TAHC Continues Efforts to Eradicate Scrapie
NEWS RELEASE
For Immediate Release Feb. 5, 2013 Contact: Yvonne "Bonnie" Ramirez,
Director of Communications (512) 719-0710 Texas Animal Health Commission (TAHC)
TAHC Continues Efforts to Eradicate Scrapie
AUSTIN - The Texas Animal Health Commission (TAHC) continues to work with
the Texas sheep and goat industries toward the eradication of Scrapie. Texas
currently leads the nation in sheep and goat production. A common goal of the US
Sheep Industry and the American Sheep Industry (ASI) is to eradicate Scrapie
from the US borders by 2017. To help achieve this goal, the USDA is considering
a proposed rule that would make the identification requirements for goats
similar to those currently in place for sheep, as well as possibly expanding
surveillance efforts for Scrapie in goats. Once the disease is eradicated, the
US would then seek recognition as Scrapie-free in accordance with the World
Organization for Animal Health. (OIE)
Texas leads the nation in sheep and goats production. Since 2009, there
have been no confirmed cases of Scrapie in Texas. The last big spike in Texas
Scrapie cases was in 2006 with 9 infected herds. According to USDA regulations,
Texas must conduct adequate Scrapie surveillance by a collecting a minimum of
598 sheep samples annually. In 2012 there were 1,050 samples collected from
animals with Texas tags.
Dr. Dee Ellis, State Veterinarian, said, "Texas has made significant
progress in battling this disease. The Scrapie Program has proven to be
successful in Texas. Fighting this disease and implementing an animal
identification program has worked." To date, Texas has 30 participating flocks
enrolled in the Scrapie Flock Certification program.
Nationally, in 2005, there was a peak in Scrapie numbers. In the last
fiscal year, for the first time ever, there were more Scrapie field cases in
goats than in sheep. In fiscal years 2008 and 2011, two significant Scrapie
outbreaks occurred in goats involving a total of 18 positive goats.
The National Scrapie Eradication Program continued to make excellent
progress in fiscal year 2012. In FY 2012, the percent of cull sheep found
positive at slaughter decreased. This measure of prevalence decreased 96.2
percent since slaughter surveillance started in FY 2003 and 24.7 percent,
respectively since FY 2011. Additionally, there was a 47% decrease in the number
of infected and source flocks identified during FY 2012 compared to the previous
fiscal year.
Scrapie is a degenerative disease of the nervous system that falls into
the category of Transmissible Spongiform Encephalopathies (TSE). The disease is
caused by a transmissible prion or abnormal protein which is very stable in the
environment. Traditional blood tests are not reliable to diagnose Scrapie, so a
sample is needed to diagnose it. Currently, no treatment exists for Scrapie.
There is no known evidence of Scrapie transmission to humans.
While animals of any age may be exposed to Scrapie, lambs and kids are at
the greatest risk of contracting the disease and are often infected by their
dams shortly after birth.
Typically, infected animals don't show signs of Scrapie, such as behavioral
changes, tremors, and incoordination that progresses to recumbency and death,
until they are two years of age or older.
The most effective method of Scrapie prevention is to maintain a closed
flock. Raising replacement ewes, purchasing genetically resistant (RR) rams or
buying from a certified-free Scrapie flock are other options to reduce the risk
the Scrapie. At this time the resistant genetic markers in goats have not been
identified, therefore it is important to maintain your sheep and goat herds
separately.
Since the incubation period for Scrapie is typically two to five years,
producers should record individual identification numbers and the seller's
premises identification number on purchase and sales records. These records must
be maintained for a minimum of five years. "The success of the Scrapie
Eradication Program is tied to producers keeping good records of sales and
purchases," said Dr. Ellis.
TAHC rules regulate official identification tags or a registration tattoo
be applied to all sheep 18 months of age and older, all breeding sheep, all
breeding goats except those commingled with other sheep, and all sexually intact
show or exhibition animals.
Producers should notify the Texas Animal Health Commission (800-550-8242)
or the USDA-Austin Office (512-383-2400) if they have a sheep or goat over 18
months with neurologic signs such as incoordination, behavioral changes, or
intense itching with wool loss. Producers may order Scrapie identification tags
by calling 866-873-2824. For more information, please visit our web site at
www.tahc.texas.gov or give us a call.
The Texas Animal Health Commission (TAHC) is one of the oldest state
regulatory agencies. TAHC was founded by the legislature in 1893 with a mission
to combat fever ticks that plagued the Texas Cattle Industry. Today, the agency
works to protect the health of all Texas livestock including: cattle, equine,
sheep, goats, swine, poultry, exotic livestock and fowl.
CORRECTION TO FEB. 5 NEWS RELEASE
For Immediate Release
Feb. 8, 2013 Contact: Yvonne "Bonnie" Ramirez, Director of Communications (512) 719-0710 Texas
Animal Health Commission (TAHC) TAHC Continues Efforts to Eradicate Scrapie
Below is a REVISED Scrapie News Release. This news release replaces the previous one that was emailed on Feb. 5, 2013.
