EFSA Journal 2013;11(2):3119 [46 pp.]. doi:10.2903/j.efsa.2013.3119
European Food Safety AuthorityAcknowledgment Contact
Type: Scientific Report of EFSA On request from: European Free Trade
Association (EFTA) Surveillance Authority Question number: EFSA-Q-2012-00577
Approved: 20 February 2013 Published: 25 February 2013 Affiliation: European
Food Safety Authority (EFSA) Parma Italy
Article(1.7 Mb)
Abstract
This Scientific Report of EFSA provides scientific and technical assistance
to the European Free Trade Association (EFTA) Surveillance Authority in
evaluating i) if the Norwegian continuous use of fishmeal in feed for ruminants
until 30 April 2010 has had an impact on the overall risk of BSE in the country;
and ii) if a proposed Norwegian revised annual monitoring programme for BSE
allows the detection of BSE with a yearly design prevalence of at least one case
per 100,000 in the adult population at a confidence level of 95%. Data related
to the implementation of the Norwegian feed ban were collected and assessed. The
Cattle TSE Monitoring Model (C-TSEMM) was used in order to answer the second
term of reference of the mandate received. It is concluded that the use of
fishmeal in feed for ruminants might have had a potential impact on the risk of
cattle exposure to BSE in Norway. While it is not possible to quantitatively
assess this risk, the lack of detection of BSE cases by the Norwegian monitoring
system (in spite of its sensitivity limits) suggests that BSE has not
significantly spread in the Norwegian cattle population. The proposed revised
Norwegian BSE monitoring regime would not be able to meet a yearly design
prevalence of at least one case per 100,000 in the adult cattle population at a
confidence level of 95%. Moreover, in statistical terms it is not feasible for
Norway to achieve the requested design prevalence. It is furthermore highlighted
that passing from a sample-based to an exhaustive monitoring scheme (i.e.
testing all animals over a certain age that are slaughtered or dead) would
provide the most sensitive BSE surveillance system currently possible.
© European Food Safety Authority, 2013
Summary
Following a request from the European Free Trade Association (EFTA)
Surveillance Authority, the European Food Safety Authority (EFSA) was asked to
provide scientific and technical assistance on a revision of the Norwegian
annual monitoring programme for Bovine Spongiform Encephalopathy (BSE). The
current Norwegian monitoring programme for BSE is based on a specific adaptation
of the Agreement on the European Economic Area (EEA) to Regulation (EC) No
999/2001, allowing Norway to test a random sample of 10,000 healthy slaughtered
cattle over 30 months of age per year. The Norwegian legislation is currently in
line with the European Union’s (EU)5 one as regards to the feedban. However, the
use of fishmeal for ruminants was legally allowed in Norway until 30 April 2010.
Within this context, and taking into consideration the animal age limits set in
Commission Decision 2009/719/EC (72 and 48 months of age, respectively, for
healthy slaughtered and at risk animals), Norway requested to the EFTA
Surveillance Authority the agreement for a revised annual monitoring programme
for BSE prescribing i) the testing of a random sample of 2,000 healthy
slaughtered cattle over 72 months of age per year, ii) the testing of all
at-risk cattle above 48 months of age and iii) the mandatory notification and
examination of any animal clinically suspected of being infected by a TSE. EFTA
Surveillance Authority asked EFSA: i) to undertake an assessment of whether
Norway’s continuous use of fishmeal in feed for ruminants until 30 April 2010
has had an impact on the overall risk of BSE in the country; and ii) to evaluate
whether the design of the proposed annual regime of 2,000 randomly selected
samples in the subpopulation of healthy slaughtered animals over 72 months of
age allows the detection of BSE with a yearly design prevalence of at least one
case per 100,000 in the adult population at a confidence level of 95% in Norway.
In case Norway’s proposed regime would fail meeting this criterion, EFSA was
requested to propose a minimum annual sample size in the subpopulation of
healthy slaughtered animals over 72 months of age allowing to reach the proposed
criterion. Data related to the implementation of the Norwegian feed ban were
collected and assessed. In Norway the only way by which fishmeal could have
represented a risk for BSE infection in ruminants was due to the potential
cross-contamination with infected Meat and Bone Meal (MBM). The monitoring of
ruminant feed and fishmeal for the presence of MBM in Norway did not give rise
to positive results. However, considering the number of tests and the total
amount of terrestrial animal feed and fishmeal produced and used in Norway the
significance of these results is probably limited. Moreover, according to the
reports of the missions carried out by the EFTA Surveillance Authority in Norway
there were insufficient measures in place to prevent the potential for
cross-contamination of fishmeal with MBM. The results of the BSE monitoring
system carried out during the period 2001 – 2011 were considered. Overall
200,165 BSE screening tests were performed in Norway with no positive results.
