EFSA update on TSE in sheep
Last updated: 09 March 2006
The Community Reference Laboratory (CRL) has notified the European Commission (EC) of the results of a second level of testing for Transmissible Spongiform Encephalopathy (TSE)[1] of samples from one sheep from Cyprus and two sheep from France.
Press statement
EFSA update on TSE in sheep
The Community Reference Laboratory (CRL) has notified the European Commission (EC) of the results of a second level of testing for Transmissible Spongiform Encephalopathy (TSE)[1] of samples from one sheep from Cyprus and two sheep from France. Although a second level of testing could not classify any of the samples conclusively as BSE in sheep, there is insufficient evidence to definitively rule out the presence of BSE. Therefore, a more comprehensive third test will now be carried out consisting of a 12-18 month mouse bioassay in order to determine the types of TSE in question.
EFSA's Scientific Experts and its Panel on Biological Hazards (BIOHAZ) will be meeting during the week beginning 13th March and will review the relevant scientific data and address relevant questions in relation to the CRL results. In addition, EFSA is proceeding with its ongoing preparation of a quantitative risk assessment of the BSE risk associated with sheep products. This assessment will be ready towards autumn 2006.
___________________________
For media enquiries, please contact:
Alun Jones, Press Officer
Tel: + 39 0521 036 487 or E-mail: [email protected].
_________________________________
[1] TSE = Transmissible Spongiform Encephalopathy: A family of transmissible progressive diseases that mainly affects the central nervous system characterized by spongiform degeneration and a long incubation period. Examples of TSEs are Creutzfeldt-Jakob Disease (CJD) and kuru in humans, scrapie in small ruminants and Bovine Spongiform Encephalopathy (BSE) in bovines.
Publication date: 09 March 2006
http://www.efsa.eu.int/press_room/press_statements/1388_en.html
http://www.efsa.eu.int/press_room/press_statements/1388/efsa_statement_tse_sheep_update1.pdf
Published online before print October 20, 2005
Proc. Natl. Acad. Sci. USA, 10.1073/pnas.0502296102
Medical Sciences
A newly identified type of scrapie agent can naturally infect sheep with resistant PrP genotypes
( sheep prion | transgenic mice )
Annick Le Dur *, Vincent Béringue *, Olivier Andréoletti , Fabienne Reine *, Thanh Lan Laï *, Thierry Baron , Bjørn Bratberg ¶, Jean-Luc Vilotte ||, Pierre Sarradin **, Sylvie L. Benestad ¶, and Hubert Laude *
*Virologie Immunologie Moléculaires and ||Génétique Biochimique et Cytogénétique, Institut National de la Recherche Agronomique, 78350 Jouy-en-Josas, France; Unité Mixte de Recherche, Institut National de la Recherche Agronomique-Ecole Nationale Vétérinaire de Toulouse, Interactions Hôte Agent Pathogène, 31066 Toulouse, France; Agence Française de Sécurité Sanitaire des Aliments, Unité Agents Transmissibles Non Conventionnels, 69364 Lyon, France; **Pathologie Infectieuse et Immunologie, Institut National de la Recherche Agronomique, 37380 Nouzilly, France; and ¶Department of Pathology, National Veterinary Institute, 0033 Oslo, Norway
Edited by Stanley B. Prusiner, University of California, San Francisco, CA, and approved September 12, 2005 (received for review March 21, 2005)
Scrapie in small ruminants belongs to transmissible spongiform encephalopathies (TSEs), or prion diseases, a family of fatal neurodegenerative disorders that affect humans and animals and can transmit within and between species by ingestion or inoculation. Conversion of the host-encoded prion protein (PrP), normal cellular PrP (PrPc), into a misfolded form, abnormal PrP (PrPSc), plays a key role in TSE transmission and pathogenesis. The intensified surveillance of scrapie in the European Union, together with the improvement of PrPSc detection techniques, has led to the discovery of a growing number of so-called atypical scrapie cases. These include clinical Nor98 cases first identified in Norwegian sheep on the basis of unusual pathological and PrPSc molecular features and "cases" that produced discordant responses in the rapid tests currently applied to the large-scale random screening of slaughtered or fallen animals. Worryingly, a substantial proportion of such cases involved sheep with PrP genotypes known until now to confer natural resistance to conventional scrapie. Here we report that both Nor98 and discordant cases, including three sheep homozygous for the resistant PrPARR allele (A136R154R171), efficiently transmitted the disease to transgenic mice expressing ovine PrP, and that they shared unique biological and biochemical features upon propagation in mice. These observations support the view that a truly infectious TSE agent, unrecognized until recently, infects sheep and goat flocks and may have important implications in terms of scrapie control and public health.
