BMC Res Notes. 2015 Jul 24;8:312. doi: 10.1186/s13104-015-1260-3.
Further characterisation of transmissible spongiform encephalopathy
phenotypes after inoculation of cattle with two temporally separated sources of
sheep scrapie from Great Britain.
Konold T1, Nonno R2, Spiropoulos J3, Chaplin MJ4, Stack MJ5, Hawkins SA6,
Cawthraw S7, Wilesmith JW8, Wells GA9, Agrimi U10, Di Bari MA11, Andréoletti
O12, Espinosa JC13, Aguilar-Calvo P14, Torres JM15.
Author information
Abstract
BACKGROUND:
The infectious agent responsible for the bovine spongiform encephalopathy
(BSE) epidemic in Great Britain is a transmissible spongiform encephalopathy
(TSE) strain with uniform properties but the origin of this strain remains
unknown. Based on the hypothesis that classical BSE may have been caused by a
TSE strain present in sheep, cattle were inoculated intracerebrally with two
different pools of brains from scrapie-affected sheep sourced prior to and
during the BSE epidemic to investigate resulting disease phenotypes and
characterise their causal agents by transmission to rodents.
RESULTS:
As reported in 2006, intracerebral inoculation of cattle with pre-1975 and
post-1990 scrapie brain pools produced two distinct disease phenotypes, which
were unlike classical BSE. Subsequent to that report none of the remaining
cattle, culled at 10 years post inoculation, developed a TSE. Retrospective
Western immunoblot examination of the brains from TSE cases inoculated with the
pre-1975 scrapie pool revealed a molecular profile similar to L-type BSE. The
inoculation of transgenic mice expressing the bovine, ovine, porcine, murine or
human prion protein gene and bank voles with brains from scrapie-affected cattle
did not detect classical or atypical BSE strains but identified two previously
characterised scrapie strains of sheep.
CONCLUSIONS:
Characterisation of the causal agents of disease resulting from exposure of
cattle to naturally occurring scrapie agents sourced in Great Britain did not
reveal evidence of classical or atypical BSE, but did identify two distinct
previously recognised strains of scrapie. Although scrapie was still
recognizable upon cattle passage there were irreconcilable discrepancies between
the results of biological strain typing approaches and molecular profiling
methods, suggesting that the latter may not be appropriate for the
identification and differentiation of atypical, particularly L-type, BSE agents
from cattle experimentally infected with a potential mixture of classical
scrapie strains from sheep sources.
PMID: 26205536 [PubMed - in process]
Conclusions
Two different disease phenotypes were produced after intracerebral
inoculation of cattle with scrapie brain pools sourced pre-1975 and post-1990 in
GB, which were not readily explained by any differences in PrP genotype of the
cattle. Based on pathological and molecular characteristics and biological
characterisation in bank voles and transgenic mice there was no clear evidence
of an agent derived from the cattle resembling classical or atypical forms of
BSE. Transmissions in bank voles identified previously isolated scrapie strains
and some similarities to the experimental isolate CH1641. Contrary to the
transmission results in rodents, the results for the molecular techniques, which
have been adopted for the detection of atypical BSE cases, suggest that they may
not be appropriate for differentiating WB profiles in cattle following infection
from an ovine scrapie source.
Wednesday, January 18, 2012
Selection of Distinct Strain Phenotypes in Mice Infected by Ovine Natural
Scrapie Isolates Similar to CH1641 Experimental Scrapie
Journal of Neuropathology & Experimental Neurology:
February 2012 - Volume 71 - Issue 2 - p 140–147
doi: 10.1097/NEN.0b013e3182439519
Original Articles
Selection of Distinct Strain Phenotypes in Mice Infected by Ovine Natural
Scrapie Isolates Similar to CH1641 Experimental Scrapie
Vulin, Johann PhD; Beck, Katy E. PhD; Bencsik, Anna PhD; Lakhdar, Latefa
PhD; Spiropoulos, John PhD; Baron, Thierry PhD
Supplemental Author Material
Abstract
Abstract: A few cases of transmissible spongiform encephalopathies in sheep
have been described in France in which the protease-resistant prion protein
(PrPres) exhibited some features in Western blot of experimental bovine
spongiform encephalopathy in sheep. Their molecular characteristics were
indistinguishable from those produced in the CH1641 experimental scrapie
isolate. Four of these CH1641-like isolates were inoculated intracerebrally into
wild-type C57Bl/6 mice. In striking contrast to previous results in ovine
transgenic mice, CH1641 transmission in wild-type mice was efficient. Several
components of the strain signature, that is, PrPres profile, brain distribution,
and morphology of the deposits of the disease-associated prion protein, had some
similarities with “classical” scrapie and clearly differed from both bovine
spongiform encephalopathy in sheep and CH1641 transmission in ovine transgenic
mice. These results on CH1641-like isolates in wild-type mice may be consistent
with the presence in these isolates of mixed conformers with different abilities
to propagate and mediate specific disease phenotypes in different species.
Bovine spongiform encephalopathy, CH1641, Prion disease pathogenesis
© 2012 American Association of Neuropathologists, Inc
Wednesday, January 18, 2012
BSE IN GOATS CAN BE MISTAKEN FOR SCRAPIE
February 1, 2012
TSE PRION UPDATE USA 2012
re-BSE in goats can be mistaken for scrapie
Wednesday, January 18, 2012
Selection of Distinct Strain Phenotypes in Mice Infected by Ovine Natural
Scrapie Isolates Similar to CH1641 Experimental Scrapie
Journal of Neuropathology & Experimental Neurology:
February 2012 - Volume 71 - Issue 2 - p 140–147
In the US, scrapie is reported primarily in sheep homozygous for 136A/171Q
(AAQQ) and the disease phenotype is similar to that seen with experimental
strain CH1641.
Thursday, July 14, 2011
Histopathological Studies of "CH1641-Like" Scrapie Sources Versus Classical
Scrapie and BSE Transmitted to Ovine Transgenic Mice (TgOvPrP4)
EVIDENCE OF SCRAPIE IN SHEEP AS A RESULT OF FOOD BORNE EXPOSURE
This is provided by the statistically significant increase in the incidence
of sheep scrape from 1985, as determined from analyses of the submissions made
to VI Centres, and from individual case and flock incident studies.
........
RISK OF BSE TO SHEEP VIA FEED
Marion Simmons communicated surprising evidence for oral transmissibility
of Nor98/atypical scrapie in neonatal sheep and although bioassay is ongoing,
infectivity of the distal ileum of 12 and 24 month infected sheep is positive in
Tg338 mice.
SUMMARY REPORTS OF MAFF BSE TRANSMISSION STUDIES AT THE CVL ;
THE RISK TO HUMANS FROM SHEEP;
EXPERIMENTAL TRANSMISSION OF BSE TO SHEEP
SHEEP AND BSE
PERSONAL AND CONFIDENTIAL
SHEEP AND BSE
A. The experimental transmission of BSE to sheep.
Studies have shown that the ''negative'' line NPU flock of Cheviots can be
experimentally infected with BSE by intracerebral (ic) or oral challenge (the
latter being equivalent to 0.5 gram of a pool of four cow brains from animals
confirmed to have BSE).
RB264
BSE - TRANSMISSION STUDIES
Monday, March 21, 2011
Sheep and Goat BSE Propagate More Efficiently than Cattle BSE in Human PrP
Transgenic Mice
snip...
On the other hand, this component would not be distinguishable from
bovine-passaged BSE prions due to the current limits of the standard biological
methods and/or the molecular tools employed here to characterize prion strains.
Whatever the mechanism, the notion that a passage through an intermediate
species can profoundly alter prion virulence for the human species has important
public-health issues, regarding emerging and/or expanding TSEs, like atypical
scrapie or CWD.
snip...
Taken all together, our results suggest that the possibility of a small
ruminant BSE prion as vCJD causal agent could not be ruled out, which has
important implications on public and animal health policies. On one hand,
although the exact magnitude and characteristic of the vCJD epidemic is still
unclear, its link with cattle BSE is supported by strong epidemiological ground
and several experimental data. On the other hand, the molecular typing performed
in our studies, indicates that the biochemical characteristics of the PrPres
detected in brains of our sheep and goat BSE-inoculated mice seem to be
indistinguishable from that observed in vCJD. Considering the similarity in
clinical manifestation of BSE- and scrapie-affected sheep [48], a masker effect
of scrapie over BSE, as well as a potential adaptation of the BSE agent through
subsequent passages, could not be ruled out. As BSE infected sheep PrPSc have
been detected in many peripheral organs, small ruminant-passaged BSE prions
might be a more widespread source of BSE infectivity compared to cattle [19],
[49], [50]. This fact is even more worrying since our transmission studies
suggest that apparently Met129 human PrP favours a BSE agent with ovine rather
than a bovine sequence. Finally, it is evident that, although few natural cases
have been described and so far we cannot draw any definitive conclusion about
the origin of vCJD, we can not underestimate the risk of a potential goat and/or
sheep BSE agent.
snip...
Technical Abstract:
Prion strains may vary in their ability to transmit to humans and animals.
Few experimental studies have been done to provide evidence of differences
between U.S. strains of scrapie, which can be distinguished by incubation times
in inbred mice, microscopic lesions, immunoreactivity to various antibodies, or
molecular profile (electrophoretic mobility and glycoform ratio). Recent work on
two U.S. isolates of sheep scrapie supports that at least two distinct strains
exist based on differences in incubation time and genotype of sheep affected.
One isolate (No. 13-7) inoculated intracerebrally caused scrapie in sheep AA at
codon 136 (AA136) and QQ at codon 171 (QQ171) of the prion protein in an average
of 19 months post-inoculation (PI) whereas a second isolate (No. x124) caused
disease in less than 12 months after oral inoculation in AV136/QQ171 sheep.
