Subject: The SEAC Sheep Subgroup Position Statement
Date: March 2, 2006 at 7:12 am PST
SEAC SHEEP SUBGROUP
POSITION STATEMENT
In view of SEAC's commitment to keep the scientific evidence
underpinning the strategy of the National Scrapie Plan (NSP) under
review1, and in light of rapidly emerging scientific findings relating to
atypical scrapie, the opinion of the sheep subgroup was sought by
SEAC in consultation with Defra. A meeting of the SEAC sheep
subgroup was held on January 24th 2006, with the following aims:
• To give the best interpretation of the current data on atypical
scrapie and of the potential risks for a) animal health and b)
human health. To consider whether new data change the risk
basis underpinning the NSP, flock control, or relevant sections
of the TSE roadmap.
• To consider what additional information is necessary in order
to improve assessment of the risk for animal and human
health.
• To produce a statement for consideration at SEAC 91
The meeting brought together European experts on atypical scrapie, as
well as UK experts and officials from the relevant Government
Departments. The subgroup considered a body of unpublished data as
well as published information and ongoing studies.
Background
snip...
Data from active surveillance show that the frequency of
atypical scrapie infections in the British sheep flock is similar
to that of classical scrapie, and may be slightly higher.
Modelling of the abattoir survey results for the Great British
sheep population over 18 months old (14 million sheep)
shows that around 56 000 sheep could be infected with
classical scrapie and around 82 000 infected with atypical
scrapie15. These numbers are considerably greater than the
number of known clinical cases, in part because many
infected animals may be sent to the abattoir at an age before
clinical signs appear, but it may also reflect a degree of underreporting16.
• Atypical scrapie has been identified in many European
countries and in at least some may also be of similar or higher
prevalence than classical scrapie. For instance, Portugal has
only notified atypical scrapie cases so far from active
surveillance17, with no classical scrapie cases.
• That there are generally smaller numbers of atypicals per
infected flock compared with classical scrapie. One
interpretation is that atypical scrapie may be less readily
14 paper SS/Jan 06/5 tables 1 and 2 for the sheep subgroup meeting 24 January 2006
15 modelled data from active surveillance (abattoir survey) provided by Professor John
Wilesmith post meeting.
16 Sivam S.K., Baylis M., Gravenor M.B., Gubbins S. and Wilesmith J.W. (2003) Results of a
postal survey in 2002 into the occurrence of scrapie in Great Britain. Vet. Rec. 153, 782-783
17http://www.efsa.eu.int/science/biohaz/biohaz_opinions/1216/biohaz_op_ej_276_atypicalscrapiedefinition_en_vf1.pdf
Page 7
© SEAC 27 February 2006
transmitted naturally between sheep within a flock than is
classical scrapie.
• Atypical and classical scrapie can occur together in the same
flock but do not always do so. There is no evidence for a
direct link between the occurrence of classical scrapie and
atypical scrapie, consistent with the view that classical scrapie
and atypical scrapie should be considered as independent
TSEs.
The subgroup agreed that it was critical to know whether or not the
prevalence of atypical scrapie in the UK (and other European) flocks is
increasing. This knowledge will inform the question of whether atypical
scrapie is likely to pose a human health risk. The subgroup agreed that:
• Biochemical tests able to discriminate atypical and classical
scrapie have only been available for a few years. The limited
data available from the last 4 years only, do not suggest a
significant change in prevalence over that period.
Nevertheless, on the basis of current data it is not possible to
ascertain whether atypical scrapie is an old or new disease of
sheep, or whether the prevalence of atypical scrapie is
changing over time.
• A retrospective analysis of historical samples might help
ascertain whether atypical scrapie is a new disease and
whether or not its prevalence is changing. It was
acknowledged that only limited samples may be available
from the last 40 years, and some may not be suitable for
analysis.
• Continued surveillance using an appropriate combination of
tests is essential to ensure that atypical cases continue to be
identified.
• Proactive approaches should be taken to monitor any change
in the prevalence of atypical scrapie in UK flocks with some
urgency. It should be noted that the changing sheep PrP
genotype ratios resulting from the NSP implementation may
be a confounding factor which should be taken into account in
analysing any possible changes in prevalence of atypical
scrapie.
snip...
The subgroup agreed that:
• The species barrier from atypical scrapie in sheep to VRQ
ovinised mice appeared low since atypical scrapie could be
transmitted relatively easily to VRQ ovinised mice. However
general information on the species barriers is currently limited.