The lack of detection of BSE cases by the Norwegian monitoring system (in spite
of its sensitivity limits) suggests that BSE has not significantly spread in the
Norwegian cattle population. It was then concluded that the use of fishmeal in
feed for ruminants might have had a potential impact on the risk of cattle
exposure to BSE in Norway. However, the lack of detection of BSE cases by the
Norwegian monitoring system suggests that BSE has not significantly spread in
the Norwegian cattle population. The Cattle TSE Monitoring Model (C-TSEMM) was
used in order to answer the second term of reference of the mandate. According
to C-TSEMM the proposed revised Norwegian BSE monitoring regime would not be
able to meet a yearly design prevalence of at least one case per 100,000 in the
adult cattle population at a confidence level of 95% in Norway. Moreover, the
results of the model indicate that in statistical terms it is not feasible for
Norway to achieve the proposed design prevalence. The results of C-TSEMM have to
be interpreted in the light of its assumptions, uncertainties and limitations.
However, they can be considered to be an overestimation of what is achievable by
the Norwegian regimes considered. It is furthermore highlighted that passing
from a sample-based to an exhaustive monitoring scheme (i.e. testing all animals
over a certain age that are slaughtered or dead) would provide the most
sensitive BSE surveillance system currently possible.
snip...
CONCLUSIONS
The use of fishmeal in feed for ruminants might have had a potential impact
on the risk of cattle exposure to BSE in Norway. While it is not possible to
quantitatively assess this risk, the lack of detection of BSE cases by the
Norwegian monitoring system (in spite of its sensitivity limits) suggests that
BSE has not significantly spread in the Norwegian cattle population. According
to the model applied (C-TSEMM): – the proposed revised Norwegian BSE monitoring
regime would not be able to meet a yearly design prevalence of at least one case
per 100,000 in the adult cattle population at a confidence level of 95% in
Norway; and – even in a scenario in which all healthy slaughtered and all at
risk cattle above 72 and 48 months respectively would be tested for BSE, in
statistical terms it is not feasible to achieve the design prevalence of one
case per 100,000 in the adult cattle population at a confidence level of 95% in
Norway. The results of C-TSEMM have to be interpreted in the light of its
assumptions, uncertainties and limitations. However, they can be considered to
be an overestimation of what is achievable by the Norwegian regimes considered.
Passing from a sample-based to an exhaustive monitoring scheme (i.e. testing all
animals over a certain age that are slaughtered or dead) would provide the most
sensitive BSE surveillance system currently possible.
Keywords
BSE, Norway, monitoring, revision, design prevalence
2004
Scientific Report of the European Food Safety Authority on the Assessment
of the Geographical BSE Risk (GBR) of Norway
doi:10.2903/j.efsa.2004.8r
European Food Safety Authority
Type: Scientific Report of EFSA Question number: EFSA-Q-2003-083F Approved:
01 July 2004 Published: 20 August 2004 Last updated: 08 September 2004. This
version replaces the previous one/s.
Summary
The European Food Safety Authority and its Scientific Expert Working Group
on the Assessment of the Geographical Bovine Spongiform Encephalopathy ( BSE)
Risk (GBR) were asked by the European Commission (EC) to provide an up-to-date
scientific report on the GBR in Norway, i.e. the likelihood of the presence of
one or more cattle being infected with BSE, pre-clinically as well as
clinically, in Norway. This scientific report addresses the GBR of Norway as
assessed in 2004 based on data covering the period 1980-2003.
Between 1980 and 1990, an extremely unstable system was exposed to a
negligible/very low challenge. Between 1991 and 1999, the stability of the
system increased to very unstable and then to unstable in 2000, while the
challenge increased to moderate and subsequently decreased to negligible in
1996. Under such low/intermediate levels of risk (as judged by
challenge/stability alone), the fact that no BSE case was detected by the very
extensive surveillance carried out in Norway since 2001, makes the possibility
that BSE-infectivity could have been recycled and amplified unlikely although it
cannot be excluded.
EFSA concludes that the current geographical BSE-risk (GBR) level is II, as
it is unlikely but can not be excluded that domestic cattle are (clinically or
pre-clinically) infected with the BSE-agent. The Norwegian BSE/cattle system is
now regarded to be very stable. This implies that the probability of cattle to
become newly infected with the BSE-agent is very low. Assuming that measures in
place continue to be appropriately implemented the GBR will decrease over time
at the rate at which already infected animals leave the system. If the measures
in place are effectively implemented, the import of live animals cannot increase
the risk because the infectivity that could theoretically be harbored by them
would not reach domestic cattle.
Since recent improvements in the safety of Meat and Bone Meal (MBM)
production in many countries or significant recent reductions in the incidence
of BSE have not been taken into account for the assessment of the external
challenge in the present report, the external challenge assessed after 2001
could be overestimated and is the worst case assumption. However, all current
GBR conclusions are not dependent on these assumptions in any of the countries
assessed. For future assessments and when the impact of the production,
surveillance and true incidence changes has been fully quantified, these
developments should be taken into account. Keywords
Scientific Report of the European Food Safety Authority on the Assessment
of the Geographical BSE Risk (GBR) of Norway
snip...
5. CONCLUSION ON THE GEOGRAPHICAL BSE-RISK
5.1 The current GBR as function of the past stability and challenge
• The current geographical BSE-risk (GBR) level is II, i.e. it is unlikely
but can not be excluded that domestic cattle are (clinically or pre-clinically)
infected with the BSE-agent.
• This assessment deviates from the previous assessment (SSC opinion, 2000)
because at that time several exporting countries were not considered a potential
risk.