--------------------------------------------------------------------------------
Author contributions: H.L. designed research; A.L.D., V.B., O.A., F.R., T.L.L., J.-L.V., and H.L. performed research; T.B., B.B., P.S., and S.L.B. contributed new reagents/analytic tools; V.B., O.A., and H.L. analyzed data; and H.L. wrote the paper.
A.L.D. and V.B. contributed equally to this work.
To whom correspondence should be addressed.
Hubert Laude, E-mail: [email protected]
www.pnas.org/cgi/doi/10.1073/pnas.0502296102
http://www.pnas.org/cgi/content/abstract/0502296102v1
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
http://www.bseinquiry.gov.uk/files/yb/1976/10/12004001.pdf
Like lambs to the slaughter
31 March 2001
Debora MacKenzie
Magazine issue 2284
What if you can catch old-fashioned CJD by eating meat from a sheep infected
with scrapie?
FOUR years ago, Terry Singeltary watched his mother die horribly from a
degenerative brain disease. Doctors told him it was Alzheimer's, but
Singeltary was suspicious. The diagnosis didn't fit her violent symptoms,
and he demanded an autopsy. It showed she had died of sporadic
Creutzfeldt-Jakob disease.
Most doctors believe that sCJD is caused by a prion protein deforming by
chance into a killer. But Singeltary thinks otherwise. He is one of a number
of campaigners who say that some sCJD, like the variant CJD related to BSE,
is caused by eating meat from infected animals. Their suspicions have
focused on sheep carrying scrapie, a BSE-like disease that is widespread in
flocks across Europe and North America.
Now scientists in France have stumbled across new evidence that adds weight
to the campaigners' fears. To their complete surprise, the researchers found
that one strain of scrapie causes the same brain damage in ...
The complete article is 889 words long.
full text;
http://www.newscientist.com/article.ns?id=mg16922840.300
Neurobiology
Adaptation of the bovine spongiform encephalopathy agent to primates and
comparison with Creutzfeldt- Jakob disease: Implications for human health
Corinne Ida Lasmézas*,, Jean-Guy Fournier*, Virginie Nouvel*, Hermann Boe*,
Domíníque Marcé*, François Lamoury*, Nicolas Kopp, Jean-Jacques Hauw§, James
Ironside¶, Moira Bruce, Dominique Dormont*, and Jean-Philippe Deslys*
* Commissariat à l'Energie Atomique, Service de Neurovirologie, Direction
des Sciences du Vivant/Département de Recherche Medicale, Centre de
Recherches du Service de Santé des Armées 60-68, Avenue du Général Leclerc,
BP 6, 92 265 Fontenay-aux-Roses Cedex, France; Hôpital Neurologique Pierre
Wertheimer, 59, Boulevard Pinel, 69003 Lyon, France; § Laboratoire de
Neuropathologie, Hôpital de la Salpêtrière, 83, Boulevard de l'Hôpital,
75013 Paris, France; ¶ Creutzfeldt-Jakob Disease Surveillance Unit, Western
General Hospital, Crewe Road, Edinburgh EH4 2XU, United Kingdom; and
Institute for Animal Health, Neuropathogenesis Unit, West Mains Road,
Edinburgh EH9 3JF, United Kingdom
Edited by D. Carleton Gajdusek, Centre National de la Recherche
Scientifique, Gif-sur-Yvette, France, and approved December 7, 2000
(received for review October 16, 2000)
Abstract
There is substantial scientific evidence to support the notion that bovine
spongiform encephalopathy (BSE) has contaminated human beings, causing
variant Creutzfeldt-Jakob disease (vCJD). This disease has raised concerns
about the possibility of an iatrogenic secondary transmission to humans,
because the biological properties of the primate-adapted BSE agent are
unknown. We show that (i) BSE can be transmitted from primate to primate by
intravenous route in 25 months, and (ii) an iatrogenic transmission of vCJD
to humans could be readily recognized pathologically, whether it occurs by
the central or peripheral route. Strain typing in mice demonstrates that the
BSE agent adapts to macaques in the same way as it does to humans and
confirms that the BSE agent is responsible for vCJD not only in the United
Kingdom but also in France. The agent responsible for French iatrogenic
growth hormone-linked CJD taken as a control is very different from vCJD but
is similar to that found in one case of sporadic CJD and one sheep scrapie
isolate. These data will be key in identifying the origin of human cases of
prion disease, including accidental vCJD transmission, and could provide
bases for vCJD risk assessment.
http://www.pnas.org/cgi/content/full/041490898v1
The EMBO Journal, Vol. 19, No. 17 pp. 4425-4430, 2000
© European Molecular Biology Organization
Evidence of a molecular barrier limiting
susceptibility of humans, cattle and sheep to
chronic wasting disease
G.J. Raymond1, A. Bossers2, L.D. Raymond1, K.I. O?Rourke3,
L.E. McHolland4, P.K. Bryant III4, M.W. Miller5, E.S. Williams6, M.
