Research
Article
A Naturally Occurring Bovine Tauopathy Is Geographically Widespread in the
UK
Martin Jeffrey, Affiliation: Animal and Plant Health Agency, Lasswade
Veterinary Laboratory, Pentlands Science Park, Bush Loan, Penicuik, Midlothian,
Scotland
⨯ Pedro Piccardo, Affiliation: Laboratory of Bacterial and TSE-agents, Food
and Drug Administration, Rockville, Maryland, United States of America
⨯ Diane L. Ritchie, Affiliation: National CJD Research & Surveillance
Unit, Centre for Clinical Brain Sciences, School of Clinical Sciences,
University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh, United
Kingdom
⨯ James W. Ironside, Affiliation: National CJD Research & Surveillance
Unit, Centre for Clinical Brain Sciences, School of Clinical Sciences,
University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh, United
Kingdom
⨯ Alison J. E. Green, Affiliation: National CJD Research & Surveillance
Unit, Centre for Clinical Brain Sciences, School of Clinical Sciences,
University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh, United
Kingdom
⨯ Gillian McGovern * E-mail: gillian.mcgovern@apha.gsi.gov.uk
Affiliation: Animal and Plant Health Agency, Lasswade Veterinary
Laboratory, Pentlands Science Park, Bush Loan, Penicuik, Midlothian, Scotland
⨯ A Naturally Occurring Bovine Tauopathy Is Geographically Widespread in
the UK Martin Jeffrey, Pedro Piccardo, Diane L. Ritchie, James W. Ironside,
Alison J. E. Green, Gillian McGovern PLOS x Published: June 19, 2015 DOI:
10.1371/journal.pone.0129499
Abstract
Many human neurodegenerative diseases are associated with
hyperphosphorylation and widespread intra-neuronal and glial associated
aggregation of the microtubule associated protein tau. In contrast, animal
tauopathies are not reported with only senescent animals showing inconspicuous
tau labelling of fine processes albeit significant tau aggregation may occur in
some experimental animal disease. Since 1986, an idiopathic neurological
condition of adult cattle has been recognised in the UK as a sub-set of cattle
slaughtered as suspect bovine spongiform encephalopathy cases. This disorder is
characterised by brainstem neuronal chromatolysis and degeneration with variable
hippocampal sclerosis and spongiform change. Selected cases of idiopathic
brainstem neuronal chromatolysis (IBNC) were identified from archive material
and characterised using antibodies specific to several tau hyperphosphorylation
sites or different isoforms of the tau microtubule binding region. Labelling was
also carried out for alpha synuclein, ubiquitin, TDP43, Aβ1–42, Aβ1–40.
Widespread tau labelling was identified in all IBNC brains examined and with
each of seven tau antibodies recognising different hyperphosphorylated sites.
Labelling with each antibody was associated with dendrites, neuronal perikarya
and glia. Thus IBNC is a sporadic, progressive neurological disease
predominantly affecting aged cattle that occurs throughout the UK and is
associated with hyperphosphorylation of tau, a rare example of a
naturally-occurring tauopathy in a non-primate species. Secondary accumulation
of alpha synuclein and ubiquitin was also present. The neuropathology does not
precisely correspond with any human tauopathy. The cause of IBNC remains
undetermined but environmental factors and exposure to agrochemicals needs to be
considered in future aetiological investigations.
snip...
Discussion Tau is phosphorylated at about 30–40 sites in normal human
brains and is also minimally phosphorylated in normal adult mammalian brains. In
some human disease states tau may become hyperphosphorylated with up to 60
phosphorylation sites. In animals, P- tau has been described as thread like
processes in the brains of clinically normal aged animals [18] and is
inconsistently associated with some experimental and naturally occurring prion
diseases [19,20] as it is also in man [21]. Some presumed constitutionally
expressed isoforms of tau are abundant within the neuronal cytoplasm of some
animal species [16,22]. Numerous tauopathies exist in man [23]. Some tauopathies
such as Primary Age Related Tauopathy (formerly known as neurofibrillary
dementia) [23,24] may lack clinical features in some individuals but many
tauopathies have distinctive clinico-pathological presentations [23]. In
contrast, neither clinical disease nor age related syndromes have previously
been associated with consistent tau hyperphosphorylation in animals. In IBNC
P-tau is both invariably present and associated with neurodegenerative features
[2] in cows presenting with distinct neurological signs [3]. Thus IBNC appears
to be the first naturally occurring and geographically widespread tauopathy in a
species other than humans.
P-tau may aggregate into intra-cellular fibrillar structures. In
Alzheimer’s disease aggregated tau takes the form of paired helical filaments.
These may be identified by silver impregnation methods and are usually referred
to as neurofibrillary tangles. Fibrils composed of aggregated tau molecules are
not confined to Alzheimer’s disease but may occur as straight or random
filaments in some other human tauopathies (Table 2). IBNC appear to lack
intracellular neurofibrillary tangles, as shown by negative silver stains and by
electron microscopic examinations suggesting that aggregation of P-tau in IBNC
may not progress to formation of filaments.
Many human neurodegenerative diseases show abnormalities of tau and
microtubules and although most are considered complex proteinopathies, some
familial diseases with mutations of the microtubule associated protein gene,
such as familial fronto-temporal dementia are considered pure tauopathies
[23,25]. No genetic information about the bovine tau gene was available for
cases of IBNC, but the involvement of multiple cattle breeds and the sporadic
but geographically widespread distribution of IBNC cases across Scotland [2] and
elsewhere within the UK argues against a familial cause of disease.
IBNC shows hyperphosphorylation at numerous sites across the tau molecule,
albeit of those sites tested some were more conspicuous than others. 3R forms of
tau were recognised but not the 4R forms. Labelling of 3R tau is known to
require specific pre-treatments [16] and labelling for 4R may be capricious. The
absence of 4R labelling persisted when methods considered highly favourable for
detection of 3 and 4R isoforms in man was used [16], but in the absence of any
4R positive bovine control tissues we should be cautious of concluding that no
4R forms were present. Some species, such as the mouse, do not generate both 3R
and 4R isoforms of tau [26]. However, adult cows generate isoforms with the
N-terminal extensions 3R1N, 3R2N, 4R1N, 4R2N [26], which may suggest that IBNC
represents a predominantly 3R tauopathy in cattle.
Tauopathies in man are classified according to the physical state of
aggregation of abnormal tau, by the molecular size and nature of P-tau, by the
neuroanatomical distribution of lesions and by additional neurodegenerative
features [8,23,27,28]. The Western blot data from the three IBNC brains tested
suggests that tau with multiple molecular weights is present, albeit the Western
blots do not test the state of phosphorylation of the tau recognised. The
immunoblot data therefore confirms the presence of multiple tau molecular states
in IBNC brains, but the similar presence of tau in control adult cattle brains
makes further interpretation difficult. Significant additional work to test
specifically for the presence of hyperphosphorylated tau forms will be necessary
to provide meaningful interpretation. Nevertheless both the immunoblotting and
immunohistochemical data are consistent with IBNC brains containing multiple
molecular weight isoforms of P-tau, potentially with a range similar to that
found in Alzheimer’s disease. However, plaques or diffuse accumulations of
Aβ1–40 or Aβ1–42 were absent from IBNC brains. Hippocampal sclerosis in man may
be associated with TDP-43 immunolabelling, but this too was absent in IBNC. The
predominant glial tau association of IBNC has similarities to the tau gliopathy
reported for argyrophilic grain disease, progressive supranuclear palsy and
corticobasal degeneration [22] but, in contrast to the predominant 3R tauopathy
found in IBNC, these human neurodegenerations are all 4R tauopathies (Table 2).
In common with other protein misfolding diseases, IBNC appears to be a complex
proteinopathy with evidence for additional secondary accumulation of alpha
synuclein, ubiquitin, and possibly PrP [5]. However there is no evidence of Lewy
bodies, neurites or other primary alpha synuclein pathology such as is found in
Parkinson’s disease. Thus the nature of the tauopathy in IBNC does not precisely
parallel that of any of the existing human tauopathies ([22] and Table 2);
however, it appears to represent a naturally-occurring predominantly 3R
tauopathy in a non-primate species.
IBNC is a chronic progressive neurological illness that is widespread and
occurs sporadically throughout the UK in aged cattle. Clinical signs of IBNC
include behavioural changes, increased apprehension and locomotor problems such
as tremor and stiffness of gait, and weight loss [2,3]. Difficulty in swallowing
with increased salivation is also reported is some cases. Attempts to find the
cause of IBNC have so far been unsuccessful. Small scale and largely unpublished
studies of IBNC have not identified infectious, metabolic or micronutrient
deficiencies that are known to cause neurodegeneration in cattle [6]. It is now
widely understood that both genetic and environmental factors contribute to the
pathogenesis of some human dementias and several environmental risk factors have
been identified for some human Parkinsonian syndromes. In particular exposure to
insecticides and herbicides and employment in the agricultural or horticultural
industries increases risk [29,30,31]. Although the mechanisms remain uncertain,
it has been suggested that diverse toxins may interact with alpha synuclein to
initiate aggregation of alpha synuclein in Parkinson’s disease [32].
Experimental exposure of rodents to the insecticides rotenone, [33] the
herbicide paraquat or the fungicide maneb (a dithiocarbamate) each results in
striato-nigral dopaminergic neuron loss [32]. In the absence of any specific
aetiological cause of IBNC yet identified, and based on the existing
epidemiology and presence of P-tau we have considered the possibility that IBNC
might also have a significant environmental component. Epidemiological
investigations to explore usage of herbicides, insecticides, parasiticides and
other chemicals used in agriculture would be helpful in future investigations of
IBNC and might provide further insight into some causes of neurodegeneration in
man.
snip...
Greetings,
I was stunned by this report.
