Michigan confirms CWD in second free-ranging white-tailed deer
Michigan DNR sent this bulletin at 07/17/2015 11:53 AM EDT
Of 304 deer tested in the Core CWD Area, only two have tested positive for
CWD.
Press Release
--------------------------------------------------------------------------------
FOR IMMEDIATE RELEASE July 17, 2015
Contact: Steve Schmitt, 517-336-5030 or John Pepin, 906-228-6561
Michigan confirms chronic wasting disease in second free-ranging
white-tailed deer
The Michigan departments of Natural Resources (DNR) and Agriculture and
Rural Development (MDARD) have confirmed a second free-ranging deer in Meridian
Township (Ingham County) has tested positive for chronic wasting disease (CWD),
a fatal neurological disease that affects white-tailed deer, mule deer, elk and
moose. This second case is a 2-year-old male found less than a mile from the
initial positive female deer, confirmed this past May. Genetic testing is being
conducted to see if the two deer are related.
“Finding this second positive deer is disappointing, however, not
unexpected,” said DNR Wildlife Division Chief Russ Mason. “We will continue with
our aggressive surveillance throughout the summer and fall. With the assistance
of hunters, we hope to determine the distribution of this disease.”
To date, 304 deer have been tested in the Core CWD Area. Only two have
tested positive for CWD.
Upon the finding of the initial CWD positive deer, the DNR established the
CWD Management Zone consisting of Clinton, Ingham and Shiawassee counties.
Additionally, the Core CWD Area consisting of Lansing, Meridian,
Williamstown, Delhi, Alaiedon and Wheatfield townships in Ingham County; DeWitt
and Bath townships in Clinton County; and Woodhull Township in Shiawassee
County, was created. Feeding and baiting of deer and elk are prohibited in the
CWD Management Zone. Mandatory checking of deer will be required in the Core CWD
Area during hunting seasons and restrictions will apply to the movement of
carcasses and parts of deer taken in this area.
“Michigan has a long tradition of hunter support and conservation ethics.
Now, with these CWD findings, that support is needed more than ever,” said Steve
Schmitt, veterinarian-in-charge at the DNR Wildlife Disease Lab. “Because
hunters are often familiar with the deer herd locally, one of the best things
they can do to help manage this disease is to continue hunting and bring their
deer to check stations this season.”
In the Core CWD Area, there is an unlimited antlerless deer license quota
and the deer license or deer combo licenses may be used to harvest antlerless or
any antlered deer during firearm and muzzleloading seasons. Additional
deer-check stations will be established in the Core CWD Area and the CWD
Management Zone to accommodate hunters.
To date, there is no evidence that chronic wasting disease presents any
risk to non-cervids, including humans, either through contact with an infected
animal or from handling contaminated venison. However, as a precaution, the U.S.
Centers for Disease Control and the World Health Organization recommend that
infected animals not be consumed as food by either humans or domestic animals.
The DNR asks that the public and hunters continue to report deer that are
unusually thin and exhibiting unusual behavior (for example, acting tame around
humans and allowing someone to approach).
To report a suspicious-looking deer, call the DNR Wildlife Disease Lab at
517-336-5030 or fill out and submit the online observation report, found on the
DNR website.
DNR staff will continue with road-kill collection in the Core CWD Area. To
report road-kills found in the Core CWD Area call the Wildlife Disease Hotline
at 517-614-9602. Leave a voicemail with location information and staff will
attempt to pick up carcasses on the next open business day.
More information on CWD, including Michigan’s CWD surveillance and response
plan and weekly testing updates, are available at www.michigan.gov/cwd.
# # #
/Note to editors: Links to photos and other CWD-related information –
including to the CWD Alliance website – are available via the DNR website
www.michigan.gov/cwd./
Michigan confirms state's first case of chronic wasting disease in
free-ranging white-tailed deer Contact: Ed Golder (DNR), 517-284-5815 or Heather
Throne (MDARD), 517-284-5725 Agency: Natural Resources
May 26, 2015
The Michigan departments of Natural Resources (DNR) and Agriculture and
Rural Development (MDARD) today confirmed that a free-ranging deer in Meridian
Township (Ingham County) has tested positive for chronic wasting disease (CWD),
a fatal neurological disease that affects white-tailed deer, mule deer, elk and
moose. This is the first time the disease has been found in Michigan’s
free-ranging deer population. In 2008 a white-tailed deer from a privately owned
cervid (POC) facility in Kent County tested positive for CWD.
The animal was observed last month wandering around a Meridian Township
residence and showing signs of illness. The homeowner contacted the Meridian
Township Police Department, who then sent an officer to euthanize the animal.
The deer was collected by a DNR wildlife biologist and delivered for initial
testing to the DNR Wildlife Disease Laboratory at the Michigan State University
Diagnostic Center for Population and Animal Health in Lansing, Michigan. After
initial tests were positive, samples were forwarded to the U.S. Department of
Agriculture’s National Veterinary Services Laboratory in Ames, Iowa, for final
confirmation. The Michigan DNR received that positive confirmation last week.
To date, there is no evidence that chronic wasting disease presents any
risk to non-cervids, including humans, either through contact with an infected
animal or from handling contaminated venison. However, as a precaution, the U.S.
Centers for Disease Control and the World Health Organization recommend that
infected animals not be consumed as food by either humans or domestic animals.
“This is the first case of chronic wasting disease to be confirmed in a
free-ranging Michigan white-tailed deer,” said DNR Director Keith Creagh.
“While it is a disappointing day for Michigan, the good news is that we are
armed with a thoughtfully crafted response plan,” Creagh said. “We are working
with other wildlife experts at the local, regional, state and federal level,
using every available resource, to determine the extent of this disease, respond
appropriately to limit further transmission, and ultimately eradicate the
disease in Michigan if possible.”
The confirmed positive finding triggers several actions in the state’s
surveillance and response plan for chronic wasting disease. The plan was
developed in 2002 through cooperation between the DNR and MDARD, and was updated
in 2012. Actions the DNR will take include:
Completing a population survey in the area where the CWD-positive deer was
found. Establishing a Core CWD Area consisting of Alaiedon, Delhi, Lansing,
Meridian, Wheatfield and Williamstown townships in Ingham County; Bath and
DeWitt townships in Clinton County; and Woodhull Township in Shiawassee County.
Unlimited antlerless deer hunting licenses will be available. Mandatory checking
of deer will be required in this area during hunting seasons and restrictions
will apply to the movement of carcasses and parts of deer taken in this area.
Creating a CWD Management Zone, which will include Clinton, Ingham and
Shiawassee counties. Implementing a deer and elk feeding and baiting ban, which
will include the Core CWD Area and the larger three-county CWD Management Zone.
Prohibiting the possession or salvage of deer killed by collision with a motor
vehicle within the Core CWD Area. Also, residents are asked to call in the
locations of road-killed deer within this area so DNR staff can pick up for
testing. Research shows CWD-infected deer are more likely to be hit by vehicles
because of their illness. DNR Director Creagh will issue an interim order
approving immediate implementation of these actions.
“MDARD is working with the state’s privately owned cervid facilities within
a 15-mile surveillance zone to ensure compliance with CWD testing requirements,”
said MDARD State Veterinarian James Averill. “For POC facilities located outside
of the surveillance zone, there will be no impact. We are, however, encouraging
all POCs to continue to be our partners in the state’s CWD testing program.”
Chronic wasting disease first was identified in 1967 as a clinical disease
in captive mule deer at the Colorado Division of Wildlife Foothills Wildlife
Research Facility in Fort Collins, Colorado. Since then, most CWD cases have
occurred in western states, but in the past 15 years it has spread to some
midwestern and eastern states.