Striking differences were evident when further strain analysis was done in R111,
VM, C57Bl6, and C57Bl6xVM (F1) mice. No. 13-7 did not induce disease in any
mouse strain at any time post-inoculation (PI) nor were brain tissues positive
by western blot (WB). Positive WB results were obtained from mice inoculated
with isolate No. x124 starting at day 380 PI. Incubation times averaged 508,
559, 601, and 633 days PI for RIII, C57Bl6, VM, and F1 mice, respectively.
Further passage will be required to characterize these scrapie strains in mice.
This work provides evidence that multiple scrapie strains exist in U.S.
sheep.
One of these isolates (TR316211) behaved like the CH1641 isolate, with
PrPres features in mice similar to those in the sheep brain. From two other
isolates (O100 and O104), two distinct PrPres phenotypes were identified in
mouse brains, with either high (h-type) or low (l-type) apparent molecular
masses of unglycosylated PrPres, the latter being similar to that observed with
CH1641, TR316211, or BSE. Both phenotypes could be found in variable proportions
in the brains of the individual mice. In contrast with BSE, l-type PrPres from
"CH1641-like" isolates showed lower levels of diglycosylated PrPres. From one of
these cases (O104), a second passage in mice was performed for two mice with
distinct PrPres profiles. This showed a partial selection of the l-type
phenotype in mice infected with a mouse brain with predominant l-type PrPres,
and it was accompanied by a significant increase in the proportions of the
diglycosylated band. These results are discussed in relation to the diversity of
scrapie and BSE strains.
1: J Infect Dis 1980 Aug;142(2):205-8
Oral transmission of kuru, Creutzfeldt-Jakob disease, and scrapie to
nonhuman primates.
Gibbs CJ Jr, Amyx HL, Bacote A, Masters CL, Gajdusek DC.
Kuru and Creutzfeldt-Jakob disease of humans and scrapie disease of sheep
and goats were transmitted to squirrel monkeys (Saimiri sciureus) that were
exposed to the infectious agents only by their nonforced consumption of known
infectious tissues. The asymptomatic incubation period in the one monkey exposed
to the virus of kuru was 36 months; that in the two monkeys exposed to the virus
of Creutzfeldt-Jakob disease was 23 and 27 months, respectively; and that in the
two monkeys exposed to the virus of scrapie was 25 and 32 months, respectively.
Careful physical examination of the buccal cavities of all of the monkeys failed
to reveal signs or oral lesions. One additional monkey similarly exposed to kuru
has remained asymptomatic during the 39 months that it has been under
observation.
snip...
The successful transmission of kuru, Creutzfeldt-Jakob disease, and scrapie
by natural feeding to squirrel monkeys that we have reported provides further
grounds for concern that scrapie-infected meat may occasionally give rise in
humans to Creutzfeldt-Jakob disease.
PMID: 6997404
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=6997404&dopt=Abstract
12/10/76 AGRICULTURAL RESEARCH COUNCIL REPORT OF THE ADVISORY COMMITTE ON
SCRAPIE Office Note CHAIRMAN: PROFESSOR PETER WILDY
snip...
A The Present Position with respect to Scrapie A] The Problem Scrapie is a
natural disease of sheep and goats. It is a slow and inexorably progressive
degenerative disorder of the nervous system and it ia fatal. It is enzootic in
the United Kingdom but not in all countries. The field problem has been reviewed
by a MAFF working group (ARC 35/77). It is difficult to assess the incidence in
Britain for a variety of reasons but the disease causes serious financial loss;
it is estimated that it cost Swaledale breeders alone $l.7 M during the five
years 1971-1975. A further inestimable loss arises from the closure of certain
export markets, in particular those of the United States, to British sheep. It
is clear that scrapie in sheep is important commercially and for that reason
alone effective measures to control it should be devised as quickly as possible.
Recently the question has again been brought up as to whether scrapie is
transmissible to man. This has followed reports that the disease has been
transmitted to primates.
One particularly lurid speculation (Gajdusek 1977) conjectures that the
agents of scrapie, kuru, Creutzfeldt-Jakob disease and transmissible
encephalopathy of mink are varieties of a single "virus". The U.S. Department of
Agriculture concluded that it could "no longer justify or permit scrapie-blood
line and scrapie-exposed sheep and goats to be processed for human or animal
food at slaughter or rendering plants" (ARC 84/77)" The problem is emphasised by
the finding that some strains of scrapie produce lesions identical to the once
which characterise the human dementias" Whether true or not. the hypothesis that
these agents might be transmissible to man raises two considerations. First, the
safety of laboratory personnel requires prompt attention. Second, action such as
the "scorched meat" policy of USDA makes the solution of the acrapie problem
urgent if the sheep industry is not to suffer grievously.
snip...
76/10.12/4.6
Nature. 1972 Mar 10;236(5341):73-4.
Transmission of scrapie to the cynomolgus monkey (Macaca
fascicularis).
Gibbs CJ Jr, Gajdusek DC. Nature 236, 73 - 74 (10 March 1972);
doi:10.1038/236073a0
Transmission of Scrapie to the Cynomolgus Monkey (Macaca
fascicularis)
C. J. GIBBS jun. & D. C. GAJDUSEK National Institute of Neurological
Diseases and Stroke, National Institutes of Health, Bethesda, Maryland
SCRAPIE has been transmitted to the cynomolgus, or crab-eating, monkey
(Macaca fascicularis) with an incubation period of more than 5 yr from the time
of intracerebral inoculation of scrapie-infected mouse brain. The animal
developed a chronic central nervous system degeneration, with ataxia, tremor and
myoclonus with associated severe scrapie-like pathology of intensive astroglial
hypertrophy and proliferation, neuronal vacuolation and status spongiosus of
grey matter. The strain of scrapie virus used was the eighth passage in Swiss
mice (NIH) of a Compton strain of scrapie obtained as ninth intracerebral
passage of the agent in goat brain, from Dr R. L. Chandler (ARC, Compton,
Berkshire).
Wednesday, February 16, 2011
IN CONFIDENCE SCRAPIE TRANSMISSION TO CHIMPANZEES
IN CONFIDENCE
Wednesday, February 16, 2011 IN CONFIDENCE SCRAPIE TRANSMISSION TO
CHIMPANZEES
IN CONFIDENCE
reference...
RB3.20
TRANSMISSION TO CHIMPANZEES
1. Kuru and CJD have been successfully transmitted to chimpanzees but
scrapie and TME have not.
2. We cannot say that scrapie will not transmit to chimpanzees. There are
several scrapie strains and I am not aware that all have been tried (that would
have to be from mouse passaged material). Nor has a wide enough range of field
isolates subsequently strain typed in mice been inoculated by the appropriate
routes (i/c, ilp and i/v) :
3. I believe the proposed experiment to determine transmissibility, if
conducted, would only show the susceptibility or resistance of the chimpanzee to
infection/disease by the routes used and the result could not be interpreted for
the predictability of the susceptibility for man. Proposals for prolonged oral
exposure of chimpanzees to milk from cattle were suggested a long while ago and
rejected.
4. In view of Dr Gibbs' probable use of chimpazees Mr Wells' comments
(enclosed) are pertinent. I have yet to receive a direct communication from Dr
Schellekers but before any collaboration or provision of material we should
identify the Gibbs' proposals and objectives.
5. A positive result from a chimpanzee challenged severely would likely
create alarm in some circles even if the result could not be interpreted for
man. I have a view that all these agents could be transmitted provided a large
enough dose by appropriate routes was given and the animals kept long enough.
Until the mechanisms of the species barrier are more clearly understood it might
be best to retain that hypothesis.
6. A negative result would take a lifetime to determine but that would be a
shorter period than might be available for human exposure and it would still not
answer the question regarding mans' susceptibility. In the meantime no doubt the
negativity would be used defensively. It would however be counterproductive if
the experiment finally became positive. We may learn more about public reactions
following next Monday' s meeting.
R. Bradley
23 September 1990
CVO (+Mr Wells' comments)
Dr T W A Little
Dr B J Shreeve
90/9.23/1.1.
IN CONFIDENCE CHIMPANZEES
CODE 18-77 Reference RB3.46
Some further information that may assist in decision making has been gained
by discussion with Dr Rosalind Ridley.
She says that careful study of Gajdusek's work shows no increased
susceptibility of chimpanzees over New World Monkeys such as Squirrel Monkeys.
She does not think it would tell you anything about the susceptibility to man.
Also Gajdusek did not, she believes, challenge chimpanzees with scrapie as
severely as we did pigs and we know little of that source of scrapie.
Comparisons would be difficult. She also would not expect the Home Office to
sanction such experiments here unless there was a very clear and important
objective that would be important for human health protection. She doubted such
a case could be made. If this is the case she thought it would be unethical to
do an experiment abroad because we could not do it in our own country.
Retrospectively she feels they should have put up more marmosets than they
did. They all remain healthy. They would normally regard the transmission as
negative if no disease resulted in five years.
We are not being asked for a decision but I think that before we made one
we should gain as much knowledge as we can. If we decided to proceed we would
have to bear any criticisms for many years if there was an adverse view by
scientists ormedia. This should not be undertaken lightly. There is already
some adverse comment here, I gather, on the pig experiment though that will
subside.
The Gibbs' (as' distinct from Schellekers') study is somewhat different. We
are merely supplying material for comparative studies in a laboratory with the
greatest experience of human SEs in the world and it has been sanctioned by USDA
(though we do not know for certain yet if chimpanzees specifically will be
used). This would keep it at a lower profile than if we conducted such an
experiment in the UK or Europe.
I consider we must have very powerful and defendable objectives to go
beyond Gibbs' proposed experiments and should not initiate others just because
an offer has been made.
Scientists have a responsibility to seek other methods of investigative
research other than animal experimentation. At present no objective has
convinced me we need to do research using Chimpanzees - a species in need of
protection. Resisting such proposals would enable us to communicate that
information to the scientist and the public should the need arise. A line would
have been drawn.
