Wisconsin CWD-positive white-tailed deer found on Oconto County hunting preserve Date: September 30, 2016
CWD-positive white-tailed deer found on Oconto County hunting preserve WI
Department of Agriculture, Trade and Consumer Protection sent this bulletin at
09/30/2016 09:20 AM CDT
CWD-positive white-tailed deer found on Oconto County hunting preserve
Date: September 30, 2016
Contact: Raechelle Belli, 608-224-5005 or Bill Cosh, Communications
Director, 608-224-5020
MADISON – A white-tailed deer on an Oconto County hunting preserve has
tested positive for chronic wasting disease (CWD), State Veterinarian Dr. Paul
McGraw announced today.
The National Veterinary Services Laboratory (NVSL) in Ames, Iowa, reported
the final test results back to the state. The animal was an 18 month old female
and was one of more than an estimated 1,450 deer in the 1,363-acre
preserve.
The deer was born on the premises and killed on the preserve. Samples were
taken in accordance with Wisconsin Department of Agriculture, Trade and Consumer
Protection’s (DATCP’s) rules, which require testing of farm-raised deer and elk
when they die, go to slaughter or are killed. More than 1,000 deer from this
preserve have been tested for CWD since 2010.
The sample originally tested positive at a regional laboratory and required
a confirmatory test at the NVSL. The DATCP Animal Health Division’s
investigation will look at animal movement records, but since the deer was born
on the preserve, there will not be any trace back investigations of any other
herds.
The business will be allowed to conduct hunts on the quarantined preserve,
because properly handled dead animals leaving the premises do not pose a disease
risk.
###
*** Pathological features of chronic wasting disease in reindeer and
demonstration of horizontal transmission Major Findings for Norway ***
Title: Pathological features of chronic wasting disease in reindeer and
demonstration of horizontal transmission
Author
item Moore, Sarah item Kunkle, Robert item West greenlee, Mary item
Nicholson, Eric item Richt, Juergen item Hamir, Amirali item Waters, Wade item
Greenlee, Justin
Submitted to: Emerging Infectious Diseases Publication Type: Peer reviewed
journal Publication Acceptance Date: 8/29/2016 Publication Date: N/A Citation:
Interpretive Summary: Chronic wasting disease (CWD) is a fatal
neurodegenerative disease that occurs in farmed and wild cervids (deer and elk)
of North America and was recently diagnosed in a single free-ranging reindeer
(Rangifer tarandus tarandus) in Norway. CWD is a transmissible spongiform
encephalopathy (TSE) that is caused by infectious proteins called prions that
are resistant to various methods of decontamination and environmental
degradation. Little is known about the susceptibility of or potential for
transmission amongst reindeer. In this experiment, we tested the susceptibility
of reindeer to CWD from various sources (elk, mule deer, or white-tailed deer)
after intracranial inoculation and tested the potential for infected reindeer to
transmit to non-inoculated animals by co-housing or housing in adjacent pens.
Reindeer were susceptible to CWD from elk, mule deer, or white-tailed deer
sources after experimental inoculation. Most importantly, non-inoculated
reindeer that were co-housed with infected reindeer or housed in pens adjacent
to infected reindeer but without the potential for nose-to-nose contact also
developed evidence of CWD infection. This is a major new finding that may have a
great impact on the recently diagnosed case of CWD in the only remaining
free-ranging reindeer population in Europe as our findings imply that horizontal
transmission to other reindeer within that herd has already occurred. Further,
this information will help regulatory and wildlife officials developing plans to
reduce or eliminate CWD and cervid farmers that want to ensure that their herd
remains CWD-free, but were previously unsure of the potential for reindeer to
transmit CWD.
Technical Abstract: Chronic wasting disease (CWD) is a naturally-occurring,
fatal prion disease of cervids. Reindeer (Rangifer tarandus tarandus) are
susceptible to CWD following oral challenge, and CWD was recently reported in a
free-ranging reindeer of Norway. Potential contact between CWD-affected cervids
and Rangifer species that are free-ranging or co-housed on farms presents a
potential risk of CWD transmission. The aims of this study were to 1)
investigate the transmission of CWD from white-tailed deer (Odocoileus
virginianus; CWDwtd), mule deer (Odocoileus hemionus; CWDmd), or elk (Cervus
elaphus nelsoni; CWDelk) to reindeer via the intracranial route, and 2) to
assess for direct and indirect horizontal transmission to non-inoculated
sentinels. Three groups of 5 reindeer fawns were challenged intracranially with
CWDwtd, CWDmd, or CWDelk. Two years after challenge of inoculated reindeer,
non-inoculated negative control reindeer were introduced into the same pen as
the CWDwtd inoculated reindeer (direct contact; n=4) or into a pen adjacent to
the CWDmd inoculated reindeer (indirect contact; n=2). Experimentally inoculated
reindeer were allowed to develop clinical disease. At death/euthanasia a
complete necropsy examination was performed, including immunohistochemical
testing of tissues for disease-associated CWD prion protein (PrPcwd).
Intracranially challenged reindeer developed clinical disease from 21 months
post-inoculation (months PI). PrPcwd was detected in 5 out of 6 sentinel
reindeer although only 2 out of 6 developed clinical disease during the study
period (< 57 months PI). We have shown that reindeer are susceptible to CWD
from various cervid sources and can transmit CWD to naïve reindeer both directly
and indirectly.
see more here ;
Monday, September 05, 2016
Pathological features of chronic wasting disease in reindeer and
demonstration of horizontal transmission Major Findings for Norway
Thursday, September 22, 2016
NORWAY DETECTS 5TH CASE OF CHRONIC WASTING DISEASE CWD TSE PRION
Skrantesjuke
Wednesday, September 7, 2016
*** An assessment of the long-term persistence of prion infectivity in
aquatic environments
Friday, September 02, 2016
*** Chronic Wasting Disease Drives Population Decline of White-Tailed
Deer
Monday, August 29, 2016
*** NWHC USGS CHRONIC WASTING DISEASE CWD TSE PRION UPDATE
Thursday, August 18, 2016
*** PROCEEDINGS ONE HUNDRED AND Nineteenth ANNUAL MEETING of the USAHA BSE,
CWD, SCRAPIE, PORCINE TSE PRION October 22 28, 2015 ***
Saturday, December 12, 2015
NOTICE: Environmental Impact Statement on Large Livestock Carcasses TSE
Prion REPORT December 14, 2015
Friday, August 14, 2015
Carcass Management During a Mass Animal Health Emergency Draft Programmatic
Environmental Impact Statement—August 2015
*** Infectious agent of sheep scrapie may persist in the environment for at
least 16 years ***
Gudmundur Georgsson1, Sigurdur Sigurdarson2 and Paul Brown3
Using in vitro prion replication for high sensitive detection of prions and
prionlike proteins and for understanding mechanisms of transmission.
Claudio Soto
Mitchell Center for Alzheimer's diseases and related Brain disorders,
Department of Neurology, University of Texas Medical School at Houston.
Prion and prion-like proteins are misfolded protein aggregates with the
ability to selfpropagate to spread disease between cells, organs and in some
cases across individuals. I n T r a n s m i s s i b l e s p o n g i f o r m
encephalopathies (TSEs), prions are mostly composed by a misfolded form of the
prion protein (PrPSc), which propagates by transmitting its misfolding to the
normal prion protein (PrPC). The availability of a procedure to replicate prions
in the laboratory may be important to study the mechanism of prion and
prion-like spreading and to develop high sensitive detection of small quantities
of misfolded proteins in biological fluids, tissues and environmental samples.
Protein Misfolding Cyclic Amplification (PMCA) is a simple, fast and efficient
methodology to mimic prion replication in the test tube. PMCA is a platform
technology that may enable amplification of any prion-like misfolded protein
aggregating through a seeding/nucleation process. In TSEs, PMCA is able to
detect the equivalent of one single molecule of infectious PrPSc and propagate
prions that maintain high infectivity, strain properties and species
specificity. Using PMCA we have been able to detect PrPSc in blood and urine of
experimentally infected animals and humans affected by vCJD with high
sensitivity and specificity. Recently, we have expanded the principles of PMCA
to amplify amyloid-beta (Aβ) and alphasynuclein (α-syn) aggregates implicated in
Alzheimer's and Parkinson's diseases, respectively. Experiments are ongoing to
study the utility of this technology to detect Aβ and α-syn aggregates in
samples of CSF and blood from patients affected by these diseases.
=========================
***Recently, we have been using PMCA to study the role of environmental
prion contamination on the horizontal spreading of TSEs. These experiments have
focused on the study of the interaction of prions with plants and
environmentally relevant surfaces. Our results show that plants (both leaves and
roots) bind tightly to prions present in brain extracts and excreta (urine and
feces) and retain even small quantities of PrPSc for long periods of time.
Strikingly, ingestion of prioncontaminated leaves and roots produced disease
with a 100% attack rate and an incubation period not substantially longer than
feeding animals directly with scrapie brain homogenate. Furthermore, plants can
uptake prions from contaminated soil and transport them to different parts of
the plant tissue (stem and leaves). Similarly, prions bind tightly to a variety
of environmentally relevant surfaces, including stones, wood, metals, plastic,
glass, cement, etc. Prion contaminated surfaces efficiently transmit prion
disease when these materials were directly injected into the brain of animals
and strikingly when the contaminated surfaces were just placed in the animal
cage. These findings demonstrate that environmental materials can efficiently
bind infectious prions and act as carriers of infectivity, suggesting that they
may play an important role in the horizontal transmission of the disease.
========================
Since its invention 13 years ago, PMCA has helped to answer fundamental
questions of prion propagation and has broad applications in research areas
including the food industry, blood bank safety and human and veterinary disease
diagnosis.
see ;
with CWD TSE Prions, I am not sure there is any absolute yet, other than
what we know with transmission studies, and we know tse prion kill, and tse
prion are bad. science shows to date, that indeed soil, dirt, some better than
others, can act as a carrier. same with objects, farm furniture. take it with
how ever many grains of salt you wish, or not. if load factor plays a role in
the end formula, then everything should be on the table, in my opinion. see
;
***Recently, we have been using PMCA to study the role of environmental
prion contamination on the horizontal spreading of TSEs. These experiments have
focused on the study of the interaction of prions with plants and
environmentally relevant surfaces. Our results show that plants (both leaves and
roots) bind tightly to prions present in brain extracts and excreta (urine and
feces) and retain even small quantities of PrPSc for long periods of time.
Strikingly, ingestion of prioncontaminated leaves and roots produced disease
with a 100% attack rate and an incubation period not substantially longer than
feeding animals directly with scrapie brain homogenate. Furthermore, plants can
uptake prions from contaminated soil and transport them to different parts of
the plant tissue (stem and leaves). Similarly, prions bind tightly to a variety
of environmentally relevant surfaces, including stones, wood, metals, plastic,
glass, cement, etc. Prion contaminated surfaces efficiently transmit prion
disease when these materials were directly injected into the brain of animals
and strikingly when the contaminated surfaces were just placed in the animal
cage. These findings demonstrate that environmental materials can efficiently
bind infectious prions and act as carriers of infectivity, suggesting that they
may play an important role in the horizontal transmission of the disease.