5.2 The expected development of the GBR as a function of the past and
present stability and challenge
• The Norway BSE/cattle system is now regarded to be very stable. This
implies that the probability of cattle to become newly infected with the
BSE-agent is very low. Assuming that measures in place continue to be
appropriately implemented the GBR will decrease over time at the rate at which
already infected animals leave the system.
• If the measures in place are effectively implemented, the import of live
animals cannot increase the risk because the infectivity that could
theoretically be harboured by them would not reach domestic cattle.
• Since recent improvements in the safety of MBM production in many
countries or significant recent reductions in the incidence of BSE have not been
taken into account for the assessment of the external challenge in the present
report, the external challenge assessed after 2001 could be overestimated and is
the worst case assumption. However, all current GBR conclusions are not
dependent on these assumptions in any of the countries assessed. For future
assessments and when the impact of the production, surveillance and true
incidence changes has been fully quantified, these developments should be taken
into account.
2000
Report on the assessment of the Geographical BSE-risk of NORWAY July 2000
OVERALL ASSESSMENT The current geographical BSE-risk (GBR) of Norway is
level I, i.e. it is highly unlikely that domestic cattle are infected
(clinically or pre-clinically) with the BSE agent.
Note: This assessment leading to GBR level I is mainly based on the fact
that Norway was not exposed to significant external challenges before 1995 when
the system became stable.
Should this be proven wrong, a GBR level II would have to be assumed.
Annual Reports 2011
The surveillance and control programme for scrapie in Norway 2011
Sviland Ståle, Benestad Lafond Sylvie, Eikenæs Olav, Norström Madelaine
In 2011, Nor98 scrapie was diagnosed in 6 sheep coming from 6 different
flocks.
Introduction
Scrapie was first diagnosed in indigenous Norwegian sheep in 1981.
Increasing numbers of scrapieinfected flocks were identified in the 1990s,
culminating with 31 detected flocks in 1996 (Figure 1). By the end of 2009,
scrapie had been diagnosed in a total of 148 sheep flocks and one goat herd (1).
Scrapie has been a notifiable disease in Norway since 1965, and control measures
have involved destruction of all sheep in affected flocks and in close contact
flocks until 2004. The Norwegian scrapie surveillance and control programme was
launched in 1997 (2). In 1998 a new type of scrapie, Nor98 scrapie, was
identified in Norway. The diagnosis of Nor98 scrapie is verified by Western
blot. Nor98 scrapie differs from classical scrapie in several aspects, including
the Western blot profile, the distribution of protease resistant prion protein
(PrPSc) in the brain, and absence of detectable PrPSc in lymphoid tissues (3).
The main clinical sign observed in Nor98 scrapie cases has been ataxia. The PrP
genotype distribution among Nor98 scrapie cases differs markedly from that of
the previous cases with classical scrapie (4). The Norwegian Food Safety
Authority is responsible for carrying out the surveillance and control programme
for scrapie. The samples are collected at the abattoirs or in the herds by
inspectors from the Norwegian Food Safety Authority. The Norwegian Food Safety
Authority also carries out inspections of sheep flocks and goat herds, all of
which should be inspected every second or third year. The Norwegian Veterinary
Institute is performing the laboratory examinations and the reporting of the
results.
Materials and methods
In 2011, the surveillance programme was performed according to the European
Union Regulations,
Regulation (EC) No. 999/2001 Annex III, with amendments and included
examination of the following categories of small ruminants:
* all small ruminants with clinical signs consistent with scrapie,
irrespective of age
* 10,000 sheep older than 18 months, which had died or been killed on the
farm, but not
slaughtered for human consumption (fallen stock)
* 10,000 randomly sampled healthy sheep older than 18 months slaughtered
for human consumption
* 500 goats older than 18 months which had died or been killed on the farm,
but not slaughtered for
human consumption (fallen stock)
snip...
Prevalence
The classical scrapie and Nor98 scrapie prevalences in the fallen stock and
abattoir populations were estimated assuming an exact binominal
distribution.
Results
Sheep
Nor98 scrapie was diagnosed in 6 sheep from 6 flocks. One Nor98 scrapie
case was identified in fallen stock, five cases were apparently healthy animals
slaughtered for human consumption (Table 1).
The individual age and breed were registered, and the prion protein
genotype examined for all six scrapie cases (Table 2). Four sheep had PrP
genotypes with at least one allele with polymorphisms at codon 141 (AF141RQ) or
154 (AHQ), whereas two sheep had the PrP genotype ARR/ARR.
In total, 13,486 samples from sheep were received. Of these, 13 (0.09%)
samples were unsuitable for examination. The numbers of animals examined within
each category are presented in Table 1. The prevalence of Nor98 scrapie in the
fallen stock of sheep was estimated to 0.02% (0.0-0.12%), (95% confidence
interval [CI]) (Figure 2), and the prevalence of Nor98 scrapie in sheep
slaughtered for human consumption was estimated to 0.06% (0.0-0.13%), (95% CI)
(Figure 3).
