Animal health surveillance systems should reflect national disease control
priorities and promote the best use of public resources by maximizing
effectiveness and efficiency. A surveillance system should be routinely
evaluated to assess the degree to which the system accomplishes these goals,
fulfills its stated objectives, and meets accepted surveillance standards.
In the United States, there are a number of disparate endemic disease
surveillance and eradication programs. The National Animal Health
Surveillance System is a federal initiative designed to combine animal
health surveillance and monitoring activities into a comprehensive and
coordinated system. A protocol has been developed to facilitate the
evaluation of animal health surveillance systems and investigate
opportunities for coordination between the different surveillance and
eradication programs. The evaluation protocol was based largely on protocols
developed for public health but adapted for the specific needs and goals of
animal health surveillance. The evaluation process was designed to identify
program strengths and areas for improvement and facilitate the system's
adaptability to changing situations.
The evaluation protocol was applied to the scrapie surveillance system in
the United States; scrapie surveillance was found to be an important part of
surveillance for transmissible spongiform encephalopathies. Results from the
evaluation of sensitivity, sampling methods and representativeness are
Keywords: National Animal Health Surveillance System; Surveillance
evaluation; Scrapie; Animal health surveillance; Program evaluation
Corresponding author. Tel.: +1 970 494 7597; fax: +1 970 494 7174.
FURTHER INTO THIS STUDY ;
2.2. Evaluation of sensitivity
To estimate sensitivity of the scrapie surveillance system, scrapie prevalence estimates,
in total and by face color, were developed for sheep sampled through slaughter surveillance
during fiscal year 2004. These estimates were compared to prevalence estimates from the
2003 study of scrapie prevalence in slaughter animals (NAHMS, 2004). In addition, flocklevel
sensitivity, or the probability of detecting a scrapie-infected flock, was assessed.
Samples collected from individual animals were linked to their flocks of origin by
matching official individual animal identification (eartags) with premises identification.
Animals arriving at markets or slaughter plants without an official eartag are given a serial
number tag; occasionally, individual farms are also provided serial tags. However, these
tags are not always easily traced, and in this analysis, were usually not matched to known
premises. The proportion of animals per flock sampled in each state was calculated, and the
number of newly identified scrapie-positive flocks found through surveillance activities
was compared to the total number of new flocks identified.
Between 1 April 2003 and 31 March 2006, 71% of animals sampled at slaughter were linked
to their flocks of origin by their official identification. The majority of the 29% which were not
linked to premises had serial tags. These flocks represent 17% of U.S. flocks (USDA Agriculture
2002 Census). The proportion of animals in a flock sampled in each state varied from 0% to 55%.
During fiscal year 2005, 165 new scrapie positive flocks were identified. After accounting for multiple
positives and untraceable animals, 92 flocks were identified as a direct result of slaughter sampling. The
other 73 flocks were identified by some other means such as trace-backs from positive flock investigations,
including those identified through slaughter surveillance. These data were used to estimate a flocklevel
sensitivity of 56% across a 3-year period for slaughter testing. Since not all flocks were tested, it is likely
the true sensitivity is lower.
see full text ;
MAY SCRAPIE REPORT 2007 (OHIO still topping the list, what about CJD?)
OHIO has had a serious problem with scrapie for YEARS!
DOES anyone have any ideas as to why, IF TSE occur spontaneously (as some
would wish us to believe),
why they spontaneously happen more often in OHIO than any other state, in
regards to scrapie ???
what is the reason for this phenonimum $
MAY SCRAPIE REPORT 2007 (Nor98 documented in USA for first time)
Subject: NOR98-LIKE STRAIN OF SCRAPIE FOUND IN WYOMING
Date: April 11, 2007 at 12:47 pm PST
March 16, 2007
Wyoming Livestock Board
2020 Carey Avenue 4th Floor
Cheyenne, Wyoming 82002
For more information contact: Dr. Walter Cook at (307) 631-2974 [weekend] or
(307) 777-6443 [weekday]
*****FOR IMMEDIATE RELEASE*****
NOR98-LIKE STRAIN OF SCRAPIE FOUND IN WYOMING
CHEYENNE, Wyo. - On Friday, March 16, 2007, the Wyoming Livestock Board
(WLSB) was notified by officials of the USDA Animal Plant Health Inspection
Service (APHIS) that an adult female sheep had tested positive for a form of
scrapie consistent with the Nor98 strain. The ewe was slaughtered in
Michigan, where it was tested as part of USDA’s regulatory scrapie slaughter
surveillance program and traced back to a flock in Wyoming. The results of
this case are distinctly different from those seen for bovine spongiform
encephalopathy (BSE) or classical scrapie.