CVO cc Dr T Dr B W A Little Dr B J Shreeve
R Bradley
26 September 1990
90/9.26/3.2
SNIP...SEE FULL TEXT ;
Increased Atypical Scrapie Detections
Press reports indicate that increased surveillance is catching what
otherwise would have been unreported findings of atypical scrapie in sheep. In
2009, five new cases have been reported in Quebec, Ontario, Alberta, and
Saskatchewan. With the exception of Quebec, all cases have been diagnosed as
being the atypical form found in older animals. Canada encourages producers to
join its voluntary surveillance program in order to gain scrapie-free status.
The World Animal Health will not classify Canada as scrapie-free until no new
cases are reported for seven years. The Canadian Sheep Federation is calling on
the government to fund a wider surveillance program in order to establish the
level of prevalence prior to setting an eradication date. Besides long-term
testing, industry is calling for a compensation program for farmers who report
unusual deaths in their flocks.
J Vet Diagn Invest 21:454-463 (2009)
Nor98 scrapie identified in the United States
Christie M. Loiacono,' Bruce V. Thomsen, S. Mark Hall, Matti Kiupe!, Diane
Sutton, Katherine O'Rourke, Bradd Barr, Lucy Anthenill, Deiwyn Keane
Abstract.
A distinct strain of scrapic identified in sheep of Norway in 1998 has
since been identified in numerous countries throughout Europe. The disease is
known as Nor98 or Not-98-like scrapic. among other names. Distinctions between
classic scrapie and Nor98 scrapie are made based on histopathologv and
immunodiagnostic results. There are also differences in the epidemiology,
typical signalment, and likelihood of clinical signs being observed. In
addition, sheep that have genotypes associated with resistance to classic
scrapie are not spared from Nor98 disease. The various differences between
classic and Nor98 scrapie have been consistently reported in the vast majority
of cases described across Europe. The current study describes in detail the
patholo gic changes and diagnostic results of the first 6 cases of' Nor98
scrapic disease diagnosed in sheep of the United States.
Key words: Hisiopathology: Nor98: PrP imniunolabeling; scrapie: sheep.
snip...
Results
Case I The first case identified as consistent with Nor98 scrapie had
nonclassic PrP distribution in brain tissue, no PrPSC in lymph tissue, and
nonclassic migration of protein bands on a Western blot test. The animal was an
aged, mottled-faced ewe that was traced back to a commercial flock in Wyoming.
...
Case 2 The second case was a clinically normal 8-year-old Suffolk ewe that
had been in a quarantined flock for 5 years at a USDA facility in Iowa.
Case 3 A 16-year-old, white-faced, cross-bred wether was born to a
black-faced ewe. He lived his entire life as a pet on a farm in California.
Case 4 The fourth case of Nor98 scrapie was identified in an approximately
8-year-old Dorset ewe that was born into a flock of approximately 20 ewes in
Indiana.
Case 5 The fifth case was a clinically normal, approximately 3-year-old,
white-faced, cross-bred ewe from an approximately 400 head commercial flock in
Minnesota.
Case 6 The sixth case of Nor98 scrapie was identified in a 4-year-old,
white-faced ewe that was purchased and added to a commercial flock in
Pennsylvania
snip...
see full text ;
Scrapie Nor-98 like case in California FY 2011 AS of December 31, 2010.
Scrapie cases in goats FY 2002 - 2011 AS of December 31, 2010 Total goat
cases = 21 Scrapie cases, 0 Nor-98 like Scrapie cases (21 field cases, 0 RSSS
cases)
Last herd with infected goats disignated in FY 2008 Michigan 8 cases
UPDATE PLEASE NOTE ;
AS of June 30, 2011,
snip...
INCLUDING 10 POSITIVE GOATS FROM THE SAME HERD (FIGURE 7).
snip...
see updated APHIS scrapie report ;
PAGE 25 Transmission Studies Mule deer transmissions of CWD were by
intracerebral inoculation and compared with natural cases resulted in a more
rapidly progressive clinical disease with repeated episodes of synocopy ending
in coma. One control animal became affected, it is believed through
contamination of inoculam (?saline). Further CWD transmissions were carried out
by Dick Marsh into ferret, mink and squirrel monkey. Transmission occurred in
all of these species with the shortest incubation period in the ferret...
Clearly, it is premature to draw firm conclusions about CWD passing
naturally into humans, cattle and sheep, but the present results suggest that
CWD transmissions to humans would be as limited by PrP incompatibility as
transmissions of BSE or sheep scrapie to humans. Although there is no evidence
that sheep scrapie has affected humans, it is likely that BSE has caused variant
CJD in 74 people (definite and probable variant CJD cases to date according to
the UK CJD Surveillance Unit). Given the presumably large number of people
exposed to BSE infectivity, the susceptibility of humans may still be very low
compared with cattle, which would be consistent with the relatively inefficient
conversion of human PrP-sen by PrPBSE. Nonetheless, since humans have apparently
been infected by BSE, it would seem prudent to take reasonable measures to limit
exposure of humans (as well as sheep and cattle) to CWD infectivity as has been
recommended for other animal TSEs.
snip...
and why do we not want to do TSE transmission studies on chimpanzees $
snip...
5. A positive result from a chimpanzee challenged severly would likely
create alarm in some circles even if the result could not be interpreted for
man. I have a view that all these agents could be transmitted provided a large
enough dose by appropriate routes was given and the animals kept long enough.
Until the mechanisms of the species barrier are more clearly understood it might
be best to retain that hypothesis.
snip...
R. BRADLEY
1992
IN CONFIDENCE
BSE - ATYPICAL LESION DISTRIBUTION (RBSE 92-21367)
1992
NEW BRAIN DISORDER
3. WHAT ABOUT REPORTS OF NEW FORM OF BSE ?
THE VETERINARY RECORD HAS PUBLISHED AN ARTICLE ON A NEW BRAIN DISORDER OF
CATTLE DISCOVERED THROUGH OUR CONTROL MEASURES FOR BSE. ALTHOUGH IT PRESENTS
SIMILAR CLINICAL SIGNS TO BSE THERE ARE MAJOR DIFFERENCES IN HISTOPATHOLOGY AND
INCUBATION PERIODS BETWEEN THE TWO. MUST EMPHASISE THAT THIS IS _NOT_ BSE.
4. IS THIS NEW BRAIN DISORDER A THREAT ?
WE DO NOT EVEN KNOW WHETHER THE AGENT OF THIS DISEASE IS TRANSMISSIBLE. IN
ANY CASE, CASES SO FAR IDENTIFIED HAD SHOWN SIMILAR SYMPTOMS TO THOSE OF BSE,
AND THEREFORE HAVE BEEN SLAUGHTERED AND INCINERATED, SO THAT IF A TRANSMISSIBLE
AGENT WERE INVOLVED IT WOULD HAVE BEEN ELIMINATED. ...
Tuesday, November 17, 2009
SEAC NEW RESULTS ON IDIOPATHIC BRAINSTEM NEURONAL CHROMATOLYSIS (IBNC) FROM
THE VETERINARY LABORATORIES AGENCY (VLA) SEAC 103/1
NEW RESULTS ON IDIOPATHIC BRAINSTEM NEURONAL CHROMATOLYSIS
"All of the 15 cattle tested showed that the brains had abnormally
accumulated PrP"
2009
''THE LINE TO TAKE'' ON IBNC $$$ 1995 $$$
1995
page 9 of 14 ;
30. The Committee noted that the results were unusual. the questioned
whether there could be coincidental BSE infection or contamination with scrapie.
Dr. Tyrell noted that the feeling of the committee was that this did not
represent a new agent but it was important to be prepared to say something
publicly about these findings. A suggested line to take was that these were
scientifically unpublishable results but in line with the policy of openness
they would be made publicly available and further work done to test their
validity. Since the BSE precautions were applied to IBNC cases, human health was
protected. Further investigations should be carried out on isolations from
brains of IBNC cases with removal of the brain and subsequent handling under
strict conditions to avoid the risk of any contamination.
31. Mr. Bradley informed the Committee that the CVO had informed the CMO
about the IBNC results and the transmission from retina and he, like the
Committee was satisfied that the controls already in place or proposed were
adequate. ... snip... see full text
http://web.archive.org/web/20030327015011/http://www.bseinquiry.gov.uk/files/yb/1995/06/21005001.pdf
IN CONFIDENCE
BSE ATYPICAL LESION DISTRIBUTION
http://web.archive.org/web/20041226015813/http://www.bseinquiry.gov.uk/files/yb/1993/03/14001001.pdf
########### http://mailhost.rz.uni-karlsruhe.de/warc/bse-l.html
############
-------- Original Message --------
Subject: DEFRA INVESTIGATES AN UNUSUAL SCRAPIE CASE (similar to exp. BSE
in sheep)
Date: Wed, 7 Apr 2004 08:56:36 -0500
From: "Terry S. Singeltary Sr."
Reply-To: Bovine Spongiform Encephalopathy
To: BSE-L@uni-karlsruhe.de
######## Bovine Spongiform Encephalopathy #########
Date: April 07, 2004 Time: 13:45
DEFRA INVESTIGATES AN UNUSUAL SCRAPIE CASE
The Veterinary Laboratories Agency (VLA) have informed Defra, the Devolved
Administrations and the Food Standards Agency of a type of scrapie not
previously seen in the UK.
The VLA and other European laboratories with expertise in scrapie-like
diseases have now applied several rapid diagnostic methods to tissue samples
from a sheep with suspected scrapie. Some of the methods have indicated that the
case does not appear to resemble previously recognised cases of scrapie and,
although there were differences, it had some characteristics similar to
experimental BSE in sheep and also to an experimental strain of sheep scrapie.
More importantly, though, microscopic analysis of brain material showed that the
case neither resembled previously recognised types of scrapie or experimental
BSE in sheep.
A meeting of the scientific experts who performed these analyses, held on
the 30th March, concluded that this case could not be considered to be BSE in
sheep, although it does not behave like known types of scrapie either. Further
investigation will be needed before more can be said about how this unusual
result should be described.