For 135 (1.0%) samples (111 healthy slaughtered, 22fallen stock and one
from the ante mortem control), the flock of origin was not reported. In the
event of a positive sample from slaughtered animals, the flock identity could be
traced using the carcass number. The remaining 13,352 samples were collected
from carcasses originating in 5,596 different sheep flocks. The mean number of
animals tested per flock was 2.3 (range 1-29), flocks eradicated due to scrapie
are excluded. From 1,746 flocks more than two samples were tested. The samples
were obtained throughout the year, with approximately 26% of the samples
collected in September and October, which is the main slaughtering season for
sheep in Norway.
PrP genotyping was performed on 639 sheep randomly sampled from the healthy
slaughtered population examined in Harstad. The PrP genotypes are grouped in
accordance with the British National Scrapie Plan (NSP) (Table 3).
Goat
Scrapie was not detected in any goat in 2011.
In total, 390 samples from goats were received. In six of these the flock
of origin was not reported. None of these were unsuitable for examination. The
numbers of animals examined within each category are presented in Table 1.
The samples were collected from carcasses originating from 168 different
herds. The mean number of animals tested per herd was two (range 1-13). From 51
herds more than two samples were tested.
snip...
Scrapie was not detected in goats in 2011. The first and only scrapie case
in naturally infected goats in Norway was diagnosed in 2006 and originated from
a county with a large goat population. Both classical and atypical scrapie in
goats has been diagnosed in several countries in Europe (5).
snip...
end...
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May 15, 2012 – E-mail: postmottak@vetinst.no www.vetinst.no. ISSN 1890-9973. Title: The surveillance and control programme for scrapie in Norway 2011 ...
May 15, 2012 – E-mail: postmottak@vetinst.no www.vetinst.no. ISSN 1890-9973. Title: The surveillance and control programme for scrapie in Norway 2011 ...
Atypical scrapie in a swiss goat and implications for transmissible
spongiform encephalopathy surveillance
Seuberlich T, Botteron C, Benestad SL, Brunisholz H, Wyss R, Kihm U,
Schwermer H, Friess M, Nicolier A, Heim D, Zurbriggen A. Atypical scrapie in a
swiss goat and implications for transmissible spongiform encephalopathy
surveillance. J Vet Diagn Invest 2007; 19: 2-8.
Different types of transmissible spongiform encephalopathies (TSEs) affect
sheep and goats. In addition to the classical form of scrapie, both species are
susceptible to experimental infections with the bovine spongiform encephalopathy
(BSE) agent, and in recent years atypical scrapie cases have been reported in
sheep from different European countries. Atypical scrapie in sheep is
characterized by distinct histopathologic lesions and molecular characteristics
of the abnormal scrapie prion protein (PrPsc). Characteristics of atypical
scrapie have not yet been described in detail in goats. A goat presenting
features of atypical scrapie was identified in Switzerland. Although there was
no difference between the molecular characteristics of PrPsc in this animal and
those of atypical scrapie in sheep, differences in the distribution of
histopathologic lesions and PrPsc deposition were observed. In particular the
cerebellar cortex, a major site of PrPsc deposition in atypical scrapie in
sheep, was found to be virtually unaffected in this goat. In contrast, severe
lesions and PrPsc deposition were detected in more rostral brain structures,
such as thalamus and midbrain. Two TSE screening tests and PrPsc
immunohistochemistry were either negative or barely positive when applied to
cerebellum and obex tissues, the target samples for TSE surveillance in sheep
and goats. These findings suggest that such cases may have been missed in the
past and could be overlooked in the future if sampling and testing procedures
are not adapted. The epidemiological and veterinary public health implications
of these atypical cases, however, are not yet known.
The surveillance and control programme for Chronic Wasting Disease (CWD) in
wild and captive cervids in Norway
21.09.2009 11:12
Introduction
Chronic wasting disease (CWD) was not detected in any of the animals tested
in 2008.
CWD is a transmissible spongiform encephalopathy (TSE) of cervids (1, 2,
3). A few species of the family Cervidae are known to be naturally susceptible
to the disease: mule deer (Odocoileus hemionus), white-tailed deer (O.
virginianus), elk (Cervus elaphus), and moose (Alces alces). CWD was first
described as a clinical syndrome termed “chronic wasting disease” in captive
mule deer in Colorado, USA in the late 1960s and subsequently identified as a
TSE in 1978 (1). Chronic wasting disease is so far only diagnosed in
free-ranging and captive cervids in North America, and is yet to be diagnosed in
cervids in Europe.
Four cervid species are prevalent in natural populations in Norway: moose
(Alces alces), red deer (Cervus elaphus), roe deer (Capreolus capreolus), and
reindeer (Rangifer tarandus). Red deer predominate along the west coast, whereas
moose and roe deer mainly inhabit other areas of the country. The wild reindeer
live in dispersed populations in separate high mountain areas in southern
Norway. The number officially hunted in 2008 was: 35,600 moose, 35,700 red deer,
29,800 roe deer, and 5,200 wild reindeer. Additionally, Norway has a
semi-domestic reindeer population, mainly kept in the northern parts of the
country, presently counting about 200,000 animals.
There are 75 cervid farms in Norway. Most of the farms keep red deer, and
only a few keep fallow deer (Dama dama).
Based on the fact that Norway has large free-ranging populations of various
cervids, a number of them grazing in regions where scrapie is detected, a
passive surveillance programme for CWD in Norwegian wild and captive cervids has
been running from 2003. In addition, samples from slaughtered semi-domestic
reindeer from several regions in the country have been tested for CWD.