Smits2
and B. Caughey1,7
1NIAID/NIH Rocky Mountain Laboratories, Hamilton, MT 59840,
3USDA/ARS/ADRU, Pullman, WA 99164-7030, 4USDA/ARS/ABADRL,
Laramie, WY 82071, 5Colorado Division of Wildlife, Wildlife Research
Center, Fort Collins, CO 80526-2097, 6Department of Veterinary Sciences,
University of Wyoming, Laramie, WY 82070, USA and 2ID-Lelystad,
Institute for Animal Science and Health, Lelystad, The Netherlands
7Corresponding author e-mail: [email protected] Received June 7, 2000;
revised July 3, 2000; accepted July 5, 2000.
Abstract
Chronic wasting disease (CWD) is a transmissible
spongiform encephalopathy (TSE) of deer and elk,
and little is known about its transmissibility to other
species. An important factor controlling
interspecies TSE susceptibility is prion protein (PrP)
homology between the source and recipient
species/genotypes. Furthermore, the efficiency with which
the protease-resistant PrP (PrP-res) of one
species induces the in vitro conversion of the normal PrP
(PrP-sen) of another species to the
protease-resistant state correlates with the cross-species
transmissibility of TSE agents. Here we
show that the CWD-associated PrP-res (PrPCWD) of cervids
readily induces the conversion of recombinant cervid PrP-sen
molecules to the protease-resistant state in accordance
with the known transmissibility of CWD between cervids. In contrast,
PrPCWD-induced conversions of human and bovine PrP-sen were
much less efficient, and conversion of ovine PrP-sen was
intermediate. These results demonstrate a barrier at the
molecular level that should limit the susceptibility of these non-cervid
species to CWD.
snip...
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...
http://www.emboj.org/current.shtml
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.
PMID: 6997404
http://www.ncbi.nlm.nih.gov/entrez/query.fcgicmd=Retrieve&db=PubMed&list_uids=6997404&dopt=Abstract
TSS
Last updated: 09 March 2006
The Community Reference Laboratory (CRL) has notified the European Commission (EC) of the results of a second level of testing for Transmissible Spongiform Encephalopathy (TSE)[1] of samples from one sheep from Cyprus and two sheep from France.
Press statement
EFSA update on TSE in sheep
The Community Reference Laboratory (CRL) has notified the European Commission (EC) of the results of a second level of testing for Transmissible Spongiform Encephalopathy (TSE)[1] of samples from one sheep from Cyprus and two sheep from France. Although a second level of testing could not classify any of the samples conclusively as BSE in sheep, there is insufficient evidence to definitively rule out the presence of BSE. Therefore, a more comprehensive third test will now be carried out consisting of a 12-18 month mouse bioassay in order to determine the types of TSE in question.
EFSA's Scientific Experts and its Panel on Biological Hazards (BIOHAZ) will be meeting during the week beginning 13th March and will review the relevant scientific data and address relevant questions in relation to the CRL results. In addition, EFSA is proceeding with its ongoing preparation of a quantitative risk assessment of the BSE risk associated with sheep products. This assessment will be ready towards autumn 2006.
___________________________
For media enquiries, please contact:
Alun Jones, Press Officer
Tel: + 39 0521 036 487 or E-mail: [email protected].
_________________________________
[1] TSE = Transmissible Spongiform Encephalopathy: A family of transmissible progressive diseases that mainly affects the central nervous system characterized by spongiform degeneration and a long incubation period. Examples of TSEs are Creutzfeldt-Jakob Disease (CJD) and kuru in humans, scrapie in small ruminants and Bovine Spongiform Encephalopathy (BSE) in bovines.