As atypical scrapie is experimentally transmissible the
possibility that it may be transmissible to humans must be
considered. It was noted that BSE may be transmitted to
humans while there is no evidence that scrapie can cross this
species barrier. Further studies on the effect of route of
transmission (oral or intracerebral) on the pathogenesis of
atypical scrapie will inform on the potential risk to human and
animal health.
• The available evidence suggests that, unlike experimental
BSE in sheep, atypical scrapie may be absent from the
lymphoreticular system. Thus, assuming Specified Risk
Material (SRM) regulations remain in place, if atypical scrapie
can be transmitted to humans, it may pose a relatively lower
health risk than BSE if it ever enters the sheep flock.
However, one study using oral delivery to a VRQ sheep
suggests that PrPres may be present in the LRS. It is urgent to
clarify this issue.
• Transmission experiments between sheep of the same and
different genotypes will be very informative. The results of
experimental transmission of atypical scrapie to transgenic
mice expressing the human forms of PrP might indicate its
relative transmissibility to humans and thus inform on the
potential risk to human health of exposure to atypical scrapie.
5. Environmental persistence of TSEs and maternal transmission
The subgroup noted that transmission of classical scrapie can occur in
the absence of lambing and in the absence of direct contact with
infected sheep. Infectivity survives on pasture left fallow for at least 2
months (from ongoing VLA studies) after removal of an infected flock. It
has been speculated that this is a consequence of the widespread
distribution of classical scrapie in the body. This is in contrast to BSE in
cattle which is restricted primarily to neural tissues and does not appear
to be shed into the environment. However, BSE experimentally
introduced into genetically susceptible sheep, like classical scrapie,
appears to have a wide distribution in the body19, and it was recently
19 Bellworthy S.J., Hawkins S.A.C., Green R.B., Blamire I., Dexter G., Dexter I., Lockey R.,
Jeffrey, M., Ryder S., Berthelin-Baker C. and Simmons M.M. (2005) Tissue distribution of
bovine spongiform encephalopathy infectivity in Romney sheep up to the onset of clinical
disease after oral challenge. Vet. Rec. 156, 197-202
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© SEAC 27 February 2006
demonstrated that a BSE infection can be maintained within a sheep
flock by spreading the disease from infected ewes to their lambs20. The
detailed pathway of the infectious agent from ewe to lamb still needs to
be elucidated.
It is not known how atypical scrapie is transmitted between animals.
The possibility that it has spread through feed cannot be excluded. The
environmental persistence of atypical scrapie is unknown. The fact that
more than one case may be found in a flock may reflect a level of
environmental transmission, or a common alternative route of exposure.
It is clearly important to assess its possible route of transmission if
control measures are to be effective.
snip...
full text 13 pages;
http://www.seac.gov.uk/pdf/positionstatement-sheep-subgroup.pdf
REPORT OF THE COMMITTEE ON SCRAPIE
Chair: Dr. Jim Logan, Cheyenne, WY
Vice Chair: Dr. Joe D. Ross, Sonora, TX
Dr. Deborah L. Brennan, MS; Dr. Beth Carlson, ND; Dr. John R. Clifford, DC; Dr. Thomas F. Conner, OH; Dr. Walter E. Cook, WY; Dr. Wayne E. Cunningham, CO; Dr. Jerry W. Diemer, TX; Dr. Anita J. Edmondson, CA; Dr. Dee Ellis, TX; Dr. Lisa A. Ferguson, MD; Dr. Keith R. Forbes, NY; Dr. R. David Glauer, OH; Dr. James R. Grady, CO; Dr. William L. Hartmann, MN; Dr. Carolyn Inch, CAN; Dr. Susan J. Keller, ND; Dr. Allen M. Knowles, TN; Dr. Thomas F. Linfield, MT; Dr. Michael R. Marshall, UT; Dr. Cheryl A. Miller, In; Dr. Brian V. Noland, CO; Dr. Charles Palmer, CA; Dr. Kristine R. Petrini, MN; Mr. Stan Potratz, IA; Mr. Paul E. Rodgers, CO; Dr. Joan D. Rowe, CA; Dr. Pamela L. Smith, IA; Dr. Diane L. Sutton, MD; Dr. Lynn Anne Tesar, SD; Dr. Delwin D. Wilmot, NE; Dr. Nora E. Wineland, CO; Dr. Cindy B. Wolf, MN.
The Committee met on November 9, 2005, from 8:00am until 11:55am, Hershey Lodge and Convention Center, Hershey, Pennsylvania. The meeting was called to order by Dr. Jim Logan, chair, with vice chairman Dr. Joe D. Ross attending. There were 74 people in attendance.