Norway performed an EC survey for CWD in cervids in 2006 and 2007 according
to Commission decision 2007/182/EC. The target species relevant for Norway was
wild red deer and the survey implied sampling of a) clinical/sick, euthanized
animals, b) traffic killed animals, c) animals found dead, and d) healthy
animals shot during hunting. Additionally, for moose, roe deer, reindeer, and
farmed deer the categories a) – c) were sampled. All samples were negative for
CW
A small population of approximately 200 free-ranging musk ox (Ovibus
moschatus, belonging to the Bovidae), inhabits the Dovre high mountain plateau
in Mid-Norway. TSE has not been diagnosed in the musk ox, but the species has
been included in the programme from 2004.
Aim
The aim of the programme is to detect the possible occurrence of CWD in the
Norwegian cervid population.
Material and methods
Material
Tested animals included captive deer and wild cervids older than 18 months
that died or were euthanized due to disease or injuries. Additionally, cervids
older than 18 months necropsied at the National Veterinary Institute were
examined for CWD. Twelve ordinary hunted roe deer from Vestby in the county of
Akershus and one musk ox found dead were also tested. The number and species
analysed for CWD in 2008 are given in Table 1.
Methods
A rapid test (either TeSeE ® Bio-Rad or TeSeE Sheep & Goat ® ELISA,
Bio-Rad) was used to screen brain samples for detection of the PrPCWD. All the
samples were analysed at the National Veterinary Institute, which is the
National Reference Laboratory for TSEs in Norway.
Results
None of the 47 samples analysed tested positive for CWD in the rapid test
(Table 1).
Totally 25 of the tested animals were exclusively examined for CWD, and the
majority was healthy hunted and traffic killed roe deer (Table 1). The remaining
22 animals represent cases received at the National Veterinary Institute for
routine necropsy.
A total of two of the tested animals were captive red deer. One
semi-domestic reindeer was sampled because of showing clinical signs before it
dropped dead.
Table 1. The number of cervids tested in the Norwegian surveillance and
control programme for Chronic wasting disease (CWD) 2008, distributed by reason
for submission.
snip...
Discussion
No animals were positive for CWD in 2008. A large part of the tested
animals in 2008 was roe deer collected in Vestby, comprising hunted and traffic
killed animals. Very few captive red deer were tested.
Among the Norwegian cervid species, a higher risk for CWD can be assumed
for red deer and moose since these species are among those known to be naturally
susceptible to the disease (1, 2, 3). Regarding moose, so far, only a few
positive CWD cases has been diagnosed in hunted animals in CWD-endemic areas in
Colorado, USA (3), thus they probably represent preclinical CWD. Also, the
disease has been transmitted experimentally to moose by oral inoculation of
brain tissue from a CWD affected mule deer (4). Roe deer, reindeer and musk ox
has so far not been found naturally infected with CWD.
Monday, June 18, 2012
natural cases of CWD in eight Sika deer (Cervus nippon) and five Sika/red deer crossbreeds captive Korea and Experimental oral transmission to red deer (Cervus elaphus elaphus)
Friday, February 11, 2011
Atypical/Nor98 Scrapie Infectivity in Sheep Peripheral Tissues
Abstract
Atypical/Nor98 scrapie was first identified in 1998 in Norway. It is now
considered as a worldwide disease of small ruminants and currently represents a
significant part of the detected transmissible spongiform encephalopathies (TSE)
cases in Europe. Atypical/Nor98 scrapie cases were reported in ARR/ARR sheep,
which are highly resistant to BSE and other small ruminants TSE agents. The
biology and pathogenesis of the Atypical/Nor98 scrapie agent in its natural host
is still poorly understood. However, based on the absence of detectable abnormal
PrP in peripheral tissues of affected individuals, human and animal exposure
risk to this specific TSE agent has been considered low. In this study we
demonstrate that infectivity can accumulate, even if no abnormal PrP is
detectable, in lymphoid tissues, nerves, and muscles from natural and/or
experimental Atypical/Nor98 scrapie cases. Evidence is provided that, in
comparison to other TSE agents, samples containing Atypical/Nor98 scrapie
infectivity could remain PrPSc negative. This feature will impact detection of
Atypical/Nor98 scrapie cases in the field, and highlights the need to review
current evaluations of the disease prevalence and potential transmissibility.
Finally, an estimate is made of the infectivity loads accumulating in peripheral
tissues in both Atypical/Nor98 and classical scrapie cases that currently enter
the food chain. The results obtained indicate that dietary exposure risk to
small ruminants TSE agents may be higher than commonly believed.
snip...
In 1998 an Atypical/Nor98 Scrapie was identified in Norwegian sheep; the
PrPSc signature was partially PK resistant and displayed a multi-band pattern as
showed by Western Blot (WB) that contrasted with those normally observed in
small ruminants TSE cases [5]. After 2001 and the implementation of active TSE
surveillance plans, a number of similar cases were identified in most EU members
states as well in other countries, like Canada, USA and New Zealand [6]. The
transmissibility of Atypical/Nor98 agent has been demonstrated in both rodent
models (transgenic animals expressing the ovine Prnp gene) [7] and sheep [8],
[9]. Currently Atypical/Nor98 Scrapie represents a significant part of the TSE
cases identified in the EU small ruminant population, where its prevalence was
estimated to range between 5 to 8 positive small ruminants per 10,000 tested per
year [10].
snip...