Publication date: 09 March 2006
http://www.efsa.eu.int/press_room/press_statements/1388_en.html
http://www.efsa.eu.int/press_room/press_statements/1388/efsa_statement_tse_sheep_update1.pdf
Published online before print October 20, 2005
Proc. Natl. Acad. Sci. USA, 10.1073/pnas.0502296102
Medical Sciences
A newly identified type of scrapie agent can naturally infect sheep with resistant PrP genotypes
( sheep prion | transgenic mice )
Annick Le Dur *, Vincent Béringue *, Olivier Andréoletti , Fabienne Reine *, Thanh Lan Laï *, Thierry Baron , Bjørn Bratberg ¶, Jean-Luc Vilotte ||, Pierre Sarradin **, Sylvie L. Benestad ¶, and Hubert Laude *
*Virologie Immunologie Moléculaires and ||Génétique Biochimique et Cytogénétique, Institut National de la Recherche Agronomique, 78350 Jouy-en-Josas, France; Unité Mixte de Recherche, Institut National de la Recherche Agronomique-Ecole Nationale Vétérinaire de Toulouse, Interactions Hôte Agent Pathogène, 31066 Toulouse, France; Agence Française de Sécurité Sanitaire des Aliments, Unité Agents Transmissibles Non Conventionnels, 69364 Lyon, France; **Pathologie Infectieuse et Immunologie, Institut National de la Recherche Agronomique, 37380 Nouzilly, France; and ¶Department of Pathology, National Veterinary Institute, 0033 Oslo, Norway
Edited by Stanley B. Prusiner, University of California, San Francisco, CA, and approved September 12, 2005 (received for review March 21, 2005)
Scrapie in small ruminants belongs to transmissible spongiform encephalopathies (TSEs), or prion diseases, a family of fatal neurodegenerative disorders that affect humans and animals and can transmit within and between species by ingestion or inoculation. Conversion of the host-encoded prion protein (PrP), normal cellular PrP (PrPc), into a misfolded form, abnormal PrP (PrPSc), plays a key role in TSE transmission and pathogenesis. The intensified surveillance of scrapie in the European Union, together with the improvement of PrPSc detection techniques, has led to the discovery of a growing number of so-called atypical scrapie cases. These include clinical Nor98 cases first identified in Norwegian sheep on the basis of unusual pathological and PrPSc molecular features and "cases" that produced discordant responses in the rapid tests currently applied to the large-scale random screening of slaughtered or fallen animals. Worryingly, a substantial proportion of such cases involved sheep with PrP genotypes known until now to confer natural resistance to conventional scrapie. Here we report that both Nor98 and discordant cases, including three sheep homozygous for the resistant PrPARR allele (A136R154R171), efficiently transmitted the disease to transgenic mice expressing ovine PrP, and that they shared unique biological and biochemical features upon propagation in mice. These observations support the view that a truly infectious TSE agent, unrecognized until recently, infects sheep and goat flocks and may have important implications in terms of scrapie control and public health.
--------------------------------------------------------------------------------
Author contributions: H.L. designed research; A.L.D., V.B., O.A., F.R., T.L.L., J.-L.V., and H.L. performed research; T.B., B.B., P.S., and S.L.B. contributed new reagents/analytic tools; V.B., O.A., and H.L. analyzed data; and H.L. wrote the paper.
A.L.D. and V.B. contributed equally to this work.
To whom correspondence should be addressed.
Hubert Laude, E-mail: [email protected]
www.pnas.org/cgi/doi/10.1073/pnas.0502296102
http://www.pnas.org/cgi/content/abstract/0502296102v1
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
http://www.bseinquiry.gov.uk/files/yb/1976/10/12004001.pdf
Like lambs to the slaughter
31 March 2001
Debora MacKenzie
Magazine issue 2284
What if you can catch old-fashioned CJD by eating meat from a sheep infected
with scrapie?
FOUR years ago, Terry Singeltary watched his mother die horribly from a
degenerative brain disease. Doctors told him it was Alzheimer's, but
Singeltary was suspicious. The diagnosis didn't fit her violent symptoms,
and he demanded an autopsy. It showed she had died of sporadic
Creutzfeldt-Jakob disease.
Most doctors believe that sCJD is caused by a prion protein deforming by
chance into a killer. But Singeltary thinks otherwise. He is one of a number
of campaigners who say that some sCJD, like the variant CJD related to BSE,
is caused by eating meat from infected animals. Their suspicions have
focused on sheep carrying scrapie, a BSE-like disease that is widespread in
flocks across Europe and North America.
Now scientists in France have stumbled across new evidence that adds weight
to the campaigners' fears. To their complete surprise, the researchers found
that one strain of scrapie causes the same brain damage in ...