Since its invention 13 years ago, PMCA has helped to answer fundamental
questions of prion propagation and has broad applications in research areas
including the food industry, blood bank safety and human and veterinary disease
diagnosis.
see ;
Oral Transmissibility of Prion Disease Is Enhanced by Binding to Soil
Particles
Author Summary
Transmissible spongiform encephalopathies (TSEs) are a group of incurable
neurological diseases likely caused by a misfolded form of the prion protein.
TSEs include scrapie in sheep, bovine spongiform encephalopathy (‘‘mad cow’’
disease) in cattle, chronic wasting disease in deer and elk, and
Creutzfeldt-Jakob disease in humans. Scrapie and chronic wasting disease are
unique among TSEs because they can be transmitted between animals, and the
disease agents appear to persist in environments previously inhabited by
infected animals. Soil has been hypothesized to act as a reservoir of
infectivity and to bind the infectious agent. In the current study, we orally
dosed experimental animals with a common clay mineral, montmorillonite, or whole
soils laden with infectious prions, and compared the transmissibility to unbound
agent. We found that prions bound to montmorillonite and whole soils remained
orally infectious, and, in most cases, increased the oral transmission of
disease compared to the unbound agent. The results presented in this study
suggest that soil may contribute to environmental spread of TSEs by increasing
the transmissibility of small amounts of infectious agent in the
environment.
tse prion soil
Wednesday, December 16, 2015
Objects in contact with classical scrapie sheep act as a reservoir for
scrapie transmission
The sources of dust borne prions are unknown but it seems reasonable to
assume that faecal, urine, skin, parturient material and saliva-derived prions
may contribute to this mobile environmental reservoir of infectivity. This work
highlights a possible transmission route for scrapie within the farm
environment, and this is likely to be paralleled in CWD which shows strong
similarities with scrapie in terms of prion dissemination and disease
transmission. The data indicate that the presence of scrapie prions in dust is
likely to make the control of these diseases a considerable challenge.
>>>Particle-associated PrPTSE molecules may migrate from locations
of deposition via transport processes affecting soil particles, including
entrainment in and movement with air and overland flow. <<<
Fate of Prions in Soil: A Review
Christen B. Smith, Clarissa J. Booth, and Joel A. Pedersen*
Several reports have shown that prions can persist in soil for several
years. Significant interest remains in developing methods that could be applied
to degrade PrPTSE in naturally contaminated soils. Preliminary research suggests
that serine proteases and the microbial consortia in stimulated soils and
compost may partially degrade PrPTSE. Transition metal oxides in soil (viz.
manganese oxide) may also mediate prion inactivation. Overall, the effect of
prion attachment to soil particles on its persistence in the environment is not
well understood, and additional study is needed to determine its implications on
the environmental transmission of scrapie and CWD.
P.161: Prion soil binding may explain efficient horizontal CWD transmission
Conclusion. Silty clay loam exhibits highly efficient prion binding,
inferring a durable environmental reservoir, and an efficient mechanism for
indirect horizontal CWD transmission.
>>>Another alternative would be an absolute prohibition on the
movement of deer within the state for any purpose. While this alternative would
significantly reduce the potential spread of CWD, it would also have the
simultaneous effect of preventing landowners and land managers from implementing
popular management strategies involving the movement of deer, and would deprive
deer breeders of the ability to engage in the business of buying and selling
breeder deer. Therefore, this alternative was rejected because the department
determined that it placed an avoidable burden on the regulated
community.<<<
Wednesday, December 16, 2015
Objects in contact with classical scrapie sheep act as a reservoir for
scrapie transmission
Objects in contact with classical scrapie sheep act as a reservoir for
scrapie transmission
Timm Konold1*, Stephen A. C. Hawkins2, Lisa C. Thurston3, Ben C. Maddison4,
Kevin C. Gough5, Anthony Duarte1 and Hugh A. Simmons1
1 Animal Sciences Unit, Animal and Plant Health Agency Weybridge,
Addlestone, UK, 2 Pathology Department, Animal and Plant Health Agency
Weybridge, Addlestone, UK, 3 Surveillance and Laboratory Services, Animal and
Plant Health Agency Penrith, Penrith, UK, 4 ADAS UK, School of Veterinary
Medicine and Science, University of Nottingham, Sutton Bonington, UK, 5 School
of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington,
UK
Classical scrapie is an environmentally transmissible prion disease of
sheep and goats. Prions can persist and remain potentially infectious in the
environment for many years and thus pose a risk of infecting animals after
re-stocking. In vitro studies using serial protein misfolding cyclic
amplification (sPMCA) have suggested that objects on a scrapie affected sheep
farm could contribute to disease transmission. This in vivo study aimed to
determine the role of field furniture (water troughs, feeding troughs, fencing,
and other objects that sheep may rub against) used by a scrapie-infected sheep
flock as a vector for disease transmission to scrapie-free lambs with the prion
protein genotype VRQ/VRQ, which is associated with high susceptibility to
classical scrapie. When the field furniture was placed in clean accommodation,
sheep became infected when exposed to either a water trough (four out of five)
or to objects used for rubbing (four out of seven). This field furniture had
been used by the scrapie-infected flock 8 weeks earlier and had previously been
shown to harbor scrapie prions by sPMCA. Sheep also became infected (20 out of
23) through exposure to contaminated field furniture placed within pasture not
used by scrapie-infected sheep for 40 months, even though swabs from this
furniture tested negative by PMCA. This infection rate decreased (1 out of 12)
on the same paddock after replacement with clean field furniture. Twelve grazing
sheep exposed to field furniture not in contact with scrapie-infected sheep for
18 months remained scrapie free. The findings of this study highlight the role
of field furniture used by scrapie-infected sheep to act as a reservoir for
disease re-introduction although infectivity declines considerably if the field
furniture has not been in contact with scrapie-infected sheep for several
months. PMCA may not be as sensitive as VRQ/VRQ sheep to test for environmental
contamination.
snip...
Discussion
Classical scrapie is an environmentally transmissible disease because it
has been reported in naïve, supposedly previously unexposed sheep placed in
pastures formerly occupied by scrapie-infected sheep (4, 19, 20). Although the
vector for disease transmission is not known, soil is likely to be an important
reservoir for prions (2) where – based on studies in rodents – prions can adhere
to minerals as a biologically active form (21) and remain infectious for more
than 2 years (22). Similarly, chronic wasting disease (CWD) has re-occurred in
mule deer housed in paddocks used by infected deer 2 years earlier, which was
assumed to be through foraging and soil consumption (23).
Our study suggested that the risk of acquiring scrapie infection was
greater through exposure to contaminated wooden, plastic, and metal surfaces via
water or food troughs, fencing, and hurdles than through grazing. Drinking from
a water trough used by the scrapie flock was sufficient to cause infection in
sheep in a clean building. Exposure to fences and other objects used for rubbing
also led to infection, which supported the hypothesis that skin may be a vector
for disease transmission (9). The risk of these objects to cause infection was
further demonstrated when 87% of 23 sheep presented with PrPSc in lymphoid
tissue after grazing on one of the paddocks, which contained metal hurdles, a
metal lamb creep and a water trough in contact with the scrapie flock up to 8
weeks earlier, whereas no infection had been demonstrated previously in sheep
grazing on this paddock, when equipped with new fencing and field furniture.
When the contaminated furniture and fencing were removed, the infection rate
dropped significantly to 8% of 12 sheep, with soil of the paddock as the most
likely source of infection caused by shedding of prions from the
scrapie-infected sheep in this paddock up to a week earlier.
This study also indicated that the level of contamination of field
furniture sufficient to cause infection was dependent on two factors: stage of
incubation period and time of last use by scrapie-infected sheep. Drinking from
a water trough that had been used by scrapie sheep in the predominantly
pre-clinical phase did not appear to cause infection, whereas infection was
shown in sheep drinking from the water trough used by scrapie sheep in the later
stage of the disease. It is possible that contamination occurred through
shedding of prions in saliva, which may have contaminated the surface of the
water trough and subsequently the water when it was refilled. Contamination
appeared to be sufficient to cause infection only if the trough was in contact
with sheep that included clinical cases. Indeed, there is an increased risk of
bodily fluid infectivity with disease progression in scrapie (24) and CWD (25)
based on PrPSc detection by sPMCA. Although ultraviolet light and heat under
natural conditions do not inactivate prions (26), furniture in contact with the
scrapie flock, which was assumed to be sufficiently contaminated to cause
infection, did not act as vector for disease if not used for 18 months, which
suggest that the weathering process alone was sufficient to inactivate prions.
PrPSc detection by sPMCA is increasingly used as a surrogate for
infectivity measurements by bioassay in sheep or mice. In this reported study,
however, the levels of PrPSc present in the environment were below the limit of
detection of the sPMCA method, yet were still sufficient to cause infection of
in-contact animals. In the present study, the outdoor objects were removed from
the infected flock 8 weeks prior to sampling and were positive by sPMCA at very
low levels (2 out of 37 reactions). As this sPMCA assay also yielded 2 positive
reactions out of 139 in samples from the scrapie-free farm, the sPMCA assay
could not detect PrPSc on any of the objects above the background of the assay.
False positive reactions with sPMCA at a low frequency associated with de novo
formation of infectious prions have been reported (27, 28). This is in contrast
to our previous study where we demonstrated that outdoor objects that had been
in contact with the scrapie-infected flock up to 20 days prior to sampling
harbored PrPSc that was detectable by sPMCA analysis [4 out of 15 reactions
(12)] and was significantly more positive by the assay compared to analogous
samples from the scrapie-free farm. This discrepancy could be due to the use of
a different sPMCA substrate between the studies that may alter the efficiency of
amplification of the environmental PrPSc. In addition, the present study had a
longer timeframe between the objects being in contact with the infected flock
and sampling, which may affect the levels of extractable PrPSc. Alternatively,
there may be potentially patchy contamination of this furniture with PrPSc,
which may have been missed by swabbing. The failure of sPMCA to detect
CWD-associated PrP in saliva from clinically affected deer despite confirmation
of infectivity in saliva-inoculated transgenic mice was associated with as yet
unidentified inhibitors in saliva (29), and it is possible that the sensitivity
of sPMCA is affected by other substances in the tested material. In addition,
sampling of amplifiable PrPSc and subsequent detection by sPMCA may be more
difficult from furniture exposed to weather, which is supported by the
observation that PrPSc was detected by sPMCA more frequently in indoor than
outdoor furniture (12). A recent experimental study has demonstrated that
repeated cycles of drying and wetting of prion-contaminated soil, equivalent to
what is expected under natural weathering conditions, could reduce PMCA
amplification efficiency and extend the incubation period in hamsters inoculated
with soil samples (30). This seems to apply also to this study even though the
reduction in infectivity was more dramatic in the sPMCA assays than in the sheep
model. Sheep were not kept until clinical end-point, which would have enabled us
to compare incubation periods, but the lack of infection in sheep exposed to
furniture that had not been in contact with scrapie sheep for a longer time
period supports the hypothesis that prion degradation and subsequent loss of
infectivity occurs even under natural conditions.
