documents/digitalasset/dh_081217.pdf;
accessed 12th November 2011).
Additional control measures have been incorporated into guidance on
decontamination in dental settings in England (http://www.dh.gov.uk/en/Publicationsandstatistics/Publications/PublicationsPolicyAndGuidance/DH_109363;
accessed 12th November 2011). The emphasis on standardised decontamination
methods and single use instruments for difficult to clean devices appear
sensible and proportionate given the experimental observations described and
discussed here.
remember, all iatrogenic CJD is, is sporadic CJD until route and source is
confirmed for iatrogenic transmission. ...
Friday, November 23, 2012
sporadic Creutzfeldt-Jakob Disease update As at 5th November 2012 UK, USA,
AND CANADA
Tuesday, November 6, 2012
Transmission of New Bovine Prion to Mice, Atypical Scrapie, BSE, and
Sporadic CJD, November-December 2012 update
Thursday, October 25, 2012
Current limitations about the cleaning of luminal endoscopes and TSE prion
risk factors there from
Article in Press
Friday, August 24, 2012
Iatrogenic prion diseases in humans: an update
Monday, August 13, 2012
Summary results of the second national survey of abnormal prion prevalence
in archived appendix specimens August 2012
Friday, August 10, 2012
Incidents of Potential iatrogenic Creutzfeldt-Jakob disease (CJD) biannual
update (July 2012)
Friday, June 29, 2012
Highly Efficient Prion Transmission by Blood Transfusion
Thursday, May 17, 2012
Iatrogenic Creutzfeldt-Jakob Disease, Final Assessment
Volume 18, Number 6—June 2012
Wednesday, May 16, 2012
Alzheimer’s disease and Transmissible Spongiform Encephalopathy prion
disease, Iatrogenic, what if ?
Proposal ID: 29403
Saturday, January 16, 2010
Evidence For CJD TSE Transmission Via Endoscopes 1-24-3 re-Singeltary to
Bramble et al
Wednesday, December 28, 2011
FDA Targets Risks From Reused Devices
Monday, May 16, 2011
Does Poor Dental Health Have a Role in the Emergence of Variant Creutzfeldt
Jakob Disease in the United Kingdom?
Thursday, July 08, 2010
GLOBAL CLUSTERS OF CREUTZFELDT JAKOB DISEASE - A REVIEW 2010
[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.
Evidence For CJD/TSE Transmission Via Dental Instruments
From Terry S. Singletary, Sr
flounder@wt.net
1-24-3
J Hosp Infect 2002 Jul;51(3):233-5 Related Articles, Links [Click here to
read] Contaminated dental instruments.
Smith A, Dickson M, Aitken J, Bagg J.
Infection Research Group, Glasgow Dental Hospital & School, 378
Sauchiehall Street, Glasgow, UK. a.smith@dental.gla.ac.uk
There is current concern in the UK over the possible transmission of prions
via contaminated surgical instruments. Some dental instruments (endodontic
files) raise particular concerns by virtue of their intimate contact with
terminal branches of the trigeminal nerve. A visual assessment using a
dissecting light microscope and scanning electron microscopy of endodontic files
after clinical use and subsequent decontamination was performed. The instruments
examined were collected from general dental practices and from a dental
hospital. Seventy-six per cent (22/29) of the files retrieved from general
dental practices remained visibly contaminated, compared with 14% (5/37) from
the dental hospital. Current methods for decontaminating endodontic instruments
used in dentistry may be of an insufficient standard to completely remove
biological material. Improved cleaning methods and the feasibility of single use
endodontic instruments require further investigation.
PMID: 12144804 [PubMed - indexed for MEDLINE]
J Gen Virol 1999 Nov;80 ( Pt 11):3043-7
Transmission of the 263K scrapie strain by the dental route.
Ingrosso L, Pisani F, Pocchiari M
Laboratory of Virology, lstituto Superiore di Sanita, Viale Regina Elena
299, 00161 Rome, Italy.
Apart from a few cases of iatrogenic and familial human transmissible
spongiform encephalopathies (TSEs) or prion diseases, the cause of
Creutzfeldt-Jakob disease (CJD) remains unknown. In this paper we investigated
the possibility that dental procedures may represent a potential route of
infection. This was assessed by using the experimental model of scrapie in
hamster. In the first part of this study we found that after intraperitoneal
inoculation, oral tissues commonly involved in dental procedures (gingival and
pulp tissues) bore a substantial level of infectivity. We also found high
scrapie infectivity in the trigeminal ganglia, suggesting that the scrapie agent
had reached the oral tissues through the sensitive terminal endings of the
trigeminal nerves. In the second part of the study we inoculated a group of
hamsters in the tooth pulp and showed that all of them developed scrapie
disease. In these animals, we detected both infectivity and the pathological
prion protein (PrPsc) in the trigeminal ganglion homolateral to the site of
injection but not in the controlateral one. This finding suggests that the
scrapie agent, and likely other TSE agents as well, spreads from the buccal
tissues to the central nervous system through trigeminal nerves. Although these
findings may not apply to humans affected by TSEs, they do raise concerns about
the possible risk of transmitting these disorders through dental procedures.