This Research Report should have been titled ;
‘’It Appears A Naturally Occurring Bovine Tauopathy Is Geographically Widespread in the UK’’
This Research Report should have been titled ;
‘’It Appears A Naturally Occurring Bovine Tauopathy Is Geographically Widespread in the UK’’
I would kindly like to comment please, as follows ;
>>>Thus IBNC _appears_ to be the first naturally occurring and
geographically widespread tauopathy in a species other than humans.<<<
>>>IBNC _appear_ to lack intracellular neurofibrillary
tangles,<<<
>>>Thus IBNC _appears_ to be the first naturally occurring and
geographically widespread tauopathy in a species other than
humans<<<
>>>IBNC appears to be a complex proteinopathy with evidence for
additional secondary accumulation of alpha synuclein, ubiquitin, and possibly
PrP [5]. <<<
>>>however, it appears to represent a naturally-occurring
predominantly 3R tauopathy in a non-primate species.<<<
>>>In the absence of any specific aetiological cause of IBNC yet
identified, and based on the existing epidemiology and presence of P-tau we have
considered the possibility that IBNC might also have a significant environmental
component. Epidemiological investigations to explore usage of herbicides,
insecticides, parasiticides and other chemicals used in agriculture would be
helpful in future investigations of IBNC and might provide further insight into
some causes of neurodegeneration in man.<<<
This is supposition at best in my opinion, and at worse, I will refrain
from comment.
Too many _appears_ , appears this, appears that.
Too many _In the absence of any specific aetiological cause of IBNC yet
identified_
is this what science has come to?
has science become some entwined with corporate special interest, do we
change science now?
I believe that is far too early to rule out IBNC as a Transmissible
Spongiform Encephalopathy TSE prion disease, either of typical or typical
strain.
it can be argued that there is potential for Alzheimer’s to be a low dose
TSE Prion disease ;
what about horizontal and or vertical transmission of an atypical strain of
the BSE TSE prion disease into a low dose that is not detectible with TSE Prion
testing to date?
what about a completely different strain, another atypical, of the TSE
prion disease, to low to detect to date, and I stress to date?
to abandon the TSE prion and IBNC link there from would be foolish in my
opinion.
SEAC, FatPride, BSE Inquiry, have never found a link to pesticides, or
OP’s, or metals, as a _cause_, to any TSE prion disease.
I have also followed the metals, pesticide debate as a cause for the TSE
prion disease. to date, this has proven to be fruitless for any _cause_ of the
TSE prion disease. not to say the potential for these factors for one to be more
susceptible to a TSE prion from surrounding environmental factors i.e.
surrounding TSE prion exposures from the various routes and sources of the TSE
prion disease (see metals and pesticide i.e. FatePride towards the bottom). from
Mark Purdey and his research, to a farmer with BSE that treated his kids with
OP’s for head lice, and nothing scientific to date has confirmed a link to the
TSE prion disease as a _cause_.
We MUST not abandon transmission studies, and or any link to the TSE prion
disease.
IT appears, in the absence of any scientific link to any specific
herbicides, insecticides, parasiticides and other chemicals to date to IBNC, to
just explore other options instead of the transmission studies to prove one way
or the other whether or not the IBNC or BBD or whatever you want to call this,
while ignoring the existing epidemiology and knowledge of the TSE prion disease
with the primitive TSE prion testing to date, it appears all this would be
foolish, it appears this would be very questionable, in my opinion. ...
Terry S. Singeltary Sr.
please see ;
Prion-like transmission and spreading of tau pathology Invited Review
Prion-like transmission and spreading of tau pathology Florence
Clavaguera1, Jürgen Hench1, Michel Goedert2 and Markus Tolnay1,* DOI:
10.1111/nan.12197
This article is protected by copyright. All rights reserved.
Additional Information(Hide All) Author InformationPublication History
Author Information 1 Institute of Pathology, University Hospital Basel,
Schönbeinstrasse 40, CH-4031 Basel, Switzerland 2 MRC Laboratory of Molecular
Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK * Please send
correspondence to Markus Tolnay at the above address. Email:
markus.tolnay@usb.ch
This article has been accepted for publication and undergone full peer
review but has not been through the copyediting, typesetting, pagination and
proofreading process, which may lead to differences between this version and the
Version of Record. Please cite this article as doi: 10.1111/nan.12197
Publication History Accepted manuscript online: 17 NOV 2014 01:23AM EST
Manuscript Accepted: 13 NOV 2014
Abstract
Filaments made of hyperphosphorylated tau protein are encountered in a
number of neurodegenerative diseases referred to as “tauopathies”. In the most
prevalent tauopathy, Alzheimer's disease, tau pathology progresses in a
stereotypical manner with the first lesions appearing in the locus coeruleus and
the entorhinal cortex from where they appear to spread to the hippocampus and
neocortex. Propagation of tau pathology is also characteristic of argyrophilic
grain disease, where the tau lesions appear to spread throughout distinct
regions of the limbic system. These findings strongly implicate neuron-to-neuron
propagation of tau aggregates. Isoform composition and morphology of tau
filaments can differ between tauopathies suggesting the existence of
conformationally diverse tau strains. ***Altogether, this points to prion-like
mechanisms in the pathogenesis of tauopathies.
‘’experiments using bovinised, ovinised and humanised mice indicate that
IBNC is transmissible, the ability of surveillance to detect IBNC should be
examined. It would be important to conduct transmission experiments using brains
from IBNC cases proven, as far as possible, not to have BSE.’’
SEAC 103/1
SPONGIFORM ENCEPHALOPATHY ADVISORY COMMITTEE
Draft minutes of the 102nd meeting held on 4th March 2009 Nobel House, 17
Smith Square, London SW1P 3JR
snip...
ITEM 5 – NEW RESULTS ON IDIOPATHIC BRAINSTEM NEURONAL CHROMATOLYSIS
(IBNC) FROM THE VETERINARY LABORATORIES AGENCY (VLA)
14. Dr Martin Jeffrey (Veterinary Laboratories Agency (VLA)) presented an
overview of a recent publication on Idiopathic Brainstem Neuronal Chromatolysis
(IBNC)4. During the period 1987 to 1992, VLA examined the neuropathology of
whole brains from all submissions made under the BSE orders in Scotland to look
for possible strain variation or mutation of the existing BSE strain or other
prion diseases of cattle. During the course of these investigations a small
number of cases of IBNC were identified. Abnormally accumulated prion protein
was found in the brains of the IBNC cases. Dr Jeffrey suggested that these
findings indicate that the range of prion disease pathology may be wider than
thought or that abnormalities of prion protein gene expression might be
associated with brain lesions unconnected with classical prion diseases.
15. A member noted that IBNC appears to be a rare disease and the
prevalence of IBNC seems not to have increased over time. Dr Jeffrey noted that
the detection rate of IBNC is dependent on the design of cattle surveillance and
it is possible that cases of IBNC may be missed by current surveillance.
Nevertheless, it is likely that IBNC is rare. A member suggested that should
transmission 3 Truscott, J.E. and Ferguson, N. M. (2008) Control of scrapie in
the UK sheep population. Epidemiology and Infection, 8 August 2008, on-line,
doi: 10.1017/S0950268808001064. 4Jeffrey et al. (2008) Idiopathic Brainstem
Neuronal Chromatolysis (IBNC): a novel prion protein related disorder of cattle?
4, 38.
experiments using bovinised, ovinised and humanised mice indicate that IBNC
is transmissible, the ability of surveillance to detect IBNC should be examined.
It would be important to conduct transmission experiments using brains from IBNC
cases proven, as far as possible, not to have BSE.
16. A member asked about whether differential diagnosis was made on BSE
suspect cases that subsequently were found not to be BSE. Dr Yvonne Boyd (Defra)
noted that currently less than 10% of suspected BSE suspect cases were
subsequently confirmed. Defra was funding a research project to examine a number
of clinical BSE suspects subsequently found not to be BSE, but routine
differential diagnosis was not carried out on all such cases. Dr Jim Hope (VLA)
added that such cases were not specifically investigated for the presence of
other neurological diseases; only the presence of spongiform change and the
properties of the prion protein were assessed. However, obvious differential
diagnoses were reported, e.g. meningioencephalitis, if detected.
17. A member noted that even though prion protein accumulation was evident
in IBNC cases, the form of prion protein produced was protease sensitive,
indicating that IBNC may not be a form of TSE. Dr Jeffrey explained that, from
the biochemical studies conducted, an abnormally folded, but protease sensitive,
form of prion protein could not be ruled out.
18. A member asked if any of the cases of IBNC examined showed evidence of
possible co-infection with classical BSE. Dr Jeffrey replied that as the
neuropathological lesions of IBNC and BSE differed, co-infection should be
detectable. However, no evidence of co-infection had been detected. A member
suggested it may be possible to re-examine archived BSE brains for the
possibility of IBNC co-infection to establish whether IBNC is indeed a rare
disease. Dr Jeffrey noted that as IBNC predominantly affects older cattle, the
age of the cattle brains would be a factor in such an investigation.
19. A member asked if the sequence of the prion protein gene had been
studied in the IBNC cases as this can influence the pathogenesis and
neuropathology of prion diseases. Dr Jeffrey replied that no detailed studies
had been conducted.
20. A member noted that IBNC appeared to be a neurological condition and
therefore the specified risk material controls would confer public health
protection should IBNC be zoonotic.
21. The Chair summarised the discussion, noting that IBNC appears to pose
no immediate high risk to human health. It appears to be a rare disease,
although current surveillance may miss cases. It cannot be concluded if IBNC is
transmissible, or not. Transmission studies using material from IBNC cases
proven not to be BSE, that include transgenic mice lines, are important. Studies
to investigate whether IBNC is associated with a normal or abnormal form of
prion protein could be informative.