In conclusion, the results in the current study indicate that removal of
furniture that had been in contact with scrapie-infected animals should be
recommended, particularly since cleaning and decontamination may not effectively
remove scrapie infectivity (31), even though infectivity declines considerably
if the pasture and the field furniture have not been in contact with
scrapie-infected sheep for several months. As sPMCA failed to detect PrPSc in
furniture that was subjected to weathering, even though exposure led to
infection in sheep, this method may not always be reliable in predicting the
risk of scrapie infection through environmental contamination. These results
suggest that the VRQ/VRQ sheep model may be more sensitive than sPMCA for the
detection of environmentally associated scrapie, and suggest that extremely low
levels of scrapie contamination are able to cause infection in susceptible sheep
genotypes.
Keywords: classical scrapie, prion, transmissible spongiform
encephalopathy, sheep, field furniture, reservoir, serial protein misfolding
cyclic amplification
Wednesday, December 16, 2015
*** Objects in contact with classical scrapie sheep act as a reservoir for
scrapie transmission ***
*** Infectious agent of sheep scrapie may persist in the environment for at
least 16 years ***
Gudmundur Georgsson1, Sigurdur Sigurdarson2 and Paul Brown3
>>>Another alternative would be an absolute prohibition on the
movement of deer within the state for any purpose. While this alternative would
significantly reduce the potential spread of CWD, it would also have the
simultaneous effect of preventing landowners and land managers from implementing
popular management strategies involving the movement of deer, and would deprive
deer breeders of the ability to engage in the business of buying and selling
breeder deer. Therefore, this alternative was rejected because the department
determined that it placed an avoidable burden on the regulated
community.<<<
Circulation of prions within dust on a scrapie affected farm
Kevin C Gough1, Claire A Baker2, Hugh A Simmons3, Steve A Hawkins3 and Ben
C Maddison2*
Abstract
Prion diseases are fatal neurological disorders that affect humans and
animals. Scrapie of sheep/goats and Chronic Wasting Disease (CWD) of deer/elk
are contagious prion diseases where environmental reservoirs have a direct link
to the transmission of disease. Using protein misfolding cyclic amplification we
demonstrate that scrapie PrPSc can be detected within circulating dusts that are
present on a farm that is naturally contaminated with sheep scrapie. The
presence of infectious scrapie within airborne dusts may represent a possible
route of infection and illustrates the difficulties that may be associated with
the effective decontamination of such scrapie affected premises.
snip...
Discussion
We present biochemical data illustrating the airborne movement of scrapie
containing material within a contaminated farm environment. We were able to
detect scrapie PrPSc within extracts from dusts collected over a 70 day period,
in the absence of any sheep activity. We were also able to detect scrapie PrPSc
within dusts collected within pasture at 30 m but not at 60 m distance away from
the scrapie contaminated buildings, suggesting that the chance of contamination
of pasture by scrapie contaminated dusts decreases with distance from
contaminated farm buildings. PrPSc amplification by sPMCA has been shown to
correlate with infectivity and amplified products have been shown to be
infectious [14,15]. These experiments illustrate the potential for low dose
scrapie infectivity to be present within such samples. We estimate low ng levels
of scrapie positive brain equivalent were deposited per m2 over 70 days, in a
barn previously occupied by sheep affected with scrapie. This movement of dusts
and the accumulation of low levels of scrapie infectivity within this
environment may in part explain previous observations where despite stringent
pen decontamination regimens healthy lambs still became scrapie infected after
apparent exposure from their environment alone [16]. The presence of sPMCA
seeding activity and by inference, infectious prions within dusts, and their
potential for airborne dissemination is highly novel and may have implications
for the spread of scrapie within infected premises. The low level circulation
and accumulation of scrapie prion containing dust material within the farm
environment will likely impede the efficient decontamination of such scrapie
contaminated buildings unless all possible reservoirs of dust are removed.
Scrapie containing dusts could possibly infect animals during feeding and
drinking, and respiratory and conjunctival routes may also be involved. It has
been demonstrated that scrapie can be efficiently transmitted via the nasal
route in sheep [17], as is also the case for CWD in both murine models and in
white tailed deer [18-20].
The sources of dust borne prions are unknown but it seems reasonable to
assume that faecal, urine, skin, parturient material and saliva-derived prions
may contribute to this mobile environmental reservoir of infectivity. This work
highlights a possible transmission route for scrapie within the farm
environment, and this is likely to be paralleled in CWD which shows strong
similarities with scrapie in terms of prion dissemination and disease
transmission. The data indicate that the presence of scrapie prions in dust is
likely to make the control of these diseases a considerable challenge.
***Moreover, sporadic disease has never been observed in breeding colonies
or primate research laboratories, most notably among hundreds of animals over
several decades of study at the National Institutes of Health25, and in nearly
twenty older animals continuously housed in our own facility.***
***at present, no cervid PrP allele conferring absolute resistance to prion
infection has been identified.
P-145 Estimating chronic wasting disease resistance in cervids using real
time quaking- induced conversion
Nicholas J Haley1, Rachel Rielinqer2, Kristen A Davenport3, W. David
Walter4, Katherine I O'Rourke5, Gordon Mitchell6, Juergen A Richt2
1 Department of Microbiology and Immunology, Midwestern University, United
States; 2Department of Diagnostic Medicine and Pathobiology, Kansas State
University; 3Prion Research Center; Colorado State University; 4U.S. Geological
Survey, Pennsylvania Cooperative Fish and Wildlife Research Unit; 5Agricultural
Research Service, United States Department of Agriculture; 6Canadian Food
Inspection Agency, National and OlE Reference Laboratory for Scrapie and CWO
In mammalian species, the susceptibility to prion diseases is affected, in
part, by the sequence of the host's prion protein (PrP). In sheep, a gradation
from scrapie susceptible to resistant has been established both in vivo and in
vitro based on the amino acids present at PrP positions 136, 154, and 171, which
has led to global breeding programs to reduce the prevalence of scrapie in
domestic sheep. In cervids, resistance is commonly characterized as a delayed
progression of chronic wasting disease (CWD); at present, no cervid PrP allele
conferring absolute resistance to prion infection has been identified. To model
the susceptibility of various naturally-occurring and hypothetical cervid PrP
alleles in vitro, we compared the amplification rates and efficiency of various
CWD isolates in recombinant PrPC using real time quaking-induced conversion. We
hypothesized that amplification metrics of these isolates in cervid PrP
substrates would correlate to in vivo susceptibility - allowing susceptibility
prediction for alleles found at 10 frequency in nature, and that there would be
an additive effect of multiple resistant codons in hypothetical alleles. Our
studies demonstrate that in vitro amplification metrics predict in vivo
susceptibility, and that alleles with multiple codons, each influencing
resistance independently, do not necessarily contribute additively to
resistance. Importantly, we found that the white-tailed deer 226K substrate
exhibited the slowest amplification rate among those evaluated, suggesting that
further investigation of this allele and its resistance in vivo are warranted to
determine if absolute resistance to CWD is possible.
***at present, no cervid PrP allele conferring absolute resistance to prion
infection has been identified.
PRION 2016 CONFERENCE TOKYO
*** Grant Agreement number: 222887 ***
*** Project acronym: PRIORITY ***
*** Project title: Protecting the food chain from prions: shaping European
priorities through basic and applied research Funding ***
Scheme: Large-scale integrating project Period covered: from Oct. 1, 2009
to Sept. 30, 2014
Name of the scientific representative of the project's co-ordinator1, Title
and Organisation: Jesús R. Requena, Ph.D., Associate Professor, Department of
medicine, University of Santiago de Compostela, Spàin. Tel: 34-881815464 Fax:
34-881815403 E-mail: jesus.requena@usc.es
Project website¡Error! Marcador no definido. address: www.prionpriority.eu
PRIORITY, PROJECT FINAL REPORT
*** 14) Concluding that atypical scrapie can transmit to Humans and that
its strain properties change as it transmits between species ***
snip...
Block D: Prion epidemiology
Studies on atypical scrapie were identified as a key element of this block,
given the potential risk associated to this agent. We studied the permeability
of Human, bovine and porcine species barriers to atypical scrapie agent
transmission. Experiments in transgenic mice expressing bovine, porcine or human
PrPC suggest that this TSE agent has the intrinsic ability to propagate across
these species barriers including the Human one. Upon species barrier passage the
biological properties and phenotype of atypical scrapie seem to be altered.
Further experiments are currently ongoing (in the framework of this project but
also in other projects) in order to: (i) characterize the properties of the
prion that emerged from the propagation of atypical scrapie in tg Hu; (ii) to
confirm that the phenomena we observed are also true for atypical scrapie
isolates other than the ones we have studied.
In parallel, studies in shep have concluded that:
*** Atypical scrapie can be transmitted by both oral and intracerebral
route in sheep with various PRP genotypes
*** Low but consistent amount of infectivity accumulates in peripheral
tissue (mammary gland, lymph nodes, placenta, skeletal muscles, nerves) of sheep
incubating atypical scrapie.
*** The combination of data from all our studies leads us to conclude that:
*** Atypical scrapie passage through species barriers can lead to the
emergence of various prions including classical BSE (following propagation in
porcine PRP transgenic mice).
*** Atypical scrapie can propagate, with a low efficacy, in human PrP
expressing mice. This suggests the existence of a zoonotic potential for this
TSE agent.
snip...
We advance our main conclusions and recommendations, in particular as they
might affect public policy, including a detailed elaboration of the evidence
that led to them. Our main recommendations are:
a. The issue of re-introducing ruminant protein into the food-chain The
opinion of the members of Priority is that sustaining an absolute feed ban for
ruminant protein to ruminants is the essential requirement, especially since the
impact of non-classical forms of scrapie in sheep and goats is not fully
understood and cannot be fully estimated. Therefore, the consortium strongly
recommends prohibiting re-introduction of processed ruminant protein into the
food-chain. Arguments in support of this opinion are:
• the large (and still uncharacterized) diversity of prion agents that
circulate in animal populations;
• the uncertainties related to prion epidemiology in animal
populations;
• the unknown efficacy of industrial processes applied to reduce
microbiological risk during processed animal protein (PAP) production on most
prion agents;
• the intrinsic capacity of prions to cross interspecies transmission
barriers;
• the lack of sensitive methodology for identifying cross contamination in
food.
• the evolution of natural food chains in nature (i.e. who eats whom or
what) has generated an efficient barrier preventing, to some extent, novel prion
epidemies and that this naturally evolved ecology should be respected.
The consortium is also hesitant to introduce processed ruminant proteins
into fish food considering the paucity of data on prion infections in fishes and
sea animals including those of mammalian origin, and the risk of establishing an
environmental contamination of the oceans that cannot be controlled.
b. Atypical prion agents and surveillance
Atypical prion agents (see below) will probably continue to represent the
dominant form of prion diseases in the near future, particularly in Europe.
*** Atypical L-type BSE has clear zoonotic potential, as demonstrated in
experimental models.