The corrected content/information can be found in the third to the last paragraph of the news release in bold and italicized font.
We apologize for the confusion.
AUSTIN - The Texas Animal Health Commission (TAHC) continues to work with the Texas sheep and goat industries toward the eradication of Scrapie. Texas currently leads the nation in sheep and goat production. A common goal of the US Sheep Industry and the American Sheep Industry (ASI) is to eradicate Scrapie from the US borders by 2017. To help achieve this goal, the USDA is considering a proposed rule that would make the identification requirements for goats similar to those currently in place for sheep, as well as possibly expanding surveillance efforts for Scrapie in goats. Once the disease is eradicated, the US would then seek recognition as Scrapie-free in accordance with the World Organization for Animal Health. (OIE)
Texas leads the nation in sheep and goats production. Since 2009, there have been no confirmed cases of Scrapie in Texas. The last big spike in Texas Scrapie cases was in 2006 with 9 infected herds. According to USDA regulations, Texas must conduct adequate Scrapie surveillance by a collecting a minimum of 598 sheep samples annually. In 2012 there were 1,050 samples collected from animals with Texas tags.
Dr. Dee Ellis, State Veterinarian, said, "Texas has made significant progress in battling this disease. The Scrapie Program has proven to be successful in Texas. Fighting this disease and implementing an animal identification program has worked." To date, Texas has 30 participating flocks enrolled in the Scrapie Flock Certification program.
Nationally, in 2005, there was a peak in Scrapie numbers. In the last fiscal year, for the first time ever, there were more Scrapie field cases in goats than in sheep. In fiscal years 2008 and 2011, two significant Scrapie outbreaks occurred in goats involving a total of 18 positive goats.
The National Scrapie Eradication Program continued to make excellent progress in fiscal year 2012. In FY 2012, the percent of cull sheep found positive at slaughter decreased. This measure of prevalence decreased 96.2 percent since slaughter surveillance started in FY 2003 and 24.7 percent, respectively since FY 2011. Additionally, there was a 47% decrease in the number of infected and source flocks identified during FY 2012 compared to the previous fiscal year.
Scrapie is a degenerative disease of the nervous system that falls into the category of Transmissible Spongiform Encephalopathies (TSE). The disease is caused by a transmissible prion or abnormal protein which is very stable in the environment. Traditional blood tests are not reliable to diagnose Scrapie, so a tissue sample is needed to diagnose it. Currently, no treatment exists for Scrapie. There is no known evidence of Scrapie transmission to humans.
While animals of any age may be exposed to Scrapie, lambs and kids are at the greatest risk of contracting the disease and are often infected by their dams shortly after birth. Typically, infected animals don't show signs of Scrapie, such as behavioral changes, tremors, and incoordination that progresses to recumbency and death, until they are two years of age or older.
The most effective method of Scrapie prevention is to maintain a closed flock. Raising replacement ewes, purchasing genetically resistant (RR) rams or buying from a certified-free Scrapie flock are other options to reduce the risk the Scrapie. At this time the resistant genetic markers in goats have not been identified, therefore it is important to maintain your sheep and goat herds separately.
Since the incubation period for Scrapie is typically two to five years, producers should record individual identification numbers and the seller's premises identification number on purchase and sales records. These records must be maintained for a minimum of five years. "The success of the Scrapie Eradication Program is tied to producers keeping good records of sales and purchases," said Dr. Ellis.
TAHC rules require that official identification tags or a registration tattoo be applied to:
* All sheep 18 months of age and older
* All breeding sheep
* All breeding goats (except for commercial goats that have no contact with sheep)
* All sexually intact show or exhibition animals
Producers should notify the Texas Animal Health Commission (800-550-8242) or the USDA-Austin Office (512-383-2400) if they have an adult sheep or goat with neurologic signs such as incoordination, behavioral changes, or intense itching with wool loss. Producers may order Scrapie identification tags by calling 866-873-2824. For more information, please visit our web site at
www.tahc.state.tx.us
The Texas Animal Health Commission (TAHC) is one of the oldest state regulatory agencies. TAHC was founded by the legislature in 1893 with a mission to combat fever ticks that plagued the Texas Cattle Industry. Today, the agency works to protect the health of all Texas livestock including: cattle, equine, sheep, goats, swine, poultry, exotic livestock and fowl.
http://campaign.r20.constantcontact.com/render?llr=kpzk9zgab&v=001FbEh9Xz0N4LL62OOLkCF3kt133fvSY19OWWYJ7uYJg7QkaGN1kfsqUgYZI1TdSRiu6vKy7pdIxGWPANjEs0kfAC-Oywq2c1fM8ruOaAUKegfYrh_BNk0vw%3D%3D
2002
Subject: TEXAS FINDS FOUR SCRAPIE INFECTED FLOCKS IN 15 MONTHS (3 herd
flocks outside Texas)
Date: Mon, 26 Aug 2002 08:05:52 –0700
From: "Terry S. Singeltary Sr."