The disease is caused by the transmission of infectious, self-multiplying
proteins (prions) contained in saliva and other body fluids of infected animals.
Susceptible animals can acquire CWD by direct exposure to these fluids or from
environments contaminated with these fluids or the carcass of a diseased animal.
Once contaminated, research shows that soil can remain a source of infection for
long periods of time, making CWD a particularly difficult disease to eradicate.
Some chronically CWD-infected animals will display abnormal behaviors,
progressive weight loss and physical debilitation. There is no cure; once a deer
is infected with CWD, it will die.
Although this is the first positive CWD finding in the state’s free-ranging
deer population, it is important to note that from Jan. 1, 1998, through Dec.
31, 2014, tens of thousands of free-ranging Michigan deer were tested and no
evidence was found of chronic wasting disease in this population. In fact, that
testing included 34,207 deer, 1,607 elk and 70 moose – a large sample of animals
with no positive finding. In privately owned deer populations, approximately
21,000 samples have to date been tested for CWD. All of those have been negative
as well, with the exception of the 2008 Kent County case. MDARD conducts ongoing
surveillance of Michigan’s 365 registered, privately owned cervid
facilities.
Public awareness, support
“Strong public awareness and cooperation from residents and hunters are
critical for a rapid response to evaluate any deer suspected of having chronic
wasting disease,” said Steve Schmitt, veterinarian-in-charge at the DNR Wildlife
Disease Lab. “We’d like to thank the resident who called local authorities, as
well as the Meridian Township Police Department for its swift response.”
The DNR asks help from the public and hunters in reporting deer that
are:
Unusually thin. Exhibiting unusual behavior (for example, acting tame
around humans and allowing someone to approach). To report a suspicious-looking
deer, call the DNR Wildlife Disease Lab at 517-336-5030 or fill out and submit
the online observation report found on the DNR website.
To report road-kills found in the Core CWD Area call the Wildlife Disease
Hotline at 517-614-9602 during office hours. Leave a voicemail with location
information and staff will attempt to pick up carcasses on the next open
business day.
Additionally, Schmitt said hunters will play a key role in helping the
state manage this new wildlife challenge.
“Michigan has a long tradition of hunter support and conservation ethics.
Now, with the CWD finding, that support is needed more than ever,” Schmitt said.
“Historically, areas where chronic wasting disease has been found have
experienced a decline in hunter numbers. Because hunters are often familiar with
the deer herd locally, one of the best things they can do to help manage this
disease is to continue hunting and bring their deer to check stations this
season.”
Once the DNR has conducted targeted surveillance in the CWD Management
Zone, staff will have a better understanding of needed changes in hunting
regulations for upcoming deer hunting seasons.
Despite the CWD finding, Schmitt said there is reason for optimism.
“When it comes to chronic wasting disease, Michigan isn’t alone. A total of
23 states and two Canadian provinces have found CWD in either free-ranging or
privately owned cervids, or both,” he said. “Michigan will take full advantage
of the collective expertise and experience of those who have for years now dealt
with chronic wasting disease on a daily basis.”
Get more information on CWD – including Michigan’s CWD surveillance and
response plan, FAQs and a link to the CWD Alliance website where more photos and
video are available – at www.michigan.gov/cwd.
The Michigan Department of Natural Resources is committed to the
conservation, protection, management, use and enjoyment of the state’s natural
and cultural resources for current and future generations. For more information,
go to www.michigan.gov/dnr.
Tuesday, May 26, 2015
Michigan confirms state's first case of chronic wasting disease in
free-ranging white-tailed deer
The TSE prion disease survives ashing to 600 degrees celsius, that’s
around 1112 degrees farenheit.
you cannot cook the TSE prion disease out of meat.
you can take the ash and mix it with saline and inject that ash into a
mouse, and the mouse will go down with TSE.
Prion Infected Meat-and-Bone Meal Is Still Infectious after Biodiesel
Production as well.
the TSE prion agent also survives Simulated Wastewater Treatment Processes.
IN fact, you should also know that the TSE Prion agent will survive in the
environment for years, if not decades.
you can bury it and it will not go away.
The TSE agent is capable of infected your water table i.e. Detection of
protease-resistant cervid prion protein in water from a CWD-endemic area.
it’s not your ordinary pathogen you can just cook it out and be done with.
that’s what’s so worrisome about Iatrogenic mode of transmission, a simple
autoclave will not kill this TSE prion agent.
New studies on the heat resistance of hamster-adapted scrapie agent:
Threshold survival after ashing at 600°C suggests an inorganic template of
replication
The infectious agents responsible for transmissible spongiform
encephalopathy (TSE) are notoriously resistant to most physical and chemical
methods used for inactivating pathogens, including heat. It has long been
recognized, for example, that boiling is ineffective and that higher
temperatures are most efficient when combined with steam under pressure (i.e.,
autoclaving). As a means of decontamination, dry heat is used only at the
extremely high temperatures achieved during incineration, usually in excess of
600°C. It has been assumed, without proof, that incineration totally inactivates
the agents of TSE, whether of human or animal origin.
Prion Infected Meat-and-Bone Meal Is Still Infectious after Biodiesel
Production
Histochemical analysis of hamster brains inoculated with the solid residue
showed typical spongiform degeneration and vacuolation. Re-inoculation of these
brains into a new cohort of hamsters led to onset of clinical scrapie symptoms
within 75 days, suggesting that the specific infectivity of the prion protein
was not changed during the biodiesel process. The biodiesel reaction cannot be
considered a viable prion decontamination method for MBM, although we observed
increased survival time of hamsters and reduced infectivity greater than 6 log
orders in the solid MBM residue. Furthermore, results from our study compare for
the first time prion detection by Western Blot versus an infectivity bioassay
for analysis of biodiesel reaction products. We could show that biochemical
analysis alone is insufficient for detection of prion infectivity after a
biodiesel process.
Detection of protease-resistant cervid prion protein in water from a
CWD-endemic area
The data presented here demonstrate that sPMCA can detect low levels of
PrPCWD in the environment, corroborate previous biological and experimental data
suggesting long term persistence of prions in the environment2,3 and imply that
PrPCWD accumulation over time may contribute to transmission of CWD in areas
where it has been endemic for decades. This work demonstrates the utility of
sPMCA to evaluate other environmental water sources for PrPCWD, including
smaller bodies of water such as vernal pools and wallows, where large numbers of
cervids congregate and into which prions from infected animals may be shed and
concentrated to infectious levels.
A Quantitative Assessment of the Amount of Prion Diverted to Category 1
Materials and Wastewater During Processing
Keywords:Abattoir;bovine spongiform encephalopathy;QRA;scrapie;TSE
In this article the development and parameterization of a quantitative
assessment is described that estimates the amount of TSE infectivity that is
present in a whole animal carcass (bovine spongiform encephalopathy [BSE] for
cattle and classical/atypical scrapie for sheep and lambs) and the amounts that
subsequently fall to the floor during processing at facilities that handle
specified risk material (SRM). BSE in cattle was found to contain the most oral
doses, with a mean of 9864 BO ID50s (310, 38840) in a whole carcass compared to
a mean of 1851 OO ID50s (600, 4070) and 614 OO ID50s (155, 1509) for a sheep
infected with classical and atypical scrapie, respectively. Lambs contained the
least infectivity with a mean of 251 OO ID50s (83, 548) for classical scrapie
and 1 OO ID50s (0.2, 2) for atypical scrapie. The highest amounts of infectivity
falling to the floor and entering the drains from slaughtering a whole carcass
at SRM facilities were found to be from cattle infected with BSE at rendering
and large incineration facilities with 7.4 BO ID50s (0.1, 29), intermediate
plants and small incinerators with a mean of 4.5 BO ID50s (0.1, 18), and
collection centers, 3.6 BO ID50s (0.1, 14). The lowest amounts entering drains
are from lambs infected with classical and atypical scrapie at intermediate
plants and atypical scrapie at collection centers with a mean of 3 × 10−7 OO
ID50s (2 × 10−8, 1 × 10−6) per carcass. The results of this model provide key
inputs for the model in the companion paper published here.