Defra's Chief Scientific Adviser, Professor Howard Dalton, said "The UK,
and especially the VLA, have played an important part in improving the
diagnostic methods available for identifying TSEs in sheep. As we continue to
assess more samples with these improved methods it is likely that we will
continue to find samples, such as this, which fall outside our current knowledge
of the disease. Defra, as it does with all research, will continue to consult
scientific experts to ensure that we are investigating these cases using the
best available techniques and methods."
The National Scrapie Plan remains unaffected by this new result and SEAC
will be consulted in the near future.
Notes to editors
1. Scrapie is a fatal neurological sheep disease belonging to a group of
diseases called transmissible spongiform encephalopathies (TSEs), including BSE
in cattle and CJD in humans. It has been present in the national flock for over
250 years. It is not considered to be transmissible to humans.
2. There is a theoretical risk that BSE could be present in sheep, masked
by scrapie, but it has not been found naturally occurring in sheep.
3. There is as yet no definitive diagnostic method that can rapidly
distinguish between different TSEs for example scrapie from BSE. Consequently,
from time to time the scrapie surveillance programmes in EU member states throw
up unusual results that merit further investigations (Defra press release 371/03
refers http://www.defra.gov.uk/news/2003/030911a.htm)
4. The VLA have applied several different methods to the sample to compare
it to a wide range of previously detected scrapie cases, experimental BSE in
sheep and an experimental strain of scrapie, termed CH1461. Two main methods
have been used in this analysis:-
a. Western blot (WB) This involves taking a sample of the brain and
treating it with an enzyme proteinase k to destroy the normal prion protein
(PrPC). The diseased form of the protein (PrPSc) is able to withstand this
treatment and is then separated from other cellular material on a gel. A blot is
taken of the gel and the PrPSc is visualised using specific antibodies.
b. Immunohistochemistry (IHC) This involves taking thin slices of the
brain, and by using special (antibody) markers to detect the PrPSc it is
possible to see disease specific patterns of PrPSc distribution in the brain
under a microscope. The Western blot method found that the sample did not appear
to resemble previously recognised cases of scrapie and, although there were some
differences, some characteristics were similar to experimental BSE in sheep and
also the experimental strain of sheep scrapie, CH1461. IHC found that it neither
resembled previously recognised types of scrapie or experimental BSE in
sheep
5. The tissue sample has now been analysed using a total of 5 different
diagnostic methods claiming to be able to differentiate between scrapie and
experimental BSE in sheep. Two were performed at the VLA and three were
performed in other European laboratories.
6. The VLA is the European Reference Laboratory for TSEs and is
responsible for co-ordinating such investigations into unusual cases. Their
findings will be considered by the European Food Safety Authority's committee of
TSE experts and in the UK by the Spongiform Encephalopathy Advisory Committee
(SEAC).
7. The genotype of the suspect sheep was ARQ/ARQ which is known to be
susceptible to some strains of scrapie and, in experiments, to BSE. Background
information on scrapie, scrapie genotyping, and the National Scrapie Plan is
published on the Defra internet at www.defra.gov.uk/nsp.
8. For information and advice on BSE in sheep from the FSA please consult
their web site at www.foodstandards.gov.uk
Public enquiries 08459 335577; Press notices are available on our website
www.defra.gov.uk Defra's aim is sustainable development
End
Nobel House 17 Smith Square London SW1P 3JR Website www.defra.gov.uk
TSS
########### http://mailhost.rz.uni-karlsruhe.de/warc/bse-l.html
############
TSE in Sheep Contingency Planning Assessment of Risk due to BSE
Infectivity from Disposal of Sheep A report for DEFRA November 2001
Management Summary It has been recognised for a considerable time that
sheep in the United Kingdom may have been infected with BSE. To date no evidence
has been found to demonstrate that the national flock is actually infected with
the disease. DEFRA have prepared a draft contingency plan in the event that BSE
were to be identified in UK sheep. The worst case scenario under this plan is
the disposal of the entire UK flock, some 40 million sheep and lambs. This study
has estimated the potential exposure of the UK population to BSE infectivity
present in sheep in the event that this plan had to be put into effect.
but who would have guessed that such an important experiment/study would
have gotton so screwed up, by not being able to tell a sheep brain from a cow
brain;
© DEFRA 2002 Item 3- Scrapie Brain pool experiments- Update on current
position and audits of samples 3.1 Members were updated on experiments conducted
at the Institute of Animal Health (IAH) to examine a pool of scrapie brains
collected in the early 1990 s for evidence of BSE. SEAC had previously
recommended that the material should be examined by DNA analysis to assess
whether the pooled brain material may have been contaminated with bovine tissue.
The Laboratory of the Government Chemist (LGC) had been asked to perform the
work. Their results were completely unexpected as the analysis detected only
bovine material in the sample. SEAC had intended to meet on the 19 October to
Agreed version consider the experiment in detail. However, in view of the
result, the meeting was cancelled.
Executive Summary An audit of the sample handling procedures at IAH-E was
carried out on 24 October 2001 at the request of the Department of the
Environment, Food and Rural Affairs (DEFRA), by a team of two UKAS auditors. The
scope of the audit was limited to the traceability of cow and sheep brain
samples used in several experiments relating to transmissible spongiform
encephalopathy (TSE) agents. In particular, the team focused on the audit trail
of samples that had been sent to LGC, Teddington, the audit trail of brains
collected in 1990/92 by Veterinary Investigation Centres and the audit trail for
archived material held by IAH-E. In addition the audit team evaluated the IAH-E
procedures against the specific requirements for sampling handling of
international standard, ISO 17025 and identified opportunities for improvement.
The audit established that there was no formal documented quality system
covering this work at IAH-E and that record keeping was inadequate to give
confidence in the chain of custody of samples used in the various rendering,
genotyping and strain typing experiments audited. It was not possible to
establish clear traceability between the samples that had been used in the
individual experiments carried out by IAH-E or IAH-C with those analysed at LGC
or with those that had been collected in 1990/92. The sample handling procedures
covered by this audit at IAH-E did not meet the requirements of ISO 17025.
explaining the brain mixup blunder;
An Investigation of the Substitution of Scrapie Brain Pool Samples A
report for DEFRA November 2001
Risk Solutions Page 19 Why did the experimenters not notice that they
were working with cow brains not sheep brains? The simple answer is because for
the most part they were working with brain pool macerate (minced brain material)
not brains. It is not credible that staff collecting brains at VICs would have
uniformly supplied cow brains or cow brain parts in mistake for sheep. We have
interviewed staff at VICs and we understand from the VLA that records do not
support the possibility that significant numbers of cow brains were sent to PDM
in place of sheep brains. It is also very unlikely that the people preparing the
scrapie brain pool would not have noticed if they were for the most part
handling cow brains or cow brain parts in place of sheep brains. We cannot rule
out the possibility that some cow brain material entered the brain pool at this
stage but it is not feasible that the majority of the material was bovine. The
substitution, if substitution occurred, must have involved brain pool macerate
or rendered products. Why can t the results of the experiments tell us what
material was used? The experiments had a number of features that make the
results of the mouse bioassay difficult to interpret unambiguously and lead to
the possibility that substitution of the samples would be difficult to detect by
examining the results of the experiments: 1. The original experiments were not
designed to determine whether BSE was present in sheep. Reasonable efforts were
taken to ensure that the brain pool remained free from D5055 02 Issue 1 Risk
Solutions Page 20 contamination during preparation but the level of control
applied during the earlier experiments (272R and 372R) was not to the standard
applied later. 2. Mouse bioassay as a method of diagnosing TSEs is not based on
a full understanding of biochemical and physical processes. It is an empirical
technique that has been widely applied, for example to show v-CJD is similar to
BSE and different from scrapie. It is a complex process and the results need to
be interpreted by experts. It can take several years to generate a firm result.
The principal data collected in the experiments are lesion profiles (patterns of
lesions in the mice brains) and incubation period (time from injection of mice
to onset of clinical symptoms. The type of TSE is identified by comparing the
results with those of known provenance. There is no good agreed test of
sameness of lesion profile , so in marginal cases we are reduced to using
subjective observations of the form somewhat similar and interpretation is
difficult. The incubation times in principle give a more objective signal, but
the effect of concentration has to be controlled. The mouse bioassay data that
we understand has been collected and analysed at each stage of the experiments
is summarised in Table 4.1. Several features of these experiments are not
commonly encountered in mouse bioassay of TSEs and this makes determining the
origin of the original material from the experimental results extremely
difficult. They include: a. Mouse bioassay is generally carried out on
individual brains; experience of working with brain pools is very limited. b.
The BBP exhibited a low titre of infectivity, which can confound interpretation
of results. c. The BBP comprised bovine brains with the hindbrains removed. By
contrast most of the BSE strain typing has been carried out on the hindbrains,
which may give a different pattern of results. d. The 272R titrations used a
different strain of mice than the 372R titrations, so direct comparison of the
resulting lesion profiles cannot be made. e. The 246 experiments used brain pool
which was in an unsatisfactorily autolysed state. f. The strain typing data
collected (incubation time and lesion profiles) are very sparse. Judging the
sameness or difference of samples is a less challenging task for strain typing
than identifying a strain and it may be possible to compare data from the 246
experiments with both the 272R and 372R experiments to determine whether the
samples are similar or clearly different. However, the data are sparse and the
result is unlikely to be clear cut. Much of this work is currently unpublished.
RESPONSE TO THE UKAS REPORT FROM THE INSTITUTE FOR ANIMAL HEALTH
The Institute is concerned, therefore, that the authors of this UKAS
report may have based their findings on an unrepresentative and limited
examination of procedures in place at IAH-E.
DEFRA Department for Environment, Food & Rural Affairs
Area 307, London, SW1P 4PQ Telephone: 0207 904 6000 Direct line: 0207 904
6287 E-mail: h.mcdonagh.defra.gsi.gov.uk
GTN: FAX:
Mr T S Singeltary P.O. Box 42 Bacliff Texas USA 77518
21 November 2001
Dear Mr Singeltary
TSE IN HOUNDS
Thank you for e-mail regarding the hounds survey. I am sorry for the long
delay in responding.