ITEM 6 – UPDATE ON CJD EPIDEMIOLOGY
22. Professor Richard Knight (National CJD Surveillance Unit) updated SEAC
on the latest figures for the number of clinical vCJD and sporadic CJD (sCJD)
cases. To date there had been 168 definite and probable clinical cases of vCJD
in the UK - 165 from dietary infection with BSE and three from vCJD infection
via blood transfusion. Four cases are still alive. The number of deaths from
vCJD peaked at 28 in 2000 and had since declined with one known death in 2008.
The trend in incidence of vCJD deaths fits the quadratic-exponential model. The
median age of death is 28 years of age. No individuals born after 1989 have
developed vCJD to date. Analysis of vCJD deaths by birth cohort supports the
hypothesis that susceptibility to vCJD from dietary exposure to BSE may be
age-related with a peak in susceptibility between five and 20 years of
age.
23. Professor Knight explained that all the clinical vCJD cases genotyped
to date were of the MM genotype with the exception of one case of the MV
genotype recently classified as possible vCJD. This patient had died. Although
the clinical features in life suggested this was a case of vCJD, it had not been
possible to undertake a tonsil biopsy in life or neuropathological examination
post mortem so the diagnosis could not be confirmed. The patient was born in
1978, with disease onset in 2007 and death in 2009. The clinical profile of this
MV case was consistent with that observed for MM cases suggesting that the
neuropathological profile of vCJD in MV and MM cases may be similar.
24. Professor Knight noted that four vCJD patients had been treated with
intra-ventricular pentosan polysulphate (PPS) in the UK, in addition to one
sCJD, two Gerstmann-Sträussler-Scheinker (GSS) disease and one human growth
hormone (hGH) case. There is no evidence of benefit from the use of PPS for the
sCJD, GSS and hGH cases. However, it appears PPS may have significantly
prolonged the clinical phase of the illness in the vCJD cases treated, although
no significant improvement in the clinical condition of these patients had been
observed.
25. Professor Knight explained that elsewhere in the world 44 clinical vCJD
cases had been reported with 23 in France, five in Spain, four in the Republic
of Ireland, three in each of the USA and the Netherlands, two in Portugal and
single cases in Canada, Saudi Arabia, Italy and Japan. Infection was presumed to
have occurred in the UK in respect of two Irish and two USA cases, one French
case, one Japanese case and one Canadian case. The time of the peak of onset of
vCJD was five years later in non-UK countries than in the UK.
26. Professor Knight summarised studies to examine potential bloodborne
exposures to vCJD. The Transfusion Medicine Epidemiology Review (TMER)
identified 66 patients as recipients of labile blood components from donors whom
later developed vCJD. Forty three of those patients had died due to non-vCJD
related illnesses but three recipients developed clinical vCJD and one
subclinical vCJD infections. The reverse TMER study identified three vCJD cases
as receiving blood from vCJD infected donors. A study of plasma donations
prepared from 1986 to 1998 plasma had identified 25 units of plasma prepared
from donations from 11 individuals who later developed vCJD.
27. Professor Knight summarised data on sCJD cases. From May 1990 to
January 2009, 1027 cases of sCJD had been identified in the UK with a mean age
at death of 67 years and genotype distribution of 63% MM, 19% MV and 18% VV at
codon 129 of the prion protein gene.
28. Members asked in what circumstances an autopsy is legally required.
Professor Knight explained that autopsy may be legally required when the cause
of death is considered not to be from natural causes or is unknown. However, the
wishes of the family of the deceased are also considered.
29. Dr Elaine Gadd (Department of Health (DH)) asked about the clinical
state of the vCJD cases treated with PPS. Professor Knight explained that the
neurological impairment of the patients when treatment began was so advanced
that any subtle changes in clinical state would be difficult to assess
objectively. The condition of two patients is considered to have significantly
deteriorated, whilst one patient may have improved slightly.
ITEM 7 – COMPARING THE RELATIVE RISK OF vCJD TRANSMISSION VIA SINGLE UNIT
AND POOLED PLASMA FROM UK AND NON-UK SOURCES (SEAC 102/3)
30. Mr Stephen Dobra (DH) presented an overview of the risk assessment that
had been developed by the Department of Health. He explained that there are
three Fresh Frozen Plasma (FFP) products in use in the UK: (i) single unit FFP
from UK donors given to recipients over 16 years of age, (ii) single unit
methylene-blue treated FFP sourced from donors in the United States of America
and given to patients under 16 years of age, and (iii) solvent detergent treated
FFP (SD FFP) manufactured from pooled plasma currently sourced from countries
with no known vCJD cases (although some, such as Germany, have a known BSE risk)
given to patients with Thrombotic Thrombocytopenic Purpura (TTP). As most FFP is
sourced from UK donors, there is a potential risk of vCJD transmission from its
use. Prion reduction technologies may be available in the future for pooled SD
FFP.
31. Mr Dobra explained that the risk assessment had been prepared to
support decision making by the Advisory Committee on the Safety of Blood,
Tissues and Organs (SaBTO) which is considering options for extending the use of
imported plasma to all recipients and National Health Service Blood and
Transplant which is considering the procurement of plasma from alternative
source countries. The risk assessment examines the relative residual risk from
use of plasma taking into account the source country, whether it is single unit
or pooled, and the method of processing. SEAC was being asked to review the
methodology used for the sourcing and pooling elements of the risk assessment.
DH will convene an expert group to assess the impact of processing taking into
account previous SEAC advice.
32. Members suggested that the presentation of the risk assessment could be
improved to provide greater clarity on the reasoning behind some of the
assumptions made.
33. A member asked about the estimation of the probability that infectivity
would be carried by a plasma product from pooled plasma donations that had been
contaminated by a donor infected with vCJD. Mr Dobra suggested that in low
infectivity scenarios, infectivity might not be present in all of the plasma
product units produced from a contaminated pool as there may be an uneven
distribution of infectivity throughout the pool. Members noted that the
physico-chemical nature of infectivity in plasma is not known. It may be
homogeneously spread within the pool or remain in the form of discrete entities
spread unevenly, or something between these two extremes. There may be no low
dose threshold for infection.
34. Members asked what confidence there may be in the results from the risk
assessment given the large number of variables with large uncertainties. It was
noted that as the relative risks (as opposed to absolute risks) posed by plasma
products were being estimated, assumptions around the timing, level and
distribution of infectivity in blood where there is much uncertainty would not
appreciably affect the estimations made. The best way to manage other
assumptions where there is large uncertainty, such as around the prevalence of
vCJD in the UK and other countries, would be to develop a range of scenarios
incorporating reasonable high and low value estimates for such parameters. It
was noted that some patients received a large number of transfusions of plasma
and plasma products. It may be possible to rule out some scenarios on the basis
of observations made on these groups of patients. Members reiterated the
importance SEAC placed on obtaining better estimates for the prevalence of
subclinical vCJD through a post mortem tissue archive.
35. A member suggested that experiments to examine the infectivity of
unused batches of plasma products might provide useful data. It was considered
that such experiments may be difficult to conduct as there may be a small number
of contaminated batches and they would be difficult to identify.
36. A member asked why prion reduction technologies would only be applied
to pooled plasma. Mr Dobra explained that the only proposal of which he was
aware had been developed by a manufacturer of pooled plasma and involved
filtering a large volume of plasma through a column. The Chair remarked on the
lack of independent validation of the efficacy of prion reduction filters to
date.
37. A member asked whether the risk assessment could take into account the
measures taken in different countries to prevent dietary exposure to BSE and the
movement of people from other countries to the UK during the BSE epidemic. Mr
Dobra explained that there are no consistent data available to assess
differences in dietary exposure to BSE in different European countries. Most
countries excluded from donating blood anyone who had visited or been resident
in the UK for a significant period of time.
38. A member noted that the risk of vCJD transmission alters depending on
the age of the blood donor and asked whether restrictions on the age of donation
could be introduced to manage the vCJD transmission risks. Mr Dobra explained
that this was possible but would require clear advice from SEAC on the
difference in risk and was complicated by the need to ensure sufficient supplies
of blood.
39. The Chair summarised the discussion, noting that the committee felt
that the best way of handling the uncertainties around key assumptions made in
the risk assessment is to use reasonable high and low values for each parameter
to derive a range of scenarios. Scenarios could be validated against the number
of infections observed in populations that had received large numbers of
transfusions of plasma products.
snip...
Saturday, October 19, 2013
A comparative study of modified confirmatory techniques and additional
immuno-based methods for non-conclusive autolytic Bovine spongiform
encephalopathy cases
BMC Veterinary Research 2013, 9:212 doi:10.1186/1746-6148-9-212 Rocío
Sarasa (rociosar@unizar.es) Dietmar Becher (becher@micromun.de) Juan J Badiola
(badiola@unizar.es) Marta Monzón (mmonzon@unizar.es)
ISSN 1746-6148
Article type Research article
Submission date 6 March 2013
Acceptance date 9 October 2013
Publication date 18 October 2013
Article URL http://www.biomedcentral.com/1746-6148/9/212
BMC Veterinary Research
© 2013 Sarasa et al.
This is an open access article distributed under the terms of the Creative
Commons Attribution License (http://creativecommons.org/licenses/by/2.0),
which permits unrestricted use, distribution, and reproduction in any medium,
provided the original work is properly cited.