The Scrapie Program Update was provided by Dr. Diane Sutton, National Scrapie Program Coordinator, United States Department of Agriculture (USDA), Animal and Plant Health Inspection Services (APHIS), Veterinary Services (VS). The complete text of the Status Report is included in these Proceedings.
Dr. Patricia Meinhardt, USDA-APHIS-VS-National Veterinary Services Laboratory (NVSL) gave the Update on Genotyping Labs and Discrepancies in Results. NVSL conducts investigations into discrepancies on genotype testing results associated with the Scrapie Eradication Program. It is the policy of the Program to conduct a second genotype test at a second laboratory on certain individual animals. Occasionally, there are discrepancies in those results. The NVSL conducts follow-up on these situations through additional testing on additional samples from the field and archive samples from the testing laboratories.
For the period of time from January 1, 2005, until October 15, 2005, there were 23 instances of discrepancies in results from 35 flocks. Of those 23 instances, 14 were caused by laboratory error (paperwork or sample mix-up), 3 results from field error, 5 were not completely resolved, and 1 originated from the use of a non-approved laboratory for the first test. As a result of inconsistencies, one laboratory's certification was revoked by APHIS-VS.
snip...
Infected and Source Flocks
As of September 30, 2005, there were 105 scrapie infected and source flocks. There were a total of 165** new infected and source flocks reported for FY 2005. The total infected and source flocks that have been released in FY 2005 was 128. The ratio of infected and source flocks cleaned up or placed on clean up plans vs. new infected and source flocks discovered in FY 2005 was 1.03 : 1*. In addition 622 scrapie cases were confirmed and reported by the National Veterinary Services Laboratories (NVSL) in FY 2005, of which 130 were RSSS cases. Fifteen cases of scrapie in goats have been reported since 1990. The last goat case was reported in May 2005. Approximately 5,626 animals were indemnified comprised of 49% non-registered sheep, 45% registered sheep, 1.4% non-registered goats and 4.6% registered goats.
Regulatory Scrapie Slaughter Surveillance (RSSS)
RSSS was designed to utilize the findings of the Center for Epidemiology and Animal Health (CEAH) Scrapie: Ovine Slaughter Surveillance (SOSS) study. The results of SOSS can be found at http://www.aphis.usda.gov/vs/ceah/cahm/Sheep/sheep.htm . RSSS started April 1,
2003. It is a targeted slaughter surveillance program which is designed to identify infected flocks for clean-up. During FY 2005 collections increased by 32% overall and by 90% for black and mottled faced sheep improving overall program effectiveness and efficiency as demonstrated by the 26% decrease in percent positive black faced sheep compared to FY 2004. Samples have been collected from 62,864 sheep since April 1, 2003, of which results have been reported for 59,105 of which 209 were confirmed positive. During FY 2005, 33,137 samples were collected from 81 plants. There have been 130 NVSL confirmed positive cases (30 collected in FY 2004 and confirmed in FY 2005 and 100 collected and confirmed in FY 2005) in FY 2005. Face colors of these positives were 114 black, 14 mottled, 1 white and 1 unknown. The percent positive by face color is shown in the chart below.
Scrapie Testing
In FY 2005, 35,845 animals have been tested for scrapie: 30,192 RSSS; 4,742 regulatory field cases; 772 regulatory third eyelid biopsies; 10 third eyelid validations; and 129 necropsy validations (chart 9).
Animal ID
As of October 04, 2005, 103,580 sheep and goat premises have been assigned identification numbers in the Scrapie National Generic Database. Official eartags have been issued to 73,807 of these premises.
*This number based on an adjusted 12 month interval to accommodate the 60 day period for setting up flock plans.
http://www.usaha.org/committees/reports/2005/report-scr-2005.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
Transmission of Creutzfeldt-Jakob disease by handling of dura mater.
The Lancet Volume 341(8837) January 9, 1993 pp
123-124
Weber, Thomas; Tumani, Hayrettin; Holdorff, Bernd; Collinge, John; Palmer,
Mark; Kretzschmar, Hans A.; Felgenhauer, Klaus
Sir,- Creutzfeldt-Jakob disease (CJD) can be transmitted iatrogenically by
human pituitary growth hormone, corneal transplants, and dura mater grafts
(1). Possible accidental transmission has been reported in only four
people-a neurosurgeon (2), a pathologist (3), and two laboratory technicians
(4,5) . We have encountered an unusually rapid case of CJD probably acquired
through handling of sheep and human dura mater.