*** Similarly, there are now some data that seem to indicate that the
atypical scrapie agent can cross various species barriers.
*** Moreover, the current EU policy for eradicating scrapie (genetic
selection in affected flocks) is ineffective for preventing atypical scrapie.
*** The recent identification of cell-to-cell propagation and the
protein-encoded strain properties of human neurodegenerative diseases such as
Alzheimer's disease and Parkinson's disease, suggest that they bear the
potential to be transmissible even if not with the same efficiency as CJD. More
epidemiological data from large cohorts are necessary to reach any conclusion on
the impact of their transmissibility on public health. Re-evaluations of safety
precautions may become necessary depending on the outcome of these studies. In
that context it would appear valuable
• to develop knowledge related to the pathogenesis and inter-individual
transmission of atypical prion agents in ruminants (both intra- and
inter-species)
• to improve the sensitivity of detection assays that are applied in the
field towards this type of agent
• to maintain a robust surveillance of both animal and human populations
c. The need for extended research on prions
Intensified searching for a molecular determinants of the species barrier
is recommended, since this barrier is a key for many important policy areas -
risk assessment, proportional policies, the need for screening of human products
and food. In this respect, prion strain structural language also remains an
important issue for public health for the foreseeable future. Understanding the
structural basis for strains and the basis for adaptation of a strain to a new
host will require continued fundamental research. Prions maintain a complex
two-way relationship with the host cell and fundamental research is needed on
mechanisms for their transmission, replication and cause of nervous system
dysfunction and death.
Early detection of prion infection, ideally at preclinical stage, also
remains crucial for development of effective treatment strategies in humans
affected by the disease.
Position of the Priority consortium
Nearly 30 years ago, the appearance in the UK of Bovine Spongiform
Encephalopathy (BSE) quickly brought the previously obscure “prion diseases” to
the spotlight. The ensuing health and food crises that spread throughout Europe
had devastating consequences. In the UK alone, there were more than 36,000 farms
directly affected by BSE and the transmission of BSE prions to humans via the
food chain has caused over 200 people in Europe to die from variant
Creutzfeldt-Jakob disease (vCJD) (http://www.cjd.ed.ac.uk
Origins of prion epidemies
Classical BSE now appears to be under control, with 18 EU Member States
having achieved the World Organisation for Animal Health (Office International
Epizooties) „negligible risk‟ status (May 2014; http://www.oie.int/en/animal-health-in-the-world/official-disease-status/bse/list-of-bse-risk-status/),
and the remaining MS assessed as „controlled‟ risk. Of note, research, including
EU-funded research, has played a key role in this success: while the origin of
the infection was never defined, the principle driver of the epidemic was
identified as prions in Meat and Bone Meal (MBM). Tests based on prion
protein-specific antibodies were developed, allowing detection of infected
animals, and a better understanding of disease pathogenesis and the distribution
of infectivity in edible tissues; experimental investigation of transmission
barriers between different species allowed a rational estimation of risks, etc.
All of this led to the implementation of rational and effective policies, such
as the MBM ban to protect the animal feed chain, and the Specified Risk Material
(SRM) regulations to protect the human food chain.
In spite of this progress, prions are still a threat. Epidemiological
re-assessment indicates that the ∼10 year incubation period separating the peaks
of the BSE and the vCJD epidemics is probably too short. In addition, results
from a large number of human tonsil and appendix analyses in the UK suggest that
there may be a high number of asymptomatic individuals who are positive for the
disease-associated conformer prion protein PrPSc. While vCJD is the only form of
human prion disease that has been consistently demonstrated to have
lymphoreticular involvement, there has been no systematic investigation of
lymphoid tissue in cases with other prion diseases.
The human prion problem
The clinical cases of vCJD identified to date have all shared a common PrP
genotype (M129M), although one pre-clinical case was confirmed as an M129V
heterozygote, and it has been mooted that perhaps only the M129M proportion of
the population is susceptible. However, in the UK appendix study, PrP
accumulation was described in samples representing every codon 129 genotype,
raising the possibility that genotype does not confer resistance but instead
modulates incubation period. Apart from the two UK studies, the lymphoid tissues
of non-CJD patients have not been examined for the presence of PrPSc, so, these
cases may not solely represent pre-clinical vCJD, but also other forms of prion
disease.
Recent experiments in highly susceptible mouse models indicate the presence
of infectivity in blood or blood components at late disease stages in sporadic
CJD. The significance of this experimental finding for humans has to be explored
in more detail and, at the present time, there is no evidence for the
transmission of prions via blood in sporadic CJD. However a likely scenario is
that all those with signs of infection or abnormal PrP accumulation in
peripheral tissue could have infective blood, posing the risk for transmission
via blood products, which has been clearly demonstrated in experimental models,
and confirmed in several cases of vCJD in man. Altogether, these data clearly
demonstrate the potential risk of a second wave of vCJD, particularly when the
number people identified with lymphoid accumulation of PrPSc (16/32,411) gives a
prevalence estimate in the UK of 493 per million, much higher than the number of
clinical cases seen to date.
The animal prion problem
An increasing number of reports on cases of “atypical” BSE in cattle
throughout the EU and beyond may lead to a new epidemic, particularly since we
still do not understand all factors determining the species barrier. Ovine
scrapie is another concern, because it could mask ovine BSE, presumably
transmissible to humans. Scrapie is endemic and not likely to be eradicated
soon, although current control measures are effective at greatly reducing
disease incidence. Atypical forms, which may be spontaneous, are not affected by
these control measures and these forms of disease will persist in the global
animal population. The low prevalence of these disease forms makes effective
surveillance very challenging. However, there is a clear risk attendant on
ignoring these cases without an understanding of their possible zoonotic
potential, particularly when most forms of human disease have no established
aetiology. In summary, atypical cases of BSE and scrapie presently clearly
outnumber classical cases in cattle and sheep in all member states.
We will highlight the state-of-the-art knowledge and point out scientific
challenges and the major questions for research. Strategic objectives and
priorities in Europe in the future for research that aims to control, eliminate
or eradicate the threat posed by prions to our food and health are also
indicated.
The Priority project has focused on 4 themes, namely the structure,
function, conversion and toxicity of prions; detection of prions; mechanisms of
prion transmission and spreading and epidemiology of prion diseases. This paper
summarizes the opinions/positions reached within these themes at the end of the
project.
WS-01: Prion diseases in animals and zoonotic potential 2016
Prion. 10:S15-S21. 2016 ISSN: 1933-6896 printl 1933-690X online
Taylor & Francis
Prion 2016 Animal Prion Disease Workshop Abstracts
WS-01: Prion diseases in animals and zoonotic potential
Juan Maria Torres a, Olivier Andreoletti b, J uan-Carlos Espinosa a.
Vincent Beringue c. Patricia Aguilar a,
Natalia Fernandez-Borges a. and Alba Marin-Moreno a
"Centro de Investigacion en Sanidad Animal ( CISA-INIA ). Valdeolmos,
Madrid. Spain; b UMR INRA -ENVT 1225 Interactions Holes Agents Pathogenes. ENVT.
Toulouse. France: "UR892. Virologie lmmunologie MolécuIaires, Jouy-en-Josas.
France
Dietary exposure to bovine spongiform encephalopathy (BSE) contaminated
bovine tissues is considered as the origin of variant Creutzfeldt Jakob (vCJD)
disease in human. To date, BSE agent is the only recognized zoonotic prion.
Despite the variety of Transmissible Spongiform Encephalopathy (TSE) agents that
have been circulating for centuries in farmed ruminants there is no apparent
epidemiological link between exposure to ruminant products and the occurrence of
other form of TSE in human like sporadic Creutzfeldt Jakob Disease (sCJD).
However, the zoonotic potential of the diversity of circulating TSE agents has
never been systematically assessed. The major issue in experimental assessment
of TSEs zoonotic potential lies in the modeling of the ‘species barrier‘, the
biological phenomenon that limits TSE agents’ propagation from a species to
another. In the last decade, mice genetically engineered to express normal forms
of the human prion protein has proved essential in studying human prions
pathogenesis and modeling the capacity of TSEs to cross the human species
barrier.
To assess the zoonotic potential of prions circulating in farmed ruminants,
we study their transmission ability in transgenic mice expressing human PrPC
(HuPrP-Tg). Two lines of mice expressing different forms of the human PrPC
(129Met or 129Val) are used to determine the role of the Met129Val dimorphism in
susceptibility/resistance to the different agents.
These transmission experiments confirm the ability of BSE prions to
propagate in 129M- HuPrP-Tg mice and demonstrate that Met129 homozygotes may be
susceptible to BSE in sheep or goat to a greater degree than the BSE agent in
cattle and that these agents can convey molecular properties and
neuropathological indistinguishable from vCJD. However homozygous 129V mice are
resistant to all tested BSE derived prions independently of the originating
species suggesting a higher transmission barrier for 129V-PrP variant.
Transmission data also revealed that several scrapie prions propagate in
HuPrP-Tg mice with efficiency comparable to that of cattle BSE. While the
efficiency of transmission at primary passage was low, subsequent passages
resulted in a highly virulent prion disease in both Met129 and Val129 mice.
Transmission of the different scrapie isolates in these mice leads to the
emergence of prion strain phenotypes that showed similar characteristics to
those displayed by MM1 or VV2 sCJD prion. These results demonstrate that scrapie
prions have a zoonotic potential and raise new questions about the possible link
between animal and human prions.
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. ***
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.
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.
P.73: Oral challenge of goats with atypical scrapie
Silvia Colussi1, Maria Mazza1, Francesca Martucci1, Simone Peletto1,
Cristiano Corona1, Marina Gallo1, Cristina Bona1, Romolo Nonno2, Michele Di
Bari2, Claudia D’Agostino2, Nicola Martinelli3, Guerino Lombardi3, and Pier
Luigi Acutis1 1Istituto Zooprofilattico Sperimentale del Piemonte; Liguria e
Valle d’Aosta; Turin, Italy; 2Istituto Superiore di Sanit a; Rome, Italy;
3Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia Romagna;
Brescia, Italy
Atypical scrapie transmission has been demonstrated in sheep by
intracerebral and oral route (Simmons et al., Andreoletti et al., 2011) but data
about goats are not available yet. In 2006 we orally challenged four goats, five
months old, with genotype R/H and R/R at codon 154. Animals died starting from
24 to 77 months p.i. without clinical signs. They all resulted negative for
scrapie in CNS and peripheral tissues using Western blot and
immunohistochemistry. Nevertheless these goats could still represent carriers.
This hypothesis was investigated through bioassay in tg338 mice, a sensitive
animal model for atypical scrapie infectivity. By end-point dilution titration,
the starting inoculum contained 106.8 ID50/g. In contrast, all tissues from
challenged goats were negative by bioassay. These negative results could be
explained with the low infectivity of the starting inoculum, which could have
been unable to induce Prion 2015 Poster Abstracts S49 disease or infectivity
within our period of observation. However the challenge conditions could have
been a bias too: as the matter of the fact, while the oral challenge of
classical scrapie is still effective in sheep 6–10 months old (Andreoletti et
al., 2011), Simmons et al. (2011) demonstrated a very short efficacy period for
atypical scrapie (24 hours after birth), hypothesizing that natural transmission
could occur mainly via milk. Our work suggests that this could be true also for
goats and it should be taken into account in oral challenges. However a low
susceptibility of goats to atypical scrapie transmission via oral route cannot
be excluded.