Atypical/Nor98 cases are identified in older animals in comparison to
classical scrapie [6], [40]. The lack of PrPSc detection in peripheral tissues
of reported cases suggested that Atypical/Nor98 scrapie agent could be
restricted to CNS. This is supportive of the hypothesis that Atypical/Nor98
scrapie could be a spontaneous disorder of PrP folding and metabolism occurring
in aged animals without external cause [6], [38].
However, this hypothesis is questioned by the evidence reported here that a
negative PrPSc testing result could be observed in animals harbouring high
infectious titre in their brain and that the infectious agent can be present in
peripheral tissues of Atypical/Nor98 scrapie incubating sheep. TSE are
considered to be transmitted following oral exposure; initial uptake is followed
by a peripheral replication phase which is generally associated with a
dissemination of the agent in the lymphoid system and the deposition of large
amounts of PrPSc. This peripheral replication phase is later followed by the
entry of the infectious agent into the CNS through the autonomic nervous system
[25], [27], [35], [36]. However, in several situations, like BSE in cattle [41],
[42], [43] or classical scrapie in ARR heterozygote sheep [44], [45], the
involvement of secondary lymphoid system is marginal, which does not preclude
central neuro-invasion through the autonomic nervous system [46]. It could be
proposed that Atypical Scrapie/Nor98 might occur following oral exposure to a
TSE agent, which would spread marginally in lymphoid tissues before
neuro-invasion. The slow propagation of Atypical Scrapie/Nor98 in its host (long
incubation period) and the impaired detection sensitivity level of PrPSc based
assays would explain the apparent old age of detected cases.
The results presented here are insufficient to rule out the hypothesis of a
spontaneous/non contagious disorder or to consider this alternative scenario as
a plausible hypothesis. Indeed, the presence of Atypical scrapie/Nor98
infectivity in peripheral tissues could be alternatively due to the centripetal
spreading of the agent from the CNS. However, our findings point out that
further clarifications on Atypical/Nor98 scrapie agent biology are needed before
accepting that this TSE is a spontaneous and non contagious disorder of small
ruminants. Assessing Atypical/Nor98 scrapie transmissibility through oral route
in natural host and presence in placenta and in colostrum/milk (which are
considered as major sources for TSE transmission between small ruminants) [28],
[32] will provide crucial data.
The presence of infectivity in peripheral tissues that enter the food chain
clearly indicates that the risk of dietary exposure to Atypical/Nor98 scrapie
cannot be disregarded. However, according to our observations, in comparison to
the brain, the infectious titres in the peripheral tissues were five log10 lower
in Atypical/Nor98 scrapie than in classical scrapie. Therefore, the reduction of
the relative exposure risk following SRM removal (CNS, head, spleen and ileum)
is probably significantly higher in Atypical/Nor98 scrapie cases than in
classical scrapie cases. However, considering the currently estimated prevalence
of Atypical/Nor98 scrapie in healthy slaughtered EU population [10], it is
probable that atypical scrapie infectivity enters in the food chain despite the
prevention measures in force.
Finally, the capacity of Atypical/Nor98 scrapie agent (and more generally
of small ruminants TSE agents) to cross species barrier that naturally limits
the transmission risk is insufficiently documented. Recently, the transmission
of an Atypical/Nor98 scrapie isolate was reported into transgenic mice
over-expressing the porcine PrP [47]. Such results cannot directly be
extrapolated to natural exposure conditions and natural hosts. However, they
underline the urgent need for further investigations on the potential capacity
of Atypical/Nor98 scrapie to propagate in other species than small
ruminants.
please see more transmissions studies here ;
Friday, February 11, 2011
Atypical/Nor98 Scrapie Infectivity in Sheep Peripheral Tissues
Monday, April 25, 2011
Experimental Oral Transmission of Atypical Scrapie to Sheep
Volume 17, Number 5-May 2011
Tuesday, July 17, 2012
O.I.E. BSE, CWD, SCRAPIE, TSE PRION DISEASE Final Report of the 80th
General Session, 20 - 25 May 2012
Thursday, December 20, 2012
OIE GROUP RECOMMENDS THAT SCRAPE PRION DISEASE BE DELISTED AND SAME OLD BSe
WITH BOVINE MAD COW DISEASE
***The pathology features of Nor98 in the cerebellum of the affected sheep
showed similarities with those of sporadic Creutzfeldt-Jakob disease in
humans.
*** Intriguingly, these conclusions suggest that some pathological features
of Nor98 are reminiscent of Gerstmann-Sträussler-Scheinker disease.
119
*** 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.
Furthermore, after adaptation in the porcine mouse model this prion showed
similar biological and biochemical characteristics than BSE adapted to this
porcine mouse model. Altogether these data indicate.
(i) the unsuspected potential abilities of atypical scrapie to cross
species barriers
(ii) the possible capacity of this agent to acquire new characteristics
when crossing species barrier
These findings raise some interrogation on the concept of TSE strain and on
the origin of the diversity of the TSE agents and could have consequences on
field TSE control measures.