In May, 1992, a 55-year-old orthopaedic surgeon developed paraesthesia of
the left arm. A few days later he had spatial disorientation, apraxia, and
gait ataxia. In June he was admitted and a neurologist suspected CJD on the
basis of the clinical signs, typical electroencephalogram (EEG) pattern, and
history. An EEG in June revealed a typical pattern of periodic biphasic and
triphasic sharp wave complexes. We saw the patient in July, 1992. He was
awake and oriented, with dyscalculia, dysgraphia, disturbed vision, apraxia
mainly of the left side, rigidity of wrists, spasticity of all muscles,
myoclonus of the left arm, increased tendon reflexes, ataxia of limbs and
trunk, and incoordination of left arm. Within 3 weeks he had impaired
consciousness and attention, mildly impaired memory, and threatening visual
hallucinations with restless turning. He had periodic states with movements
of his head and eye-bulbs resembling tonic adversive seizures. During sleep
these motor disturbances stopped. 2 1/2 months later the patient died.
This patient had worked with sheep and human dura mater from 1968 to 1972.
He handled about 150 specimens of ovine origin and at least a dozen human
preparations for research. Handling involved opening skulls with a band saw,
removing dura, and testing them either fresh (usually), preserved, or
lyophilised for mechanical qualities. These specimens were sent to a company
that has sold dura mater preparations by which CJD was transmitted in six
instances. No information was available from the company about a possible
connection with this patient's disease and the earlier cases of transmitted
CJD. Brain biopsy was consistent with diagnosis of CJD. Cerebrospinal fluid
obtained in July showed neuron-specific enolase (NSE) at 82.0 ng/mL,
compared with 16.7 ng/mL in serum of other cases (6). Proton magnetic
resonance spectroscopy of parieto-occipital and temporal grey matter,
parietal white matter, and thalamus revealed a 20-30% reduction of
N-acetylaspartate, as described (7). DNA was genotyped with allele-specific
oligonucleotides (8) and was homozygous for methionine at the polymorphic
codon 129. Subsequent direct DNA sequencing for the PrP gene open-reading
frame demonstrated normal sequence on both alleles, excluding known or novel
pathogenic PrP mutations.
It is tempting to speculate that prions were transmitted to this patient
from sheep or human dura mater through small lacerations of his skin, but
the patient and his wife did not remember any significant injury during his
four years of working with these samples. It cannot be excluded that this
was a case of sporadic CJD although this assumption is unlikely in view of
the clinical course which was similar to iatrogenic CJD transmitted by
peripheral inoculation, such as with human pituitary growth hormone or
gonadotropin or to kuru (1). Iatrogenic cases resulting from intracerebral
inoculation with the transmissible agent, for instance following dura mater
grafts (2-5), present with a dementing picture, as is usual in sporadic CJD,
rather than with ataxia as in this case.
1. Brown P, Preece MA, Will RG. "Friendly fire" in medicine: hormones,
homografts, and Creutzfeldt-Jakob disease. Lancet 1992; 340: 24-27. [Medline
Link] [Context Link]
2. Schoene WC, Masters CL, Gibbs CJ Jr, et al. Transmissible spongiform
encephalopathy (Creutzfeldt-Jakob Disease): atypical clinical and
pathological findings. Arch Neurol 1981; 38: 473-77. [Medline Link] [Context
Link]
3. Gorman DG, Benson DF, Vogel DG, Vinters HV. Creutzfeldt-Jakob disease in
a pathologist. Neurology 1992; 42: 463. [Medline Link] [Context Link]
4. Miller DC. Creutzfeldt-Jakob disease in histopathology technicians. N
Engl J Med 1988; 318: 853-54. [Medline Link] [Context Link]
5. Sitwell L, Lach B, Atack E, Atack D, Izukawa D. Creutzfeldt-Jakob disease
in histopathology technicians. N Engl J Med 1988; 318: 854. [Medline Link]
[Context Link]
6. Wakayama Y, Shibuya S, Kawase J, Sagawa F, Hashizume Y. High
neuron-specific enolase level of cerebrospinal fluid in the early stage of
Creutzfeldt-Jakob disease. Klin Wochenschr 1987; 65: 798-801. [Medline Link]
[Context Link]
7. Bruhn H, Weber T, Thorwirth V, Frahm J. In-vivo monitoring of neuronal
loss in Creutzfeldt-Jakob disease by proton magnetic resonance spectroscopy.