*** Infectious agent of sheep scrapie may persist in the environment for at
least 16 years***
Gudmundur Georgsson1, Sigurdur Sigurdarson2 and Paul Brown3
Longitudinal Detection of Prion Shedding in Saliva and Urine by
CWD-Infected Deer by RT-QuIC
Davin M. Henderson1, Nathaniel D. Denkers1, Clare E. Hoover1, Nina
Garbino1, Candace K. Mathiason1 and Edward A. Hoover1# + Author
Affiliations
1Prion Research Center, Department of Microbiology, Immunology, and
Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado
State University, Fort Collins, CO 80523 ABSTRACT Chronic Wasting Disease (CWD)
is an emergent, rapidly spreading prion disease of cervids. Shedding of
infectious prions in saliva and urine is thought to be an important factor in
CWD transmission. To help elucidate this issue, we applied an in vitro
amplification assay to determine the onset, duration, and magnitude of prion
shedding in longitudinally collected saliva and urine samples from CWD-exposed
white-tailed deer. We detected prion shedding as early as 3 months after CWD
exposure and sustained shedding throughout the disease course. We estimated that
a 50% lethal dose (LD50) for cervidized transgenic mice would be contained in 1
ml of infected deer saliva or 10 ml or urine. Given the average course of
infection and daily production of these body fluids, an infected deer would shed
thousands of prion infectious dosesover the course of CWD infection. The direct
and indirect environmental impact of this magnitude of prion shedding for cervid
and non-cervid species is surely significant.
Importance: Chronic wasting disease (CWD) is an emerging and uniformly
fatal prion disease affecting free ranging deer and elk and now recognized in 22
United States and 2 C anadian Provinces. It is unique among prion diseases in
that it is transmitted naturally though wild populations. A major hypothesis for
CWD's florid spread is that prions are shed in excreta and transmitted via
direct or indirect environmental contact. Here we use a rapid in vitro assay to
show that infectious doses of CWD prions are in fact shed throughout the
multi-year disease course in deer. This finding is an important advance in
assessing the risks posed by shed CWD prions to animals as well as humans.
FOOTNOTES
↵#To whom correspondence should be addressed: Edward A. Hoover, Prion
Research Center, Department of Microbiology, Immunology and Pathology, Colorado
State University, Fort Collins, Colorado, US Email: edward.hoover@colostate.edu
Approximately 4,200 fawns, defined as deer under 1 year of age, were
sampled from the eradication zone over the last year. The majority of fawns
sampled were between the ages of 5 to 9 months, though some were as young as 1
month. Two of the six fawns with CWD detected were 5 to 6 months old. All six of
the positive fawns were taken from the core area of the CWD eradication zone
where the highest numbers of positive deer have been identified.
"This is the first intensive sampling for CWD in fawns anywhere," said Dr.
Julie Langenberg, Department of Natural Resources wildlife veterinarian, "and we
are trying to learn as much as we can from these data".
Saturday, February 04, 2012
Wisconsin 16 MONTH age limit on testing dead deer Game Farm CWD Testing
Protocol Needs To Be Revised
Articles of Significant Interest Selected from This Issue by the Editors
Next Section Prions in the Blood of Infected Hosts: Early and Persistent Prions
circulate in the blood of prion-infected hosts, including humans with variant
Creutzfeldt-Jakob disease. Determining the parameters of blood-borne prions
during the long asymptomatic phase of disease characteristic of all prion
diseases has been a long-standing problem in prion biology. Elder et. al (p.
7421–7424) have demonstrated amyloid formation, a biomarker for prions, in the
blood of prion-infected rodent and cervid hosts as early as 15 minutes
post-mucosal or -intravenous infection. This prionemia persists throughout the
disease course, indicating a role for hematogenous prions throughout the
preclinical stage of illness.
***Immediate and Ongoing Detection of Prions in the Blood of Hamsters and
Deer following Oral, Nasal, or Blood Inoculations
Alan M. Eldera, Davin M. Hendersona, Amy V. Nallsa, Edward A. Hoovera,
Anthony E. Kincaidb,c, Jason C. Bartzb and Candace K. Mathiasona aDepartment of
Microbiology, Immunology and Pathology, Colorado State University, Fort Collins,
Colorado, USA bMedical Microbiology and Immunology, Creighton University, Omaha,
Nebraska, USA cDepartment of Pharmacy Sciences, Creighton University, Omaha,
Nebraska, USA S. Perlman, Editor + Author Affiliations
what about CWD infection rates on some of these game farms ???
CHRONIC WASTING DISEASE CWD WISCONSIN Almond Deer (Buckhorn Flats)
FarmUpdate DECEMBER 2011The CWD infection rate was nearly 80%, the highest ever
in a North American captive herd. RECOMMENDATION: That the Board approve the
purchase of 80acres of land for $465,000 for the Statewide Wildlife Habitat
Program inPortage County and approve the restrictions on public use of the
site.SUMMARY:
For Immediate Release Thursday, October 2, 2014
Dustin Vande Hoef 515/281-3375 or 515/326-1616 (cell) or
Dustin.VandeHoef@IowaAgriculture.gov
TEST RESULTS FROM CAPTIVE DEER HERD WITH CHRONIC WASTING DISEASE RELEASED
79.8 percent of the deer tested positive for the disease
DES MOINES – The Iowa Department of Agriculture and Land Stewardship today
announced that the test results from the depopulation of a quarantined captive
deer herd in north-central Iowa showed that 284 of the 356 deer, or 79.8% of the
herd, tested positive for Chronic Wasting Disease (CWD). The owners of the
quarantined herd have entered into a fence maintenance agreement with the Iowa
Department of Agriculture and Land Stewardship,which requires the owners to
maintain the 8’ foot perimeter fence around the herd premises for five years
after the depopulation was complete and the premises had been cleaned and
disinfected CWD is a progressive, fatal, degenerative neurological disease of
farmed and free-ranging deer, elk, and moose. There is no known treatment or
vaccine for CWD. CWD is not a disease that affects humans.On July 18, 2012, USDA
Animal and Plant Health Inspection Service’s (APHIS)National Veterinary Services
Lab in Ames, IA confirmed that a male whitetail deer harvested from a hunting
preserve in southeast IA was positive for CWD. An investigation revealed that
this animal had just been introduced into the hunting preserve from the
above-referenced captive deer herd in north-central Iowa.The captive deer herd
was immediately quarantined to prevent the spread of CWD. The herd has remained
in quarantine until its depopulation on August 25 to 27, 2014.The Iowa
Department of Agriculture and Land Stewardship participated in a joint operation
to depopulate the infected herd with USDA Veterinary Services, which was the
lead agency, and USDA Wildlife Services.Federal indemnity funding became
available in 2014. USDA APHIS appraised the captive deer herd of 376 animals at
that time, which was before depopulation and testing, at $1,354,250. At that
time a herd plan was developed with the owners and officials from USDA and the
Iowa Department of Agriculture and Land Stewardship.Once the depopulation was
complete and the premises had been cleaned and disinfected, indemnity of
$917,100.00 from the USDA has been or will be paid to the owners as compensation
for the 356 captive deer depopulated.The Iowa Department of Agriculture and Land
Stewardship operates a voluntary CWD program for farms that sell live animals.