Reply-To: Bovine Spongiform Encephalopathy To: BSE-L@uni-karlsruhe.de
######## Bovine Spongiform Encephalopathy #########
August 1 signaled the deadline for sheep, as well as many goats, to be
identified with an ear tag approved by the U.S. Department of Agriculture (USDA)
when the animals are moved from the farm for exhibition or sale. The ear tag is
imprinted with a ranch identification number, which makes it possible to trace
the animal back to the farm where it was born, in case scrapie infection is
detected later in the animal. The identification tags, combined with accurate
record keeping, are key elements of the national program to eradicate scrapie,
the fatal, degenerative disease that can affect the brains of sheep and,
sometimes, goats.
"In November 2001, USDA introduced a new national scrapie eradication
program at the request of the American Sheep Industry Association. Since then,
we've been in a 'grace period,' while producers obtained ear tag supplies and
became familiar with the regulations," said Dr. Linda Logan, Texas' state
veterinarian and head of the Texas Animal Health Commission (TAHC), the state's
livestock health regulatory agency. "August 1 signaled the end of this 'phase-in
period,' and the deadline for identification tags to be applied to sheep and
many goats before they are sold or commingled with those from other
farms."
"During the past eight months, more than 9,300 Texas ranchers have called
the TAHC for a premise, or ranch identification number. This number is printed
on the rancher's supply of the metal or plastic ear tags provided at no cost by
the USDA," said Dr. Logan. "The back side of the tag is imprinted with an
individual animal number, so ranchers may keep detailed records on each sheep or
goat, if they wish."
Scrapie regulations require the following animals to have the official ear
tag before they are sold or are exhibited: * all breeding sheep, regardless of
age * all sheep 18 months of age or older
* all breeding goats and goats over 18 months of age, except low-risk
goats. Low-risk goats are goats that have not been commingled with sheep, except
low-risk (white-faced) commercial sheep. * sexually intact sheep or goats for
show or exhibition. (Sexually intact animals are animals that have not been
neutered.) * any sheep or goats that are considered to be at high risk, exposed
to or positive for scrapie
"In lieu of an ear tag, a tattoo can be used as identification for
registered meat or dairy show goats, as long as the animals move with their
registration papers," explained veterinarian Terry Conger, TAHC's state
epidemiologist. A premise identification ear tag is to be placed on the animal
when it moves to slaughter, or if it sold without registration papers, he
said.
"Wethers, which are neutered sheep, do not have to be tagged prior to an
exhibition or a sale. Furthermore, commercial goats that haven't had any contact
with sheep, don't have to be tagged for sale," explained Dr. Conger. "Commercial
goats are those that are raised or bred for meat or fiber production and are not
used for exhibition and are not registered with a breed association."
"Ranchers who haven't obtained a premise number and ear tags can still sell
their animals," explained Dr. Logan. "Animals can be tagged by livestock market
personnel, who may charge a small fee, to cover costs for ear tag application
and for the required record keeping."
Dr. Conger also said slaughter house operators, agricultural science
teachers, veterinarians or agricultural extension agents likewise may apply tags
for producers. However, he encouraged producers to get their own premise
identification number and tags by calling the TAHC's 'tag line' at
1-866-873-2824. There's no charge for the call, premise number or tags, he
said.
The TAHC has operated under the USDA scrapie regulations since November
2001, while state regulations were developed to support the national program,
said Dr. Logan. "We've worked closely with the sheep and goat industry in Texas
to ensure Texas scrapie regulations reflect the federal rules. All states must
meet or exceed these national standards," said Dr. Logan. "On Tuesday, July 30,
the 12 TAHC commissioners adopted Texas scrapie regulations, and these will go
into effect September 1." In the meantime, she said the TAHC will continue to
operate under the national regulations.
Key elements of Texas' scrapie regulations for animal identification and
movement requirements include:
* Tagging of eligible animals prior to in-state or interstate movement or
exhibitions.
* Maintaining records for five years. Ranchers, markets, terminal feedlots,
or persons
providing tags must keep records that include: -- date, number and species
of animals tagged, bought or sold.
-- name and address of the person or market from which the animals were
obtained or sold.
-- agents, such as agricultural science teachers or livestock markets, who
supply ear tags, must maintain records that include the animal owner's name,
address and the premise identification number for each animal.
All sheep and goats transported into Texas from other states must have had
a certificate of veterinary inspection issued within the previous 30 days by a
USDA-accredited private veterinary practitioner. Information to be included on
the inspection document:
-- date inspection was made
-- number, species and gender of the animals -- reason for transport
(exhibition, breeding purposes, feeding or slaughter) -- name and address of
both the consignor and the recipient of the animals -- statement by the issuing
veterinarian that the animals were not exhibiting clinical signs indicative of
scrapie or any other infectious disease. The veterinarian must attest that the
animals are not from a scrapie-infected, high-risk or exposed flock. -- all
breeding or exhibition sheep and goats must be identified with an official ear
tag, with the premise identification number recorded on the certificate of
veterinary inspection.
-- sheep and goats entering Texas for feeding and/or slaughter also must
meet the tagging and information record keeping requirements. The only exemption
applies to feeder and/or slaughter sheep younger than 18 months and goats that
have not been commingled with sheep.