As you note, the hound survey remains unpublished. However the Spongiform
Encephalopathy Advisory Committee (SEAC), the UK Government's independent
Advisory Committee on all aspects related to BSE-like disease, gave the hound
study detailed consideration at their meeting in January 1994. As a summary of
this meeting published in the BSE inquiry noted, the Committee were clearly
concerned about the work that had been carried out, concluding that there had
clearly been problems with it, particularly the control on the histology, and
that it was more or less inconclusive. However was agreed that there should be a
re-evaluation of the pathological material in the study.
Later, at their meeting in June 95, The Committee re-evaluated the hound
study to see if any useful results could be gained from it. The Chairman
concluded that there were varying opinions within the Committee on further work.
It did not suggest any further transmission studies and thought that the lack of
clinical data was a major weakness.
Overall, it is clear that SEAC had major concerns about the survey as
conducted. As a result it is likely that the authors felt that it would not
stand up to r~eer review and hence it was never published. As noted above, and
in the detailed minutes of the SEAC meeting in June 95, SEAC considered whether
additional work should be performed to examine dogs for evidence of TSE
infection. Although the Committee had mixed views about the merits of conducting
further work, the Chairman noted that when the Southwood Committee made their
recommendation to complete an assessment of possible spongiform disease in dogs,
no TSEs had been identified in other species and hence dogs were perceived as a
high risk population and worthy of study. However subsequent to the original
recommendation, made in 1990, a number of other species had been identified with
TSE ( e.g. cats) so a study in hounds was less
critical. For more details see- http://www.bseinquiry,
gov.uk/files/yb/1995/06/21005001 .pdf
As this study remains unpublished, my understanding is that the ownership
of the data essentially remains with the original researchers. Thus
unfortunately, I am unable to help with your request to supply information on
the hound survey directly. My only suggestion is that you contact one of the
researchers originally involved in the project, such as Gerald Wells. He can be
contacted at the following address.
Dr Gerald Wells, Veterinary Laboratories Agency, New Haw, Addlestone,
Surrey, KT 15 3NB, UK
You may also wish to be aware that since November 1994 all suspected cases
of spongiform encephalopathy in animals and poultry were made notifiable. Hence
since that date there has been a requirement for vets to report any suspect SE
in dogs for further investigation. To date there has never been positive
identification of a TSE in a dog.
I hope this is helpful
Yours sincerely 4
HUGH MCDONAGH BSE CORRESPONDENCE SECTION
======================================
OR-09: Canine spongiform encephalopathy—A new form of animal prion disease
Monique David, Mourad Tayebi UT Health; Houston, TX USA
It was also hypothesized that BSE might have originated from an
unrecognized sporadic or genetic case of bovine prion disease incorporated into
cattle feed or even cattle feed contaminated with prion-infected human remains.1
However, strong support for a genetic origin of BSE has recently been
demonstrated in an H-type BSE case exhibiting the novel mutation E211K.2
Furthermore, a specific prion protein strain causing BSE in cattle is believed
to be the etiological agent responsible for the novel human prion disease,
variant Creutzfeldt-Jakob disease (vCJD).3 Cases of vCJD have been identified in
a number countries, including France, Italy, Ireland, the Netherlands, Canada,
Japan, US and the UK with the largest number of cases. Naturally occurring
feline spongiform encephalopathy of domestic cats4 and spongiform
encephalopathies of a number of zoo animals so-called exotic ungulate
encephalopathies5,6 are also recognized as animal prion diseases, and are
thought to have resulted from the same BSE-contaminated food given to cattle and
humans, although and at least in some of these cases, a sporadic and/or genetic
etiology cannot be ruled out. The canine species seems to display resistance to
prion disease and no single case has so far been reported.7,8 Here, we describe
a case of a 9 week old male Rottweiler puppy presenting neurological deficits;
and histological examination revealed spongiform vacuolation characteristic of
those associated with prion diseases.9 Initial biochemical studies using
anti-PrP antibodies revealed the presence of partially proteinase K-resistant
fragment by western blotting. Furthermore, immunohistochemistry revealed
spongiform degeneration consistent with those found in prion disease and
displayed staining for PrPSc in the cortex.
Of major importance, PrPSc isolated from the Rottweiler was able to cross
the species barrier transmitted to hamster in vitro with PMCA and in vivo (one
hamster out of 5). Futhermore, second in vivo passage to hamsters, led to 100%
attack rate (n = 4) and animals displayed untypical lesional profile and shorter
incubation period.
In this study, we show that the canine species might be sensitive to prion
disease and that PrPSc isolated from a dog can be transmitted to dogs and
hamsters in vitro using PMCA and in vivo to hamsters.
If our preliminary results are confirmed, the proposal will have a major
impact on animal and public health and would certainly lead to implementing new
control measures for ‘canine spongiform encephalopathy’ (CSE).
References 1. Colchester AC, Colchester NT. The origin of bovine spongiform
encephalopathy: the human prion disease hypothesis. Lancet 2005; 366:856-61;
PMID:16139661; http://
dx.doi.org/10.1016/S0140-6736(05)67218-2.
2. Richt JA, Hall SM. BSE case associated with prion protein gene mutation.
PLoS Pathog 2008; 4:e1000156; PMID:18787697; http://dx.doi.org/10.1371/journal.
ppat.1000156.
3. Collinge J. Human prion diseases and bovine spongiform encephalopathy
(BSE). Hum Mol Genet 1997; 6:1699-705; PMID:9300662; http://dx.doi.org/10.1093/
hmg/6.10.1699.
4. Wyatt JM, Pearson GR, Smerdon TN, Gruffydd-Jones TJ, Wells GA, Wilesmith
JW. Naturally occurring scrapie-like spongiform encephalopathy in five domestic
cats. Vet Rec 1991; 129:233-6; PMID:1957458; http://dx.doi.org/10.1136/vr.129.11.233.
5. Jeffrey M, Wells GA. Spongiform encephalopathy in a nyala (Tragelaphus
angasi). Vet Pathol 1988; 25:398-9; PMID:3232315; http://dx.doi.org/10.1177/030098588802500514.
6. Kirkwood JK, Wells GA, Wilesmith JW, Cunningham AA, Jackson SI.
Spongiform encephalopathy in an arabian oryx (Oryx leucoryx) and a greater kudu
(Tragelaphus strepsiceros). Vet Rec 1990; 127:418-20; PMID:2264242.
7. Bartz JC, McKenzie DI, Bessen RA, Marsh RF, Aiken JM. Transmissible mink
encephalopathy species barrier effect between ferret and mink: PrP gene and
protein analysis. J Gen Virol 1994; 75:2947-53; PMID:7964604; http://dx.doi.org/10.1099/0022-1317-
75-11-2947.
8. Lysek DA, Schorn C, Nivon LG, Esteve-Moya V, Christen B, Calzolai L, et
al. Prion protein NMR structures of cats, dogs, pigs, and sheep. Proc Natl Acad
Sci U S A 2005; 102:640-5; PMID:15647367; http://dx.doi.org/10.1073/pnas.0408937102.
9. Budka H. Neuropathology of prion diseases. Br Med Bull 2003; 66:121-30;
PMID:14522854; http://dx.doi.org/10.1093/bmb/66.1.121.
Monday, March 26, 2012
CANINE SPONGIFORM ENCEPHALOPATHY: A NEW FORM OF ANIMAL PRION DISEASE
http://caninespongiformencephalopathy.blogspot.com/2012/03/canine-spongiform-encephalopathy-new.html
Monday, March 8, 2010
Canine Spongiform Encephalopathy aka MAD DOG DISEASE
Wednesday, July 15, 2015
Additional BSE TSE prion testing detects pathologic lesion in unusual brain
location and PrPsc by PMCA only, how many cases have we missed?
***however in 1 C-type challenged animal, Prion 2015 Poster Abstracts S67
PrPsc was not detected using rapid tests for BSE.
***Subsequent testing resulted in the detection of pathologic lesion in
unusual brain location and PrPsc detection by PMCA only.
***IBNC Tauopathy or TSE Prion disease, it appears, no one is sure
***
Posted by flounder on 03 Jul 2015 at 16:53 GMT
HOUND STUDY
*** AS implied in the Inset 25 we must not _ASSUME_ that transmission of
BSE to other species will invariably present pathology typical of a scrapie-like
disease.***
snip...
Evidence That Transmissible Mink Encephalopathy Results from Feeding
Infected Cattle Over the next 8-10 weeks, approximately 40% of all the adult
mink on the farm died from TME.
snip...
The rancher was a ''dead stock'' feeder using mostly (>95%) downer or
dead dairy cattle...
In Confidence - Perceptions of unconventional slow virus diseases of
animals in the USA - APRIL-MAY 1989 - G A H Wells
3. Prof. A. Robertson gave a brief account of BSE. The US approach was to
accord it a very low profile indeed. Dr. A Thiermann showed the picture in the
''Independent'' with cattle being incinerated and thought this was a fanatical
incident to be avoided in the US at all costs. ...
98 | Veterinary Record | January 24, 2015
EDITORIAL
Scrapie: a particularly persistent pathogen
Cristina Acín
Resistant prions in the environment have been the sword of Damocles for
scrapie control and eradication. Attempts to establish which physical and
chemical agents could be applied to inactivate or moderate scrapie infectivity
were initiated in the 1960s and 1970s,with the first study of this type focusing
on the effect of heat treatment in reducing prion infectivity (Hunter and
Millson 1964). Nowadays, most of the chemical procedures that aim to inactivate
the prion protein are based on the method developed by Kimberlin and
collaborators (1983). This procedure consists of treatment with 20,000 parts per
million free chlorine solution, for a minimum of one hour, of all surfaces that
need to be sterilised (in laboratories, lambing pens, slaughterhouses, and so
on). Despite this, veterinarians and farmers may still ask a range of questions,
such as ‘Is there an official procedure published somewhere?’ and ‘Is there an
international organisation which recommends and defines the exact method of
scrapie decontamination that must be applied?’