Currently 145 Iowa farms participate in the voluntary program. The
above-referenced captive deer facility left the voluntary CWD program prior to
the discovery of the disease as they had stopped selling live animals. All deer
harvested in a hunting preserve must be tested for CWD. -30-
*** see history of this CWD blunder here ;
On June 5, 2013, DNR conducted a fence inspection, after gaining approval
from surrounding landowners, and confirmed that the fenced had beencut or
removed in at least four separate locations; that the fence had degraded and was
failing to maintain the enclosure around the Quarantined Premises in at least
one area; that at least three gates had been opened;and that deer tracks were
visible in and around one of the open areas in the sand on both sides of the
fence, evidencing movement of deer into the Quarantined Premises.
Friday, December 14, 2012
DEFRA U.K. What is the risk of Chronic Wasting Disease CWD being introduced
into Great Britain? A Qualitative Risk Assessment October 2012
snip...
In the USA, under the Food and Drug Administration’s BSE Feed Regulation
(21 CFR 589.2000) most material (exceptions include milk, tallow, and gelatin)
from deer and elk is prohibited for use in feed for ruminant animals. With
regards to feed for non-ruminant animals, under FDA law, CWD positive deer may
not be used for any animal feed or feed ingredients. For elk and deer considered
at high risk for CWD, the FDA recommends that these animals do not enter the
animal feed system. However, this recommendation is guidance and not a
requirement by law.
Animals considered at high risk for CWD include:
1) animals from areas declared to be endemic for CWD and/or to be CWD
eradication zones and
2) deer and elk that at some time during the 60-month period prior to
slaughter were in a captive herd that contained a CWD-positive animal.
Therefore, in the USA, materials from cervids other than CWD positive
animals may be used in animal feed and feed ingredients for non-ruminants.
The amount of animal PAP that is of deer and/or elk origin imported from
the USA to GB can not be determined, however, as it is not specified in TRACES.
It may constitute a small percentage of the 8412 kilos of non-fish origin
processed animal proteins that were imported from US into GB in 2011.
Overall, therefore, it is considered there is a __greater than negligible
risk___ that (nonruminant) animal feed and pet food containing deer and/or elk
protein is imported into GB.
There is uncertainty associated with this estimate given the lack of data
on the amount of deer and/or elk protein possibly being imported in these
products.
snip...
36% in 2007 (Almberg et al., 2011). In such areas, population declines of
deer of up to 30 to 50% have been observed (Almberg et al., 2011). In areas of
Colorado, the prevalence can be as high as 30% (EFSA, 2011). The clinical signs
of CWD in affected adults are weight loss and behavioural changes that can span
weeks or months (Williams, 2005). In addition, signs might include excessive
salivation, behavioural alterations including a fixed stare and changes in
interaction with other animals in the herd, and an altered stance (Williams,
2005). These signs are indistinguishable from cervids experimentally infected
with bovine spongiform encephalopathy (BSE). Given this, if CWD was to be
introduced into countries with BSE such as GB, for example, infected deer
populations would need to be tested to differentiate if they were infected with
CWD or BSE to minimise the risk of BSE entering the human food-chain via
affected venison.
snip...
The rate of transmission of CWD has been reported to be as high as 30% and
can approach 100% among captive animals in endemic areas (Safar et al., 2008).
snip...
In summary, in endemic areas, there is a medium probability that the soil
and surrounding environment is contaminated with CWD prions and in a
bioavailable form. In rural areas where CWD has not been reported and deer are
present, there is a greater than negligible risk the soil is contaminated with
CWD prion.
snip...
In summary, given the volume of tourists, hunters and servicemen moving
between GB and North America, the probability of at least one person travelling
to/from a CWD affected area and, in doing so, contaminating their clothing,
footwear and/or equipment prior to arriving in GB is greater than negligible.
For deer hunters, specifically, the risk is likely to be greater given the
increased contact with deer and their environment. However, there is significant
uncertainty associated with these estimates.
snip...
Therefore, it is considered that farmed and park deer may have a higher
probability of exposure to CWD transferred to the environment than wild deer
given the restricted habitat range and higher frequency of contact with tourists
and returning GB residents.
snip...
Friday, December 14, 2012
DEFRA U.K. What is the risk of Chronic Wasting Disease CWD being introduced
into Great Britain? A Qualitative Risk Assessment October 2012
CHRONIC WASTING DISEASE CWD TSE PRION, how much does it pay to find CWD
$$$
CWD, spreading it around...
for the game farm industry, and their constituents, to continue to believe
that they are _NOT_, and or insinuate that they have _NEVER_ been part of the
problem, will only continue to help spread cwd. the game farming industry, from
the shooting pens, to the urine mills, the antler mills, the sperm mills, velvet
mills, shooting pens, to large ranches, are not the only problem, but it is
painfully obvious that they have been part of the problem for decades and
decades, just spreading it around, as with transportation and or exportation and
or importation of cervids from game farming industry, and have been proven to
spread cwd. no one need to look any further than South Korea blunder ;
===========================================
spreading cwd around...
Between 1996 and 2002, chronic wasting disease was diagnosed in 39 herds of
farmed elk in Saskatchewan in a single epidemic. All of these herds were
depopulated as part of the Canadian Food Inspection Agency’s (CFIA) disease
eradication program. Animals, primarily over 12 mo of age, were tested for the
presence CWD prions following euthanasia. Twenty-one of the herds were linked
through movements of live animals with latent CWD from a single infected source
herd in Saskatchewan, 17 through movements of animals from 7 of the secondarily
infected herds.
***The source herd is believed to have become infected via importation of
animals from a game farm in South Dakota where CWD was subsequently diagnosed
(7,4). A wide range in herd prevalence of CWD at the time of herd depopulation
of these herds was observed. Within-herd transmission was observed on some
farms, while the disease remained confined to the introduced animals on other
farms.
spreading cwd around...
Friday, May 13, 2011
Chronic Wasting Disease (CWD) outbreaks and surveillance program in the
Republic of Korea
Hyun-Joo Sohn, Yoon-Hee Lee, Min-jeong Kim, Eun-Im Yun, Hyo-Jin Kim,
Won-Yong Lee, Dong-Seob Tark, In- Soo Cho, Foreign Animal Disease Research
Division, National Veterinary Research and Quarantine Service, Republic of Korea
Chronic wasting disease (CWD) has been recognized as an important prion
disease in native North America deer and Rocky mountain elks. The disease is a
unique member of the transmissible spongiform encephalopathies (TSEs), which
naturally affects only a few species. CWD had been limited to USA and Canada
until 2000.
On 28 December 2000, information from the Canadian government showed that a
total of 95 elk had been exported from farms with CWD to Korea. These consisted
of 23 elk in 1994 originating from the so-called “source farm” in Canada, and 72
elk in 1997, which had been held in pre export quarantine at the “source
farm”.Based on export information of CWD suspected elk from Canada to Korea, CWD
surveillance program was initiated by the Ministry of Agriculture and Forestry
(MAF) in 2001.
All elks imported in 1997 were traced back, however elks imported in 1994
were impossible to identify. CWD control measures included stamping out of all
animals in the affected farm, and thorough cleaning and disinfection of the
premises. In addition, nationwide clinical surveillance of Korean native
cervids, and improved measures to ensure reporting of CWD suspect cases were
implemented.
Total of 9 elks were found to be affected. CWD was designated as a
notifiable disease under the Act for Prevention of Livestock Epidemics in 2002.
Additional CWD cases - 12 elks and 2 elks - were diagnosed in 2004 and
2005.
Since February of 2005, when slaughtered elks were found to be positive,
all slaughtered cervid for human consumption at abattoirs were designated as
target of the CWD surveillance program. Currently, CWD laboratory testing is
only conducted by National Reference Laboratory on CWD, which is the Foreign
Animal Disease Division (FADD) of National Veterinary Research and Quarantine
Service (NVRQS).