>>> These results suggest that (i) at the level of protein-protein
interactions, CWD adapts to a new species more readily than does BSE and (ii)
the barrier preventing transmission of CWD to humans may be less robust than
estimated.
Accepted manuscript posted online 8 July 2015.
Insights into Chronic Wasting Disease and Bovine Spongiform Encephalopathy
Species Barriers by Use of Real-Time Conversion
Kristen A. Davenport, Davin M. Henderson, Jifeng Bian, Glenn C. Telling,
Candace K. Mathiason and Edward A. Hoover Prion Research Center, Department of
Microbiology, Immunology and Pathology, College of Veterinary Medicine and
Biomedical Sciences, Colorado State University, Fort Collins, Colorado, USA K.
L. Beemon, Editor + Author Affiliations
Next Section ABSTRACT The propensity for transspecies prion transmission is
related to the structural characteristics of the enciphering and new host PrP,
although the exact mechanism remains incompletely understood. The effects of
variability in prion protein on cross-species prion transmission have been
studied with animal bioassays, but the influence of prion protein structure
versus that of host cofactors (e.g., cellular constituents, trafficking, and
innate immune interactions) remains difficult to dissect. To isolate the effects
of protein-protein interactions on transspecies conversion, we used recombinant
PrPC and real-time quaking-induced conversion (RT-QuIC) and compared chronic
wasting disease (CWD) and classical bovine spongiform encephalopathy (cBSE)
prions. To assess the impact of transmission to a new species, we studied feline
CWD (fCWD) and feline BSE (i.e., feline spongiform encephalopathy [FSE]). We
cross-seeded fCWD and FSE into each species' full-length, recombinant PrPC and
measured the time required for conversion to the amyloid (PrPRes) form, which we
describe here as the rate of amyloid conversion. These studies revealed the
following: (i) CWD and BSE seeded their homologous species' PrP best; (ii) fCWD
was a more efficient seed for feline rPrP than for white-tailed deer rPrP; (iii)
conversely, FSE more efficiently converted bovine than feline rPrP; (iv) and
CWD, fCWD, BSE, and FSE all converted human rPrP, although not as efficiently as
homologous sCJD prions. These results suggest that (i) at the level of
protein-protein interactions, CWD adapts to a new species more readily than does
BSE and (ii) the barrier preventing transmission of CWD to humans may be less
robust than estimated.
IMPORTANCE We demonstrate that bovine spongiform encephalopathy prions
maintain their transspecies conversion characteristics upon passage to cats but
that chronic wasting disease prions adapt to the cat and are distinguishable
from the original prion. Additionally, we showed that chronic wasting disease
prions are effective at seeding the conversion of normal human prion protein to
an amyloid conformation, perhaps the first step in crossing the species barrier.
snip...
Enciphering characteristics of cBSE and cBSE-derived prions are conserved
after transspecies transmission.cBSE and CWD are prion diseases that have been
naturally passaged in their respective species (cattle and deer), whereas feline
spongiform encephalopathy (FSE) and feline chronic wasting disease (fCWD) are
first-passage infections in a new host species (cat). To investigate the
biochemical properties of cBSE and CWD after transspecies transmission to
felines, we compared the amyloidogenicity of fCWD and FSE in the original host
and in feline substrate. We found fCWD to be a more efficient seed for its new
(feline) host, suggesting that adaptation to the new host had occurred (Fig.
4A). In contrast, FSE remained a more efficient seed for its enciphering
(bovine) host, despite its derivation from feline brain PrPC (Fig. 4B). Thereby,
these cross-species seeding experiments in RT-QuIC indicated that the
characteristics of cBSE were maintained upon passage to a new species whereas
CWD had adapted to its new host. These findings in felids suggest that cBSE may
retain its ability to cross species barriers even after transmission to a new
host species and that CWD may change substantially upon transspecies
transmission.
Human rPrPC can be converted by bovine, feline, and cervid prions.The
threat of zoonotic transmission of prion disease is evident and well documented,
yet such transmission is uncommonly observed and incompletely understood. We
thereby explored the propensity of heterologous prions to convert human rPrP. In
these human rPrPC experiments, we used sporadic CJD brain as a positive control
and normal bovine, white-tailed deer, and feline brain as negative controls.
sCJD, as expected, seeded human rPrPC most efficiently, so all other seeds were
normalized to the rate of conversion of sCJD. We found human rPrPC to be a
competent substrate in RT-QuIC for CWD, fCWD, cBSE, and FSE (Fig. 5A).
Interestingly, CWD and fCWD converted human rPrPC more efficiently than did cBSE
and FSE. These data suggest that at the level of PrPC-PrP seed interaction, CWD
has the ability to template the conversion of human rPrPC to ThT-positive
amyloid. In order to assess whether CWD was faster than cBSE due to an increased
concentration of prion seed, we performed Western blotting on the seed inocula.
Western blots indicated that the cBSE sample had a higher concentration of
PrPRes than the CWD sample, indicating that CWD was not a better seed than cBSE
due to PrPRes content (Fig. 5B). Finally, we assessed the behavior of 8 CWD
field isolates, brain samples from white-tailed deer infected naturally and
verified to be positive using full-length white-tailed deer RT-QuIC (Fig. 5C).
All 8 of these isolates converted human rPrPC, confirming that our observations
were not due to the use of experimentally CWD (Fig. 5D). In all, these
experiments suggest that the CWD prions naturally circulating in the western
United States have the capacity to convert human rPrPC in this assay of
protein-protein interactions.
snip...
In summary, real-time conversion demonstrates that CWD and BSE prions
differ in their enciphering rigidity and plasticity across species barriers. One
illustration is the conservation versus adaptation of enciphering prion
characteristics upon passage to cats. These experiments also demonstrate that
human rPrP can be converted to amyloid by both cBSE and CWD prions. These data
point to the importance of deciphering the mechanisms by which prions infect and
adapt to a new species and of prompt continued vigilance regarding indirect
pathways that may facilitate transspecies prion transmission.
Monday, September 19, 2016
Evidence of scrapie transmission to sheep via goat milk
CWD TSE PRION HUMAN ZOONOSIS POTENTIAL, has it already happened, and being
masked as sporadic CJD? and what about iatrogenic, or the pass if forward,
friendly fire mode of transmission of cwd to humans, same thing, sporadic cjd ?
*** WDA 2016 NEW YORK ***
We found that CWD adapts to a new host more readily than BSE and that human
PrP was unexpectedly prone to misfolding by CWD prions. In addition, we
investigated the role of specific regions of the bovine, deer and human PrP
protein in resistance to conversion by prions from another species. We have
concluded that the human protein has a region that confers unusual
susceptibility to conversion by CWD prions.
Student Presentations Session 2
The species barriers and public health threat of CWD and BSE prions
Ms. Kristen Davenport1, Dr. Davin Henderson1, Dr. Candace Mathiason1, Dr.
Edward Hoover1 1Colorado State University
Chronic wasting disease (CWD) is spreading rapidly through cervid
populations in the USA. Bovine spongiform encephalopathy (BSE, mad cow disease)
arose in the 1980s because cattle were fed recycled animal protein. These and
other prion diseases are caused by abnormal folding of the normal prion protein
(PrP) into a disease causing form (PrPd), which is pathogenic to nervous system
cells and can cause subsequent PrP to misfold. CWD spreads among cervids very
efficiently, but it has not yet infected humans. On the other hand, BSE was
spread only when cattle consumed infected bovine or ovine tissue, but did infect
humans and other species. The objective of this research is to understand the
role of PrP structure in cross-species infection by CWD and BSE. To study the
propensity of each species’ PrP to be induced to misfold by the presence of PrPd
from verious species, we have used an in vitro system that permits detection of
PrPd in real-time. We measured the conversion efficiency of various combinations
of PrPd seeds and PrP substrate combinations. We observed the cross-species
behavior of CWD and BSE, in addition to feline-adapted CWD and BSE. We found
that CWD adapts to a new host more readily than BSE and that human PrP was
unexpectedly prone to misfolding by CWD prions. In addition, we investigated the
role of specific regions of the bovine, deer and human PrP protein in resistance
to conversion by prions from another species. We have concluded that the human
protein has a region that confers unusual susceptibility to conversion by CWD
prions. CWD is unique among prion diseases in its rapid spread in natural
populations. BSE prions are essentially unaltered upon passage to a new species,
while CWD adapts to the new species. This adaptation has consequences for
surveillance of humans exposed to CWD.
Wildlife Disease Risk Communication Research Contributes to Wildlife Trust
Administration Exploring perceptions about chronic wasting disease risks among
wildlife and agriculture professionals and stakeholders
PRION 2016 TOKYO
Zoonotic Potential of CWD Prions: An Update
Ignazio Cali1, Liuting Qing1, Jue Yuan1, Shenghai Huang2, Diane Kofskey1,3,
Nicholas Maurer1, Debbie McKenzie4, Jiri Safar1,3,5, Wenquan Zou1,3,5,6,
Pierluigi Gambetti1, Qingzhong Kong1,5,6
1Department of Pathology, 3National Prion Disease Pathology Surveillance
Center, 5Department of Neurology, 6National Center for Regenerative Medicine,
Case Western Reserve University, Cleveland, OH 44106, USA.
4Department of Biological Sciences and Center for Prions and Protein
Folding Diseases, University of Alberta, Edmonton, Alberta, Canada,
2Encore Health Resources, 1331 Lamar St, Houston, TX 77010
Chronic wasting disease (CWD) is a widespread and highly transmissible
prion disease in free-ranging and captive cervid species in North America. The
zoonotic potential of CWD prions is a serious public health concern, but the
susceptibility of human CNS and peripheral organs to CWD prions remains largely
unresolved. We reported earlier that peripheral and CNS infections were detected
in transgenic mice expressing human PrP129M or PrP129V. Here we will present an
update on this project, including evidence for strain dependence and influence
of cervid PrP polymorphisms on CWD zoonosis as well as the characteristics of
experimental human CWD prions.