A comparative study of modified confirmatory techniques and additional
immuno-based methods for non-conclusive autolytic Bovine spongiform
encephalopathy cases
Rocío Sarasa1 Email: rociosar@unizar.es Dietmar Becher2 Email:
becher@micromun.de Juan J Badiola1 Email: badiola@unizar.es Marta Monzón1* *
Corresponding author Email: mmonzon@unizar.es 1 Research Centre for
Encephalopathies and Transmissible Emerging Diseases, University of Zaragoza,
Zaragoza, Spain 2 Micromun Privates Institut für Mikrobiologische Forschung
GmbH, Greifswald,
Germany
Abstract
Background
In the framework of the Bovine Spongiform Encephalopathy (BSE) surveillance
programme, samples with non-conclusive results using the OIE confirmatory
techniques have been repeatedly found. It is therefore necessary to question the
adequacy of the previously established consequences of this non-conclusive
result: the danger of failing to detect potentially infected cattle or erroneous
information that may affect the decision of culling or not of an entire bovine
cohort. Moreover, there is a very real risk that the underreporting of cases may
possibly lead to distortion of the BSE epidemiological information for a given
country.
In this study, samples from bovine nervous tissue presenting non-conclusive
results by conventional OIE techniques (Western blot and immunohistochemistry)
were analyzed. Their common characteristic was a very advanced degree of
autolysis. All techniques recommended by the OIE for BSE diagnosis were applied
on all these samples in order to provide a comparative study.
Specifically, immunohistochemistry, Western blotting, SAF detection by
electron microscopy and mouse bioassay were compared. Besides, other non
confirmatory techniques, confocal scanning microscopy and colloidal gold
labelling of fibrils, were applied on these samples for confirming and improving
the results.
snip...
Discussion
All the studied bovine samples were confirmed as BSE positive cases thanks
to the results provided by immunocytochemistry, electron microscopy and
bioassay. Despite all the applied techniques being standardized for increasing
their capability to detect PrPsc, the extremely scarce concentration of PrPsc in
the samples is proposed here as the most coherent reason why non-conclusive
results (weak signal presenting an unconventional pattern) were provided by
Western blotting as well as showing different titers in the bioassay (reflected
by the lack of 100% success of transmission in all the mice included in it).
Therefore, the positive results provided by immunohistochemistry on murine
bioassay ultimately demonstrated that initial samples were infectious and
transmitted the disease. This was also concluded by immunocytochemistry and SAF
detection by electron microscopy being applied on the initial samples. However,
rapid tests and immunoblotting did not result useful for convincingly confirming
these results.
Although rapid techniques applied in this study achieved their objective as
screening tests by showing a non-conclusive signal in the samples analyzed, they
were not able to give definite results, demonstrating a lower sensitivity
compared to some of the confirmatory techniques (not all in this occasion, since
immunoblotting, despite the combined protocol described, was not able to improve
the results provided by rapid tests in terms of sensitivity). Nonconclusive
diagnosis obtained by these techniques in the bovine as well as false negative
diagnosis in the murine samples have been previously justified on the basis of
the low PrPsc concentration and the unsuitable selection of area to be analyzed
[29]. Both are unavoidable and intrinsic features for the samples studied here.
Overall, these findings might call into question the recent proposal determined
by the OIE which dictates that two equal results with two different rapid
techniques are enough to give an official BSE confirmation [30]. Furthermore,
the results of this study confirm immunocytochemistry as a useful and rapid tool
for diagnosis in liquid state samples, solving a relevant problem in BSE and
Scrapie epidemiology. As it had been previously impossible to apply
histopathological examination due to the advanced degree of autolyisis of the
analyzed samples, immunohistochemistry was evidenced as the first and reliable
technique to diagnosis of samples included here.
Immunocytochemistry has been demonstrated here as a technique capable to
provide final results for bovine samples. Moreover, this study first
demonstrates the reliability of this technique established by Monleón et al.
[18] since their results have been corroborated by other confirmatory
techniques, specifically, by electron microscopy and by in vivo tools
(bioassay). Confirmation of the immunocytochemical positive results by electron
microscopy clearly discards the possible subjectivity and non-specificity which
some authors could state for the immunocytochemical assessment established,
since SAF visualization has been demonstrated to be exclusive to TSEs [31]. In
spite of the proportion and length of fibrils being lower than those previously
described in conventional positive cases [32], the immunolabelling of these
fibrils by colloidal gold [33] unequivocally identified PrPsc in all of them.
This slight difference in appearance is probably associated with the low PrPsc
concentration assumed at the beginning and finally evidenced in this study.
Besides, the visualization of paired gold deposits which seem to correspond with
PrPsc dimers described by Dourmashkin et al. [34], supports this hypothesis,
associating gold deposits to areas of potential formation of fibrils [35]. As a
consequence, although it is a technique currently fallen into disuse, SAF
visualization by electron microscopy is confirmed in this study as a technique
with high sensitivity despite PrPsc concentration and autolysis of the sample,
demonstrating to be useful for diagnosing this kind of samples.
On the other hand, although the bioassay presented a transmission rate
lower than expected (only 24% of the inoculated mice developing clinical signs),
its sensitivity was 100% since it confirmed the positive diagnosis of the bovine
samples. The low number of affected mice, expressed in the low percentage of
animals which presented clinical signs or positive result by diagnostic
techniques, could be explained by several reasons. Despite partly avoiding the
problem of species barrier by use of bovinized transgenic mice [36], the
autolytic state of samples could have hampered the choice of the area of study
where PrPsc was present.
Nevertheless, the main responsible factor for this failure seems to be the
low initial PrPsc concentration due to, advancement of the protease digestion
associated with the putrefaction process, the serial dilutions and heat
treatment which had to be applied on the samples before inoculation. This scarce
PrPsc presence could elongate the incubation period and, indirectly, cause false
negatives in those mice which died prematurely, by natural death or euthanasia,
before presenting clinical signs [37] or not presenting enough concentration of
PrPsc to be detected by the applied techniques at that moment [38]. The fact
that the only mouse clearly considered positive by rapid tests and the only
mouse showing PrPsc plaques (as usually seen in BSE inoculated mice) [39]
belonged to the group of animals where the highest concentration was used for
inoculation, confirms this theory. Moreover, the presence of isolated fibrils in
the mice analyzed [40] instead of grouped fibrils visualized by electron
microscopy in the only positive mouse by rapid tests [41], would, once again,
correlate with this hypothesis.
As for the variance between the presence of PrPsc deposits and presentation
of clinical signs found in some mice, PrPsc concentration used for inoculation
could affect the results but also other explanations arise on this matter [42].
The possibility of a transmission of the disease without neurological signs [43]
or a possible non-exclusive relationship between PrPsc and infectivity [44-46]
and neurodegeneration [47], among them. Besides, the demonstration of the
existence of animals as persistent carriers [48] or with a subclinical state of
the disease [47], already described in mice with high titers of infection but no
symptoms [49], should be borne in mind. This same lack of correlation between
PrPsc and infectivity could be reflecting in the animals with symptoms but no
PrPsc deposits [50], considering in this case that the disease might be
transmitted without detectable PrPsc [44], even with high titers [51]. Further
studies with non-diagnostic aims but for identification of astrocytes
co-locating with PrPsc were developed here, as mentioned in Material and Methods
section. The relationship between PrPsc and glial cells observed by conventional
immunohistochemistry, was confirmed by confocal microscopy showing an evident
co-localization. This finding would put in evidence the possibility of the
participation of these cells, possibly across the haematoencephalic barrier
[27,52], in the prion propagation in the model used here [53]. On this occasion,
it was not possible to associate the studied samples to classical or atypical
BSE owing to the lack of success to provide a clear banding pattern by Western
blotting and/or a characteristic profile by immunohistochemistry, the lack of
reference to previous data on incubation periods and the inability to determine
lesion profiles in the mouse line. All these facts, as it has been stated,
probably due to the very scarce concentration of PrPsc. Otherwise, whether the
agent present in samples was atypical BSE or classical BSE with really low PrPsc
deposits and low infectivity titers was not possible to be determined.
Conclusions
In conclusion, demonstration of transmission of the disease even with low
concentrations of PrPsc [54], highlights BSE’s ability to adopt different
behavior, even sometimes similar to Scrapie [55], should reinforce that
vigilance is required in interpreting results so that subtle changes do not go
unnoticed. Additionally, to maintain a continued supervision of the techniques
which are applied in the routine diagnosis would prove essential for the
ultimate eradication of the disease. A study of the actual BSE presence should
be considered as necessary because a state of sporadic prevalence could exist
[56] and samples without a diagnosis [57,58] could reach the food chain,
involving therefore a risk for public health.
Keywords
TSEs, BSE, Confirmatory diagnosis, Non-conclusive cases
From: Terry S. Singeltary Sr.
Sent: Tuesday, August 13, 2013 3:58 PM
To: Science.Advisory.Council@defra.gsi.gov.uk
Subject: Idiopathic Brainstem Neuronal Chromatolysis (IBNC): a novel prion
protein related disorder of cattle?
Greetings Honorable Science Advisory Council et al @ DEFRA,
I wish to ask a question about something I have seen no updates on, that
concerns me.
IDIOPATHIC BRAINSTEM NEURONAL CHROMATOLYSIS IBNC or what I some times call,
IBNC BSE.
I have seen nothing in the scientific literature updated on this in years,
since around 2008, then it was like it fell off the face of the earth ?
can you please give me some sort of update on the IBNC BSE science to date
?
how many cases of IBNC BSE have been detected ?
is there an ongoing surveillance for this the IBNC BSE, and are the BSE
test even capable of detecting it ?
could the USA and or North America even detect, if they were even looking
for it ?
latest studies, if any more since "All of the 15 cattle tested showed that
the brains had abnormally accumulated PrP" ?
thank you,
kind regards, terry
references as follows ;
Research article Idiopathic Brainstem Neuronal Chromatolysis (IBNC): a
novel prion protein related disorder of cattle? Martin Jeffrey1*, Belinda
Baquero Perez2, Stuart Martin1, Linda Terry2 and Lorenzo González1
* Corresponding author: Martin Jeffrey m.jeffrey@vla.defra.gsi.gov.uk
Author Affiliations
1 Veterinary Laboratories Agency (VLA-Lasswade), Pentlands Science Park,
Bush Loan, Midlothian EH26 0PZ, UK
2 VLA-Weybridge, Addlestone, Surrey, KT15 3NB, UK
For all author emails, please log on.