In July 2010, one out of 3 elks from Farm 1 which were slaughtered for the
human consumption was confirmed as positive. Consequently, all cervid – 54 elks,
41 Sika deer and 5 Albino deer – were culled and one elk was found to be
positive. Epidemiological investigations were conducted by Veterinary
Epidemiology Division (VED) of NVRQS in collaboration with provincial veterinary
services.
Epidemiologically related farms were found as 3 farms and all cervid at
these farms were culled and subjected to CWD diagnosis. Three elks and 5
crossbreeds (Red deer and Sika deer) were confirmed as positive at farm 2.
All cervids at Farm 3 and Farm 4 – 15 elks and 47 elks – were culled and
confirmed as negative.
Further epidemiological investigations showed that these CWD outbreaks were
linked to the importation of elks from Canada in 1994 based on circumstantial
evidences.
In December 2010, one elk was confirmed as positive at Farm 5.
Consequently, all cervid – 3 elks, 11 Manchurian Sika deer and 20 Sika deer –
were culled and one Manchurian Sika deer and seven Sika deer were found to be
positive. This is the first report of CWD in these sub-species of deer.
Epidemiological investigations found that the owner of the Farm 2 in CWD
outbreaks in July 2010 had co-owned the Farm 5.
In addition, it was newly revealed that one positive elk was introduced
from Farm 6 of Jinju-si Gyeongsang Namdo. All cervid – 19 elks, 15 crossbreed
(species unknown) and 64 Sika deer – of Farm 6 were culled, but all confirmed as
negative.
*** 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
Chronic wasting disease (CWD) is a widespread and expanding prion disease
in free-ranging and captive cervid species in North America. The zoonotic
potential of CWD prions is a serious public health concern. Current literature
generated with in vitro methods and in vivo animal models (transgenic mice,
macaques and squirrel monkeys) reports conflicting results. The susceptibility
of human CNS and peripheral organs to CWD prions remains largely unresolved. In
our earlier bioassay experiments using several humanized transgenic mouse lines,
we detected protease-resistant PrPSc in the spleen of two out of 140 mice that
were intracerebrally inoculated with natural CWD isolates, but PrPSc was not
detected in the brain of the same mice. Secondary passages with such
PrPSc-positive CWD-inoculated humanized mouse spleen tissues led to efficient
prion transmission with clear clinical and pathological signs in both humanized
and cervidized transgenic mice. Furthermore, a recent bioassay with natural CWD
isolates in a new humanized transgenic mouse line led to clinical prion
infection in 2 out of 20 mice. 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
The propensity for trans-species prion transmission is related to the
structural characteristics of the enciphering and heterologous PrP, but the
exact mechanism remains mostly mysterious. Studies of the effects of primary or
tertiary prion protein structures on trans-species prion transmission have
relied primarily upon animal bioassays, making the influence of prion protein
structure vs. host co-factors (e.g. cellular constituents, trafficking, and
innate immune interactions) difficult to dissect. As an alternative strategy, we
used real-time quakinginduced conversion (RT-QuIC) to investigate trans-species
prion conversion.
To assess trans-species conversion in the RT-QuIC system, we compared
chronic wasting disease (CWD) and bovine spongiform encephalopathy (BSE) prions,
as well as feline CWD (fCWD) and feline spongiform encephalopathy (FSE). Each
prion was seeded into each host recombinant PrP (full-length rPrP of
white-tailed deer, bovine or feline). We demonstrated that fCWD is a more
efficient seed for feline rPrP than for white-tailed deer rPrP, which suggests
adaptation to the new host.
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.***
================
Willingham, Erin McNulty, Kelly Anderson, Jeanette Hayes-Klug, Amy Nalls,
and Candace Mathiason Colorado State University; Fort Collins, CO USA
Chronic wasting disease (CWD) is the transmissible spongiform
encephalopathy (TSE), of free-ranging and captive cervids (deer, elk and moose).
The presence of infectious prions in the tissues, bodily fluids and
environments of clinical and preclinical CWD-infected animals is thought to
account for its high transmission efficiency. Recently it has been recognized
that mother to offspring transmission may contribute to the facile transmission
of some TSEs. Although the mechanism behind maternal transmission is not yet
known, the extended asymptomatic TSE carrier phase (lasting years to decades)
suggests that it may have implications in the spread of prions.
Placental trafficking and/or secretion in milk are 2 means by which
maternal prion transmission may occur. In these studies we explore these avenues
during early and late infection using a transgenic mouse model expressing cervid
prion protein. Na€ıve and CWD-infected dams were bred at both timepoints, and
were allowed to bear and raise their offspring. Milk was collected from the dams
for prion analysis, and the offspring were observed for TSE disease progression.
Terminal tissues harvested from both dams and offspring were analyzed for
prions.
We have demonstrated that
(1) CWDinfected TgCerPRP females successfully breed and bear offspring, and
(2) the presence of PrPCWD in reproductive and mammary tissue from
CWD-infected dams.
We are currently analyzing terminal tissue harvested from offspring born to
CWD-infected dams for the detection of PrPCWD and amplification competent
prions. These studies will provide insight into the potential mechanisms and
biological significance associated with mother to offspring transmission of
TSEs.
==============
P.157: Uptake of prions into plants
Christopher Johnson1, Christina Carlson1, Matthew Keating1,2, Nicole
Gibbs1, Haeyoon Chang1, Jamie Wiepz1, and Joel Pedersen1 1USGS National Wildlife
Health Center; Madison, WI USA; 2University of Wisconsin - Madison; Madison, WI
USA
Soil may preserve chronic wasting disease (CWD) and scrapie infectivity in
the environment, making consumption or inhalation of soil particles a plausible
mechanism whereby na€ıve animals can be exposed to prions. Plants are known to
absorb a variety of substances from soil, including whole proteins, yet the
potential for plants to take up abnormal prion protein (PrPTSE) and preserve
prion infectivity is not known. In this study, we assessed PrPTSE uptake into
roots using laser scanning confocal microscopy with fluorescently tagged PrPTSE
and we used serial protein misfolding cyclic amplification (sPMCA) and detect
and quantify PrPTSE levels in plant aerial tissues. Fluorescence was identified
in the root hairs of the model plant Arabidopsis thaliana, as well as the crop
plants alfalfa (Medicago sativa), barley (Hordeum vulgare) and tomato (Solanum
lycopersicum) upon exposure to tagged PrPTSE but not a tagged control
preparation. Using sPMCA, we found evidence of PrPTSE in aerial tissues of A.
thaliana, alfalfa and maize (Zea mays) grown in hydroponic cultures in which
only roots were exposed to PrPTSE. Levels of PrPTSE in plant aerial tissues
ranged from approximately 4 £ 10 ¡10 to 1 £ 10 ¡9 g PrPTSE g ¡1 plant dry weight
or 2 £ 105 to 7 £ 106 intracerebral ID50 units g ¡1 plant dry weight. Both stems
and leaves of A. thaliana grown in culture media containing prions are
infectious when intracerebrally-injected into mice. ***Our results suggest that
prions can be taken up by plants and that contaminated plants may represent a
previously unrecognized risk of human, domestic species and wildlife exposure to
prions.
