IOWA CHRONIC WASTING DISEASE FOUND AT A DEER FARM IN BUCHANAN COUNTY
Dustin Vande Hoef 515/281-3375 or 515/326-1616 (cell) or
Dustin.VandeHoef@IowaAgriculture.gov
CHRONIC WASTING
DISEASE FOUND AT A DEER FARM IN BUCHANAN COUNTY
DES MOINES – Chronic Wasting Disease (CWD) has been
confirmed in one captive white-tail at a deer farm in Buchanan County, Iowa.
The Iowa Department of Agriculture and Land Stewardship has quarantined the
site.
The disease was detected as part of the Department’s
voluntary CWD monitoring program. The farm where the disease was found
participates in the program which requires CWD surveillance and testing of all
farmed deer and elk 12 months of age and older that dies. Test results must be
shared with the Department.
CWD was found in neighboring Wisconsin in 2002. Since then,
Iowa has tested for CWD in 57,765 wild deer and 10,157 captive deer and elk as
part of its surveillance program. The Iowa Department of Natural Resources will
increase testing of wild deer in the Buchanan County area. DNR staff will work
with hunters and landowners to collect samples from hunter-harvested deer,
roadkills and targeted deer displaying symptoms of CWD.
There is no evidence that CWD can spread to humans, pets or
domestic livestock. CWD is a neurological disease that only affects deer, elk
and moose. It is caused by an abnormal protein, called a prion, which affects
the brains of infected animals, causing them to lose weight, display abnormal
behavior and lose bodily functions. The prions can attach to soil and spread
the disease among deer. Symptoms of the disease include excessive salivation,
thirst and urination, loss of appetite, progressive weight loss, listlessness
as well as drooping ears and head. Chronic wasting disease was first identified
in captive mule deer at a research facility in Colorado in 1967.
Friday, February 05, 2016
IOWA Two Wild Deer Test Positive for Chronic Wasting Disease
in Allamakee County
DNR News Releases
Sunday, January 24, 2016
IOWA CHRONIC WASTING TSE PRION DISEASE UPDATE
Sunday, December 11, 2016
Clay Components in Soil Dictate Environmental Stability and
Bioavailability of Cervid Prions in Mice
Wednesday, December 14, 2016
Increased Abundance of M Cells in the Gut Epithelium
Dramatically Enhances Oral Prion Disease Susceptibility
some of you may be interested in these videos presented
recently at the WYOMING CWD FORUM.
Thursday, December 15, 2016
Wyoming National Elk Refuge CWD forum update December 8,
2016
Friday, November 18, 2016
Missouri MDC Collected 19,200 Tissue Samples for CWD Testing
MDC thanks hunters for help in collecting 19,200 tissue
samples for CWD testing
cwd resistant cervid???
***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
Saturday, May 28,
2016
*** Infection and detection of PrPCWD in soil from CWD
infected farm in Korea Prion 2016 Tokyo ***
Sunday, December 11, 2016
Clay Components in Soil Dictate Environmental Stability and
Bioavailability of Cervid Prions in Mice
*** 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...tss
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
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
snip...see full text ;
Scrapie Field Trial
Experiments Mission, Texas, The Moore Air Force Base Scrapie Experiment 1964
How Did CWD Get Way Down In Medina County, Texas?
Confucius ponders...
Could the Scrapie experiments back around 1964 at Moore Air
Force near Mission, Texas, could this area have been ground zero for CWD TSE
Prion (besides the CWD cases that have waltzed across the Texas, New Mexico
border near WSMR Trans Pecos region since around 2001)?
Epidemiology of Scrapie in the United States 1977
snip...
Scrapie Field Trial Experiments Mission, Texas
A Scrapie Field Trial was developed at Mission, Texas, to
provide additional information for the eradication program on the epidemiology
of natural scrapie. The Mission Field Trial Station is located on 450 acres of
pastureland, part of the former Moore Air Force Base, near Mission, Texas. It
was designed to bring previously exposed, and later also unexposed, sheep or
goats to the Station and maintain and breed them under close observation for
extended periods to determine which animals would develop scrapie and define
more closely the natural spread and other epidemiological aspects of the
disease.