Wednesday, January 18, 2012
Selection of Distinct Strain Phenotypes in Mice Infected by Ovine Natural
Scrapie Isolates Similar to CH1641 Experimental Scrapie
Journal of Neuropathology & Experimental Neurology:
February 2012 - Volume 71 - Issue 2 - p 140–147
Thursday, March 29, 2012
atypical Nor-98 Scrapie has spread from coast to coast in the USA 2012
NIAA Annual Conference April 11-14, 2011San Antonio, Texas
Monday, November 30, 2009
USDA AND OIE COLLABORATE TO EXCLUDE ATYPICAL SCRAPIE NOR-98 ANIMAL HEALTH
CODE
Thursday, December 20, 2012
OIE GROUP RECOMMENDS THAT SCRAPE PRION DISEASE BE DELISTED
why do we not want to do TSE transmission studies on chimpanzees $
5. A positive result from a chimpanzee challenged severly would likely
create alarm in some circles even if the result could not be interpreted for
man. I have a view that all these agents could be transmitted provided a large
enough dose by appropriate routes was given and the animals kept long enough.
Until the mechanisms of the species barrier are more clearly understood it might
be best to retain that hypothesis.
snip...
R. BRADLEY
Wednesday, February 16, 2011
IN CONFIDENCE
SCRAPIE TRANSMISSION TO CHIMPANZEES
IN CONFIDENCE
Sunday, December 12, 2010
EFSA reviews BSE/TSE infectivity in small ruminant tissues News Story 2
December 2010
Sunday, April 18, 2010
SCRAPIE AND ATYPICAL SCRAPIE TRANSMISSION STUDIES A REVIEW 2010
Thursday, December 23, 2010
Molecular Typing of Protease-Resistant Prion Protein in Transmissible
Spongiform Encephalopathies of Small Ruminants, France, 2002-2009
Volume 17, Number 1 January 2011
Thursday, November 18, 2010
Increased susceptibility of human-PrP transgenic mice to bovine spongiform
encephalopathy following passage in sheep
Michigan and California have had a high spike in Goat Scrapie cases,
compared to elsewhere ???
three is a serious problem with scrapie in goats around Michigan, Ohio, and
California, that no one can explain, and it’s not because I have not tried to
make them aware of it ;
----- Original Message -----
From: "BioMed Central Comments"
To:
Sent: Wednesday, February 16, 2011 4:13 AM
Subject: Your comment on BMC Veterinary Research 2011, 7:7
Your discussion posting "Scrapie cases Goats from same herd USA Michigan"
has been rejected by the moderator as not being appropriate for inclusion on the
site.
Dear Mr Singeltary,
Thank you for submitting your comment on BMC Veterinary Research article
(2011, 7:7). We have read your comment with interest but we feel that only the
authors of the article can answer your question about further investigation of
the route of infection of the five goats in Michigan. We advise that you contact
the authors directly rather than post a comment on the article.
With best wishes,
Maria
Maria Kowalczuk, PhD Deputy Biology Editor BMC-series Journals
BioMed Central 236 Gray's Inn Road London, WC1X 8HB
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comments@biomedcentral.com
Regards
BMC Veterinary Research
=========END...TSS=========
Tuesday, February 01, 2011
Sparse PrP-Sc accumulation in the placentas of goats with naturally
acquired scrapie
(Figure 6) including five goat cases in FY 2008 that originated from the
same herd in Michigan. This is highly unusual for goats, and I strenuously urge
that there should be an independent investigation into finding the common
denominator for these 5 goats in the same herd in Michigan with Scrapie. ...
Wednesday, February 20, 2013
World Organization for Animal Health Recommends United States' BSE Risk
Status Be Upgraded
Statement from Agriculture Secretary Tom Vilsack:
Thursday, February 14, 2013
The Many Faces of Mad Cow Disease Bovine Spongiform Encephalopathy BSE and
TSE prion disease
Friday, February 08, 2013
*** Behavior of Prions in the Environment: Implications for Prion Biology
Friday, November 09, 2012
*** Chronic Wasting Disease CWD in cervidae and transmission to other
species
Sunday, November 11, 2012
*** Susceptibilities of Nonhuman Primates to Chronic Wasting Disease
November 2012
Friday, December 14, 2012
Susceptibility Chronic Wasting Disease (CWD) in wild cervids to Humans 2005
- December 14, 2012
>>>There are 75 cervid farms in Norway. Most of the farms keep red deer, and only a few keep fallow deer (Dama dama).<<<<
Tuesday, December 18, 2012
*** A Growing Threat How deer breeding could put public trust wildlife at
risk
NORWAY HUMAN TSE PRION DISEASE
EUROCJD Surveillance Data
Total Cases of CJD/GSS (Deaths)
All Definite And Probable Cases:
Sporadic, Familial/Genetic, FFI, GSS and Iatrogenic Deaths (excluding vCJD)
Country 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005
2006 2007 2008 2009 2010 2011 Total
Norway - - - - 6 2 2 4 6 3 6 8 4 4 5 3 5 2 4 64
All CJD (excluding vCJD): Annual Mortality Rates Per Million
Norway - - - - 1.37 0.45 0.45 0.89 1.33 0.66 1.32 1.75 0.87 0.86 1.07 0.63
1.04 0.41 0.81 0.92
Creutzfeldt-Jacob disease
Incidence / incidence rate 2006
4 / 0.9 per 1 million population
All four cases of Creutzfeldt-Jacob disease (CJD) reported in 2006 were
classified as sporadic CJD following autopsies.