The complete article is 889 words long.
full text;
http://www.newscientist.com/article.ns?id=mg16922840.300
Neurobiology
Adaptation of the bovine spongiform encephalopathy agent to primates and
comparison with Creutzfeldt- Jakob disease: Implications for human health
Corinne Ida Lasmézas*,, Jean-Guy Fournier*, Virginie Nouvel*, Hermann Boe*,
Domíníque Marcé*, François Lamoury*, Nicolas Kopp, Jean-Jacques Hauw§, James
Ironside¶, Moira Bruce, Dominique Dormont*, and Jean-Philippe Deslys*
* Commissariat à l'Energie Atomique, Service de Neurovirologie, Direction
des Sciences du Vivant/Département de Recherche Medicale, Centre de
Recherches du Service de Santé des Armées 60-68, Avenue du Général Leclerc,
BP 6, 92 265 Fontenay-aux-Roses Cedex, France; Hôpital Neurologique Pierre
Wertheimer, 59, Boulevard Pinel, 69003 Lyon, France; § Laboratoire de
Neuropathologie, Hôpital de la Salpêtrière, 83, Boulevard de l'Hôpital,
75013 Paris, France; ¶ Creutzfeldt-Jakob Disease Surveillance Unit, Western
General Hospital, Crewe Road, Edinburgh EH4 2XU, United Kingdom; and
Institute for Animal Health, Neuropathogenesis Unit, West Mains Road,
Edinburgh EH9 3JF, United Kingdom
Edited by D. Carleton Gajdusek, Centre National de la Recherche
Scientifique, Gif-sur-Yvette, France, and approved December 7, 2000
(received for review October 16, 2000)
Abstract
There is substantial scientific evidence to support the notion that bovine
spongiform encephalopathy (BSE) has contaminated human beings, causing
variant Creutzfeldt-Jakob disease (vCJD). This disease has raised concerns
about the possibility of an iatrogenic secondary transmission to humans,
because the biological properties of the primate-adapted BSE agent are
unknown. We show that (i) BSE can be transmitted from primate to primate by
intravenous route in 25 months, and (ii) an iatrogenic transmission of vCJD
to humans could be readily recognized pathologically, whether it occurs by
the central or peripheral route. Strain typing in mice demonstrates that the
BSE agent adapts to macaques in the same way as it does to humans and
confirms that the BSE agent is responsible for vCJD not only in the United
Kingdom but also in France. The agent responsible for French iatrogenic
growth hormone-linked CJD taken as a control is very different from vCJD but
is similar to that found in one case of sporadic CJD and one sheep scrapie
isolate. These data will be key in identifying the origin of human cases of
prion disease, including accidental vCJD transmission, and could provide
bases for vCJD risk assessment.
http://www.pnas.org/cgi/content/full/041490898v1
The EMBO Journal, Vol. 19, No. 17 pp. 4425-4430, 2000
© European Molecular Biology Organization
Evidence of a molecular barrier limiting
susceptibility of humans, cattle and sheep to
chronic wasting disease
G.J. Raymond1, A. Bossers2, L.D. Raymond1, K.I. O?Rourke3,
L.E. McHolland4, P.K. Bryant III4, M.W. Miller5, E.S. Williams6, M.
Smits2
and B. Caughey1,7
1NIAID/NIH Rocky Mountain Laboratories, Hamilton, MT 59840,
3USDA/ARS/ADRU, Pullman, WA 99164-7030, 4USDA/ARS/ABADRL,
Laramie, WY 82071, 5Colorado Division of Wildlife, Wildlife Research
Center, Fort Collins, CO 80526-2097, 6Department of Veterinary Sciences,
University of Wyoming, Laramie, WY 82070, USA and 2ID-Lelystad,
Institute for Animal Science and Health, Lelystad, The Netherlands
7Corresponding author e-mail: [email protected] Received June 7, 2000;
revised July 3, 2000; accepted July 5, 2000.
Abstract
Chronic wasting disease (CWD) is a transmissible
spongiform encephalopathy (TSE) of deer and elk,
and little is known about its transmissibility to other
species. An important factor controlling
interspecies TSE susceptibility is prion protein (PrP)
homology between the source and recipient
species/genotypes. Furthermore, the efficiency with which
the protease-resistant PrP (PrP-res) of one
species induces the in vitro conversion of the normal PrP
(PrP-sen) of another species to the
protease-resistant state correlates with the cross-species
transmissibility of TSE agents. Here we
show that the CWD-associated PrP-res (PrPCWD) of cervids
readily induces the conversion of recombinant cervid PrP-sen
molecules to the protease-resistant state in accordance
with the known transmissibility of CWD between cervids. In contrast,
PrPCWD-induced conversions of human and bovine PrP-sen were
much less efficient, and conversion of ovine PrP-sen was
intermediate. These results demonstrate a barrier at the
molecular level that should limit the susceptibility of these non-cervid
species to CWD.
snip...
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...
http://www.emboj.org/current.shtml
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.
PMID: 6997404
http://www.ncbi.nlm.nih.gov/entrez/query.fcgicmd=Retrieve&db=PubMed&list_uids=6997404&dopt=Abstract
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