"In lieu of an ear tag, tattooed registered goats can enter Texas with
their registration papers," explained Dr. Conger. "As always, the TAHC also will
continue to require that breeding rams older than 6 months of age enter Texas
with a negative test for brucellosis within 30 days prior to shipment. The
brucellosis test results must be written on the certificate of veterinary
inspection.
"Scrapie has been difficult to eradicate since it was first introduced into
the U.S. in l947, because the disease develops slowly and, for months, the signs
of illness aren't obvious. Although older animals can be exposed and develop
infection, lambs and kids in the flock are most susceptible to the scrapie
agent, called a prion protein," said Dr. Conger. "Infected ewes shed the prion
in tissue and fluids associated with birthing and can expose many flockmates
during the lambing season."
"It can take as long as 18 months for the disease to become noticeable in
infected animals. Clinical signs include weight loss, lip smacking, tremors,
loss of coordination, swaying or wool pulling," said Dr. Logan. "Also, until
recently, there was no approved live animal test to confirm the visual
diagnosis, because brain tissue was needed for laboratory confirmation. Now
scrapie disease surveillance can be conducted with 'third eyelid testing.' In
this procedure, anesthetic drops are placed in the animal's eye, and a tiny
snippet of tissue is collected from underneath the eyelid. The tissue is then
prepared for shipment to a diagnostic laboratory for testing. Gene testing can
also identify animals that are naturally susceptible or resistant to the
disease, too."
"If an animal on the farm or at the market shows clinical signs indicative
of scrapie, TAHC regulations require that the animal be moved only under a
restricted movement permit issued by the TAHC or a USDA representative,"
commented Dr. Logan. "Movement will be restricted to a site where the animal
will be destroyed, tested and disposed of properly. When it is appropriate, the
animal may be moved back to the flock of origin, where it will be held under
restriction, while a diagnosis is made. If sick sheep or goats are identified at
a slaughter plant, they will be condemned and removed from the food chain.
Samples will be collected from the animals for diagnosis."
As part of the national eradication effort, the USDA is conducting routine,
random scrapie testing across the country. In Texas each week, the federal
agency purchases about 150 sheep and goats destined for slaughter. "Brain tissue
is collected from each of the animals and forwarded to the National Veterinary
Services Laboratory in Ames, Iowa," said Dr. Conger. "As of August 1, scrapie
has not been detected in these 'randomly sampled' animals. Within a few months,
results of this 'blind study' will be reported on a state-by-state basis, but
cases will not be identified to a flock."
"We have, however, detected four infected Texas flocks during the past 15
months. In three herds, infection was found in flocks outside of Texas, and we
traced animal movement to Texas. The infected flocks were found in Indiana,
Oklahoma and California. We found the fourth flock by tracing movement out of
one of the infected Texas flocks. Tracing disease movement is much like putting
the pieces of the puzzle together until they fit," said Dr. Conger. "Of the four
infected flocks in Texas, one has been depopulated and one is in a
quarantine-monitoring program. Two of the flocks were recently disclosed as
infected and flock management is still being decided."
"When scrapie infection is detected, we launch an epidemiological
investigation to determine if the disease has been introduced into other
flocks," said Dr. Conger. "The required ear tags and records will allow us to do
a more thorough job in tracing an infected animal's movement from birth. This
tracing is essential, if we are to eradicate scrapie."
Dr. Conger said the true prevalence of scrapie in the U.S. is not known,
but only two countries are known to be free of the disease--Australia and New
Zealand. The American Sheep Industry Association (ASI) in l998, declared scrapie
as an important trade issue, estimating that the disease costs American farmers
nearly $20 million yearly in lost export sales, extra disposal costs for dead
sheep and lost productivity. Animal health officials and the sheep industry say
scrapie can be eliminated in the U.S. by 2010. Disease eradication would be
especially helpful to Texas producers, as the state ranks first in the nation
for sheep and goat production, with more than 2.5 million head, according to the
Texas Agricultural Statistics Service (TASS).
For more information regarding scrapie regulations, voluntary scrapie flock
certification or to report clinical signs of the disease, contact the TAHC at
1-800-550-8242.
TSS
########### http://mailhost.rz.uni-karlsruhe.de/warc/bse-l.html
############
2013
TSE Policy
Test sheep peripheral tissues from animals infected with BSE and
scrapie.
A workshop of international TSE experts held at Defra concluded that it is
important to understand more about the possibility of mixed TSE infections in
ruminants that could theoretically enter the food chain. Sheep or goats infected
with both scrapie and BSE entering the food chain in the UK would risk further
cases of vCJD. Little is known about the pathogenesis and therefore the human
risk from such a mixed infection. Some experimental infections of sheep with a
mixture of BSE and scrapie have been completed and the brains have been
analysed. Brains are not consumed, but the peripheral tissues are. The aim of
this project would be to analyse the peripheral tissues collected and archived
in these experiments for the presence of BSE.