PRION 2016 TOKYO
In Conjunction with Asia Pacific Prion Symposium 2016
PRION 2016 Tokyo
Prion 2016
Cervid to human prion transmission
Kong, Qingzhong
Case Western Reserve University, Cleveland, OH, United States
Abstract
Prion disease is transmissible and invariably fatal. Chronic wasting
disease (CWD) is the prion disease affecting deer, elk and moose, and it is a
widespread and expanding epidemic affecting 22 US States and 2 Canadian
provinces so far. CWD poses the most serious zoonotic prion transmission risks
in North America because of huge venison consumption (>6 million deer/elk
hunted and consumed annually in the USA alone), significant prion infectivity in
muscles and other tissues/fluids from CWD-affected cervids, and usually high
levels of individual exposure to CWD resulting from consumption of the affected
animal among often just family and friends. However, we still do not know
whether CWD prions can infect humans in the brain or peripheral tissues or
whether clinical/asymptomatic CWD zoonosis has already occurred, and we have no
essays to reliably detect CWD infection in humans. We hypothesize that:
(1) The classic CWD prion strain can infect humans at low levels in the
brain and peripheral lymphoid tissues;
(2) The cervid-to-human transmission barrier is dependent on the cervid
prion strain and influenced by the host (human) prion protein (PrP) primary
sequence;
(3) Reliable essays can be established to detect CWD infection in
humans;and
(4) CWD transmission to humans has already occurred. We will test these
hypotheses in 4 Aims using transgenic (Tg) mouse models and complementary in
vitro approaches.
Aim 1 will prove that the classical CWD strain may infect humans in brain
or peripheral lymphoid tissues at low levels by conducting systemic bioassays in
a set of "humanized" Tg mouse lines expressing common human PrP variants using a
number of CWD isolates at varying doses and routes. Experimental "human CWD"
samples will also be generated for Aim 3.
Aim 2 will test the hypothesis that the cervid-to-human prion transmission
barrier is dependent on prion strain and influenced by the host (human) PrP
sequence by examining and comparing the transmission efficiency and phenotypes
of several atypical/unusual CWD isolates/strains as well as a few prion strains
from other species that have adapted to cervid PrP sequence, utilizing the same
panel of humanized Tg mouse lines as in Aim 1.
Aim 3 will establish reliable essays for detection and surveillance of CWD
infection in humans by examining in details the clinical, pathological,
biochemical and in vitro seeding properties of existing and future experimental
"human CWD" samples generated from Aims 1-2 and compare them with those of
common sporadic human Creutzfeldt-Jakob disease (sCJD) prions.
Aim 4 will attempt to detect clinical CWD-affected human cases by examining
a significant number of brain samples from prion-affected human subjects in the
USA and Canada who have consumed venison from CWD-endemic areas utilizing the
criteria and essays established in Aim 3. The findings from this proposal will
greatly advance our understandings on the potential and characteristics of
cervid prion transmission in humans, establish reliable essays for CWD zoonosis
and potentially discover the first case(s) of CWD infection in humans.
Public Health Relevance There are significant and increasing human exposure
to cervid prions because chronic wasting disease (CWD, a widespread and highly
infectious prion disease among deer and elk in North America) continues
spreading and consumption of venison remains popular, but our understanding on
cervid-to-human prion transmission is still very limited, raising public health
concerns. This proposal aims to define the zoonotic risks of cervid prions and
set up and apply essays to detect CWD zoonosis using mouse models and in vitro
methods. The findings will greatly expand our knowledge on the potentials and
characteristics of cervid prion transmission in humans, establish reliable
essays for such infections and may discover the first case(s) of CWD infection
in humans.
LOOKING FOR CWD IN HUMANS AS nvCJD or as an ATYPICAL CJD, LOOKING IN ALL
THE WRONG PLACES $$$
*** These results would seem to suggest that CWD does indeed have zoonotic
potential, at least as judged by the compatibility of CWD prions and their human
PrPC target. Furthermore, extrapolation from this simple in vitro assay suggests
that if zoonotic CWD occurred, it would most likely effect those of the PRNP
codon 129-MM genotype and that the PrPres type would be similar to that found in
the most common subtype of sCJD (MM1).***
PRION 2015 CONFERENCE FT. COLLINS CWD RISK FACTORS TO HUMANS
*** LATE-BREAKING ABSTRACTS PRION 2015 CONFERENCE ***
O18
Zoonotic Potential of CWD Prions
Liuting Qing1, Ignazio Cali1,2, Jue Yuan1, Shenghai Huang3, Diane Kofskey1,
Pierluigi Gambetti1, Wenquan Zou1, Qingzhong Kong1 1Case Western Reserve
University, Cleveland, Ohio, USA, 2Second University of Naples, Naples, Italy,
3Encore Health Resources, Houston, Texas, USA
*** These results indicate that the CWD prion has the potential to infect
human CNS and peripheral lymphoid tissues and that there might be asymptomatic
human carriers of CWD infection.
==================
***These results indicate that the CWD prion has the potential to infect
human CNS and peripheral lymphoid tissues and that there might be asymptomatic
human carriers of CWD infection.***
==================
P.105: RT-QuIC models trans-species prion transmission
Kristen Davenport, Davin Henderson, Candace Mathiason, and Edward Hoover
Prion Research Center; Colorado State University; Fort Collins, CO USA
Conversely, FSE maintained sufficient BSE characteristics to more
efficiently convert bovine rPrP than feline rPrP. Additionally, human rPrP was
competent for conversion by CWD and fCWD.
***This insinuates that, at the level of protein:protein interactions, the
barrier preventing transmission of CWD to humans is less robust than previously
estimated.
================
***This insinuates that, at the level of protein:protein interactions, the
barrier preventing transmission of CWD to humans is less robust than previously
estimated.***
================
*** PRICE OF CWD TSE PRION POKER GOES UP 2014 ***
Transmissible Spongiform Encephalopathy TSE PRION update January 2, 2014
*** chronic wasting disease, there was no absolute barrier to conversion of
the human prion protein.
*** Furthermore, the form of human PrPres produced in this in vitro assay
when seeded with CWD, resembles that found in the most common human prion
disease, namely sCJD of the MM1 subtype.
*** These results would seem to suggest that CWD does indeed have zoonotic
potential, at least as judged by the compatibility of CWD prions and their human
PrPC target. Furthermore, extrapolation from this simple in vitro assay suggests
that if zoonotic CWD occurred, it would most likely effect those of the PRNP
codon 129-MM genotype and that the PrPres type would be similar to that found in
the most common subtype of sCJD (MM1).***
*** The potential impact of prion diseases on human health was greatly
magnified by the recognition that interspecies transfer of BSE to humans by beef
ingestion resulted in vCJD. While changes in animal feed constituents and
slaughter practices appear to have curtailed vCJD, there is concern that CWD of
free-ranging deer and elk in the U.S. might also cross the species barrier.
Thus, consuming venison could be a source of human prion disease. Whether BSE
and CWD represent interspecies scrapie transfer or are newly arisen prion
diseases is unknown. Therefore, the possibility of transmission of prion disease
through other food animals cannot be ruled out. There is evidence that vCJD can
be transmitted through blood transfusion. There is likely a pool of unknown size
of asymptomatic individuals infected with vCJD, and there may be asymptomatic
individuals infected with the CWD equivalent. These circumstances represent a
potential threat to blood, blood products, and plasma supplies.
***********CJD REPORT 1994 increased risk for consumption of veal and
venison and lamb***********
CREUTZFELDT JAKOB DISEASE SURVEILLANCE IN THE UNITED KINGDOM THIRD ANNUAL
REPORT AUGUST 1994
Consumption of venison and veal was much less widespread among both cases
and controls. For both of these meats there was evidence of a trend with
increasing frequency of consumption being associated with increasing risk of
CJD. (not nvCJD, but sporadic CJD...tss)
These associations were largely unchanged when attention was restricted to
pairs with data obtained from relatives. ...
Table 9 presents the results of an analysis of these data.
There is STRONG evidence of an association between ‘’regular’’ veal eating
and risk of CJD (p = .0.01).
Individuals reported to eat veal on average at least once a year appear to
be at 13 TIMES THE RISK of individuals who have never eaten veal.
There is, however, a very wide confidence interval around this estimate.
There is no strong evidence that eating veal less than once per year is
associated with increased risk of CJD (p = 0.51).
The association between venison eating and risk of CJD shows similar
pattern, with regular venison eating associated with a 9 FOLD INCREASE IN RISK
OF CJD (p = 0.04).
There is some evidence that risk of CJD INCREASES WITH INCREASING FREQUENCY
OF LAMB EATING (p = 0.02).
The evidence for such an association between beef eating and CJD is weaker
(p = 0.14). When only controls for whom a relative was interviewed are included,
this evidence becomes a little STRONGER (p = 0.08).
snip...
It was found that when veal was included in the model with another
exposure, the association between veal and CJD remained statistically
significant (p = < 0.05 for all exposures), while the other exposures ceased
to be statistically significant (p = > 0.05).
snip...
In conclusion, an analysis of dietary histories revealed statistical
associations between various meats/animal products and INCREASED RISK OF CJD.
When some account was taken of possible confounding, the association between
VEAL EATING AND RISK OF CJD EMERGED AS THE STRONGEST OF THESE ASSOCIATIONS
STATISTICALLY. ...
snip...
In the study in the USA, a range of foodstuffs were associated with an
increased risk of CJD, including liver consumption which was associated with an
apparent SIX-FOLD INCREASE IN THE RISK OF CJD. By comparing the data from 3
studies in relation to this particular dietary factor, the risk of liver
consumption became non-significant with an odds ratio of 1.2 (PERSONAL
COMMUNICATION, PROFESSOR A. HOFMAN. ERASMUS UNIVERSITY, ROTTERDAM). (???...TSS)
snip...see full report ;
CJD9/10022
October 1994
Mr R.N. Elmhirst Chairman British Deer Farmers Association Holly Lodge
Spencers Lane BerksWell Coventry CV7 7BZ
Dear Mr Elmhirst,
CREUTZFELDT-JAKOB DISEASE (CJD) SURVEILLANCE UNIT REPORT
Thank you for your recent letter concerning the publication of the third
annual report from the CJD Surveillance Unit. I am sorry that you are
dissatisfied with the way in which this report was published.
The Surveillance Unit is a completely independant outside body and the
Department of Health is committed to publishing their reports as soon as they
become available. In the circumstances it is not the practice to circulate the
report for comment since the findings of the report would not be amended. In
future we can ensure that the British Deer Farmers Association receives a copy
of the report in advance of publication.
The Chief Medical Officer has undertaken to keep the public fully informed
of the results of any research in respect of CJD. This report was entirely the
work of the unit and was produced completely independantly of the the
Department.
The statistical results reqarding the consumption of venison was put into
perspective in the body of the report and was not mentioned at all in the press
release. Media attention regarding this report was low key but gave a realistic
presentation of the statistical findings of the Unit. This approach to
publication was successful in that consumption of venison was highlighted only
once by the media ie. in the News at one television proqramme.
I believe that a further statement about the report, or indeed statistical
links between CJD and consumption of venison, would increase, and quite possibly
give damaging credence, to the whole issue. From the low key media reports of
which I am aware it seems unlikely that venison consumption will suffer
adversely, if at all.
http://web.archive.org/web/20030511010117/http://www.bseinquiry.gov.uk/files/yb/1994/10/00003001.pdf
Monday, May 02, 2016
*** Zoonotic Potential of CWD Prions: An Update Prion 2016 Tokyo ***
*** PRION 2014 CONFERENCE CHRONIC WASTING DISEASE CWD
*** PPo3-7: Prion Transmission from Cervids to Humans is Strain-dependent
*** Here we report that a human prion strain that had adopted the cervid
prion protein (PrP) sequence through passage in cervidized transgenic mice
efficiently infected transgenic mice expressing human PrP,
*** indicating that the species barrier from cervid to humans is prion
strain-dependent and humans can be vulnerable to novel cervid prion strains.
