How Did CWD Get Way Down In Medina County, Texas?
How Did CWD Get Way Down In Medina County, Texas?
Confucius ponders...
Could the Scrapie experiments back around 1964 at Moore Air Force near
Mission, Texas, could this area have been ground zero for CWD (besides the CWD
cases that have waltzed across the Texas, New Mexico border near WSMR Trans
Pecos region since around 2001)?
Epidemiology of Scrapie in the United States 1977
snip...
Scrapie Field Trial Experiments Mission, Texas
A Scrapie Field Trial was developed at Mission, Texas, to provide
additional information for the eradication program on the epidemiology of
natural scrapie. The Mission Field Trial Station is located on 450 acres of
pastureland, part of the former Moore Air Force Base, near Mission, Texas. It
was designed to bring previously exposed, and later also unexposed, sheep or
goats to the Station and maintain and breed them under close observation for
extended periods to determine which animals would develop scrapie and define
more closely the natural spread and other epidemiological aspects of the
disease.
The 547 previously exposed sheep brought to the Mission Station beginning
in 1964 were of the Cheviot, Hampshire, Montadale, or Suffolk breeds. They were
purchased as field outbreaks occurred, and represented 21 bloodlines in which
scrapie had been diagnosed. Upon arrival at the Station, the sheep were
maintained on pasture, with supplemental feeding as necessary. The station was
divided into 2 areas: (1) a series of pastures and-pens occupied by male animals
only, and (2) a series of pastures and pens occupied by females and young
progeny of both sexes. ...
snip...see full text ;
Mission, Texas Scrapie transmission to cattle study
Wilbur Clarke (reference the Mission, Texas scrapie transmission
transmission to cattle study) is now the State Veterinarian for Montana based at
Helena.
I was given confidential access to sections from the Clarke scrapie-cattle
transmission experiment. Details of the experimental design were as supplied
previously by Dr. Wrathall (copy of relevant information appended). Only 3
animals (2 inoculated with 2nd pass Suffolk scrapie and 1 inoculated with Angora
goat passaged scrapie) showed clinical signs. Clinical signs were characterised
by weakness, ''a stilted hindlimb gait'', disorientation, ataxia and,
terminally, lateral recumbency. The two cattle from which I examined material
were inocluated at 8 months of age and developed signs 36 months pi (goat
scrapie inoculum) and 49 months pi (one of the Suffolk scrapie inoculated)
respectively. This latter animal was killed at 58 months of age and so the
clinical duration was only 1 month. The neuropathology was somewhat different
from BSE or the Stetsonville TME in cattle. Vacuolar changes were minimal, to
the extent that detection REQUIRED CAREFUL SEARCHING. Conversely astrocyte
hypertrophy was a widespread and prominent feature. The material requires
DETAILED NEUROPATHOLOGICAL ASSESSMENT BUT WHETHER OR NOT THIS WILL BE DONE
REMAINS A QUESTION.
Transmission Studies
Mule deer transmissions of CWD were by intracerebral inoculation and
compared with natural cases {the following was written but with a single line
marked through it ''first passage (by this route)}...TSS
resulted in a more rapidly progressive clinical disease with repeated
episodes of synocopy ending in coma. One control animal became affected, it is
believed through contamination of inoculum (?saline). Further CWD transmissions
were carried out by Dick Marsh into ferret, mink and squirrel monkey.
Transmission occurred in ALL of these species with the shortest incubation
period in the ferret.
snip...
Appendix 3
VISIT TO USA - DR A E WRATHALL - INFO OH BSE AND SCRAPIE
1. Dr Clark lately of the Scrapie Research Unit, Mission Texas has
successfully transmitted ovine and caprine scrapie to cattle. The experimental
results have not been published but there are plans to do this. This work was
initiated in 1978.
A summary of it is:-
Expt A
6 Her x Jer calves born in 1978 were inoculated as follows with
a 2nd Suffolk scrapie passage:-
i/c 1ml; i/m, 5ml; s/c 5ml; oral 30ml.
1/6 went down after 48 months with a scrapie/BSE-like disease.