Particular consideration should be taken in regard to new variant CJD patients
because they may harbour more infectivity in peripheral tissues than sporadic
CJD patients.
PMID: 10580068
a simple auto-claving just will not kill this agent, considering the fact
this agent can survive ashing to 600 degrees celsius;
New studies on the heat resistance of hamster-adapted scrapie agent:
Threshold survival after ashing at 600°C suggests an inorganic template of
replication
Paul Brown*,dagger , Edward H. RauDagger , Bruce K. Johnson*, Alfred E.
Bacote*, Clarence J. Gibbs Jr.*, and D. Carleton Gajdusek§
* Laboratory of Central Nervous System Studies, National Institute of
Neurological Disorders and Stroke, and Dagger Environmental Protection Branch,
Division of Safety, Office of Research Services, National Institutes of Health,
Bethesda, MD 20892; and § Institut Alfred Fessard, Centre National de la
Recherche Scientifique, 91198 Gif sur Yvette, France Contributed by D. Carleton
Gajdusek, December 22, 1999
Abstract
One-gram samples from a pool of crude brain tissue from hamsters infected
with the 263K strain of hamster-adapted scrapie agent were placed in covered
quartz-glass crucibles and exposed for either 5 or 15 min to dry heat at
temperatures ranging from 150°C to 1,000°C. Residual infectivity in the treated
samples was assayed by the intracerebral inoculation of dilution series into
healthy weanling hamsters, which were observed for 10 months; disease
transmissions were verified by Western blot testing for proteinase-resistant
protein in brains from clinically positive hamsters. Unheated control tissue
contained 9.9 log10LD50/g tissue; after exposure to 150°C, titers equaled or
exceeded 6 log10LD50/g, and after exposure to 300°C, titers equaled or exceeded
4 log10LD50/g. Exposure to 600°C completely ashed the brain samples, which, when
reconstituted with saline to their original weights, transmitted disease to 5 of
35 inoculated hamsters. No transmissions occurred after exposure to 1,000°C.
These results suggest that an inorganic molecular template with a decomposition
point near 600°C is capable of nucleating the biological replication of the
scrapie agent.
transmissible spongiform encephalopathy | scrapie | prion | medical waste |
incineration
Introduction
The infectious agents responsible for transmissible spongiform
encephalopathy (TSE) are notoriously resistant to most physical and chemical
methods used for inactivating pathogens, including heat. It has long been
recognized, for example, that boiling is ineffective and that higher
temperatures are most efficient when combined with steam under pressure (i.e.,
autoclaving). As a means of decontamination, dry heat is used only at the
extremely high temperatures achieved during incineration, usually in excess of
600°C. It has been assumed, without proof, that incineration totally inactivates
the agents of TSE, whether of human or animal origin. It also has been assumed
that the replication of these agents is a strictly biological process (1),
although the notion of a "virus" nucleant of an inorganic molecular cast of the
infectious beta -pleated peptide also has been advanced (2). In this paper, we
address these issues by means of dry heat inactivation studies.
see full text:
Sunday, December 9, 2012
Prions, prionoids and pathogenic proteins in Alzheimer disease
http://betaamyloidcjd.blogspot.com/2012/12/prions-prionoids-and-pathogenic.html
Greetings again,
please believe me when i tell you this goes far far beyond the
hamburger/deer burger/elk burger/sheep burger. Pandora's box of the demented has
been opened for decades, closing it will be most impossible with current
safeguards. until they can perfect a test, not only to confirm TSE agent, but
also to differentiate between the many different strains (there are over 20 in
sheep scrapie, and sheep scrapie is the sole model for CJD studies), they then
will have to perfect a test that will differentiate between the many different
routes. so, as you can see, this could very well take many more decades to
answer these questions. but in the mean time, i will not now or ever accept the
'spontaneous/sporadic' theory, in 85%+ of all sCJD cases, without any source and route. i plan to continue
to fan the fire until we know what killed our loved ones...
CJD/TSEs MUST BE MADE REPORTABLE NATIONALLY, SUPPORTED WITH A CJD
QUESTIONNAIRE TO EVERY VICTIM/FAMILY THAT ASK REAL QUESTIONS PERTAINING TO
ROUTE/SOURCE...TSS
Diagnosis and Reporting of Creutzfeldt-Jakob Disease
T. S. Singeltary, Sr; D. E. Kraemer; R. V. Gibbons, R. C. Holman, E. D.
Belay, L. B. Schonberger
kind regards, terry
posted by Terry S. Singeltary Sr. | 1:02 PM
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