PPo2-27:
Generation of a Novel form of Human PrPSc by Inter-species Transmission of
Cervid Prions
*** Our findings suggest that CWD prions have the capability to infect
humans, and that this ability depends on CWD strain adaptation, implying that
the risk for human health progressively increases with the spread of CWD among
cervids.
PPo2-7:
Biochemical and Biophysical Characterization of Different CWD Isolates
*** The data presented here substantiate and expand previous reports on the
existence of different CWD strains.
Envt.07:
Pathological Prion Protein (PrPTSE) in Skeletal Muscles of Farmed and Free
Ranging White-Tailed Deer Infected with Chronic Wasting Disease
***The presence and seeding activity of PrPTSE in skeletal muscle from
CWD-infected cervids suggests prevention of such tissue in the human diet as a
precautionary measure for food safety, pending on further clarification of
whether CWD may be transmissible to humans.
>>>CHRONIC WASTING DISEASE , THERE WAS NO ABSOLUTE BARRIER TO
CONVERSION OF THE HUMAN PRION PROTEIN<<<
*** PRICE OF CWD TSE PRION POKER GOES UP 2014 ***
Transmissible Spongiform Encephalopathy TSE PRION update January 2, 2014
Wednesday, January 01, 2014
Molecular Barriers to Zoonotic Transmission of Prions
*** chronic wasting disease, there was no absolute barrier to conversion of
the human prion protein.
*** Furthermore, the form of human PrPres produced in this in vitro assay
when seeded with CWD, resembles that found in the most common human prion
disease, namely sCJD of the MM1 subtype.
Envt.07:
Pathological Prion Protein (PrPTSE) in Skeletal Muscles of Farmed and Free
Ranging White-Tailed Deer Infected with Chronic Wasting Disease
***The presence and seeding activity of PrPTSE in skeletal muscle from
CWD-infected cervids suggests prevention of such tissue in the human diet as a
precautionary measure for food safety, pending on further clarification of
whether CWD may be transmissible to humans.
Yet, it has to be noted that our assessments of PrPTSE levels in skeletal
muscles were based on findings in presumably pre- or subclinically infected
animals. Therefore, the concentration of PrPTSE in skeletal muscles of WTD with
clinically manifest CWD may possibly exceed our estimate which refers to
clinically inconspicuous animals that are more likely to enter the human food
chain. Our tissue blot findings in skeletal muscles from CWD-infected WTD would
be consistent with an anterograde spread of CWD prions via motor nerve fibres to
muscle tissue (figure 4A). Similar neural spreading pathways of muscle infection
were previously found in hamsters orally challenged with scrapie [28] and
suggested by the detection of PrPTSE in muscle fibres and muscle-associated
nerve fascicles of clinically-ill non-human primates challenged with BSE prions
[29]. Whether the absence of detectable PrPTSE in myofibers observed in our
study is a specific feature of CWD in WTD, or was due to a pre- or subclinical
stage of infection in the examined animals, remains to be established. In any
case, our observations support previous findings suggesting the precautionary
prevention of muscle tissue from CWD-infected WTD in the human diet, and
highlight the need to comprehensively elucidate of whether CWD may be
transmissible to humans. While the understanding of TSEs in cervids has made
substantial progress during the past few years, the assessment and management of
risks possibly emanating from prions in skeletal muscles of CWD-infected cervids
requires further research.
Prions in Skeletal Muscles of Deer with Chronic Wasting Disease Rachel C.
Angers1,*, Shawn R. Browning1,*,†, Tanya S. Seward2, Christina J. Sigurdson4,‡,
Michael W. Miller5, Edward A. Hoover4, Glenn C. Telling1,2,3,§ + Author
Affiliations
1 Department of Microbiology, Immunology and Molecular Genetics, University
of Kentucky, Lexington, KY 40536, USA. 2 Sanders Brown Center on Aging,
University of Kentucky, Lexington, KY 40536, USA. 3 Department of Neurology,
University of Kentucky, Lexington, KY 40536, USA. 4 Department of Microbiology,
Immunology and Pathology, Colorado State University, Fort Collins, CO 80523,
USA. 5 Colorado Division of Wildlife, Wildlife Research Center, Fort Collins, CO
80526, USA. ↵§ To whom correspondence should be addressed. E-mail:
gtell2@uky.edu ↵* These authors contributed equally to this work.
↵† Present address: Department of Infectology, Scripps Research Institute,
5353 Parkside Drive, RF-2, Jupiter, FL 33458, USA.
↵‡ Present address: Institute of Neuropathology, University of Zurich,
Schmelzbergstrasse 12, 8091 Zurich, Switzerland.
Abstract The emergence of chronic wasting disease (CWD) in deer and elk in
an increasingly wide geographic area, as well as the interspecies transmission
of bovine spongiform encephalopathy to humans in the form of variant Creutzfeldt
Jakob disease, have raised concerns about the zoonotic potential of CWD. Because
meat consumption is the most likely means of exposure, it is important to
determine whether skeletal muscle of diseased cervids contains prion
infectivity. Here bioassays in transgenic mice expressing cervid prion protein
revealed the presence of infectious prions in skeletal muscles of CWD-infected
deer, demonstrating that humans consuming or handling meat from CWD-infected
deer are at risk to prion exposure.
Exotic Meats USA Announces Urgent Statewide Recall of Elk Tenderloin
Because It May Contain Meat Derived From An Elk Confirmed To Have Chronic
Wasting Disease
Contact: Exotic Meats USA 1-800-680-4375
FOR IMMEDIATE RELEASE -- February 9, 2009 -- Exotic Meats USA of San
Antonio, TX is initiating a voluntary recall of Elk Tenderloin because it may
contain meat derived from an elk confirmed to have Chronic Wasting Disease
(CWD). The meat with production dates of December 29, 30 and 31, 2008 was
purchased from Sierra Meat Company in Reno, NV. The infected elk came from Elk
Farm LLC in Pine Island, MN and was among animals slaughtered and processed at
USDA facility Noah’s Ark Processors LLC.
Chronic Wasting Disease (CWD) is a fatal brain and nervous system disease
found in elk and deer. The disease is caused by an abnormally shaped protein
called a prion, which can damage the brain and nerves of animals in the deer
family. Currently, it is believed that the prion responsible for causing CWD in
deer and elk is not capable of infecting humans who eat deer or elk contaminated
with the prion, but the observation of animal-to-human transmission of other
prion-mediated diseases, such as bovine spongiform encephalopathy (BSE), has
raised a theoretical concern regarding the transmission of CWD from deer or elk
to humans. At the present time, FDA believes the risk of becoming ill from
eating CWD-positive elk or deer meat is remote. However, FDA strongly advises
consumers to return the product to the place of purchase, rather than disposing
of it themselves, due to environmental concerns.
Exotic Meats USA purchased 1 case of Elk Tenderloins weighing 16.9 lbs. The
Elk Tenderloin was sold from January 16 – 27, 2009. The Elk Tenderloins was
packaged in individual vacuum packs weighing approximately 3 pounds each. A
total of six packs of the Elk Tenderloins were sold to the public at the Exotic
Meats USA retail store. Consumers who still have the Elk Tenderloins should
return the product to Exotic Meats USA at 1003 NE Loop 410, San Antonio, TX
78209. Customers with concerns or questions about the Voluntary Elk Recall can
call 1-800-680-4375. The safety of our customer has always been and always will
be our number one priority.
Exotic Meats USA requests that for those customers who have products with
the production dates in question, do not consume or sell them and return them to
the point of purchase. Customers should return the product to the vendor. The
vendor should return it to the distributor and the distributor should work with
the state to decide upon how best to dispose. If the consumer is disposing of
the product he/she should consult with the local state EPA office.
#
COLORADO: Farmer's market meat recalled after testing positive for CWD
24.dec.08 9News.com Jeffrey Wolf
Elk meat that was sold at a farmer's market is being recalled because tests
show it was infected with chronic wasting disease. The Boulder County Health
Department and Colorado Department of Public Health and Environment issued the
recall Wednesday after the meat was sold at the Boulder County Fairgrounds on
Dec. 13. Although there isn't any human health risk connected with CWD, the
recalled was issued as a precaution. About 15 elk were bought from a commercial
ranch in Colorado in early December and processed at a licensed plant. All 15
were tested for CWD and one came up positive. The labeling on the product would
have the following information: *Seller: High Wire Ranch *The type of cut:
"chuck roast," "arm roast," "flat iron," "ribeye steak," "New York steak,"
"tenderloin," "sirloin tip roast," "medallions" or "ground meat." *Processor:
Cedaredge Processing *The USDA triangle containing the number "34645" People
with questions about this meat can contact John Pape, epidemiologist at the
Colorado Department of Public Health and Environment at 303-692-2628.
COULD NOT FIND any warning or recalls on these two sites confirming their
recall of CWD infected meat. ...TSS
Wednesday, April 06, 2011
Presence and Seeding Activity of Pathological Prion Protein (PrPTSE) in
Skeletal Muscles of White-Tailed Deer Infected with Chronic Wasting Disease
Prion Infectivity in Fat of Deer with Chronic Wasting Disease
Brent Race,# Kimberly Meade-White,# Richard Race, and Bruce Chesebro* Rocky
Mountain Laboratories, 903 South 4th Street, Hamilton, Montana 59840
Received 2 June 2009/ Accepted 24 June 2009
ABSTRACT Top ABSTRACT TEXT REFERENCES
Chronic wasting disease (CWD) is a neurodegenerative prion disease of
cervids. Some animal prion diseases, such as bovine spongiform encephalopathy,
can infect humans; however, human susceptibility to CWD is unknown. In
ruminants, prion infectivity is found in central nervous system and lymphoid
tissues, with smaller amounts in intestine and muscle. In mice, prion
infectivity was recently detected in fat. Since ruminant fat is consumed by
humans and fed to animals, we determined infectivity titers in fat from two
CWD-infected deer. Deer fat devoid of muscle contained low levels of CWD
infectivity and might be a risk factor for prion infection of other species.
snip...
The highest risk of human contact with CWD might be through exposure to
high-titer CNS tissue through accidental skin cuts or corneal contact at the
time of harvest and butchering. However, the likelihood of a human consuming fat
infected with a low titer of the CWD agent is much higher. It is impossible to
remove all the fat present within muscle tissue, and fat consumption is
inevitable when eating meat. Of additional concern is the fact that meat from an
individual deer harvested by a hunter is typically consumed over multiple meals
by the same group of people. These individuals would thus have multiple
exposures to the CWD agent over time, which might increase the chance for
transfer of infection.