From a European perspective, it is difficult to find a treatment that could
be applied, especially in relation to the disinfection of surfaces in lambing
pens of affected flocks. A 999/2001 EU regulation on controlling spongiform
encephalopathies (European Parliament and Council 2001) did not specify a
particular decontamination measure to be used when an outbreak of scrapie is
diagnosed. There is only a brief recommendation in Annex VII concerning the
control and eradication of transmissible spongiform encephalopathies (TSE s).
Chapter B of the regulation explains the measures that must be applied if
new caprine animals are to be introduced to a holding where a scrapie outbreak
has previously been diagnosed. In that case, the statement indicates that
caprine animals can be introduced ‘provided that a cleaning and disinfection of
all animal housing on the premises has been carried out following destocking’.
Issues around cleaning and disinfection are common in prion prevention
recommendations, but relevant authorities, veterinarians and farmers may have
difficulties in finding the specific protocol which applies. The European Food
and Safety Authority (EFSA ) published a detailed report about the efficacy of
certain biocides, such as sodium hydroxide, sodium hypochlorite, guanidine and
even a formulation of copper or iron metal ions in combination with hydrogen
peroxide, against prions (EFSA 2009). The report was based on scientific
evidence (Fichet and others 2004, Lemmer and others 2004, Gao and others 2006,
Solassol and others 2006) but unfortunately the decontamination measures were
not assessed under outbreak conditions.
The EFSA Panel on Biological Hazards recently published its conclusions on
the scrapie situation in the EU after 10 years of monitoring and control of the
disease in sheep and goats (EFSA 2014), and one of the most interesting findings
was the Icelandic experience regarding the effect of disinfection in scrapie
control. The Icelandic plan consisted of: culling scrapie-affected sheep or the
whole flock in newly diagnosed outbreaks; deep cleaning and disinfection of
stables, sheds, barns and equipment with high pressure washing followed by
cleaning with 500 parts per million of hypochlorite; drying and treatment with
300 ppm of iodophor; and restocking was not permitted for at least two years.
Even when all of these measures were implemented, scrapie recurred on several
farms, indicating that the infectious agent survived for years in the
environment, even as many as 16 years after restocking (Georgsson and others
2006).
In the rest of the countries considered in the EFSA (2014) report,
recommendations for disinfection measures were not specifically defined at the
government level. In the report, the only recommendation that is made for sheep
is repopulation with sheep with scrapie-resistant genotypes. This reduces the
risk of scrapie recurrence but it is difficult to know its effect on the
infection.
Until the EFSA was established (in May 2003), scientific opinions about TSE
s were provided by the Scientific Steering Committee (SSC) of the EC, whose
advice regarding inactivation procedures focused on treating animal waste at
high temperatures (150°C for three hours) and high pressure alkaline hydrolysis
(SSC 2003). At the same time, the TSE Risk Management Subgroup of the Advisory
Committee on Dangerous Pathogens (ACDP) in the UK published guidance on safe
working and the prevention of TSE infection. Annex C of the ACDP report
established that sodium hypochlorite was considered to be effective, but only if
20,000 ppm of available chlorine was present for at least one hour, which has
practical limitations such as the release of chlorine gas, corrosion,
incompatibility with formaldehyde, alcohols and acids, rapid inactivation of its
active chemicals and the stability of dilutions (ACDP 2009).
In an international context, the World Organisation for Animal Health (OIE)
does not recommend a specific disinfection protocol for prion agents in its
Terrestrial Code or Manual. Chapter 4.13 of the Terrestrial Code, General
recommendations on disinfection and disinsection (OIE 2014), focuses on
foot-and-mouth disease virus, mycobacteria and Bacillus anthracis, but not on
prion disinfection. Nevertheless, the last update published by the OIE on bovine
spongiform encephalopathy (OIE 2012) indicates that few effective
decontamination techniques are available to inactivate the agent on surfaces,
and recommends the removal of all organic material and the use of sodium
hydroxide, or a sodium hypochlorite solution containing 2 per cent available
chlorine, for more than one hour at 20ºC.
The World Health Organization outlines guidelines for the control of TSE s,
and also emphasises the importance of mechanically cleaning surfaces before
disinfection with sodium hydroxide or sodium hypochlorite for one hour (WHO
1999).
Finally, the relevant agencies in both Canada and the USA suggest that the
best treatments for surfaces potentially contaminated with prions are sodium
hydroxide or sodium hypochlorite at 20,000 ppm. This is a 2 per cent solution,
while most commercial household bleaches contain 5.25 per cent sodium
hypochlorite. It is therefore recommended to dilute one part 5.25 per cent
bleach with 1.5 parts water (CDC 2009, Canadian Food Inspection Agency 2013).
So what should we do about disinfection against prions? First, it is
suggested that a single protocol be created by international authorities to
homogenise inactivation procedures and enable their application in all
scrapie-affected countries. Sodium hypochlorite with 20,000 ppm of available
chlorine seems to be the procedure used in most countries, as noted in a paper
summarised on p 99 of this issue of Veterinary Record (Hawkins and others 2015).
But are we totally sure of its effectiveness as a preventive measure in a
scrapie outbreak? Would an in-depth study of the recurrence of scrapie disease
be needed?
What we can conclude is that, if we want to fight prion diseases, and
specifically classical scrapie, we must focus on the accuracy of diagnosis,
monitoring and surveillance; appropriate animal identification and control of
movements; and, in the end, have homogeneous and suitable protocols to
decontaminate and disinfect lambing barns, sheds and equipment available to
veterinarians and farmers. Finally, further investigations into the resistance
of prion proteins in the diversity of environmental surfaces are required.
References
snip...
98 | Veterinary Record | January 24, 2015
Persistence of ovine scrapie infectivity in a farm environment following
cleaning and decontamination
Steve A. C. Hawkins, MIBiol, Pathology Department1, Hugh A. Simmons, BVSc
MRCVS, MBA, MA Animal Services Unit1, Kevin C. Gough, BSc, PhD2 and Ben C.
Maddison, BSc, PhD3 + Author Affiliations
1Animal and Plant Health Agency, Woodham Lane, New Haw, Addlestone, Surrey
KT15 3NB, UK 2School of Veterinary Medicine and Science, The University of
Nottingham, Sutton Bonington, Loughborough, Leicestershire LE12 5RD, UK 3ADAS
UK, School of Veterinary Medicine and Science, The University of Nottingham,
Sutton Bonington, Loughborough, Leicestershire LE12 5RD, UK E-mail for
correspondence: ben.maddison@adas.co.uk Abstract Scrapie of sheep/goats and
chronic wasting disease of deer/elk are contagious prion diseases where
environmental reservoirs are directly implicated in the transmission of disease.
In this study, the effectiveness of recommended scrapie farm decontamination
regimens was evaluated by a sheep bioassay using buildings naturally
contaminated with scrapie. Pens within a farm building were treated with either
20,000 parts per million free chorine solution for one hour or were treated with
the same but were followed by painting and full re-galvanisation or replacement
of metalwork within the pen. Scrapie susceptible lambs of the PRNP genotype
VRQ/VRQ were reared within these pens and their scrapie status was monitored by
recto-anal mucosa-associated lymphoid tissue. All animals became infected over
an 18-month period, even in the pen that had been subject to the most stringent
decontamination process. These data suggest that recommended current guidelines
for the decontamination of farm buildings following outbreaks of scrapie do
little to reduce the titre of infectious scrapie material and that environmental
recontamination could also be an issue associated with these premises.
SNIP...
Discussion
Thorough pressure washing of a pen had no effect on the amount of
bioavailable scrapie infectivity (pen B). The routine removal of prions from
surfaces within a laboratory setting is treatment for a minimum of one hour with
20,000 ppm free chlorine, a method originally based on the use of brain
macerates from infected rodents to evaluate the effectiveness of decontamination
(Kimberlin and others 1983). Further studies have also investigated the
effectiveness of hypochlorite disinfection of metal surfaces to simulate the
decontamination of surgical devices within a hospital setting. Such treatments
with hypochlorite solution were able to reduce infectivity by 5.5 logs to lower
than the sensitivity of the bioassay used (Lemmer and others 2004). Analogous
treatment of the pen surfaces did not effectively remove the levels of scrapie
infectivity over that of the control pens, indicating that this method of
decontamination is not effective within a farm setting. This may be due to the
high level of biological matrix that is present upon surfaces within the farm
environment, which may reduce the amount of free chlorine available to
inactivate any infectious prion. Remarkably 1/5 sheep introduced into pen D had
also became scrapie positive within nine months, with all animals in this pen
being RAMALT positive by 18 months of age. Pen D was no further away from the
control pen (pen A) than any of the other pens within this barn. Localised hot
spots of infectivity may be present within scrapie-contaminated environments,
but it is unlikely that pen D area had an amount of scrapie contamination that
was significantly different than the other areas within this building.
Similarly, there were no differences in how the biosecurity of pen D was
maintained, or how this pen was ventilated compared with the other pens. This
observation, perhaps, indicates the slower kinetics of disease uptake within
this pen and is consistent with a more thorough prion removal and
recontamination. These observations may also account for the presence of
inadvertent scrapie cases within other studies, where despite stringent
biosecurity, control animals have become scrapie positive during challenge
studies using barns that also housed scrapie-affected animals (Ryder and others
2009). The bioassay data indicate that the exposure of the sheep to a farm
environment after decontamination efforts thought to be effective in removing
scrapie is sufficient for the animals to become infected with scrapie. The main
exposure routes within this scenario are likely to be via the oral route, during
feeding and drinking, and respiratory and conjunctival routes. It has been
demonstrated that scrapie infectivity can be efficiently transmitted via the
nasal route in sheep (Hamir and others 2008), as is the case for CWD in both
murine models and in white-tailed deer (Denkers and others 2010, 2013).