BMC Veterinary Research 2008, 4:38 doi:10.1186/1746-6148-4-38
The electronic version of this article is the complete one and can be found
online at: http://www.biomedcentral.com/1746-6148/4/38
Received: 3 April 2008 Accepted: 30 September 2008 Published: 30 September
2008
© 2008 Jeffrey et al; licensee BioMed Central Ltd.
This is an Open Access article distributed under the terms of the Creative
Commons Attribution License (http://creativecommons.org/licenses/by/2.0),
which permits unrestricted use, distribution, and reproduction in any medium,
provided the original work is properly cited.
Abstract Background The epidemic form of Bovine Spongiform Encephalopathy
(BSE) is generally considered to have been caused by a single prion strain but
at least two strain variants of cattle prion disorders have recently been
recognized. An additional neurodegenerative condition, idiopathic brainstem
neuronal chromatolysis and hippocampal sclerosis (IBNC), a rare neurological
disease of adult cattle, was also recognised in a sub-set of cattle submitted
under the BSE Orders in which lesions of BSE were absent. Between the years of
1988 and 1991 IBNC occurred in Scotland with an incidence of 7 cases per 100,000
beef suckler cows over the age of 6 years.
Results When the brains of 15 IBNC cases were each tested by
immunohistochemistry, all showed abnormal labelling for prion protein (PrP).
Immunohistological labelling for PrP was also present in the retina of a single
case available for examination. The pattern of PrP labelling in brain is
distinct from that seen in other ruminant prion diseases and is absent from
brains with other inflammatory conditions and from normal control brains. Brains
of IBNC cattle do not reveal abnormal PrP isoforms when tested by the commercial
BioRad or Idexx test kits and do not reveal PrPres when tested by Western
blotting using stringent proteinase digestion methods. However, some weakly
protease resistant isoforms of PrP may be detected when tissues are examined
using mild proteinase digestion techniques.
Conclusion The study shows that a distinctive neurological disorder of
cattle, which has some clinical similarities to BSE, is associated with abnormal
PrP labelling in brain but the pathology and biochemistry of IBNC are distinct
from BSE. The study is important either because it raises the possibility of a
significant increase in the scope of prion disease or because it demonstrates
that widespread and consistent PrP alterations may not be confined to prion
diseases. Further studies, including transmission experiments, are needed to
establish whether IBNC is a condition in which prion protein is abnormally
regulated or it is yet a further example of an infectious cattle prion disease.
1992
NEW BRAIN DISORDER
3. WHAT ABOUT REPORTS OF NEW FORM OF BSE ?
THE VETERINARY RECORD HAS PUBLISHED AN ARTICLE ON A NEW BRAIN DISORDER OF
CATTLE DISCOVERED THROUGH OUR CONTROL MEASURES FOR BSE. ALTHOUGH IT PRESENTS
SIMILAR CLINICAL SIGNS TO BSE THERE ARE MAJOR DIFFERENCES IN HISTOPATHOLOGY AND
INCUBATION PERIODS BETWEEN THE TWO. MUST EMPHASISE THAT THIS IS _NOT_ BSE.
4. IS THIS NEW BRAIN DISORDER A THREAT ?
WE DO NOT EVEN KNOW WHETHER THE AGENT OF THIS DISEASE IS TRANSMISSIBLE. IN
ANY CASE, CASES SO FAR IDENTIFIED HAD SHOWN SIMILAR SYMPTOMS TO THOSE OF BSE,
AND THEREFORE HAVE BEEN SLAUGHTERED AND INCINERATED, SO THAT IF A TRANSMISSIBLE
AGENT WERE INVOLVED IT WOULD HAVE BEEN ELIMINATED. ...
Tuesday, November 17, 2009
SEAC NEW RESULTS ON IDIOPATHIC BRAINSTEM NEURONAL CHROMATOLYSIS (IBNC) FROM
THE VETERINARY LABORATORIES AGENCY (VLA) SEAC 103/1
NEW RESULTS ON IDIOPATHIC BRAINSTEM NEURONAL CHROMATOLYSIS
"All of the 15 cattle tested showed that the brains had abnormally
accumulated PrP"
2009
''THE LINE TO TAKE'' ON IBNC $$$ 1995 $$$
1995
page 9 of 14 ;
30. The Committee noted that the results were unusual. the questioned
whether there could be coincidental BSE infection or contamination with scrapie.
Dr. Tyrell noted that the feeling of the committee was that this did not
represent a new agent but it was important to be prepared to say something
publicly about these findings. A suggested line to take was that these were
scientifically unpublishable results but in line with the policy of openness
they would be made publicly available and further work done to test their
validity. Since the BSE precautions were applied to IBNC cases, human health was
protected. Further investigations should be carried out on isolations from
brains of IBNC cases with removal of the brain and subsequent handling under
strict conditions to avoid the risk of any contamination.
31. Mr. Bradley informed the Committee that the CVO had informed the CMO
about the IBNC results and the transmission from retina and he, like the
Committee was satisfied that the controls already in place or proposed were
adequate. ...
snip... see full text
http://web.archive.org/web/20030327015011/http://www.bseinquiry.gov.uk/files/yb/1995/06/21005001.pdf
Wednesday, July 28, 2010
*** Atypical prion proteins and IBNC in cattle DEFRA project code SE1796
FOIA Final report ***
IN CONFIDENCE
*** BSE ATYPICAL LESION DISTRIBUTION
http://web.archive.org/web/20041226015813/http://www.bseinquiry.gov.uk/files/yb/1993/03/14001001.pdf
Tuesday, November 02, 2010
*** BSE - ATYPICAL LESION DISTRIBUTION (RBSE 92-21367) statutory (obex
only) diagnostic criteria CVL 1992
BSE: BRAIN STEM NEURONAL CHROMATOLYSIS – ‘’BOVINE BRAIN DISORDER’’
zinc link to cows speculative
DRAFT IN CONFIDENCE
IDIOPATHIC BRAIN STEM NEURONAL CHROMATOLYSIS AND HIPPOCAMPAL SCLEROSIS
(Vet. Rec. 1992, M Jeffrey, J W Wilemsith p359-362)
NEW RESULTS ON IDIOPATHIC BRAINSTEM NEURONAL CHROMATOLYSIS TYPE BSE
"All of the 15 cattle tested showed that the brains had abnormally
accumulated PrP" 2009 SEAC 102/2
Wednesday, October 08, 2008
Idiopathic Brainstem Neuronal Chromatolysis (IBNC): a novel prion protein
related disorder of cattle?
Wednesday, May 27, 2015
BSE Case Associated with Prion Protein Gene Mutation
BSE: DISCLOSURE OF INFORMATION AND FORECAST
Thursday, August 15, 2013
Stability properties of PrPSc from cattle with experimental transmissible
spongiform encephalopathies: use of a rapid whole homogenate, protease-free
assay
Thursday, August 15, 2013
The emergence of novel BSE prions by serial passages of H-type BSE in
bovinized mice
Monday, September 02, 2013
Atypical BSE: role of the E211K prion polymorphism Research Project:
TRANSMISSION, DIFFERENTIATION, AND PATHOBIOLOGY OF TRANSMISSIBLE SPONGIFORM
ENCEPHALOPATHIES Location: Virus and Prion Research Unit
Sunday, September 1, 2013
Evaluation of the Zoonotic Potential of Transmissible Mink Encephalopathy
We previously described the biochemical similarities between PrPres derived
from L-BSE infected macaque and cortical MM2 sporadic CJD: those observations
suggest a link between these two uncommon prion phenotypes in a primate model
(it is to note that such a link has not been observed in other models less
relevant from the human situation as hamsters or transgenic mice overexpressing
ovine PrP [28]). We speculate that a group of related animal prion strains
(L-BSE, c-BSE and TME) would have a zoonotic potential and lead to prion
diseases in humans with a type 2 PrPres molecular signature (and more
specifically type 2B for vCJD)
snip...
*** Together with previous experiments performed in ovinized and bovinized
transgenic mice and hamsters [8,9] indicating similarities between TME and
L-BSE, the data support the hypothesis that L-BSE could be the origin of the TME
outbreaks in North America and Europe during the mid-1900s.
PLEASE note, most important ;
"exposure to metal-enriched food and soils "is a risk factor" that
increases _susceptibility_ to prion diseases." ...
PRION 2015 ORAL AND POSTER CONGRESSIONAL ABSTRACTS
THANK YOU PRION 2015 TAYLOR & FRANCIS, Professor Chernoff, and
Professor Aguzzi et al, for making these PRION 2015 Congressional Poster and
Oral Abstracts available freely to the public. ...Terry S. Singeltary Sr.
O.05: Transmission of prions to primates after extended silent incubation
periods: Implications for BSE and scrapie risk assessment in human populations
Emmanuel Comoy, Jacqueline Mikol, Val erie Durand, Sophie Luccantoni,
Evelyne Correia, Nathalie Lescoutra, Capucine Dehen, and Jean-Philippe Deslys
Atomic Energy Commission; Fontenay-aux-Roses, France
Prion diseases (PD) are the unique neurodegenerative proteinopathies
reputed to be transmissible under field conditions since decades. The
transmission of Bovine Spongiform Encephalopathy (BSE) to humans evidenced that
an animal PD might be zoonotic under appropriate conditions. Contrarily, in the
absence of obvious (epidemiological or experimental) elements supporting a
transmission or genetic predispositions, PD, like the other proteinopathies, are
reputed to occur spontaneously (atpical animal prion strains, sporadic CJD
summing 80% of human prion cases). Non-human primate models provided the first
evidences supporting the transmissibiity of human prion strains and the zoonotic
potential of BSE. Among them, cynomolgus macaques brought major information for
BSE risk assessment for human health (Chen, 2014), according to their
phylogenetic proximity to humans and extended lifetime. We used this model to
assess the zoonotic potential of other animal PD from bovine, ovine and cervid
origins even after very long silent incubation periods. We recently observed the
direct transmission of a natural classical scrapie isolate to macaque after a
10-year silent incubation period, with features similar to some reported for
human cases of sporadic CJD, albeit requiring fourfold longe incubation than
BSE. Scrapie, as recently evoked in humanized mice (Cassard, 2014), is the third
potentially zoonotic PD (with BSE and L-type BSE), ***thus questioning the
origin of human sporadic cases. We will present an updated panorama of our
different transmission studies and discuss the implications of such extended
incubation periods on risk assessment of animal PD for human health.