Trends
Suspected and confirmed cases of human transmissible spongiform
encephalopathies were made notifiable conditions in 1997.
All cases of CJD registered in Norway so far have been sporadic CJD
confirmed by autopsy. One of the cases is suspected to be a hereditary case.
Cases of iatrogenic or variant CJD have never been registered in Norway. BSE has
never been identified in Norwegian cattle.
Table 35. Creutzfeldt-Jakob disease notifications in Norway 2000-2006 by
year of death.
2000 2001 2002 2003 2004 2005 2006
3 5 3 5 7 4 4
*** The discovery of previously unrecognized prion diseases in both humans
and animals (i.e., Nor98 in small ruminants) demonstrates that the range of
prion diseases might be wider than expected and raises crucial questions about
the epidemiology and strain properties of these new forms. We are investigating
this latter issue by molecular and biological comparison of VPSPr, GSS and
Nor98.
VARIABLY PROTEASE-SENSITVE PRIONOPATHY IS TRANSMISSIBLE ...price of prion
poker goes up again $
OR-10: Variably protease-sensitive prionopathy is transmissible in bank
voles
Romolo Nonno,1 Michele Di Bari,1 Laura Pirisinu,1 Claudia D’Agostino,1
Stefano Marcon,1 Geraldina Riccardi,1 Gabriele Vaccari,1 Piero Parchi,2 Wenquan
Zou,3 Pierluigi Gambetti,3 Umberto Agrimi1 1Istituto Superiore di Sanità; Rome,
Italy; 2Dipartimento di Scienze Neurologiche, Università di Bologna; Bologna,
Italy; 3Case Western Reserve University; Cleveland, OH USA
Background. Variably protease-sensitive prionopathy (VPSPr) is a recently
described “sporadic”neurodegenerative disease involving prion protein
aggregation, which has clinical similarities with non-Alzheimer dementias, such
as fronto-temporal dementia. Currently, 30 cases of VPSPr have been reported in
Europe and USA, of which 19 cases were homozygous for valine at codon 129 of the
prion protein (VV), 8 were MV and 3 were MM. A distinctive feature of VPSPr is
the electrophoretic pattern of PrPSc after digestion with proteinase K (PK).
After PK-treatment, PrP from VPSPr forms a ladder-like electrophoretic pattern
similar to that described in GSS cases. The clinical and pathological features
of VPSPr raised the question of the correct classification of VPSPr among prion
diseases or other forms of neurodegenerative disorders. Here we report
preliminary data on the transmissibility and pathological features of VPSPr
cases in bank voles.
Materials and Methods. Seven VPSPr cases were inoculated in two genetic
lines of bank voles, carrying either methionine or isoleucine at codon 109 of
the prion protein (named BvM109 and BvI109, respectively). Among the VPSPr cases
selected, 2 were VV at PrP codon 129, 3 were MV and 2 were MM. Clinical
diagnosis in voles was confirmed by brain pathological assessment and western
blot for PK-resistant PrPSc (PrPres) with mAbs SAF32, SAF84, 12B2 and 9A2.
Results. To date, 2 VPSPr cases (1 MV and 1 MM) gave positive transmission
in BvM109. Overall, 3 voles were positive with survival time between 290 and 588
d post inoculation (d.p.i.). All positive voles accumulated PrPres in the form
of the typical PrP27–30, which was indistinguishable to that previously observed
in BvM109 inoculated with sCJDMM1 cases.
In BvI109, 3 VPSPr cases (2 VV and 1 MM) showed positive transmission until
now. Overall, 5 voles were positive with survival time between 281 and 596
d.p.i.. In contrast to what observed in BvM109, all BvI109 showed a GSS-like
PrPSc electrophoretic pattern, characterized by low molecular weight PrPres.
These PrPres fragments were positive with mAb 9A2 and 12B2, while being negative
with SAF32 and SAF84, suggesting that they are cleaved at both the C-terminus
and the N-terminus. Second passages are in progress from these first successful
transmissions.
Conclusions. Preliminary results from transmission studies in bank voles
strongly support the notion that VPSPr is a transmissible prion disease.
Interestingly, VPSPr undergoes divergent evolution in the two genetic lines of
voles, with sCJD-like features in BvM109 and GSS-like properties in BvI109.
The discovery of previously unrecognized prion diseases in both humans and
animals (i.e., Nor98 in small ruminants) demonstrates that the range of prion
diseases might be wider than expected and raises crucial questions about the
epidemiology and strain properties of these new forms. We are investigating this
latter issue by molecular and biological comparison of VPSPr, GSS and Nor98.
Wednesday, March 28, 2012
VARIABLY PROTEASE-SENSITVE PRIONOPATHY IS TRANSMISSIBLE, price of prion
poker goes up again $
Thursday, February 21, 2013
National Prion Disease Pathology Surveillance Center Cases Examined January
16, 2013
tss