Recently, it has also been demonstrated that CWD prions presented as dust when
bound to the soil mineral montmorillonite can be infectious via the nasal route
(Nichols and others 2013). When considering pens C and D, the actual source of
the infectious agent in the pens is not known, it is possible that biologically
relevant levels of prion survive on surfaces during the decontamination regimen
(pen C). With the use of galvanising and painting (pen D) covering and sealing
the surface of the pen, it is possible that scrapie material recontaminated the
pens by the movement of infectious prions contained within dusts originating
from other parts of the barn that were not decontaminated or from other areas of
the farm.
Given that scrapie prions are widespread on the surfaces of affected farms
(Maddison and others 2010a), irrespective of the source of the infectious prions
in the pens, this study clearly highlights the difficulties that are faced with
the effective removal of environmentally associated scrapie infectivity. This is
likely to be paralleled in CWD which shows strong similarities to scrapie in
terms of both the dissemination of prions into the environment and the facile
mode of disease transmission. These data further contribute to the understanding
that prion diseases can be highly transmissible between susceptible individuals
not just by direct contact but through highly stable environmental reservoirs
that are refractory to decontamination.
The presence of these environmentally associated prions in farm buildings
make the control of these diseases a considerable challenge, especially in
animal species such as goats where there is lack of genetic resistance to
scrapie and, therefore, no scope to re-stock farms with animals that are
resistant to scrapie.
Scrapie Sheep Goats Transmissible spongiform encephalopathies (TSE)
Accepted October 12, 2014. Published Online First 31 October 2014
Monday, November 3, 2014
Persistence of ovine scrapie infectivity in a farm environment following
cleaning and decontamination
PPo3-22:
Detection of Environmentally Associated PrPSc on a Farm with Endemic
Scrapie
Ben C. Maddison,1 Claire A. Baker,1 Helen C. Rees,1 Linda A. Terry,2 Leigh
Thorne,2 Susan J. Belworthy2 and Kevin C. Gough3 1ADAS-UK LTD; Department of
Biology; University of Leicester; Leicester, UK; 2Veterinary Laboratories
Agency; Surry, KT UK; 3Department of Veterinary Medicine and Science; University
of Nottingham; Sutton Bonington, Loughborough UK
Key words: scrapie, evironmental persistence, sPMCA
Ovine scrapie shows considerable horizontal transmission, yet the routes of
transmission and specifically the role of fomites in transmission remain poorly
defined. Here we present biochemical data demonstrating that on a
scrapie-affected sheep farm, scrapie prion contamination is widespread. It was
anticipated at the outset that if prions contaminate the environment that they
would be there at extremely low levels, as such the most sensitive method
available for the detection of PrPSc, serial Protein Misfolding Cyclic
Amplification (sPMCA), was used in this study. We investigated the distribution
of environmental scrapie prions by applying ovine sPMCA to samples taken from a
range of surfaces that were accessible to animals and could be collected by use
of a wetted foam swab. Prion was amplified by sPMCA from a number of these
environmental swab samples including those taken from metal, plastic and wooden
surfaces, both in the indoor and outdoor environment. At the time of sampling
there had been no sheep contact with these areas for at least 20 days prior to
sampling indicating that prions persist for at least this duration in the
environment. These data implicate inanimate objects as environmental reservoirs
of prion infectivity which are likely to contribute to disease transmission.
================================================================
BSE: TIME TO TAKE H.B. PARRY SERIOUSLY
If the scrapie agent is generated from ovine DNA and thence causes disease
in other species, then perhaps, bearing in mind the possible role of scrapie in
CJD of humans (Davinpour et al, 1985), scrapie and not BSE should be the
notifiable disease. ...
================================================================
*** Approximately 4,200 fawns, defined as deer under 1 year of age, were
sampled from the eradication zone over the last year. The majority of fawns
sampled were between the ages of 5 to 9 months, though some were as young as 1
month. Two of the six fawns with CWD detected were 5 to 6 months old. All six of
the positive fawns were taken from the core area of the CWD eradication zone
where the highest numbers of positive deer have been identified.
"This is the first intensive sampling for CWD in fawns anywhere," said Dr.
Julie Langenberg, Department of Natural Resources wildlife veterinarian, "and we
are trying to learn as much as we can from these data".
Saturday, February 04, 2012
Wisconsin 16 MONTH age limit on testing dead deer Game Farm CWD Testing
Protocol Needs To Be Revised
Articles of Significant Interest Selected from This Issue by the Editors
Next Section Prions in the Blood of Infected Hosts: Early and Persistent Prions
circulate in the blood of prion-infected hosts, including humans with variant
Creutzfeldt-Jakob disease. Determining the parameters of blood-borne prions
during the long asymptomatic phase of disease characteristic of all prion
diseases has been a long-standing problem in prion biology. Elder et. al (p.
7421–7424) have demonstrated amyloid formation, a biomarker for prions, in the
blood of prion-infected rodent and cervid hosts as early as 15 minutes
post-mucosal or -intravenous infection. This prionemia persists throughout the
disease course, indicating a role for hematogenous prions throughout the
preclinical stage of illness.
***Immediate and Ongoing Detection of Prions in the Blood of Hamsters and
Deer following Oral, Nasal, or Blood Inoculations
Alan M. Eldera, Davin M. Hendersona, Amy V. Nallsa, Edward A. Hoovera,
Anthony E. Kincaidb,c, Jason C. Bartzb and Candace K. Mathiasona aDepartment of
Microbiology, Immunology and Pathology, Colorado State University, Fort Collins,
Colorado, USA bMedical Microbiology and Immunology, Creighton University, Omaha,
Nebraska, USA cDepartment of Pharmacy Sciences, Creighton University, Omaha,
Nebraska, USA S. Perlman, Editor + Author Affiliations
CREUTZFELDT JAKOB DISEASE SURVEILLANCE IN THE UNITED KINGDOM THIRD ANNUAL
REPORT AUGUST 1994
Consumption of venison and veal was much less widespread among both cases
and controls. For both of these meats there was evidence of a trend with
increasing frequency of consumption being associated with increasing risk of
CJD. (not nvCJD, but sporadic CJD...tss) These associations were largely
unchanged when attention was restricted to pairs with data obtained from
relatives. ...
Table 9 presents the results of an analysis of these data.
There is STRONG evidence of an association between ‘’regular’’ veal eating
and risk of CJD (p = .0.01).
Individuals reported to eat veal on average at least once a year appear to
be at 13 TIMES THE RISK of individuals who have never eaten veal.
There is, however, a very wide confidence interval around this estimate.
There is no strong evidence that eating veal less than once per year is
associated with increased risk of CJD (p = 0.51).
The association between venison eating and risk of CJD shows similar
pattern, with regular venison eating associated with a 9 FOLD INCREASE IN RISK
OF CJD (p = 0.04).
There is some evidence that risk of CJD INCREASES WITH INCREASING FREQUENCY
OF LAMB EATING (p = 0.02).
The evidence for such an association between beef eating and CJD is weaker
(p = 0.14). When only controls for whom a relative was interviewed are included,
this evidence becomes a little STRONGER (p = 0.08).
snip...
It was found that when veal was included in the model with another
exposure, the association between veal and CJD remained statistically
significant (p = < 0.05 for all exposures), while the other exposures ceased
to be statistically significant (p = > 0.05).
snip...
In conclusion, an analysis of dietary histories revealed statistical
associations between various meats/animal products and INCREASED RISK OF CJD.
When some account was taken of possible confounding, the association between
VEAL EATING AND RISK OF CJD EMERGED AS THE STRONGEST OF THESE ASSOCIATIONS
STATISTICALLY. ...
snip...
In the study in the USA, a range of foodstuffs were associated with an
increased risk of CJD, including liver consumption which was associated with an
apparent SIX-FOLD INCREASE IN THE RISK OF CJD. By comparing the data from 3
studies in relation to this particular dietary factor, the risk of liver
consumption became non-significant with an odds ratio of 1.2 (PERSONAL
COMMUNICATION, PROFESSOR A. HOFMAN. ERASMUS UNIVERSITY, ROTTERDAM). (???...TSS)
snip...see full report ;
CJD9/10022
October 1994
Mr R.N. Elmhirst Chairman British Deer Farmers Association Holly Lodge
Spencers Lane BerksWell Coventry CV7 7BZ
Dear Mr Elmhirst,
CREUTZFELDT-JAKOB DISEASE (CJD) SURVEILLANCE UNIT REPORT
Thank you for your recent letter concerning the publication of the third
annual report from the CJD Surveillance Unit. I am sorry that you are
dissatisfied with the way in which this report was published.
The Surveillance Unit is a completely independant outside body and the
Department of Health is committed to publishing their reports as soon as they
become available. In the circumstances it is not the practice to circulate the
report for comment since the findings of the report would not be amended. In
future we can ensure that the British Deer Farmers Association receives a copy
of the report in advance of publication.
The Chief Medical Officer has undertaken to keep the public fully informed
of the results of any research in respect of CJD. This report was entirely the
work of the unit and was produced completely independantly of the the
Department.
The statistical results reqarding the consumption of venison was put into
perspective in the body of the report and was not mentioned at all in the press
release. Media attention regarding this report was low key but gave a realistic
presentation of the statistical findings of the Unit. This approach to
publication was successful in that consumption of venison was highlighted only
once by the media ie. in the News at one television proqramme.
I believe that a further statement about the report, or indeed statistical
links between CJD and consumption of venison, would increase, and quite possibly
give damaging credence, to the whole issue. From the low key media reports of
which I am aware it seems unlikely that venison consumption will suffer
adversely, if at all.
http://web.archive.org/web/20030511010117/http://www.bseinquiry.gov.uk/files/yb/1994/10/00003001.pdf
CREUTZFELDT JAKOB DISEASE SURVEILLANCE IN THE UNITED KINGDOM THIRD ANNUAL
REPORT AUGUST 1994
Consumption of venison and veal was much less widespread among both cases
and controls. For both of these meats there was evidence of a trend with
increasing frequency of consumption being associated with increasing risk of
CJD. (not nvCJD, but sporadic CJD...tss) These associations were largely
unchanged when attention was restricted to pairs with data obtained from
relatives. ...