Scrapie is a transmissible spongiform encephalopathy and falls into the same
category of diseases as chronic wasting disease, found in deer and elk, and
bovine spongiform encephalopathy, found in cattle. The disease is limited to
sheep and goats and takes years to affect an animal after it has been
infected. Scrapie causes sheep to itch and scratch (scrape) wool off, change
their behavior and lose body condition; it ultimately ends in death.
Nor98-like scrapie differs from classical scrapie in the distribution of
brain lesions and in the course of disease progression and epidemiology.
Some sheep that are genetically resistant to the classic form of the disease
may be susceptible to the Nor98-like strain. Oddly, Nor98-like scrapie is
usually diagnosed during surveillance in animals without clinical signs.
There are no known human health risks associated with either form of
This is the first time a Nor98-like strain of scrapie has been documented in
the United States. It gets the "Nor98-like" name because it is similar to a
case first diagnosed in Norway in 1998. This strain of scrapie is a rare
disease even in Europe. Since 1998, fewer than 300 cases have been diagnosed
in all of Europe. It is usually seen in single animals and does not tend to
become widespread in a flock. In contrast, in flocks infected by classical
scrapie typically more than 10 percent of the genetically susceptible
animals test positive.
"This provides evidence that the surveillance program is working," said
Bryce Reece, executive director of the Wyoming Wool Growers Association. "It
also indicates that the program is on the cutting-edge of science to detect
such a rare disease during standard surveillance."
The Wyoming Livestock Board does not expect the Nor98-like strain of scrapie
to become a major disease problem for the sheep industry in Wyoming. Risk is
limited because diagnosis of Nor98-like scrapie is usually an incidental
event, with even highly-exposed flock mates of the positive animal normally
The infected ewe lambed in it in what is considered a low-risk,
range-lambing environment. Nonetheless, the WLSB, APHIS and the Wyoming Wool
Growers Association plan to assertively pursue this case to make sure that
this strain of scrapie is extinguished and does not establish itself in the
The agencies continue to encourage producers to monitor their sheep for
signs of scrapie and other diseases, and to notify their veterinarian if
they discover anything unusual.
The positive ewe was purchased as an adult within the last several years and
moved to a Wyoming flock near the Black Hills. The producer was notified and
his flock quarantined as a precautionary measure. An epidemiologic
investigation is ongoing and the producer has been cooperative. The case
fits the pattern found in Europe - a single, older sheep that was not
exhibiting clinical signs of scrapie.
The regulatory scrapie slaughter surveillance program is a targeted
slaughter surveillance program for sheep and goats designed to identify
infected animals and flocks. USDA is conducting this surveillance as part of
a program to eradicate scrapie from the United States by the end of 2010.
Reece said that the sheep industry supports this program and is committed to
eliminating scrapie from the United States.
Published online before print October 20, 2005
Proc. Natl. Acad. Sci. USA, 10.1073/pnas.0502296102
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
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: firstname.lastname@example.org
Reference FOIA 07-566
DECLARATION OF EXTRAORDINARY EMERGENCY BECAUSE OF AN ATYPICAL T.S.E.
(PRION DISEASE) OF FOREIGN ORIGIN IN THE UNITED STATES [Docket No. 00-072-1]
July 11, 2007
AGRICULTURAL RESEARCH COUNCIL
REPORT OF THE ADVISORY COMMITTE ON SCRAPIE
CHAIRMAN: PROFESSOR PETER WILDY
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
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
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
Like lambs to the slaughter
31 March 2001
Magazine issue 2284
What if you can catch old-fashioned CJD by eating meat from a sheep infected
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
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.
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)
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.
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.
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@example.com Received June 7, 2000;
revised July 3, 2000; accepted July 5, 2000.
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.
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.
Oral transmission of kuru, Creutzfeldt-Jakob disease, and scrapie to
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.