Lancet 1991; 337: 1610-11. [Medline Link] [Context Link]
8. Collinge J, Palmer MS, Dryden AJ. Genetic predisposition to iatrogenic
Creutzfeldt-Jakob disease. Lancet 1991; 337: 1444-42. [Medlin
http://www.mad-cow.org/jul99_late_news.html#ggg
0208h023: UK exports of sheep, goats and sheep/goat meats and meat products (1988 - 2001)
http://www.vegsource.com/articles/sheep_exports.htm
TSS
Date: March 2, 2006 at 7:12 am PST
SEAC SHEEP SUBGROUP
POSITION STATEMENT
In view of SEAC's commitment to keep the scientific evidence
underpinning the strategy of the National Scrapie Plan (NSP) under
review1, and in light of rapidly emerging scientific findings relating to
atypical scrapie, the opinion of the sheep subgroup was sought by
SEAC in consultation with Defra. A meeting of the SEAC sheep
subgroup was held on January 24th 2006, with the following aims:
• To give the best interpretation of the current data on atypical
scrapie and of the potential risks for a) animal health and b)
human health. To consider whether new data change the risk
basis underpinning the NSP, flock control, or relevant sections
of the TSE roadmap.
• To consider what additional information is necessary in order
to improve assessment of the risk for animal and human
health.
• To produce a statement for consideration at SEAC 91
The meeting brought together European experts on atypical scrapie, as
well as UK experts and officials from the relevant Government
Departments. The subgroup considered a body of unpublished data as
well as published information and ongoing studies.
Background
snip...
Data from active surveillance show that the frequency of
atypical scrapie infections in the British sheep flock is similar
to that of classical scrapie, and may be slightly higher.
Modelling of the abattoir survey results for the Great British
sheep population over 18 months old (14 million sheep)
shows that around 56 000 sheep could be infected with
classical scrapie and around 82 000 infected with atypical
scrapie15. These numbers are considerably greater than the
number of known clinical cases, in part because many
infected animals may be sent to the abattoir at an age before
clinical signs appear, but it may also reflect a degree of underreporting16.
• Atypical scrapie has been identified in many European
countries and in at least some may also be of similar or higher
prevalence than classical scrapie. For instance, Portugal has
only notified atypical scrapie cases so far from active
surveillance17, with no classical scrapie cases.
• That there are generally smaller numbers of atypicals per
infected flock compared with classical scrapie. One
interpretation is that atypical scrapie may be less readily
14 paper SS/Jan 06/5 tables 1 and 2 for the sheep subgroup meeting 24 January 2006
15 modelled data from active surveillance (abattoir survey) provided by Professor John
Wilesmith post meeting.
16 Sivam S.K., Baylis M., Gravenor M.B., Gubbins S. and Wilesmith J.W. (2003) Results of a
postal survey in 2002 into the occurrence of scrapie in Great Britain. Vet. Rec. 153, 782-783
17http://www.efsa.eu.int/science/biohaz/biohaz_opinions/1216/biohaz_op_ej_276_atypicalscrapiedefinition_en_vf1.pdf
Page 7
© SEAC 27 February 2006
transmitted naturally between sheep within a flock than is
classical scrapie.
• Atypical and classical scrapie can occur together in the same
flock but do not always do so. There is no evidence for a
direct link between the occurrence of classical scrapie and
atypical scrapie, consistent with the view that classical scrapie
and atypical scrapie should be considered as independent
TSEs.
The subgroup agreed that it was critical to know whether or not the
prevalence of atypical scrapie in the UK (and other European) flocks is
increasing. This knowledge will inform the question of whether atypical
scrapie is likely to pose a human health risk. The subgroup agreed that:
• Biochemical tests able to discriminate atypical and classical
scrapie have only been available for a few years. The limited
data available from the last 4 years only, do not suggest a
significant change in prevalence over that period.
Nevertheless, on the basis of current data it is not possible to
ascertain whether atypical scrapie is an old or new disease of
sheep, or whether the prevalence of atypical scrapie is
changing over time.
• A retrospective analysis of historical samples might help
ascertain whether atypical scrapie is a new disease and
whether or not its prevalence is changing. It was
acknowledged that only limited samples may be available
from the last 40 years, and some may not be suitable for
analysis.
• Continued surveillance using an appropriate combination of
tests is essential to ensure that atypical cases continue to be
identified.
• Proactive approaches should be taken to monitor any change
in the prevalence of atypical scrapie in UK flocks with some
urgency. It should be noted that the changing sheep PrP
genotype ratios resulting from the NSP implementation may
be a confounding factor which should be taken into account in
analysing any possible changes in prevalence of atypical
scrapie.
snip...
The subgroup agreed that:
• The species barrier from atypical scrapie in sheep to VRQ
ovinised mice appeared low since atypical scrapie could be
transmitted relatively easily to VRQ ovinised mice. However
general information on the species barriers is currently limited.
As atypical scrapie is experimentally transmissible the
possibility that it may be transmissible to humans must be
considered. It was noted that BSE may be transmitted to
humans while there is no evidence that scrapie can cross this
species barrier. Further studies on the effect of route of
transmission (oral or intracerebral) on the pathogenesis of
atypical scrapie will inform on the potential risk to human and
animal health.