Table 9 presents the results of an analysis of these data.
There is STRONG evidence of an association between ‘’regular’’ veal eating
and risk of CJD (p = .0.01).
Individuals reported to eat veal on average at least once a year appear to
be at 13 TIMES THE RISK of individuals who have never eaten veal.
There is, however, a very wide confidence interval around this estimate.
There is no strong evidence that eating veal less than once per year is
associated with increased risk of CJD (p = 0.51).
The association between venison eating and risk of CJD shows similar
pattern, with regular venison eating associated with a 9 FOLD INCREASE IN RISK
OF CJD (p = 0.04).
There is some evidence that risk of CJD INCREASES WITH INCREASING FREQUENCY
OF LAMB EATING (p = 0.02).
The evidence for such an association between beef eating and CJD is weaker
(p = 0.14). When only controls for whom a relative was interviewed are included,
this evidence becomes a little STRONGER (p = 0.08).
snip...
It was found that when veal was included in the model with another
exposure, the association between veal and CJD remained statistically
significant (p = < 0.05 for all exposures), while the other exposures ceased
to be statistically significant (p = > 0.05).
snip...
In conclusion, an analysis of dietary histories revealed statistical
associations between various meats/animal products and INCREASED RISK OF CJD.
When some account was taken of possible confounding, the association between
VEAL EATING AND RISK OF CJD EMERGED AS THE STRONGEST OF THESE ASSOCIATIONS
STATISTICALLY. ...
snip...
In the study in the USA, a range of foodstuffs were associated with an
increased risk of CJD, including liver consumption which was associated with an
apparent SIX-FOLD INCREASE IN THE RISK OF CJD. By comparing the data from 3
studies in relation to this particular dietary factor, the risk of liver
consumption became non-significant with an odds ratio of 1.2 (PERSONAL
COMMUNICATION, PROFESSOR A. HOFMAN. ERASMUS UNIVERSITY, ROTTERDAM). (???...TSS)
snip...see full report ;
Friday, May 22, 2015
*** Chronic Wasting Disease and Program Updates - 2014 NEUSAHA Annual
Meeting 12-14 May 2014 ***
Wednesday, July 29, 2015
*** Porcine Prion Protein Amyloid or mad pig disease PSE
Saturday, May 30, 2015
PRION 2015 ORAL AND POSTER CONGRESSIONAL ABSTRACTS
Comments on technical aspects of the risk assessment were then submitted to
FSIS.
Comments were received from Food and Water Watch, Food Animal Concerns
Trust (FACT), Farm Sanctuary, R-CALF USA, Linda A Detwiler, and Terry S.
Singeltary.
This document provides itemized replies to the public comments received on
the 2005 updated Harvard BSE risk assessment. Please bear the following points
in mind:
Owens, Julie
From: Terry S. Singeltary Sr. [flounder9@verizon.net]
Sent: Monday, July 24, 2006 1:09 PM
To: FSIS RegulationsComments
Subject: [Docket No. FSIS-2006-0011] FSIS Harvard Risk Assessment of Bovine
Spongiform Encephalopathy (BSE)
Page 1 of 98
FSIS, USDA, REPLY TO SINGELTARY
PRION 2015 ORAL AND POSTER CONGRESSIONAL ABSTRACTS
THANK YOU PRION 2015 TAYLOR & FRANCIS, Professor Chernoff, and
Professor Aguzzi et al, for making these PRION 2015 Congressional Poster and
Oral Abstracts available freely to the public. ...Terry S. Singeltary Sr.
O.05: Transmission of prions to primates after extended silent incubation
periods: Implications for BSE and scrapie risk assessment in human populations
Emmanuel Comoy, Jacqueline Mikol, Val erie Durand, Sophie Luccantoni,
Evelyne Correia, Nathalie Lescoutra, Capucine Dehen, and Jean-Philippe Deslys
Atomic Energy Commission; Fontenay-aux-Roses, France
Prion diseases (PD) are the unique neurodegenerative proteinopathies
reputed to be transmissible under field conditions since decades. The
transmission of Bovine Spongiform Encephalopathy (BSE) to humans evidenced that
an animal PD might be zoonotic under appropriate conditions. Contrarily, in the
absence of obvious (epidemiological or experimental) elements supporting a
transmission or genetic predispositions, PD, like the other proteinopathies, are
reputed to occur spontaneously (atpical animal prion strains, sporadic CJD
summing 80% of human prion cases). Non-human primate models provided the first
evidences supporting the transmissibiity of human prion strains and the zoonotic
potential of BSE. Among them, cynomolgus macaques brought major information for
BSE risk assessment for human health (Chen, 2014), according to their
phylogenetic proximity to humans and extended lifetime. We used this model to
assess the zoonotic potential of other animal PD from bovine, ovine and cervid
origins even after very long silent incubation periods. We recently observed the
direct transmission of a natural classical scrapie isolate to macaque after a
10-year silent incubation period, with features similar to some reported for
human cases of sporadic CJD, albeit requiring fourfold longe incubation than
BSE. Scrapie, as recently evoked in humanized mice (Cassard, 2014), is the third
potentially zoonotic PD (with BSE and L-type BSE), ***thus questioning the
origin of human sporadic cases. We will present an updated panorama of our
different transmission studies and discuss the implications of such extended
incubation periods on risk assessment of animal PD for human health.
===============
***thus questioning the origin of human sporadic cases...TSS
===============
Saturday, May 30, 2015
PRION 2015 ORAL AND POSTER CONGRESSIONAL ABSTRACTS
PRION 2015 CONFERENCE FT. COLLINS CWD RISK FACTORS TO HUMANS
*** LATE-BREAKING ABSTRACTS PRION 2015 CONFERENCE ***
O18
Zoonotic Potential of CWD Prions
Liuting Qing1, Ignazio Cali1,2, Jue Yuan1, Shenghai Huang3, Diane Kofskey1,
Pierluigi Gambetti1, Wenquan Zou1, Qingzhong Kong1 1Case Western Reserve
University, Cleveland, Ohio, USA, 2Second University of Naples, Naples, Italy,
3Encore Health Resources, Houston, Texas, USA
Chronic wasting disease (CWD) is a widespread and expanding prion disease
in free-ranging and captive cervid species in North America. The zoonotic
potential of CWD prions is a serious public health concern. Current literature
generated with in vitro methods and in vivo animal models (transgenic mice,
macaques and squirrel monkeys) reports conflicting results. The susceptibility
of human CNS and peripheral organs to CWD prions remains largely unresolved. In
our earlier bioassay experiments using several humanized transgenic mouse lines,
we detected protease-resistant PrPSc in the spleen of two out of 140 mice that
were intracerebrally inoculated with natural CWD isolates, but PrPSc was not
detected in the brain of the same mice. Secondary passages with such
PrPSc-positive CWD-inoculated humanized mouse spleen tissues led to efficient
prion transmission with clear clinical and pathological signs in both humanized
and cervidized transgenic mice. Furthermore, a recent bioassay with natural CWD
isolates in a new humanized transgenic mouse line led to clinical prion
infection in 2 out of 20 mice. These results indicate that the CWD prion has the
potential to infect human CNS and peripheral lymphoid tissues and that there
might be asymptomatic human carriers of CWD infection.
==================
***These results indicate that the CWD prion has the potential to infect
human CNS and peripheral lymphoid tissues and that there might be asymptomatic
human carriers of CWD infection.***
==================
P.105: RT-QuIC models trans-species prion transmission
Kristen Davenport, Davin Henderson, Candace Mathiason, and Edward Hoover
Prion Research Center; Colorado State University; Fort Collins, CO USA
The propensity for trans-species prion transmission is related to the
structural characteristics of the enciphering and heterologous PrP, but the
exact mechanism remains mostly mysterious. Studies of the effects of primary or
tertiary prion protein structures on trans-species prion transmission have
relied primarily upon animal bioassays, making the influence of prion protein
structure vs. host co-factors (e.g. cellular constituents, trafficking, and
innate immune interactions) difficult to dissect. As an alternative strategy, we
used real-time quakinginduced conversion (RT-QuIC) to investigate trans-species
prion conversion.
To assess trans-species conversion in the RT-QuIC system, we compared
chronic wasting disease (CWD) and bovine spongiform encephalopathy (BSE) prions,
as well as feline CWD (fCWD) and feline spongiform encephalopathy (FSE). Each
prion was seeded into each host recombinant PrP (full-length rPrP of
white-tailed deer, bovine or feline). We demonstrated that fCWD is a more
efficient seed for feline rPrP than for white-tailed deer rPrP, which suggests
adaptation to the new host.
Conversely, FSE maintained sufficient BSE characteristics to more
efficiently convert bovine rPrP than feline rPrP. Additionally, human rPrP was
competent for conversion by CWD and fCWD. ***This insinuates that, at the level
of protein:protein interactions, the barrier preventing transmission of CWD to
humans is less robust than previously estimated.
================
***This insinuates that, at the level of protein:protein interactions, the
barrier preventing transmission of CWD to humans is less robust than previously
estimated.***
================
I strenuously once again urge the FDA and its industry constituents, to
make it MANDATORY that all ruminant feed be banned to all ruminants, and this
should include all cervids as soon as possible for the following
reasons...
======
In the USA, under the Food and Drug Administrations BSE Feed Regulation (21
CFR 589.2000) most material (exceptions include milk, tallow, and gelatin) from
deer and elk is prohibited for use in feed for ruminant animals. With regards to
feed for non-ruminant animals, under FDA law, CWD positive deer may not be used
for any animal feed or feed ingredients. For elk and deer considered at high
risk for CWD, the FDA recommends that these animals do not enter the animal feed
system.
***However, this recommendation is guidance and not a requirement by law.
======
31 Jan 2015 at 20:14 GMT
*** Ruminant feed ban for cervids in the United States? ***
Singeltary et al
31 Jan 2015 at 20:14 GMT
Terry S. Singeltary Sr.