Oral transmission of L-type BSE to small ruminants
Oral transmissions use established methods. This project will demonstrate
whether atypical L-type BSE (a disease that current evidence suggests may
transmit to humans) can be acquired in small ruminants (SR) through feed and the
environment. Tissues which would enter the food chain will be sampled at post
mortem from animals of the appropriate age and tested for abnormal
prion/infectivity
2012 atypical L-type BSE BASE California reports
Saturday, August 4, 2012
*** Final Feed Investigation Summary - California BSE Case - July 2012
SUMMARY REPORT CALIFORNIA BOVINE SPONGIFORM ENCEPHALOPATHY CASE
INVESTIGATION JULY 2012
Summary Report BSE 2012
Executive Summary
Saturday, August 4, 2012
Update from APHIS Regarding Release of the Final Report on the BSE
Epidemiological Investigation
Sunday, August 26, 2012
Susceptibility of young sheep to oral infection with bovine spongiform
encephalopathy decreases significantly after weaning
Wednesday, January 18, 2012
BSE IN GOATS CAN BE MISTAKEN FOR SCRAPIE
February 1, 2012
The Limits of Test-Based Scrapie Eradication Programs in Goats
Fabien Corbière, Affiliation: UMR 1225 INRA-ENVT Interactions Hôtes Agents
Pathogènes, Ecole Nationale Vétérinaire, Toulouse, France
X Cécile Chauvineau-Perrin, Affiliation: ANSES, Laboratoire d’études et
recherches caprines, Niort, France
X Caroline Lacroux, Affiliation: UMR 1225 INRA-ENVT Interactions Hôtes
Agents Pathogènes, Ecole Nationale Vétérinaire, Toulouse, France
X Séverine Lugan, Affiliation: UMR 1225 INRA-ENVT Interactions Hôtes Agents
Pathogènes, Ecole Nationale Vétérinaire, Toulouse, France
X Pierrette Costes, Affiliation: UMR 1225 INRA-ENVT Interactions Hôtes
Agents Pathogènes, Ecole Nationale Vétérinaire, Toulouse, France
X Myriam Thomas, Affiliation: ANSES, Laboratoire d’études et recherches
caprines, Niort, France
X Isabelle Brémaud, Affiliation: ANSES, Laboratoire d’études et recherches
caprines, Niort, France
X Christophe Chartier, Affiliation: ANSES, Laboratoire d’études et
recherches caprines, Niort, France
X Francis Barillet, Affiliation: INRA, UR 631, Station d’Amélioration
Génétique des Animaux, Castanet-Tolosan, France
X François Schelcher, Affiliation: UMR 1225 INRA-ENVT Interactions Hôtes
Agents Pathogènes, Ecole Nationale Vétérinaire, Toulouse, France
X Olivier Andréoletti mail
Abstract
Small ruminant post-mortem testing programs were initially designed for
monitoring the prevalence of prion disease. They are now considered as a
potential alternative to genetic selection for eradicating/controlling classical
scrapie at population level. If such policy should be implemented, its success
would be crucially dependent on the efficiency of the surveillance system used
to identify infected flocks. In this study, we first determined the performance
of post-mortem classical scrapie detection in eight naturally affected goat
herds (total n = 1961 animals) according to the age at culling. These results
provided us with necessary parameters to estimate, through a Monte Carlo
simulation model, the performance of scrapie detection in a commercial
population. According to this model, whatever the number of tests performed,
post mortem surveillance will have limited success in identifying infected
herds. These data support the contention that scrapie eradication programs
relying solely on post mortem testing in goats will probably fail. Considering
the epidemiological and pathological similarities of scrapie in sheep and goats,
the efficiency of scrapie surveillance in both species is likely to be similar.
Citation: Corbière F, Chauvineau-Perrin C, Lacroux C, Lugan S, Costes P, et
al. (2013) The Limits of Test-Based Scrapie Eradication Programs in Goats. PLoS
ONE 8(1): e54911. doi:10.1371/journal.pone.0054911
Editor: Jason Bartz, Creighton University, United States of America
Received: September 17, 2012; Accepted: December 19, 2012; Published:
January 23, 2013
Copyright: © 2013 Corbière et al. This is an open-access article
distributed under the terms of the Creative Commons Attribution License, which
permits unrestricted use, distribution, and reproduction in any medium, provided
the original author and source are credited.
Funding: This work was funded by GIS PRION grant 31B06134, by INRA grant
AIP P00297, by the Poitou-Charentes region grants 04/RPC-A-103 and 05/RPC-A-13,
by the EU FP7 ‘Goat BSE’ project CT-2006-36353 and EMIDA 2012 ‘Goat TSE free’
project. The funders had no role in study design, data collection and analysis,
decision to publish, or preparation of the manuscript.
Competing interests: The authors have declared that no competing interests
exist.
* E-mail: o.andreoletti@envt.fr
snip...
Discussion
Our study involved a relatively large number of classical scrapie cases (n
= 183) recruited from eight naturally infected herds. It therefore provided a
solid basis for assessing the performances of the TSE tests and/or choice of
target tissue for classical scrapie detection in goats. However, like all
previous studies focusing on the performance of PrPSc based TSE detection assay,
this approach suffers from an intrinsic pitfall, i.e. the absence of a
gold-standard that would provide a definitive TSE status for each individual.