• The available evidence suggests that, unlike experimental
BSE in sheep, atypical scrapie may be absent from the
lymphoreticular system. Thus, assuming Specified Risk
Material (SRM) regulations remain in place, if atypical scrapie
can be transmitted to humans, it may pose a relatively lower
health risk than BSE if it ever enters the sheep flock.
However, one study using oral delivery to a VRQ sheep
suggests that PrPres may be present in the LRS. It is urgent to
clarify this issue.
• Transmission experiments between sheep of the same and
different genotypes will be very informative. The results of
experimental transmission of atypical scrapie to transgenic
mice expressing the human forms of PrP might indicate its
relative transmissibility to humans and thus inform on the
potential risk to human health of exposure to atypical scrapie.
5. Environmental persistence of TSEs and maternal transmission
The subgroup noted that transmission of classical scrapie can occur in
the absence of lambing and in the absence of direct contact with
infected sheep. Infectivity survives on pasture left fallow for at least 2
months (from ongoing VLA studies) after removal of an infected flock. It
has been speculated that this is a consequence of the widespread
distribution of classical scrapie in the body. This is in contrast to BSE in
cattle which is restricted primarily to neural tissues and does not appear
to be shed into the environment. However, BSE experimentally
introduced into genetically susceptible sheep, like classical scrapie,
appears to have a wide distribution in the body19, and it was recently
19 Bellworthy S.J., Hawkins S.A.C., Green R.B., Blamire I., Dexter G., Dexter I., Lockey R.,
Jeffrey, M., Ryder S., Berthelin-Baker C. and Simmons M.M. (2005) Tissue distribution of
bovine spongiform encephalopathy infectivity in Romney sheep up to the onset of clinical
disease after oral challenge. Vet. Rec. 156, 197-202
Page 10
© SEAC 27 February 2006
demonstrated that a BSE infection can be maintained within a sheep
flock by spreading the disease from infected ewes to their lambs20. The
detailed pathway of the infectious agent from ewe to lamb still needs to
be elucidated.
It is not known how atypical scrapie is transmitted between animals.
The possibility that it has spread through feed cannot be excluded. The
environmental persistence of atypical scrapie is unknown. The fact that
more than one case may be found in a flock may reflect a level of
environmental transmission, or a common alternative route of exposure.
It is clearly important to assess its possible route of transmission if
control measures are to be effective.
snip...
full text 13 pages;
http://www.seac.gov.uk/pdf/positionstatement-sheep-subgroup.pdf
REPORT OF THE COMMITTEE ON SCRAPIE
Chair: Dr. Jim Logan, Cheyenne, WY
Vice Chair: Dr. Joe D. Ross, Sonora, TX
Dr. Deborah L. Brennan, MS; Dr. Beth Carlson, ND; Dr. John R. Clifford, DC; Dr. Thomas F. Conner, OH; Dr. Walter E. Cook, WY; Dr. Wayne E. Cunningham, CO; Dr. Jerry W. Diemer, TX; Dr. Anita J. Edmondson, CA; Dr. Dee Ellis, TX; Dr. Lisa A. Ferguson, MD; Dr. Keith R. Forbes, NY; Dr. R. David Glauer, OH; Dr. James R. Grady, CO; Dr. William L. Hartmann, MN; Dr. Carolyn Inch, CAN; Dr. Susan J. Keller, ND; Dr. Allen M. Knowles, TN; Dr. Thomas F. Linfield, MT; Dr. Michael R. Marshall, UT; Dr. Cheryl A. Miller, In; Dr. Brian V. Noland, CO; Dr. Charles Palmer, CA; Dr. Kristine R. Petrini, MN; Mr. Stan Potratz, IA; Mr. Paul E. Rodgers, CO; Dr. Joan D. Rowe, CA; Dr. Pamela L. Smith, IA; Dr. Diane L. Sutton, MD; Dr. Lynn Anne Tesar, SD; Dr. Delwin D. Wilmot, NE; Dr. Nora E. Wineland, CO; Dr. Cindy B. Wolf, MN.
The Committee met on November 9, 2005, from 8:00am until 11:55am, Hershey Lodge and Convention Center, Hershey, Pennsylvania. The meeting was called to order by Dr. Jim Logan, chair, with vice chairman Dr. Joe D. Ross attending. There were 74 people in attendance.
The Scrapie Program Update was provided by Dr. Diane Sutton, National Scrapie Program Coordinator, United States Department of Agriculture (USDA), Animal and Plant Health Inspection Services (APHIS), Veterinary Services (VS). The complete text of the Status Report is included in these Proceedings.