The 547 previously exposed sheep brought to the Mission
Station beginning in 1964 were of the Cheviot, Hampshire, Montadale, or Suffolk
breeds. They were purchased as field outbreaks occurred, and represented 21
bloodlines in which scrapie had been diagnosed. Upon arrival at the Station,
the sheep were maintained on pasture, with supplemental feeding as necessary.
The station was divided into 2 areas: (1) a series of pastures and-pens
occupied by male animals only, and (2) a series of pastures and pens occupied
by females and young progeny of both sexes. ...
snip...see full text ;
Thursday, June 09, 2016
Scrapie Field Trial Experiments Mission, Texas, The Moore
Air Force Base Scrapie TSE Prion Experiment 1964
How Did CWD Get Way Down In Medina County, Texas?
Friday, April 22, 2016
*** Texas Scrapie Confirmed in a Hartley County Sheep where
CWD was detected in a Mule Deer
Thursday, December 08, 2016
USDA APHIS National Scrapie Eradication Program October 2016
Monthly Report Fiscal Year 2017 atypical NOR-98 Scrapie
Title: Pathological features of chronic wasting disease in
reindeer and demonstration of horizontal transmission
*** Title: Pathological features of chronic wasting disease
in reindeer and demonstration of horizontal transmission
*** December 2016 CDC Emerging Infectious Disease Journal
CWD Horizontal Transmission
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
SUNDAY, OCTOBER 02, 2016
*** What is the risk of a cervid TSE being introduced from
Norway into Great Britain? Qualitative Risk Assessment September 2016
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
Saturday, December 03, 2016
TEXAS CHRONIC WASTING DISEASE CWD TSE PRION UPDATE 35 CASES
TO DATE
Wednesday, December 07, 2016
Student Assistant (Temporary) – Chronic Wasting Disease:
Texas A&M Veterinary Medical Diagnostic Laboratory
Chronic Wasting
Disease (CWD) Susceptibility of Several North American Rodents That Are
Sympatric with Cervid CWD Epidemics▿
Thursday, December 15, 2016
Wyoming National Elk Refuge CWD forum update December 8,
2016
cwd zoonosis, and the
science there from of late...as follows;
*** 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
Monday, May 02, 2016
*** Zoonotic Potential of CWD Prions: An Update Prion 2016
Tokyo ***
Saturday, April 23, 2016
PRION 2016 TOKYO
Saturday, April 23, 2016
SCRAPIE 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
ef?ciency comparable to that of cattle BSE. While the ef?ciency 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.
why do we not want to
do TSE transmission studies on chimpanzees $
5. A positive result from a chimpanzee challenged severly
would likely create alarm in some circles even if the result could not be
interpreted for man. I have a view that all these agents could be transmitted
provided a large enough dose by appropriate routes was given and the animals
kept long enough. Until the mechanisms of the species barrier are more clearly
understood it might be best to retain that hypothesis.
snip...
R. BRADLEY
Title: Transmission of scrapie prions to primate after an
extended silent incubation period)
*** In complement to the recent demonstration that humanized
mice are susceptible to scrapie, we report here the first observation of direct
transmission of a natural classical scrapie isolate to a macaque after a
10-year incubation period. Neuropathologic examination revealed all of the
features of a prion disease: spongiform change, neuronal loss, and accumulation
of PrPres throughout the CNS.
*** This observation
strengthens the questioning of the harmlessness of scrapie to humans, at a time
when protective measures for human and animal health are being dismantled and
reduced as c-BSE is considered controlled and being eradicated.
*** Our results
underscore the importance of precautionary and protective measures and the
necessity for long-term experimental transmission studies to assess the
zoonotic potential of other animal prion strains.
SCRAPIE WS-01: Prion diseases in animals and zoonotic
potential 2016
Prion. 10:S15-S21. 2016 ISSN: 1933-6896 printl 1933-690X
online
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, Valerie 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 long incubation than BSE. Scrapie, as recently evoked in humanized
mice (Cassard, 2014),
***is the third
potentially zoonotic PD (with BSE and L-type BSE),
***thus questioning
the origin of human sporadic cases. We will present an updated panorama of our
different transmission studies and discuss the implications of such extended
incubation periods on risk assessment of animal PD for human health.
===============
***thus questioning the origin of human sporadic cases***
***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.
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).***
*** 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.
Terry S. Singeltary Sr.
posted by Terry S. Singeltary Sr. at
6:29 PM
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