In the Rocky Mountain region of North America, wild deer are subject to
predation by wolves, coyotes, bears, and mountain lions. Although canines such
as wolves and coyotes are not known to be susceptible to prion diseases, felines
definitely are susceptible to BSE (9) and might also be infected by the CWD
agent. Deer infected with the CWD agent are more likely to be killed by
predators such as mountain lions (11). Peripheral tissues, including lymph
nodes, muscle, and fat, which harbor prion infectivity are more accessible for
consumption than CNS tissue, which has the highest level of infectivity late in
disease. Therefore, infectivity in these peripheral tissues may be important in
potential cross-species CWD transmissions in the wild.
The present finding of CWD infectivity in deer fat tissue raises the
possibility that prion infectivity might also be found in fat tissue of other
infected ruminants, such as sheep and cattle, whose fat and muscle tissues are
more widely distributed in both the human and domestic-animal food chains.
Although the infectivity in fat tissues is low compared to that in the CNS,
there may be significant differences among species and between prion strains.
Two fat samples from BSE agent-infected cattle were reported to be negative by
bioassay in nontransgenic RIII mice (3, 6). However, RIII mice are
10,000-fold-less sensitive to BSE agent infection than transgenic mice
expressing bovine PrP (4). It would be prudent to carry out additional
infectivity assays on fat from BSE agent-infected cattle and scrapie
agent-infected sheep using appropriate transgenic mice or homologous species to
determine the risk from these sources.
0C7.04
North American Cervids Harbor Two Distinct CWD Strains
Authors
Angers, R. Seward, T, Napier, D., Browning, S., Miller, M., Balachandran
A., McKenzie, D., Hoover, E., Telling, G. 'University of Kentucky; Colorado
Division of Wildlife, Canadian Food Inspection Agency; University Of Wisconsin;
Colorado State University.
Content
Despite the increasing geographic distribution and host range of CWD,
little is known about the prion strain(s) responsible for distinct outbreaks of
the disease. To address this we inoculated CWD-susceptible Tg(CerPrP)1536+/·
mice with 29 individual prion samples from various geographic locations in North
America. Upon serial passage, intrastudy incubation periods consistently
diverged and clustered into two main groups with means around 210 and 290 days,
with corresponding differences in neuropathology. Prion strain designations were
utilized to distinguish between the two groups: Type I CWD mice succumbed to
disease in the 200 day range and displayed a symmetrical pattern of vacuolation
and PrPSc deposition, whereas Type II CWD mice succumbed to disease near 300
days and displayed a strikingly different pattern characterized by large local
accumulations of florid plaques distributed asymmetrically. Type II CWD bears a
striking resemblance to unstable parental scrapie strains such as 87A which give
rise to stable, short incubation period strains such as ME7 under certain
passage conditions. In agreement, the only groups of CWD-inoculated mice with
unwavering incubation periods were those with Type I CWD. Additionally,
following endpoint titration of a CWD sample, Type I CWD could be recovered only
at the lowest dilution tested (10-1), whereas Type II CWD was detected in mice
inoculated with all dilutions resulting in disease. Although strain properties
are believed to be encoded in the tertiary structure of the infectious prion
protein, we found no biochemical differences between Type I and Type II CWD. Our
data confirm the co·existence of two distinct prion strains in CWD-infected
cervids and suggest that Type II CWD is the parent strain of Type I CWD.
see page 29, and see other CWD studies ;
Sunday, November 23, 2008
PRION October 8th - 10th 2008 Book of Abstracts
Research Project: TRANSMISSION, DIFFERENTIATION, AND PATHOBIOLOGY OF
TRANSMISSIBLE SPONGIFORM ENCEPHALOPATHIES Location: Virus and Prion Research
2015 Annual Report
1a. Objectives (from AD-416): 1. Investigate the pathobiology of atypical
transmissible spongiform encephalopathies (TSEs) in natural hosts. A.
Investigate the pathobiology of atypical scrapie. B. Investigate the
pathobiology of atypical bovine spongiform encephalopathy (BSE). 2. Investigate
the horizontal transmission of TSEs. A. Assess the horizontal transmission of
sheep scrapie in the absence of lambing. B. Determine routes of transmission in
chronic wasting disease (CWD) infected premises. C. Assess oral transmission of
CWD in reindeer. 3. Investigate determinants of CWD persistence. A. Determine
CWD host range using natural routes of transmission. B. Investigate the
pathobiology of CWD.
1b. Approach (from AD-416): The studies will focus on three animal
transmissible spongiform encephalopathy (TSE) agents found in the United States:
bovine spongiform encephalopathy (BSE); scrapie of sheep and goats; and chronic
wasting disease (CWD) of deer, elk, and moose. The research will address sites
of accumulation, routes of infection, environmental persistence, and ante mortem
diagnostics with an emphasis on controlled conditions and natural routes of
infection. Techniques used will include clinical exams, histopathology,
immunohistochemistry and biochemical analysis of proteins. The enhanced
knowledge gained from this work will help mitigate the potential for
unrecognized epidemic expansions of these diseases in populations of animals
that could either directly or indirectly affect food animals.
3. Progress Report: Research efforts directed toward meeting objective 1 of
our project plan include work in previous years starting with the inoculation of
animals for studies designed to address the pathobiology of atypical scrapie,
atypical bovine spongiform encephalopathy (BSE), as well as a genetic version of
BSE. Post-mortem examination of the animals inoculated with atypical scrapie has
been initiated and laboratory analysis of the tissues is ongoing. Atypical BSE
animals have developed disease and evaluation of the samples is currently
underway. Animals inoculated with a genetic version of BSE have developed
disease with a manuscript reporting these results was published (2012), and
additional laboratory comparisons of genetic BSE to atypical and classical BSE
are ongoing. In addition, we have investigated the possibility that atypical
scrapie was present earlier than previously detected in the national flock by
analyzing archived field isolates using methods that were unavailable at the
time of original diagnosis. Sample quality was sufficiently degraded that modern
methods, beyond those applied to the tissues at the time the tissues were
archived, were not suitable for evaluation. In research pertaining to objective
2, "Investigate the horizontal transmission of TSEs", we have initiated a study
to determine if cohousing non-lambing scrapie inoculated sheep is sufficient to
transmit scrapie to neonatal lambs. At this time, scrapie free ewes have lambed
in the presence of scrapie inoculated animals and the lambs are cohoused with
these inoculated animals.
4. Accomplishments 1. Changes in retinal function in cattle can be used to
identify different types of bovine spongiform encephalopathy (BSE). BSE belongs
to a group of fatal, transmissible protein misfolding diseases known as
transmissible spongiform encephalopathies (TSEs). Like other protein misfolding
diseases including Parkinson's disease and Alzheimer's disease, TSEs are
generally not diagnosed until the onset of disease after the appearance of
unequivocal clinical signs. As such, identification of the earliest clinical
signs of disease may facilitate diagnosis. The retina is the most accessible
part of the central nervous system. ARS scientist in Ames IA described
antemortem changes in retinal function and thickness that are detectable in BSE
inoculated animals up to 11 months prior to the appearance of any other signs of
clinical disease. Differences in the severity of these clinical signs reflect
the amount of PrPSc accumulation in the retina and the resulting inflammatory
response of the tissue. These results are the earliest reported clinical signs
associated with TSE infection and provide a basis for understanding the
pathology and evaluating therapeutic interventions. Further, this work shows
that High-type BSE and classical BSE can be differentiated by eye examination
alone, the first time BSE strains have been differentiable in a live animal.
2. Sheep genetics influences the susceptibility of sheep to scrapie. Sheep
scrapie is a transmissible spongiform encephalopathy that can be transmitted
between affected animals resulting in significant economic losses in affected
flocks. The prion protein gene (PRNP) profoundly influences the susceptibility
of sheep to the scrapie agent and the tissue levels and distribution of PrPSc in
affected sheep. In this study, sheep of 3 different prion genetic types (denoted
VRQ/VRQ, VRQ/ARR and ARQ/ARR) were inoculated and subsequently euthanized upon
onset of disease. Disease aspects were uniform across genotypes and consistent
with manifestations of classical scrapie. Mean survival time differences were
associated with the genetic type such that VRQ/VRQ sheep survived 18 months,
whereas VRQ/ARR and ARQ/ARR sheep survived 60 and 56 months, respectively.
Microscopic evaluation revealed similar accumulations in central nervous system
tissues regardless of host genetic type. PrPSc in lymphoid tissue was
consistently abundant in VRQ/VRQ, present but confined to tonsil or
retropharyngeal lymph node in 4/5 VRQ/ARR, and totally absent in ARQ/ARR sheep.
The results of this study demonstrate the susceptibility of sheep with the
ARQ/ARR genotype to scrapie by the intracranial inoculation route with PrPSc
accumulation in CNS tissues, but prolonged incubation times and lack of PrPSc in
lymphoid tissue. These results are important for science based policy with
regard to testing of sheep for scrapie where some live animal testing is
conducted using lymphoid tissues which would not detect scrapie in some specific
genetic types which could limit the national scrapie eradication program.
Review Publications Greenlee J.J. 2014. The prion diseases of animals. In:
McManus, L.M., Mitchell, R.N., editors. Pathobiology of Human Disease. San
Diego: Elsevier. p. 1124-1133. Greenlee, J.J., Kunkle, R.A., Richt, J.A.,
Nicholson, E.M., Hamir, A.N. 2014. Lack of prion accumulation in lymphoid
tissues of PRNP ARQ/ARR sheep intracranially inoculated with the agent of
scrapie. PLoS One. 9(9):e108029. Greenlee, J.J., West Greenlee, M.,H. 2015. The
transmissible spongiform encephalopathies of livestock. ILAR Journal.
56(1):7-25. Munoz-Gutierrez, J.F., Schneider, D.A., Baszler, T.V., Dinkel, K.D.,
Greenlee, J.J., Nicholson, E.M., Stanton, J.J. 2015. hTERT-immortalized ovine
microglia propagate natural scrapie isolates. Virus Research. 198:35-43.
Nicholson, E.M. 2015. Detection of the disease-associated form of the prion
protein in biological samples. Bioanalysis. 7(2):253-261. West Greenlee, M.H.,
Smith, J.D., Platt, E.M., Juarez, J.R., Timms, L.L, Greenlee, J.J. 2015. Changes
in retinal function and morphology are early clinical signs of disease in cattle
with bovine spongiform encephalopathy. PLoS ONE. 10(3):e0119431. Comoy, E.E.,
Mikol, J., Luccantoni-Freire, S., Correia, E., Lescoutra-Etchegaray, N., Durand,
V., Dehen, C., Andreoletti, O., Casalone, C., Richt, J.A., Greenlee, J.J.,
Baron, T., Benestad, S., Brown, P., Deslys, J. 2015. Transmission of scrapie
prions to primate after an extended silent incubation period. Scientific
Reports. 5:11573.
Subject: Wisconsin Governor Scott Walker's DNR et al have floundered again
on taking any actions on CWD TSE Prion disease, decides to put off now until
March 2017
see past history of CWD in Wisconsin here ;
Thursday, September 29, 2016
Wisconsin Governor Scott Walker's DNR et al have floundered again on taking
any actions on CWD TSE Prion disease, decides to put off now until March 2017
Terry S. Singeltary Sr.
posted by Terry S. Singeltary Sr. at
11:46 AM
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