Dr. Patricia Meinhardt, USDA-APHIS-VS-National Veterinary Services Laboratory (NVSL) gave the Update on Genotyping Labs and Discrepancies in Results. NVSL conducts investigations into discrepancies on genotype testing results associated with the Scrapie Eradication Program. It is the policy of the Program to conduct a second genotype test at a second laboratory on certain individual animals. Occasionally, there are discrepancies in those results. The NVSL conducts follow-up on these situations through additional testing on additional samples from the field and archive samples from the testing laboratories.
For the period of time from January 1, 2005, until October 15, 2005, there were 23 instances of discrepancies in results from 35 flocks. Of those 23 instances, 14 were caused by laboratory error (paperwork or sample mix-up), 3 results from field error, 5 were not completely resolved, and 1 originated from the use of a non-approved laboratory for the first test. As a result of inconsistencies, one laboratory's certification was revoked by APHIS-VS.
snip...
Infected and Source Flocks
As of September 30, 2005, there were 105 scrapie infected and source flocks. There were a total of 165** new infected and source flocks reported for FY 2005. The total infected and source flocks that have been released in FY 2005 was 128. The ratio of infected and source flocks cleaned up or placed on clean up plans vs. new infected and source flocks discovered in FY 2005 was 1.03 : 1*. In addition 622 scrapie cases were confirmed and reported by the National Veterinary Services Laboratories (NVSL) in FY 2005, of which 130 were RSSS cases. Fifteen cases of scrapie in goats have been reported since 1990. The last goat case was reported in May 2005. Approximately 5,626 animals were indemnified comprised of 49% non-registered sheep, 45% registered sheep, 1.4% non-registered goats and 4.6% registered goats.
Regulatory Scrapie Slaughter Surveillance (RSSS)
RSSS was designed to utilize the findings of the Center for Epidemiology and Animal Health (CEAH) Scrapie: Ovine Slaughter Surveillance (SOSS) study. The results of SOSS can be found at http://www.aphis.usda.gov/vs/ceah/cahm/Sheep/sheep.htm . RSSS started April 1,
2003. It is a targeted slaughter surveillance program which is designed to identify infected flocks for clean-up. During FY 2005 collections increased by 32% overall and by 90% for black and mottled faced sheep improving overall program effectiveness and efficiency as demonstrated by the 26% decrease in percent positive black faced sheep compared to FY 2004. Samples have been collected from 62,864 sheep since April 1, 2003, of which results have been reported for 59,105 of which 209 were confirmed positive. During FY 2005, 33,137 samples were collected from 81 plants. There have been 130 NVSL confirmed positive cases (30 collected in FY 2004 and confirmed in FY 2005 and 100 collected and confirmed in FY 2005) in FY 2005. Face colors of these positives were 114 black, 14 mottled, 1 white and 1 unknown. The percent positive by face color is shown in the chart below.
Scrapie Testing
In FY 2005, 35,845 animals have been tested for scrapie: 30,192 RSSS; 4,742 regulatory field cases; 772 regulatory third eyelid biopsies; 10 third eyelid validations; and 129 necropsy validations (chart 9).
Animal ID
As of October 04, 2005, 103,580 sheep and goat premises have been assigned identification numbers in the Scrapie National Generic Database. Official eartags have been issued to 73,807 of these premises.
*This number based on an adjusted 12 month interval to accommodate the 60 day period for setting up flock plans.
http://www.usaha.org/committees/reports/2005/report-scr-2005.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
Transmission of Creutzfeldt-Jakob disease by handling of dura mater.
The Lancet Volume 341(8837) January 9, 1993 pp
123-124
Weber, Thomas; Tumani, Hayrettin; Holdorff, Bernd; Collinge, John; Palmer,
Mark; Kretzschmar, Hans A.; Felgenhauer, Klaus
Sir,- Creutzfeldt-Jakob disease (CJD) can be transmitted iatrogenically by
human pituitary growth hormone, corneal transplants, and dura mater grafts
(1). Possible accidental transmission has been reported in only four
people-a neurosurgeon (2), a pathologist (3), and two laboratory technicians
(4,5) . We have encountered an unusually rapid case of CJD probably acquired
through handling of sheep and human dura mater.