Currently, only bioassay (with no species barrier) could be considered as a
pertinent tool to establish/exclude TSE agent presence in a sample. However,
considering the number of samples that should be tested in an experiment like
this one, systematic bioassay testing of each tissue is not feasible. In that
context, we cannot exclude that some of the animals involved in this study might
have been inaccurately considered to be TSE negative.
Since their implementation in the EU and in North America, the rationale of
TSE active surveillance systems in small ruminants has been debated; the number
and age of tested animals, the choice of TSE screening tests and the choice of
testing on posterior brainstem have been extensively discussed [10]. As
anticipated from knowledge related to classical scrapie pathogenesis in small
ruminants (late neuro-invasion during the incubation phase), our results
demonstrate that the detection of TSE infected individuals would be
significantly improved by using tonsil or mesenteric lymph node rather than
posterior brainstem for PrPSc testing [7], [18]. The high concordance of the
results obtained using a rapid PrPSc detection assay (Biorad TeSeE sheep/goat®)
and a reference OIE confirmatory method (IHC) indicates that there is no
technical limitation for developing a field TSE surveillance program based on
PrPSc testing in lymphoid tissues.
At the population level, whatever the testing scenario (number of tests
performed each year) the results of our simulation study also indicated that TSE
active surveillance strategies based on PrPSc testing on tonsil rather than on
posterior brainstem would allow the detection of a higher number of classical
scrapie infected herds. However, the performance gain (between 2% and 10% of
additional scrapie infected herd detected) would remain relatively limited and
whatever the testing regimen the system would fail to detect 100% of the
infected herds.
In addition, it must be considered that in a large number of countries,
small ruminant TSE surveillance programs intend to monitor the prevalence of
both classical and atypical scrapie [6], [19]. The lack of detectable PrPSc in
the peripheral tissue of atypical scrapie infected individuals precludes the use
of lymphoid tissues for atypical scrapie surveillance [5].
Therefore, considering the current limits of TSE detection tests, and under
the hypothesis that the sole objective of TSE surveillance programs is to
provide a global picture of TSE prevalence in the small ruminants populations
the use of posterior brainstem for PrPSc remains the best compromise for TSE
monitoring in field.
Over the last decade, the EU policy for long term TSE control and
eradication in small ruminants has relied on the identification of infected
herds and the selection of genetically resistant animals in both infected flocks
and in the general population [20]. In sheep, the ARR PRP allele provides a
strong but not absolute resistance to classical scrapie and BSE agent [21],
[22]. The recent identification of PrP polymorphisms in goats that might provide
a strong, if not absolute, resistance to TSE agent infection could also provide
opportunities for genetic selection in that species [23]–[26]. The selection of
the ARR allele is an efficient tool for disease control/eradication in classical
scrapie infected flocks [20]. However, the sustainability of genetic selection
to control and eradicate TSE in small ruminants is still disputed. The existence
of TSE agents (like atypical scrapie) that can develop in ARR homozygote sheep
and the potential loss of genetic variability in animal populations are the two
main arguments used by people arguing against genetic selection. Eradication
policy based on the post mortem PrPSc testing and the stamping out of infected
herds/flocks, without genetic selection is therefore still given consideration
as an alternative to breeding for resistance. Our results clearly demonstrate
that over a year the random testing of 20 000 individuals in an 850 000
individuals population only allow the identification of a very limited
proportion (12%) of infected herds.
The simulation models that we developed rely on the French goat population
and breeding system. They cannot be directly inferred to scrapie surveillance in
sheep. However all the critical parameters that were used for modelling scrapie
in the goat population were similar to those reported in sheep. The age
distribution of cases that we used in goat was comparable to the one described
in susceptible PrP genotype sheep [27], [28]. The age at which PrPSc become
detectable in the posterior brainstem in goat (as reported here) and in
naturally scrapie infected ARQ/ARQ sheep were also comparable [15]. In addition,
the estimates obtained with our model are consistent with those reported by Hopp
et al. [29] when assessing the performance of TSE active surveillance in the
Norwegian sheep population. Therefore, it is our opinion that the results
obtained in this study are also pertinent for estimating the likely performances
of the post mortem scrapie surveillance program in sheep.
TSE in small ruminants is mainly considered as an animal health issue.
However, the uncertainties related to the capacity of other ruminant prions to
cross species barriers [30] remain a concern for public health. Considering the
results of our study and the capacity of TSE agents to persist in the
environment, it can be concluded that a classical scrapie eradication policy
that would solely rely on currently available TSE screening tests is unlikely to
succeed.
Supporting Information
snip...see full text ;
Tuesday, November 02, 2010
IN CONFIDENCE
The information contained herein should not be disseminated further except
on the basis of "NEED TO KNOW".