===========
***Our results suggest that prions can be taken up by plants and that
contaminated plants may represent a previously unrecognized risk of human,
domestic species and wildlife exposure to prions.***
SEE ;
Friday, May 15, 2015
Grass Plants Bind, Retain, Uptake, and Transport Infectious Prions
Report
============
P.19: Characterization of chronic wasting disease isolates from freeranging
deer (Odocoileus sp) in Alberta and Saskatchewan, Canada
Camilo Duque Velasquez1, Chiye Kim1, Nathalie Daude1, Jacques van der
Merwe1, Allen Herbst1, Trent Bollinger2, Judd Aiken1, and Debbie McKenzie1
1Centre for Prions and Protein Folding Diseases; University of Alberta;
Edmonton, Canada; 2Western College of Veterinary Medicine; University of
Saskatchewan; Saskatoon, Canada
Chronic wasting disease (CWD) is an emerging prion disease of free ranging
and captive species of Cervidae. In North America, CWD is enzootic in some wild
cervid populations and can circulate among different deer species. The
contagious nature of CWD prions and the variation of cervid PRNP alleles, which
influence host susceptibility, can result in the emergence and adaptation of
different CWD strains. These strains may impact transmission host range, disease
diagnosis, spread dynamics and efficacy of potential vaccines. We are
characterizing different CWD agents by biochemical analysis of the PrPCWD
conformers, propagation in vitro cell assays1 and by comparing transmission
properties and neuropathology in Tg33 (Q95G96) and Tg60 (Q95S96) mice.2 Although
Tg60 mice expressing S96- PrPC have been shown resistant to CWD infectivity from
various cervid species,2,3
***these transgenic mice are susceptible to H95 C CWD, a CWD strain derived
from experimental infection of deer expressing H95G96-PrPC. The diversity of
strains present in free-ranging mule deer (Odocoileus hemionus) and white-tailed
deer (Odocoileus virginianus) from Alberta and Saskatchewan is being determined
and will allow us to delineate the properties of CWD agents circulating in CWD
enzootic cervid populations of Canada.
References
1. van der Merwe J, Aiken J, Westaway D, McKenzie D. The standard scrapie
cell assay: Development, utility and prospects. Viruses 2015; 7(1):180–198;
PMID:25602372; http://dx.doi.org/10.3390/v7010180
2. Meade-White K, Race B, Trifilo M, Bossers A, Favara C, Lacasse R, Miller
M, Williams E, Oldstone M, Race R, Chesebro B. Resistance to chronic wasting
disease in transgenic mice expressing a naturally occurring allelic variant of
deer prion protein. J Virol 2007; 81(9):4533–4539; PMID: 17314157; http://dx. doi.org/10.1128/JVI.02762-06
3. Race B, Meade-White K, Miller MW, Fox KA, Chesebro B. In vivo comparison
of chronic wasting disease infectivity from deer with variation at prion protein
residue 96. J Virol 2011; 85(17):9235–9238; PMID: 21697479; http://dx.doi.org/10.1128/JVI.00790-11
=========
***these transgenic mice are susceptible to H95 C CWD, a CWD strain derived
from experimental infection of deer expressing H95G96-PrPC.
==========
P.136: Mother to offspring transmission of CWD—Detection in fawn tissues
using the QuIC assay
Amy Nalls, Erin McNulty, Clare Hoover, Jeanette Hayes-Klug, Kelly Anderson,
Edward Hoover, and Candace Mathiason Colorado State University; Fort Collins, CO
USA
To investigate the role mother to offspring transmission plays in chronic
wasting disease (CWD), we have employed a small, polyestrous breeding, indoor
maintainable cervid model, the Reeves’ muntjac deer. Muntjac doe were inoculated
with CWD and tested positive by lymphoid biopsy at 4 months post inoculation.
From these CWD-infected doe, we obtained 3 viable fawns. These fawns tested
IHC-positive for CWD by lymphoid biopsy as early as 40 d post birth, and all
have been euthanized due to clinical disease at 31, 34 and 59 months post birth.
The QuIC assay demonstrates sensitivity and specificity in the detection of
conversion competent prions in peripheral IHC-positive tissues including tonsil,
mandibular, partotid, retropharyngeal, and prescapular lymph nodes, adrenal
gland, spleen and liver. In summary, using the muntjac deer model, we have
demonstrated CWD clinical disease in offspring born to CWD-infected doe and
found that the QuIC assay is an effective tool in the detection of prions in
peripheral tissues. ***Our findings demonstrate that transmission of prions from
mother to offspring can occur, and may be underestimated for all prion
diseases.
===============
***Our findings demonstrate that transmission of prions from mother to
offspring can occur, and may be underestimated for all prion diseases.
===============
I strenuously once again urge the FDA and its industry constituents, to
make it MANDATORY that all ruminant feed be banned to all ruminants, and this
should include all cervids as soon as possible for the following
reasons...
======
In the USA, under the Food and Drug Administrations BSE Feed Regulation (21
CFR 589.2000) most material (exceptions include milk, tallow, and gelatin) from
deer and elk is prohibited for use in feed for ruminant animals. With regards to
feed for non-ruminant animals, under FDA law, CWD positive deer may not be used
for any animal feed or feed ingredients. For elk and deer considered at high
risk for CWD, the FDA recommends that these animals do not enter the animal feed
system.
***However, this recommendation is guidance and not a requirement by law.
======
31 Jan 2015 at 20:14 GMT
*** Ruminant feed ban for cervids in the United States? ***
31 Jan 2015 at 20:14 GMT
Friday, May 22, 2015
*** Chronic Wasting Disease and Program Updates - 2014 NEUSAHA Annual
Meeting 12-14 May 2014 ***
Saturday, May 30, 2015
PRION 2015 ORAL AND POSTER CONGRESSIONAL ABSTRACTS
98 | Veterinary Record | January 24, 2015
EDITORIAL
Scrapie: a particularly persistent pathogen
Cristina Acín
Resistant prions in the environment have been the sword of Damocles for
scrapie control and eradication. Attempts to establish which physical and
chemical agents could be applied to inactivate or moderate scrapie infectivity
were initiated in the 1960s and 1970s,with the first study of this type focusing
on the effect of heat treatment in reducing prion infectivity (Hunter and
Millson 1964). Nowadays, most of the chemical procedures that aim to inactivate
the prion protein are based on the method developed by Kimberlin and
collaborators (1983). This procedure consists of treatment with 20,000 parts per
million free chlorine solution, for a minimum of one hour, of all surfaces that
need to be sterilised (in laboratories, lambing pens, slaughterhouses, and so
on). Despite this, veterinarians and farmers may still ask a range of questions,
such as ‘Is there an official procedure published somewhere?’ and ‘Is there an
international organisation which recommends and defines the exact method of
scrapie decontamination that must be applied?’
From a European perspective, it is difficult to find a treatment that could
be applied, especially in relation to the disinfection of surfaces in lambing
pens of affected flocks. A 999/2001 EU regulation on controlling spongiform
encephalopathies (European Parliament and Council 2001) did not specify a
particular decontamination measure to be used when an outbreak of scrapie is
diagnosed. There is only a brief recommendation in Annex VII concerning the
control and eradication of transmissible spongiform encephalopathies (TSE
s).
Chapter B of the regulation explains the measures that must be applied if
new caprine animals are to be introduced to a holding where a scrapie outbreak
has previously been diagnosed. In that case, the statement indicates that
caprine animals can be introduced ‘provided that a cleaning and disinfection of
all animal housing on the premises has been carried out following
destocking’.
Issues around cleaning and disinfection are common in prion prevention
recommendations, but relevant authorities, veterinarians and farmers may have
difficulties in finding the specific protocol which applies. The European Food
and Safety Authority (EFSA ) published a detailed report about the efficacy of
certain biocides, such as sodium hydroxide, sodium hypochlorite, guanidine and
even a formulation of copper or iron metal ions in combination with hydrogen
peroxide, against prions (EFSA 2009). The report was based on scientific
evidence (Fichet and others 2004, Lemmer and others 2004, Gao and others 2006,
Solassol and others 2006) but unfortunately the decontamination measures were
not assessed under outbreak conditions.