===============
***thus questioning the origin of human sporadic cases...TSS
===============
O.08: H-type bovine spongiform encephalopathy associated with E211K prion
protein polymorphism: Clinical and pathologic features in wild-type and E211K
cattle following intracranial inoculation
S Jo Moore, M Heather West Greenlee, Jodi Smith, Eric Nicholson, Cathy
Vrentas, and Justin Greenlee United States Department of Agriculture; Ames, IA
USA
In 2006 an H-type bovine spongiform encephalopathy (BSE) case was reported
in an animal with an unusual polymorphism (E211K) in the prion protein gene.
Although the prevalence of this polymorphism is low, cattle carrying the K211
allele are predisposed to rapid onset of H-type BSE when exposed. The purpose of
this study was to investigate the phenotype of this BSE strain in wild-type
(E211E) and E211K heterozygous cattle. One calf carrying the wild-type allele
and one E211K calf were inoculated intracranially with H-type BSE brain
homogenate from the US 2006 case that also carried one K211 allelle. In
addition, one wild-type calf and one E211K calf were inoculated intracranially
with brain homogenate from a US 2003 classical BSE case. All animals succumbed
to clinical disease. Survival times for E211K H-type BSE inoculated catttle (10
and 18 months) were shorter than the classical BSE inoculated cattle (both 26
months). Significant changes in retinal function were observed in H-type BSE
challenged cattle only. Animals challenged with the same inoculum showed similar
severity and neuroanatomical distribution of vacuolation and disease-associated
prion protein deposition in the brain, though differences in neuropathology were
observed between E211K H-type BSE and classical BSE inoculated animals. Western
blot results for brain tissue from challenged animals were consistent with the
inoculum strains. ***This study demonstrates that the phenotype of E211K H-type
BSE remains stable when transmitted to cattle without the E211K polymorphism,
and exhibits a number of features that differ from classical BSE in both
wild-type and E211K cattle.
==============
***This study demonstrates that the phenotype of E211K H-type BSE remains
stable when transmitted to cattle without the E211K polymorphism, and exhibits a
number of features that differ from classical BSE in both wild-type and E211K
cattle.***
PLEASE SEE ;
Wednesday, May 27, 2015
BSE Case Associated with Prion Protein Gene Mutation
==============
P.108: Successful oral challenge of adult cattle with classical BSE
Sandor Dudas1,*, Kristina Santiago-Mateo1, Tammy Pickles1, Catherine
Graham2, and Stefanie Czub1 1Canadian Food Inspection Agency; NCAD Lethbridge;
Lethbridge, Alberta, Canada; 2Nova Scotia Department of Agriculture; Pathology
Laboratory; Truro, Nova Scotia, Canada
Classical Bovine spongiform encephalopathy (C-type BSE) is a feed- and
food-borne fatal neurological disease which can be orally transmitted to cattle
and humans. Due to the presence of contaminated milk replacer, it is generally
assumed that cattle become infected early in life as calves and then succumb to
disease as adults.
Here we challenged three 14 months old cattle per-orally with 100 grams of
C-type BSE brain to investigate age-related susceptibility or resistance. During
incubation, the animals were sampled monthly for blood and feces and subjected
to standardized testing to identify changes related to neurological
disease.
At 53 months post exposure, progressive signs of central nervous system
disease were observed in these 3 animals, and they were euthanized. Two of the
C-BSE animals tested strongly positive using standard BSE rapid tests, however
in 1 C-type challenged animal, Prion 2015 Poster Abstracts S67 PrPsc was not
detected using rapid tests for BSE. Subsequent testing resulted in the detection
of pathologic lesion in unusual brain location and PrPsc detection by PMCA
only.
Our study demonstrates susceptibility of adult cattle to oral transmission
of classical BSE. We are further examining explanations for the unusual disease
presentation in the third challenged animal.
========================
***Our study demonstrates susceptibility of adult cattle to oral
transmission of classical BSE. ***
P.86: Estimating the risk of transmission of BSE and scrapie to ruminants
and humans by protein misfolding cyclic amplification
Morikazu Imamura, Naoko Tabeta, Yoshifumi Iwamaru, and Yuichi Murayama
National Institute of Animal Health; Tsukuba, Japan
To assess the risk of the transmission of ruminant prions to ruminants and
humans at the molecular level, we investigated the ability of abnormal prion
protein (PrPSc) of typical and atypical BSEs (L-type and H-type) and typical
scrapie to convert normal prion protein (PrPC) from bovine, ovine, and human to
proteinase K-resistant PrPSc-like form (PrPres) using serial protein misfolding
cyclic amplification (PMCA).
Six rounds of serial PMCA was performed using 10% brain homogenates from
transgenic mice expressing bovine, ovine or human PrPC in combination with PrPSc
seed from typical and atypical BSE- or typical scrapie-infected brain
homogenates from native host species. In the conventional PMCA, the conversion
of PrPC to PrPres was observed only when the species of PrPC source and PrPSc
seed matched. However, in the PMCA with supplements (digitonin, synthetic polyA
and heparin), both bovine and ovine PrPC were converted by PrPSc from all tested
prion strains. On the other hand, human PrPC was converted by PrPSc from typical
and H-type BSE in this PMCA condition.
Although these results were not compatible with the previous reports
describing the lack of transmissibility of H-type BSE to ovine and human
transgenic mice, ***our findings suggest that possible transmission risk of
H-type BSE to sheep and human. Bioassay will be required to determine whether
the PMCA products are infectious to these animals.
================
***our findings suggest that possible transmission risk of H-type BSE to
sheep and human. ***
ALSO, PLEASE SEE ;
31 Jan 2015 at 20:14 GMT
*** Ruminant feed ban for cervids in the United States? ***
31 Jan 2015 at 20:14 GMT
Saturday, May 30, 2015
PRION 2015 ORAL AND POSTER CONGRESSIONAL ABSTRACTS
Wednesday, June 10, 2015
Zoonotic Potential of CWD Prions
LATE-BREAKING ABSTRACTS
please see attached pdf file, with references of breaches in the USA triple
BSE mad cow firewalls, and recent science on the TSE prion disease. ...TSS No
documents available. Attachments View All (1) Docket No. APHIS-2014-0107 Bovine
Spongiform Encephalopathy; Importation of Animals and Animal Products Singeltary
Submission View Attachment:
Thursday, May 28, 2015
OIE cuts six European countries' mad cow risk level, while increasing risk
factors for humans to the BSE TSE PRION DISEASE around the globe
COOL H.R. 2393 Agriculture Chairman K. Michael Conaway (R-TX) Fears of US
imports infected with mad cow disease is emerging as an issue in trans-Pacific
trade talks
Posted by Terry S. Singeltary Sr. on May 20, 2015 at 9:00am
Sunday, June 14, 2015
Larry’s Custom Meats Inc. Recalls Beef Tongue Products That May Contain
Specified Risk Materials BSE TSE Prion
spontaneous atypical BSE ???
if that's the case, then France is having one hell of an epidemic of
atypical BSE, probably why they stopped testing for BSE, problem solved $$$
As of December 2011, around 60 atypical BSE cases have currently been
reported in 13 countries, *** with over one third in France.
so 20 cases of atypical BSE in France, compared to the remaining 40 cases
in the remaining 12 Countries, divided by the remaining 12 Countries, about 3+
cases per country, besides Frances 20 cases. you cannot explain this away with
any spontaneous BSe. ...TSS
Sunday, October 5, 2014
France stops BSE testing for Mad Cow Disease
Thursday, July 24, 2014
*** Protocol for further laboratory investigations into the distribution of
infectivity of Atypical BSE SCIENTIFIC REPORT OF EFSA New protocol for Atypical
BSE investigations
Subject: FATEPriDE Environmental Factors that Affect the Development of
Prion Diseases
Date: February 18, 2006 at 9:24 am PST
FATEPriDE
Environmental Factors that Affect the Development of Prion Diseases.
Project funded by the European Commission under the Quality of Life
Programme.
Contract No: QLK4-CT-2002-02723
Project No: QLRT-2001-02723
Start Date
1st January 2003
Duration
36 months plus 6 month extension
Partners
1. The University of Bristol, UK (Co-ordinator) 2. National Environment
Research Council-The British Geological Society, UK 3. University of Bath, UK 4.
Free University of Berlin, Germany 5. University of Iceland, Iceland 6.
Universita degli studi di Perugia, Italy 7. Universite Joseph Fourier Grenoble,
France 8. Alpine Institute of Environmental Dynamics, France
Introduction
The work proposed here brings together top EU geo and biochemists focusing
on determining the environmental factors that affect the development of prion
diseases such as scrapie, bovine spongiform enchpalitis (BSE), chronic wasting
disease (CWD) and Creutzfeld-Jacobs disease (CJD). First the geographical
distribution of manganese and copper in soils will be investigated as risk
factors. This will be undertaken due to the fact that prion diseases often are
found in clusters. It now has been established that the normal metal for prion
protein is copper but if that metal is replaced with manganese, the structure of
the prion protein is altered. The role of organophosphate pesticides will also
be investigated because it has been suggested that copper is complexed with
organophosphate, preventing copper absorption.