BSE - ATYPICAL LESION DISTRIBUTION (RBSE 92-21367) statutory (obex only)
diagnostic criteria CVL 1992
2009 UPDATE ON ALABAMA AND TEXAS MAD COWS 2005 and 2006
Wednesday, January 18, 2012
Selection of Distinct Strain Phenotypes in Mice Infected by Ovine Natural
Scrapie Isolates Similar to CH1641 Experimental Scrapie
Journal of Neuropathology & Experimental Neurology: February 2012 -
Volume 71 - Issue 2 - p 140–147
Wednesday, February 16, 2011
IN CONFIDENCE
SCRAPIE TRANSMISSION TO CHIMPANZEES
IN CONFIDENCE
Sunday, December 12, 2010
EFSA reviews BSE/TSE infectivity in small ruminant tissues News Story 2
December 2010
Sunday, April 18, 2010
SCRAPIE AND ATYPICAL SCRAPIE TRANSMISSION STUDIES A REVIEW 2010
Thursday, December 23, 2010
Molecular Typing of Protease-Resistant Prion Protein in Transmissible
Spongiform Encephalopathies of Small Ruminants, France, 2002-2009
Volume 17, Number 1 January 2011
Thursday, November 18, 2010
Increased susceptibility of human-PrP transgenic mice to bovine spongiform
encephalopathy following passage in sheep
Monday, April 25, 2011
Experimental Oral Transmission of Atypical Scrapie to Sheep
Volume 17, Number 5-May 2011
Friday, February 11, 2011
Atypical/Nor98 Scrapie Infectivity in Sheep Peripheral Tissues
Thursday, March 29, 2012
atypical Nor-98 Scrapie has spread from coast to coast in the USA 2012
NIAA Annual Conference April 11-14, 2011San Antonio, Texas
Wednesday, April 4, 2012
20120402 - Breach of quarantine/Violation de la mise en quarantaine of an
ongoing Scrapie investigation
Michigan and California have had a high spike in Goat Scrapie cases,
compared to elsewhere ???
Tuesday, February 01, 2011
Sparse PrP-Sc accumulation in the placentas of goats with naturally
acquired scrapie
(Figure 6) including five goat cases in FY 2008 that originated from the
same herd in Michigan. This is highly unusual for goats, and I strenuously urge
that there should be an independent investigation into finding the common
denominator for these 5 goats in the same herd in Michigan with Scrapie. ...
Thursday, February 23, 2012
Atypical Scrapie NOR-98 confirmed Alberta Canada sheep January 2012
RESEARCH
Emerging Infectious Diseases • www.cdc.gov/eid • Vol. 17, No. 5, May 2011
Experimental Oral Transmission of Atypical Scrapie to Sheep
Marion M. Simmons, S. Jo Moore,1 Timm Konold, Lisa Thurston, Linda A.
Terry, Leigh Thorne, Richard Lockey, Chris Vickery, Stephen A.C. Hawkins,
Melanie J. Chaplin, and John Spiropoulos
To investigate the possibility of oral transmission of atypical scrapie in
sheep and determine the distribution of infectivity in the animals’ peripheral
tissues, we challenged neonatal lambs orally with atypical scrapie; they were
then killed at 12 or 24 months. Screening test results were negative for
disease-specifi c prion protein in all but 2 recipients; they had positive
results for examination of brain, but negative for peripheral tissues.
Infectivity of brain, distal ileum, and spleen from all animals was assessed in
mouse bioassays; positive results were obtained from tissues that had negative
results on screening. These fi ndings demonstrate that atypical scrapie can be
transmitted orally and indicate that it has the potential for natural
transmission and iatrogenic spread through animal feed. Detection of infectivity
in tissues negative by current surveillance methods indicates that diagnostic
sensitivity is suboptimal for atypical scrapie, and potentially infectious
material may be able to pass into the human food chain.
SNIP...
Although we do not have epidemiologic evidence that supports the effi cient
spread of disease in the fi eld, these data imply that disease is potentially
transmissible under fi eld situations and that spread through animal feed may be
possible if the current feed restrictions were to be relaxed. Additionally,
almost no data are available on the potential for atypical scrapie to transmit
to other food animal species, certainly by the oral route. However, work with
transgenic mice has demonstrated the potential susceptibility of pigs, with the
disturbing fi nding that the biochemical properties of the resulting PrPSc have
changed on transmission (40). The implications of this observation for
subsequent transmission and host target range are currently unknown.
How reassuring is this absence of detectable PrPSc from a public health
perspective? The bioassays performed in this study are not titrations, so the
infectious load of the positive gut tissues cannot be quantifi ed, although
infectivity has been shown unequivocally. No experimental data are currently
available on the zoonotic potential of atypical scrapie, either through
experimental challenge of humanized mice or any meaningful epidemiologic
correlation with human forms of TSE. However, the detection of infectivity in
the distal ileum of animals as young as 12 months, in which all the tissues
tested were negative for PrPSc by the currently available screening and confi
rmatory diagnostic tests, indicates that the diagnostic sensitivity of current
surveillance methods is suboptimal for detecting atypical scrapie and that
potentially infectious material may be able to pass into the human food chain
undetected.