The EFSA Panel on Biological Hazards recently published its conclusions on
the scrapie situation in the EU after 10 years of monitoring and control of the
disease in sheep and goats (EFSA 2014), and one of the most interesting findings
was the Icelandic experience regarding the effect of disinfection in scrapie
control. The Icelandic plan consisted of: culling scrapie-affected sheep or the
whole flock in newly diagnosed outbreaks; deep cleaning and disinfection of
stables, sheds, barns and equipment with high pressure washing followed by
cleaning with 500 parts per million of hypochlorite; drying and treatment with
300 ppm of iodophor; and restocking was not permitted for at least two years.
Even when all of these measures were implemented, scrapie recurred on several
farms, indicating that the infectious agent survived for years in the
environment, even as many as 16 years after restocking (Georgsson and others
2006).
In the rest of the countries considered in the EFSA (2014) report,
recommendations for disinfection measures were not specifically defined at the
government level. In the report, the only recommendation that is made for sheep
is repopulation with sheep with scrapie-resistant genotypes. This reduces the
risk of scrapie recurrence but it is difficult to know its effect on the
infection.
Until the EFSA was established (in May 2003), scientific opinions about TSE
s were provided by the Scientific Steering Committee (SSC) of the EC, whose
advice regarding inactivation procedures focused on treating animal waste at
high temperatures (150°C for three hours) and high pressure alkaline hydrolysis
(SSC 2003). At the same time, the TSE Risk Management Subgroup of the Advisory
Committee on Dangerous Pathogens (ACDP) in the UK published guidance on safe
working and the prevention of TSE infection. Annex C of the ACDP report
established that sodium hypochlorite was considered to be effective, but only if
20,000 ppm of available chlorine was present for at least one hour, which has
practical limitations such as the release of chlorine gas, corrosion,
incompatibility with formaldehyde, alcohols and acids, rapid inactivation of its
active chemicals and the stability of dilutions (ACDP 2009).
In an international context, the World Organisation for Animal Health (OIE)
does not recommend a specific disinfection protocol for prion agents in its
Terrestrial Code or Manual. Chapter 4.13 of the Terrestrial Code, General
recommendations on disinfection and disinsection (OIE 2014), focuses on
foot-and-mouth disease virus, mycobacteria and Bacillus anthracis, but not on
prion disinfection. Nevertheless, the last update published by the OIE on bovine
spongiform encephalopathy (OIE 2012) indicates that few effective
decontamination techniques are available to inactivate the agent on surfaces,
and recommends the removal of all organic material and the use of sodium
hydroxide, or a sodium hypochlorite solution containing 2 per cent available
chlorine, for more than one hour at 20ºC.
The World Health Organization outlines guidelines for the control of TSE s,
and also emphasises the importance of mechanically cleaning surfaces before
disinfection with sodium hydroxide or sodium hypochlorite for one hour (WHO
1999).
Finally, the relevant agencies in both Canada and the USA suggest that the
best treatments for surfaces potentially contaminated with prions are sodium
hydroxide or sodium hypochlorite at 20,000 ppm. This is a 2 per cent solution,
while most commercial household bleaches contain 5.25 per cent sodium
hypochlorite. It is therefore recommended to dilute one part 5.25 per cent
bleach with 1.5 parts water (CDC 2009, Canadian Food Inspection Agency
2013).
So what should we do about disinfection against prions? First, it is
suggested that a single protocol be created by international authorities to
homogenise inactivation procedures and enable their application in all
scrapie-affected countries. Sodium hypochlorite with 20,000 ppm of available
chlorine seems to be the procedure used in most countries, as noted in a paper
summarised on p 99 of this issue of Veterinary Record (Hawkins and others 2015).
But are we totally sure of its effectiveness as a preventive measure in a
scrapie outbreak? Would an in-depth study of the recurrence of scrapie disease
be needed?
What we can conclude is that, if we want to fight prion diseases, and
specifically classical scrapie, we must focus on the accuracy of diagnosis,
monitoring and surveillance; appropriate animal identification and control of
movements; and, in the end, have homogeneous and suitable protocols to
decontaminate and disinfect lambing barns, sheds and equipment available to
veterinarians and farmers. Finally, further investigations into the resistance
of prion proteins in the diversity of environmental surfaces are required.
References
snip...
98 | Veterinary Record | January 24, 2015
Persistence of ovine scrapie infectivity in a farm environment following
cleaning and decontamination
Steve A. C. Hawkins, MIBiol, Pathology Department1, Hugh A. Simmons, BVSc
MRCVS, MBA, MA Animal Services Unit1, Kevin C. Gough, BSc, PhD2 and Ben C.
Maddison, BSc, PhD3 + Author Affiliations
1Animal and Plant Health Agency, Woodham Lane, New Haw, Addlestone, Surrey
KT15 3NB, UK 2School of Veterinary Medicine and Science, The University of
Nottingham, Sutton Bonington, Loughborough, Leicestershire LE12 5RD, UK 3ADAS
UK, School of Veterinary Medicine and Science, The University of Nottingham,
Sutton Bonington, Loughborough, Leicestershire LE12 5RD, UK E-mail for
correspondence: ben.maddison@adas.co.uk Abstract Scrapie of sheep/goats and
chronic wasting disease of deer/elk are contagious prion diseases where
environmental reservoirs are directly implicated in the transmission of disease.
In this study, the effectiveness of recommended scrapie farm decontamination
regimens was evaluated by a sheep bioassay using buildings naturally
contaminated with scrapie. Pens within a farm building were treated with either
20,000 parts per million free chorine solution for one hour or were treated with
the same but were followed by painting and full re-galvanisation or replacement
of metalwork within the pen. Scrapie susceptible lambs of the PRNP genotype
VRQ/VRQ were reared within these pens and their scrapie status was monitored by
recto-anal mucosa-associated lymphoid tissue. All animals became infected over
an 18-month period, even in the pen that had been subject to the most stringent
decontamination process. These data suggest that recommended current guidelines
for the decontamination of farm buildings following outbreaks of scrapie do
little to reduce the titre of infectious scrapie material and that environmental
recontamination could also be an issue associated with these premises.
SNIP...
Discussion
Thorough pressure washing of a pen had no effect on the amount of
bioavailable scrapie infectivity (pen B). The routine removal of prions from
surfaces within a laboratory setting is treatment for a minimum of one hour with
20,000 ppm free chlorine, a method originally based on the use of brain
macerates from infected rodents to evaluate the effectiveness of decontamination
(Kimberlin and others 1983). Further studies have also investigated the
effectiveness of hypochlorite disinfection of metal surfaces to simulate the
decontamination of surgical devices within a hospital setting. Such treatments
with hypochlorite solution were able to reduce infectivity by 5.5 logs to lower
than the sensitivity of the bioassay used (Lemmer and others 2004). Analogous
treatment of the pen surfaces did not effectively remove the levels of scrapie
infectivity over that of the control pens, indicating that this method of
decontamination is not effective within a farm setting. This may be due to the
high level of biological matrix that is present upon surfaces within the farm
environment, which may reduce the amount of free chlorine available to
inactivate any infectious prion. Remarkably 1/5 sheep introduced into pen D had
also became scrapie positive within nine months, with all animals in this pen
being RAMALT positive by 18 months of age. Pen D was no further away from the
control pen (pen A) than any of the other pens within this barn. Localised hot
spots of infectivity may be present within scrapie-contaminated environments,
but it is unlikely that pen D area had an amount of scrapie contamination that
was significantly different than the other areas within this building.