Objectives
There is clear evidence that the occurrence of prion diseases often has a
non-random distribution, suggesting a link to some environmental factors. The
work proposed here will investigate risk factors, including the role of trace
elements and organophosphates. Analysis of regional variation in local
manganese/copper levels will be determined and compared to the incidence of the
diseases. The ability of manganese and/or organophosphates in influencing
conversion of the prion protein to an abnormal and/or infectious protein will be
determined. In combination with geographical occurrence and geo-chemical
considerations this program will identify whether these environmental
considerations should be acted upon to bring about effective prevention or at
least risk minimalisation of prion diseases in the EU and further afield.
Description of the Work
Recently it has been suggested that disbalance in dietary trace-elements
and/or exposure to organophosphates might either cause or be a risk factor for
prion disease development. In particular, high incidence of scrapie (e.g. in
Iceland), chronic wasting disease, and in Slovakia and Italy CJD are associated
with regions where soil and foliage are reported to be low in copper and high in
manganese. This proposal will address whether exposure to a diet that has a high
manganese/copper ratio can influence prion disease will also be addressed. In
particular, we shall investigate this theory at the level of protein, cells,
animals as well as geographical and geo-chemical associations with prion
diseases. Animal models of prion disease and sheep from farms in regions of high
scrapie will be investigated for a possible influence of level of manganese and
copper on incidence or onset of these diseases. Bio-chemical and biophysical
techniques will be used to investigate interaction of the prion protein with
copper and manganese to determine the mechanism by which Mn substitution for Cu
influences conversion to the abnormal isoform of the protein and whether such
conversion results in protein that is infectious in mouse bioassay for
infectivity. Additionally, a cell culture model will be used to generate
abnormal prion protein by exposure to manganese. Cell culture model of infection
will be used to assay whether prion disease alters manganese metabolism and
transport of manganese into cells. The level of expression of the prion protein
is in itself a risk factor for prion disease as it shortens the incubation time
for the disease. This research will result in understanding of the role of
disbalance in the trace elements Cu and Mn on the onset and mechanisms behind
the occurrence of prion diseases and will for the first time define whether
there are environmental risk factors for prion diseases.
Milestones and Expected Results
The study proposed here will produce a geo-chemical map of Europe for
manganese and copper. These maps will be used to target field areas where prion
diseases have occurred as clusters. The bio-chemical studies will establish
whether the replacement of manganese for copper in prion protein is a risk
factor for the disease _development_. Organophosphate will also be investigated
as a risk factor. The study aims at minimising the risk of prion diseases for
humans and animals in the EU.
a) As regards the involvement of organophosphates in the origin of BSE, no
new scientific information providing evidence or supporting the hypothesis by
valid data became available after the adoption of the last opinion of the SSC on
this issue. Consequently there is no reason for modifying the existing opinions.
b) Regarding the possibility of OP poisoning, the European legislation for
registration of plant protection products and veterinary medicines ? addressed
in the enquiries ? provide the basis for safe use of registered compounds and
their formulations. Regarding the alleged intoxication cases reported and OP
exposure it must be concluded that safety measures may not have been strictly
followed.
References
Brown, D.R., Qin, K., Herms, J.W., Madlung, A., Manson, J., Strome, R.,
Fraser, P.E., Kruck, T., von Bohlen, A., Schulz- Schaeffer, W., Giese, A.,
Westaway, D. and Kretzschmar, H. (1997) The Cellular Prion Protein Binds Copper
In Vivo, Nature, 390, 684-7. Purdey, M. (2000) Ecosystems Supporting Clusters of
Sporadic TSEs Demonstrate Excesses of the Radical- Generating Divalent Cation
Manganese and Deficiencies of Antioxidant Co-Factors Cu, Se, Fe, Zn Medical
Hypotheses, 54, 278-306. Scientific Steering Committee, 1998. Opinion on
possible links between BSE and Organophosphates. Adopted on 25-26 June 1998
Scientific Steering Committee, 2001. Opinion on Hypotheses on the origin and
transmission of BSE. Adopted on 29-30 November 2001.
FATEPRIDE
ITEM 6 FATEPRIDE (SEAC 97/4) 35.
The Chair explained that FATEPriDE is a multi-centre European Union funded
project that examined the possible influence of environmental trace elements on
the occurrence of TSEs. 36. Professor David Brown (University of Bath) explained
that the project had principally studied potential interactions between prion
disease and copper and manganese, although interactions with other environmental
factors such as organophosphates had also been assessed. No link, other than
with manganese, between many environmental factors studied, including
organophosphates, and TSEs was found. The key experiments and findings had been
summarised in SEAC paper 97/4. The main conclusions were that manganese binds to
PrP with similar affinity to known manganese binding proteins, induces
conformational change in PrP, catalyses PrP aggregation, induces protease
resistance in PrP, increases PrP expression levels and increases cellular
susceptibility to prion infection. Manganese had also been found at high levels
on farms with a high classical scrapie incidence and manganese was found to
increase the stability of PrP in soil. Although it had been the intention to
create maps of bioavailable manganese and compare those to similar maps of TSE
hotspots, this had not been possible as no data of sufficient precision relating
the location of BSE or scrapie cases was made available. Further studies were
required to investigate the interactions of manganese and prions.
37. Members noted that the study suggested an association between high
levels of bioavailable manganese, low levels of bioavailable copper and
classical scrapie in field studies. However, it was likely that other factors
such as soil pH and organic matter may also be involved. It was acknowledged
that it was very difficult in environmental studies to exclude potential
confounding factors. The experimental and field data suggested that manganese
may influence the susceptibility to TSEs.
However, there was no evidence that environmental factors, including
manganese, cause disease.
38. Members noted that data on BSE should allow spatial mapping of cases,
however sheep movements were so complex that it is not possible to create
similar maps for classical or atypical scrapie. 39. Members suggested that
further research could investigate the differential stability of a range of TSE
agents bound with manganese in soil, although other modifying factors in soil
such as 12 © SEAC 2006 soil content and pH are likely. In addition, further
animal studies could examine the effect of manganese on a range of TSE
agents.
Subject: FATEPriDE KEY FINDINGS ORGANOPHOSPHATE NO RELATIONSHIP TO CAUSE
TSE Date: May 3, 2007 at 8:41 am PST
KEY FINDINGS
Organophosphate Studies
6. Studies using phosmet (an organophosphate pesticide) were carried out
throughout the project. No relationship between this compound and the potential
to cause a TSE were identified. In studies with oral dosing of rats, it was
shown that PrP expression levels increased in the brain but there was no
association between this and formation of proteinase K (PK) resistant PrP.
snip...
12. A model of seed protein aggregation and fibril formation was
established using PrP charged with Mn2+. PrP-Mn2+ was found to form small
circular aggregates able to catalyse further protein aggregation and
fibrilisation of PrP. This model unlike other published models (for example
those of Baskakov et al.1) does not require the presence of denaturants and is
not an autocatalytic process (i.e. the substrate of the reaction did not
aggregate). The results suggest that Mn2+ may play a role in the formation of
prion seeds
__although further studies showed that this material was not infectious in
mouse bioassay.__
snip...
24. The project also generated information concerning the relation of TSEs
to environmental factors: • __Potentially no role for organophosphates in
TSEs.__ • Increased Mn in the diet results in higher PrP levels in the brain. •
No conclusion is yet possible in terms of the relationship between environmental
trace element concentrations and the geographical occurrence of TSEs (classical
scrapie or BSE). • Some confirmation was provided that in some specific farms
occurrence of classical scrapie correlates with high Mn levels.
OP'S MEETING WITH PURDEY
http://web.archive.org/web/20010614051238/http://www.bseinquiry.gov.uk/files/yb/1994/02/09001001.pdf
Phosmet induces up-regulation of surface levels of the cellular prion
protein. Neuroreport. 9(7):1391-1395, May 11, 1998. Gordon, Irit 1; Abdulla,
Elizabeth M. 1; Campbell, Iain C. 1; Whatley, Stephen A. 1,2 Abstract: CHRONIC
(2 day) exposure of human neuroblastoma cells to the organophosphate pesticide
phosmet induced a marked concentration-dependent increase in the levels of PrP
present on the cell surface as assessed by biotin labelling and
immunoprecipitation. Levels of both phospholipase C (PIPLC)-releasable and
non-releasable forms of PrP were increased on the plasma membrane. These
increases appear to be due to post-transcriptional mechanisms, since PrP mRNA
levels as assessed by Northern blotting were unaffected by phosmet treatment.
These data raise the possibility that phosmet exposure could increase the
_susceptibility to the prion agent by altering the levels of accessible
PrP_.
(C) Lippincott-Raven Publishers.
a) As regards the involvement of organophosphates in the origin of BSE, no
new scientific information providing evidence or supporting the hypothesis by
valid data became available after the adoption of the last opinion of the SSC on
this issue. Consequently there is no reason for modifying the existing opinions.
b) Regarding the possibility of OP poisoning, the European legislation for
registration of plant protection products and veterinary medicines ? addressed
in the enquiries ? provide the basis for safe use of registered compounds and
their formulations. Regarding the alleged intoxication cases reported and OP
exposure it must be concluded that safety measures may not have been strictly
followed.