Emerging Infectious Diseases • www.cdc.gov/eid • Vol. 17, No. 5, May 2011
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
1: J Infect Dis 1980 Aug;142(2):205-8
Oral transmission of kuru, Creutzfeldt-Jakob disease, and scrapie to
nonhuman primates.
Gibbs CJ Jr, Amyx HL, Bacote A, Masters CL, Gajdusek DC.
Kuru and Creutzfeldt-Jakob disease of humans and scrapie disease of sheep
and goats were transmitted to squirrel monkeys (Saimiri sciureus) that were
exposed to the infectious agents only by their nonforced consumption of known
infectious tissues. The asymptomatic incubation period in the one monkey exposed
to the virus of kuru was 36 months; that in the two monkeys exposed to the virus
of Creutzfeldt-Jakob disease was 23 and 27 months, respectively; and that in the
two monkeys exposed to the virus of scrapie was 25 and 32 months, respectively.
Careful physical examination of the buccal cavities of all of the monkeys failed
to reveal signs or oral lesions. One additional monkey similarly exposed to kuru
has remained asymptomatic during the 39 months that it has been under
observation.
snip...
The successful transmission of kuru, Creutzfeldt-Jakob disease, and scrapie
by natural feeding to squirrel monkeys that we have reported provides further
grounds for concern that scrapie-infected meat may occasionally give rise in
humans to Creutzfeldt-Jakob disease.
PMID: 6997404
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=6997404&dopt=Abstract
Recently the question has again been brought up as to whether scrapie is
transmissible to man. This has followed reports that the disease has been
transmitted to primates. One particularly lurid speculation (Gajdusek 1977)
conjectures that the agents of scrapie, kuru, Creutzfeldt-Jakob disease and
transmissible encephalopathy of mink are varieties of a single "virus". The U.S.
Department of Agriculture concluded that it could "no longer justify or permit
scrapie-blood line and scrapie-exposed sheep and goats to be processed for human
or animal food at slaughter or rendering plants" (ARC 84/77)" The problem is
emphasised by the finding that some strains of scrapie produce lesions identical
to the once which characterise the human dementias"
Whether true or not. the hypothesis that these agents might be
transmissible to man raises two considerations. First, the safety of laboratory
personnel requires prompt attention. Second, action such as the "scorched meat"
policy of USDA makes the solution of the acrapie problem urgent if the sheep
industry is not to suffer grievously.
snip...
76/10.12/4.6
Nature. 1972 Mar 10;236(5341):73-4.
Transmission of scrapie to the cynomolgus monkey (Macaca fascicularis).
Gibbs CJ Jr, Gajdusek DC.
Nature 236, 73 - 74 (10 March 1972); doi:10.1038/236073a0
Transmission of Scrapie to the Cynomolgus Monkey (Macaca
fascicularis)
C. J. GIBBS jun. & D. C. GAJDUSEK
National Institute of Neurological Diseases and Stroke, National Institutes
of Health, Bethesda, Maryland
SCRAPIE has been transmitted to the cynomolgus, or crab-eating, monkey
(Macaca fascicularis) with an incubation period of more than 5 yr from the time
of intracerebral inoculation of scrapie-infected mouse brain. The animal
developed a chronic central nervous system degeneration, with ataxia, tremor and
myoclonus with associated severe scrapie-like pathology of intensive astroglial
hypertrophy and proliferation, neuronal vacuolation and status spongiosus of
grey matter. The strain of scrapie virus used was the eighth passage in Swiss
mice (NIH) of a Compton strain of scrapie obtained as ninth intracerebral
passage of the agent in goat brain, from Dr R. L. Chandler (ARC, Compton,
Berkshire).
IT is of my opinion, that the OIE and the USDA et al, are the soul reason,
and responsible parties, for Transmissible Spongiform Encephalopathy TSE prion
diseases, including typical and atypical BSE, typical and atypical Scrapie, and
all strains of CWD, and human TSE there from, spreading around the globe.
I have lost all confidence of this organization as a regulatory authority
on animal disease, and consider it nothing more than a National Trading
Brokerage for all strains of animal TSE, just to satisfy there commodity. AS i
said before, OIE should hang up there jock strap now, since it appears they will
buckle every time a country makes some political hay about trade protocol,
commodities and futures. IF they are not going to be science based, they should
do everyone a favor and dissolve there organization.
JUST because of low documented human body count with nvCJD and the long
incubation periods, the lack of sound science being replaced by political and
corporate science in relations with the fact that science has now linked some
sporadic CJD with atypical BSE and atypical scrapie, and the very real threat of
CWD being zoonosis, I believed the O.I.E. has failed terribly and again, I call
for this organization to be dissolved. ...
Tuesday, July 17, 2012
O.I.E. BSE, CWD, SCRAPIE, TSE PRION DISEASE Final Report of the 80th
General Session, 20 - 25 May 2012
Thursday, December 20, 2012
OIE GROUP RECOMMENDS THAT SCRAPE PRION DISEASE BE DELISTED AND SAME OLD BSe
WITH BOVINE MAD COW DISEASE
TSS
posted by Terry S. Singeltary Sr. | 12:51 PM
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