Similarly, there were no differences in how the biosecurity of pen D was
maintained, or how this pen was ventilated compared with the other pens. This
observation, perhaps, indicates the slower kinetics of disease uptake within
this pen and is consistent with a more thorough prion removal and
recontamination. These observations may also account for the presence of
inadvertent scrapie cases within other studies, where despite stringent
biosecurity, control animals have become scrapie positive during challenge
studies using barns that also housed scrapie-affected animals (Ryder and others
2009). The bioassay data indicate that the exposure of the sheep to a farm
environment after decontamination efforts thought to be effective in removing
scrapie is sufficient for the animals to become infected with scrapie. The main
exposure routes within this scenario are likely to be via the oral route, during
feeding and drinking, and respiratory and conjunctival routes. It has been
demonstrated that scrapie infectivity can be efficiently transmitted via the
nasal route in sheep (Hamir and others 2008), as is the case for CWD in both
murine models and in white-tailed deer (Denkers and others 2010, 2013).
Recently, it has also been demonstrated that CWD prions presented as dust when
bound to the soil mineral montmorillonite can be infectious via the nasal route
(Nichols and others 2013). When considering pens C and D, the actual source of
the infectious agent in the pens is not known, it is possible that biologically
relevant levels of prion survive on surfaces during the decontamination regimen
(pen C). With the use of galvanising and painting (pen D) covering and sealing
the surface of the pen, it is possible that scrapie material recontaminated the
pens by the movement of infectious prions contained within dusts originating
from other parts of the barn that were not decontaminated or from other areas of
the farm.
Given that scrapie prions are widespread on the surfaces of affected farms
(Maddison and others 2010a), irrespective of the source of the infectious prions
in the pens, this study clearly highlights the difficulties that are faced with
the effective removal of environmentally associated scrapie infectivity. This is
likely to be paralleled in CWD which shows strong similarities to scrapie in
terms of both the dissemination of prions into the environment and the facile
mode of disease transmission. These data further contribute to the understanding
that prion diseases can be highly transmissible between susceptible individuals
not just by direct contact but through highly stable environmental reservoirs
that are refractory to decontamination.
The presence of these environmentally associated prions in farm buildings
make the control of these diseases a considerable challenge, especially in
animal species such as goats where there is lack of genetic resistance to
scrapie and, therefore, no scope to re-stock farms with animals that are
resistant to scrapie.
Scrapie Sheep Goats Transmissible spongiform encephalopathies (TSE)
Accepted October 12, 2014. Published Online First 31 October 2014
Monday, November 3, 2014
Persistence of ovine scrapie infectivity in a farm environment following
cleaning and decontamination
PPo3-22:
Detection of Environmentally Associated PrPSc on a Farm with Endemic
Scrapie
Ben C. Maddison,1 Claire A. Baker,1 Helen C. Rees,1 Linda A. Terry,2 Leigh
Thorne,2 Susan J. Belworthy2 and Kevin C. Gough3 1ADAS-UK LTD; Department of
Biology; University of Leicester; Leicester, UK; 2Veterinary Laboratories
Agency; Surry, KT UK; 3Department of Veterinary Medicine and Science; University
of Nottingham; Sutton Bonington, Loughborough UK
Key words: scrapie, evironmental persistence, sPMCA
Ovine scrapie shows considerable horizontal transmission, yet the routes of
transmission and specifically the role of fomites in transmission remain poorly
defined. Here we present biochemical data demonstrating that on a
scrapie-affected sheep farm, scrapie prion contamination is widespread. It was
anticipated at the outset that if prions contaminate the environment that they
would be there at extremely low levels, as such the most sensitive method
available for the detection of PrPSc, serial Protein Misfolding Cyclic
Amplification (sPMCA), was used in this study. We investigated the distribution
of environmental scrapie prions by applying ovine sPMCA to samples taken from a
range of surfaces that were accessible to animals and could be collected by use
of a wetted foam swab. Prion was amplified by sPMCA from a number of these
environmental swab samples including those taken from metal, plastic and wooden
surfaces, both in the indoor and outdoor environment. At the time of sampling
there had been no sheep contact with these areas for at least 20 days prior to
sampling indicating that prions persist for at least this duration in the
environment. These data implicate inanimate objects as environmental reservoirs
of prion infectivity which are likely to contribute to disease transmission.
Friday, May 22, 2015
Chronic Wasting Disease and Program Updates - 2014 NEUSAHA Annual Meeting
12-14 May 2014
Friday, May 15, 2015
Grass Plants Bind, Retain, Uptake, and Transport Infectious Prions
Report
CWD TO HUMANS, AND RISK FACTORS THERE FROM (see latest science)
Monday, March 09, 2015
*** Chronic Wasting Disease CWD TSE prion and human animal risk factor
there from ***
Tuesday, May 26, 2015
Minimise transmission risk of CJD and vCJD in healthcare settings Last
updated 15 May 2015
Tuesday, May 26, 2015
Michigan confirms state's first case of chronic wasting disease in
free-ranging white-tailed deer
Friday, July 17, 2015
TPW Commission Holds Special Meeting on Chronic Wasting Disease
Wednesday, July 01, 2015
TEXAS Chronic Wasting Disease Detected in Medina County Captive Deer
Thursday, July 09, 2015
TEXAS Chronic Wasting Disease (CWD) Herd Plan for Trace-Forward Exposed
Herd with Testing of Exposed Animals
Tuesday, July 14, 2015
Texas Parks and Wildlife Commission Special Meeting Thursday on Chronic
Wasting Disease CWD
Rare report of deer disease in Texas causes stir
Houston Chronicle
Rare report of deer disease in Texas causes stir, especially since it’s the
8 case of CWD documented in Texas, and the first case of CWD in Captive deer.
here is how I would have titled this article, and why.
Shannon Tompkins Finally Breaks Silence on Texas First Captive CWD Case and
Starts Off Spreading False Information About Risk Factors. ...
Thursday, July 16, 2015
Wednesday, March 18, 2015
Chronic Wasting Disease CWD Confirmed Texas Trans Pecos March 18,
2015
Wednesday, March 25, 2015
Chronic Wasting Disease CWD Cases Confirmed In New Mexico 2013 and 2014
UPDATE 2015
Thursday, May 02, 2013
*** Chronic Wasting Disease (CWD) Texas Important Update on OBEX ONLY
TEXTING
Monday, February 11, 2013
TEXAS CHRONIC WASTING DISEASE CWD Four New Positives Found in Trans Pecos
Tuesday, July 10, 2012
Chronic Wasting Disease Detected in Far West Texas
Monday, March 26, 2012
Texas Prepares for Chronic Wasting Disease CWD Possibility in Far West
Texas
***for anyone interested, here is some history of CWD along the Texas, New
Mexico border, and my attempt to keep up with it...terry
snip...
see history CWD Texas, New Mexico Border ;
Monday, March 26, 2012
3 CASES OF CWD FOUND NEW MEXICO MULE DEER SEVERAL MILES FROM TEXAS BORDER
Sunday, October 04, 2009
CWD NEW MEXICO SPREADING SOUTH TO TEXAS 2009 2009 Summary of Chronic
Wasting Disease in New Mexico New Mexico Department of Game and Fish
Friday, May 22, 2015
*** Chronic Wasting Disease and Program Updates - 2014 NEUSAHA Annual
Meeting 12-14 May 2014
Sunday, July 12, 2015
*** Insights into CWD and BSE species barriers using real-time conversion
Wednesday, July 15, 2015
Kansas Ten Deer Test Positive for CWD in 2014-2015 7-16-15 News
Wednesday, July 01, 2015
DRAFT Virginia Deer Management Plan 2015-2024 (bans urine scents do to CWD
2015)
Tuesday, July 14, 2015
*** TWO Escaped Captive Deer on the loose in Eau Claire County Wisconsin
CWD postive farm Yellow ear tag
Thursday, June 25, 2015
Wisconsin CWD-positive white-tailed deer found on Eau Claire County farm
Terry S. Singeltary Sr.
No comments:
Post a Comment
Note: Only a member of this blog may post a comment.