In May, 1992, a 55-year-old orthopaedic surgeon developed paraesthesia of
the left arm. A few days later he had spatial disorientation, apraxia, and
gait ataxia. In June he was admitted and a neurologist suspected CJD on the
basis of the clinical signs, typical electroencephalogram (EEG) pattern, and
history. An EEG in June revealed a typical pattern of periodic biphasic and
triphasic sharp wave complexes. We saw the patient in July, 1992. He was
awake and oriented, with dyscalculia, dysgraphia, disturbed vision, apraxia
mainly of the left side, rigidity of wrists, spasticity of all muscles,
myoclonus of the left arm, increased tendon reflexes, ataxia of limbs and
trunk, and incoordination of left arm. Within 3 weeks he had impaired
consciousness and attention, mildly impaired memory, and threatening visual
hallucinations with restless turning. He had periodic states with movements
of his head and eye-bulbs resembling tonic adversive seizures. During sleep
these motor disturbances stopped. 2 1/2 months later the patient died.
This patient had worked with sheep and human dura mater from 1968 to 1972.
He handled about 150 specimens of ovine origin and at least a dozen human
preparations for research. Handling involved opening skulls with a band saw,
removing dura, and testing them either fresh (usually), preserved, or
lyophilised for mechanical qualities. These specimens were sent to a company
that has sold dura mater preparations by which CJD was transmitted in six
instances. No information was available from the company about a possible
connection with this patient's disease and the earlier cases of transmitted
CJD. Brain biopsy was consistent with diagnosis of CJD. Cerebrospinal fluid
obtained in July showed neuron-specific enolase (NSE) at 82.0 ng/mL,
compared with 16.7 ng/mL in serum of other cases (6). Proton magnetic
resonance spectroscopy of parieto-occipital and temporal grey matter,
parietal white matter, and thalamus revealed a 20-30% reduction of
N-acetylaspartate, as described (7). DNA was genotyped with allele-specific
oligonucleotides (8) and was homozygous for methionine at the polymorphic
codon 129. Subsequent direct DNA sequencing for the PrP gene open-reading
frame demonstrated normal sequence on both alleles, excluding known or novel
pathogenic PrP mutations.
It is tempting to speculate that prions were transmitted to this patient
from sheep or human dura mater through small lacerations of his skin, but
the patient and his wife did not remember any significant injury during his
four years of working with these samples. It cannot be excluded that this
was a case of sporadic CJD although this assumption is unlikely in view of
the clinical course which was similar to iatrogenic CJD transmitted by
peripheral inoculation, such as with human pituitary growth hormone or
gonadotropin or to kuru (1). Iatrogenic cases resulting from intracerebral
inoculation with the transmissible agent, for instance following dura mater
grafts (2-5), present with a dementing picture, as is usual in sporadic CJD,
rather than with ataxia as in this case.
1. Brown P, Preece MA, Will RG. "Friendly fire" in medicine: hormones,
homografts, and Creutzfeldt-Jakob disease. Lancet 1992; 340: 24-27. [Medline
Link] [Context Link]
2. Schoene WC, Masters CL, Gibbs CJ Jr, et al. Transmissible spongiform
encephalopathy (Creutzfeldt-Jakob Disease): atypical clinical and
pathological findings. Arch Neurol 1981; 38: 473-77. [Medline Link] [Context
Link]
3. Gorman DG, Benson DF, Vogel DG, Vinters HV. Creutzfeldt-Jakob disease in
a pathologist. Neurology 1992; 42: 463. [Medline Link] [Context Link]
4. Miller DC. Creutzfeldt-Jakob disease in histopathology technicians. N
Engl J Med 1988; 318: 853-54. [Medline Link] [Context Link]
5. Sitwell L, Lach B, Atack E, Atack D, Izukawa D. Creutzfeldt-Jakob disease
in histopathology technicians. N Engl J Med 1988; 318: 854. [Medline Link]
[Context Link]
6. Wakayama Y, Shibuya S, Kawase J, Sagawa F, Hashizume Y. High
neuron-specific enolase level of cerebrospinal fluid in the early stage of
Creutzfeldt-Jakob disease. Klin Wochenschr 1987; 65: 798-801. [Medline Link]
[Context Link]
7. Bruhn H, Weber T, Thorwirth V, Frahm J. In-vivo monitoring of neuronal
loss in Creutzfeldt-Jakob disease by proton magnetic resonance spectroscopy.
Lancet 1991; 337: 1610-11. [Medline Link] [Context Link]
8. Collinge J, Palmer MS, Dryden AJ. Genetic predisposition to iatrogenic
Creutzfeldt-Jakob disease. Lancet 1991; 337: 1444-42. [Medlin
http://www.mad-cow.org/jul99_late_news.html#ggg
0208h023: UK exports of sheep, goats and sheep/goat meats and meat products (1988 - 2001)
http://www.vegsource.com/articles/sheep_exports.htm
TSS