References Brown, D.R., Qin, K., Herms, J.W., Madlung, A., Manson, J.,
Strome, R., Fraser, P.E., Kruck, T., von Bohlen, A., Schulz- Schaeffer, W.,
Giese, A., Westaway, D. and Kretzschmar, H. (1997) The Cellular Prion Protein
Binds Copper In Vivo, Nature, 390, 684-7. Purdey, M. (2000) Ecosystems
Supporting Clusters of Sporadic TSEs Demonstrate Excesses of the Radical-
Generating Divalent Cation Manganese and Deficiencies of Antioxidant Co-Factors
Cu, Se, Fe, Zn Medical Hypotheses, 54, 278-306. Scientific Steering Committee,
1998. Opinion on possible links between BSE and Organophosphates. Adopted on
25-26 June 1998 Scientific Steering Committee, 2001. Opinion on Hypotheses on
the origin and transmission of BSE. Adopted on 29-30 November 2001.
UK FARMER WITH BSE (personal communication)
1) None of our animals that contracted BSE were treated with OP's, even in
utero. 2) My kids were treated with OP's as infants to control head lice. This
seems to be endemic as infection waves in UK primary schools (and possibly
elsewhere). 3) One might argue if the continued use of british beef in the UK
was ethical, none the less it happened. We have a duty to learn from it, not
least a duty to learn on behalf of those people who died so horribly....
============end...tss===========
However, i have never dusputed the remote possibility that ;
Phosmet induces up-regulation of surface levels of the cellular prion
protein.
Neuroreport. 9(7):1391-1395, May 11, 1998.
Gordon, Irit 1; Abdulla, Elizabeth M. 1; Campbell, Iain C. 1; Whatley,
Stephen A. 1,2
Abstract:
CHRONIC (2 day) exposure of human neuroblastoma cells to the
organophosphate pesticide phosmet induced a marked concentration-dependent
increase in the levels of PrP present on the cell surface as assessed by biotin
labelling and immunoprecipitation. Levels of both phospholipase C
(PIPLC)-releasable and non-releasable forms of PrP were increased on the plasma
membrane. These increases appear to be due to post-transcriptional mechanisms,
since PrP mRNA levels as assessed by Northern blotting were unaffected by
phosmet treatment. These data raise the possibility that phosmet exposure could
increase the _susceptibility to the prion agent by altering the levels of
accessible PrP_.
(C) Lippincott-Raven Publishers.
Copper deficiency in the young bovine results in dramatic decreases in
brain copper concentration ***but does not alter brain prion protein
biology
L. R. Legleiter, J. W. Spears and H. C. Liu Department of Animal Science
and Interdepartmental Nutrition Program, North Carolina State University,
Raleigh, NC
Jerry_Spears@ncsu.edu
Abstract
A manganese (Mn) for copper (Cu) substitution on cellular prion proteins
(PrPc) in the brain that results in biochemical changes to PrPc has been
implicated in the pathogenesis of transmissible spongiform encephalopathies.
Recent research in the mature bovine does _NOT_ support this theory. The present
study tested this hypothesis using progeny from gestating cows receiving
Cu-deficient diets or Cu-deficient diets coupled with high dietary Mn.
Copper-adequate cows (n = 39) were assigned randomly to treatments: 1) control
(adequate in Cu and Mn), 2) Cu-deficient (-Cu), and 3) Cu-deficient plus high
dietary Mn (-Cu Mn). Cows assigned to treatments -Cu and -Cu Mn received no
supplemental Cu and were supplemented with molybdenum (Mo) to further induce Cu
deficiency. The -Cu Mn treatment also received 500 mg supplemental Mn/kg dietary
DM. Calves were weaned at 180 d and maintained on the same treatments as their
respective dams for 260 d. Copper-deficient calves (-Cu and -Cu Mn) had
decreased (P = 0.001) brain (obex) Cu and tended to have increased (P = 0.09)
obex Mn relative to controls. Obex Mn/Cu ratios were substantially increased (P
< 0.001) in calves receiving -Cu and -Cu Mn treatments compared to controls
and were higher (P < 0.001) in -Cu Mn calves than in -Cu calves. Obex prion
protein characteristics, including proteinase K degradability, superoxide
dismutase (SOD)-like activity, and glycoform distributions, were largely
unaffected. Obex tissue antioxidant capacity was not compromised by
perturbations in brain metals, but Cu-deficient calves tended to have decreased
(P = 0.06) Cu/Zn SOD activity and increased (P = 0.06) Mn SOD activity. Although
obex copper was decreased due to Cu deficiency and Mn increased due to exposure
to high dietary Mn, the obex metal imbalance had minimal effects on PrPc
functional characteristics in the calves.
2015
P.46: Mitigation of prion infectivity and conversion capacity by a
simulated natural process—repeated cycles of drying and wetting
Qi Yuan2,*, Thomas Eckland2, Glenn Telling3, Jason Bartz2, and Shannon
Bartelt-Hunt1 1University of Nebraska-Lincoln; Omaha, NE, USA; 2Creighton
University; Omaha, NE, USA; 3Colorado State University; Fort Collins, CO,
USA
Prions enter the environment from infected hosts, bind to a wide range of
soil and soil minerals, and remain highly infectious. Environmental sources of
prions almost certainly contribute to the transmission of chronic wasting
disease in cervids and scrapie in sheep and goats. While much is known about the
introduction of prions into the environment and their interaction with soil,
relatively little is known about prion degradation and inactivation by natural
environmental processes. In this study, we examined the effect of repeated
cycles of drying and wetting on prion fitness and determined that 10 cycles of
repeated drying and wetting could reduce PrPSc abundance, PMCA amplification
efficiency and extend the incubation period of disease. Importantly, prions
bound to soil were more susceptible Prion 2015 Poster Abstracts S35 to
inactivation by repeated cycles of drying and wetting compared to unbound
prions, a result which may be due to conformational changes in soil-bound PrPSc
or consolidation of the bonding between PrPSc and soil. This novel finding
demonstrates that naturallyoccurring environmental process can degrade
prions.
==========
P.66: Transport of CWD prions in Alberta soils
Alsu Kuznetsova1, Debbie McKenzie2, Tariq Siddique1, and Judd Aiken2
1University of Alberta; Department of Renewable Resources; Edmonton, Canada;
2University of Alberta; Centre for Prions and Protein Folding Diseases;
Edmonton, Canada
The transmission of chronic wasting disease (CWD) includes environmental
pathways, particularly soils as disease reservoirs. Soils differ dramatically in
their capacity to adsorb PrPCWD due to differences in mineral composition, humus
content and particle surface area. Mineral and organic compounds have the
ability to bind PrPCWD impacting infectious properties. The extreme variability
of these soil constituents suggests that the PrPCWD fate and behavior will
depend on specific soil properties. The soil moisture regime also has the
potential to affect transportation of compounds through a soil profile. PrPCWD
can be bound to soil particles with Prion 2015 Poster Abstracts S45 3
hypothetical scenarios for prion fate: (i) prions stay in the surface soil
horizon and remain bioavailable for grazing animals; (ii) prions can be
transported into lower soil horizons and become unavailable for consumption; or
(iii) prions can migrate through the soil profile and end up in ground water. We
performed bench-scale experiments with soil columns to evaluate the potential
for transportation of PrPCWD using soils from different regions of Alberta,
Canada. The Luvisols found in northern Alberta have an ustic/udic moisture
regime and illite as a predominant clay mineral. The prion binding capacity of
illite is poor suggesting it cannot contribute to prion binding and PrPCWD can
migrate through the soil profile. Chernozems are found in the CWD-endemic region
in southern Alberta and have an aridic soil moisture regime, high amount of
humus content and contain montmorillonite. In the Chernozem soil columns PrPCWD
remains on the soil surface and does not migrate in lower horizons.
========
P.161: Prion soil binding may explain efficient horizontal CWD
transmission
Nathaniel Denkers1, Davin Henderson1, Shannon Bartelt-Hunt2, Jason Bartz3,
and Edward Hoover1 1Colorado State University; Fort Collins, Colorado USA;
2University of Nebraska-Lincoln; Omaha, Nebraska USA; 3Creighton University;
Omaha, Nebraska USA
Background. Chronic wasting disease (CWD) is unique due to the facile
spread in nature. The interaction of excreted CWD prions and soil is a
hypothesized contributor in environmental transmission. The present study
examines whether and to what degree CWD prions bind to silty clay loam (SCL)
using an adapted version of real-time quaking-induced conversion (RT-QuIC)
methodology.
Materials and Methods. Varying amounts (50–3.12 mg) of SCL were incubated
with 1 mL-serial dilutions of CWD (C), CWD (¡), or no brain homogenate (BH).
Samples were centrifuged, washed, diluted 1:10 in 0.1% SDS, and 2.5 uL seeded in
RT-QuIC assays employing recombinant Syrian hamster prion PrP substrate.
Multiple well replicates of sample and supernatant fractions were assayed for
positive seeding activity (recorded as thioflavin T fluorescence emission; 480
nm). Samples were considered positive if they crossed a threshold of 25,000.
Reaction rates (RR) were calculated, averaged, and expressed as 1/RR. Results.
Positive seeding activity was detected for most SCL samples incubated with CWD
(C) BH dilutions. Higher SCL concentrations (50 mg) produced low fluorescent
readings due to optical interference. Lower SCL concentrations (6.25 mg)
produced minimal optical interference and removed the vast majority of seeding
activity from CWDC BH in a concentration-dependent manner; determined by seeding
activity in residual BH supernatants. Control SCL and supernatants produced
minimal falsepositive reactions (8 of 240 replicates; 3.3%). We estimated the
prion binding capacity of SCL to be 0.16 ng/mg.
Conclusion. Silty clay loam exhibits highly efficient prion binding,
inferring a durable environmental reservoir, and an efficient mechanism for
indirect horizontal CWD transmission.
Saturday, March 15, 2014
Potential role of soil properties in the spread of CWD in western
Canada
Tuesday, June 23, 2015
Report on the monitoring and testing of ruminants for the presence of
transmissible spongiform encephalopathies (TSEs) in the EU in 2013 Final version
18 May 2015
end...TSS
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