Expt B
6 Her or Jer or HxJ calves were inoculated with angora Goat
virus 2/6 went down similarly after 36 months.
Expt C
Mice inoculated from brains of calves/cattle in expts A • B were resistant,
only 1/20 going down with scrapie and this was the reason given for not
publishing.
Diagnosis in A, B, C was by histopath. No reports on SAT were given.
2. Dr Warren Foote indicated success so far in eliminating scrapie in
offspring from experimentally- (and naturally) infected sheep by ET. He had
found difficulty in obtaining embryos from naturally infected sheep (cf
SPA).
3. Prof. A Robertson gave a brief account of BSE. The US approach was to
accord it a very low profile indeed. Dr A Thiermann showed the picture in the
"Independent" with cattle being incinerated and thought this was a fanatical
incident to be avoided in the US at all costs. BSE was not reported in
USA.
4. Scrapie incidents (ie affected flocks) have shown a dramatic increase
since 1978. In 1953 when the National Control Scheme was started there were
10-14 incidents, in 1978 - 1 and in 1988 so far 60.
5. Scrapie agent was reported to have been isolated from a solitary
fetus.
6. A western blotting diagnostic technique (? on PrP) shows some
promise.
7. Results of a questionnaire sent to 33 states on the subject of the
national sheep scrapie programme survey indicated
17/33 wished to drop it
6/33 wished to develop it
9/13/2005
33
Page 15 of 17
8/33 had few sheep and were neutral
Information obtained from Dr Wrathall's notes of a meeting of the U.S.
Animal Health Association at Little Rock, Arkansas Nov. 1988.
end...TSS
Spongiform Encephalopathy in Captive Wild ZOO BSE INQUIRY
P.97: Scrapie transmits to white-tailed deer by the oral route and has a
molecular profile similar to chronic wasting disease and distinct from the
scrapie inoculum
Justin Greenlee1, S Jo Moore1, Jodi Smith1, M Heather West Greenlee2, and
Robert Kunkle1
1National Animal Disease Center; Ames, IA USA;
2Iowa State University; Ames, IA USA
The purpose of this work was to determine susceptibility of white-tailed
deer (WTD) to the agent of sheep scrapie and to compare the resultant PrPSc to
that of the original inoculum and chronic wasting disease (CWD). We inoculated
WTD by a natural route of exposure (concurrent oral and intranasal (IN); n D 5)
with a US scrapie isolate. All scrapie-inoculated deer had evidence of PrPSc
accumulation. PrPSc was detected in lymphoid tissues at preclinical time points,
and deer necropsied after 28 months post-inoculation had clinical signs,
spongiform encephalopathy, and widespread distribution of PrPSc in neural and
lymphoid tissues. Western blotting (WB) revealed PrPSc with 2 distinct molecular
profiles. WB on cerebral cortex had a profile similar to the original scrapie
inoculum, whereas WB of brainstem, cerebellum, or lymph nodes revealed PrPSc
with a higher profile resembling CWD. Homogenates with the 2 distinct profiles
from WTD with clinical scrapie were further passaged to mice expressing cervid
prion protein and intranasally to sheep and WTD. In cervidized mice, the 2
inocula have distinct incubation times. Sheep inoculated intranasally with WTD
derived scrapie developed disease, but only after inoculation with the inoculum
that had a scrapie-like profile. The WTD study is ongoing, but deer in both
inoculation groups are positive for PrPSc by rectal mucosal biopsy. In summary,
this work demonstrates that WTD are susceptible to the agent of scrapie, 2
distinct molecular profiles of PrPSc are present in the tissues of affected
deer, and inoculum of either profile readily passes to deer.
Research Project: TRANSMISSION, DIFFERENTIATION, AND PATHOBIOLOGY OF
TRANSMISSIBLE SPONGIFORM ENCEPHALOPATHIES
Title: Scrapie transmits to white-tailed deer by the oral route and has a
molecular profile similar to chronic wasting disease
Authors
item Greenlee, Justin item Moore, S - item Smith, Jodi - item Kunkle,
Robert item West Greenlee, M -
Submitted to: American College of Veterinary Pathologists Meeting
Publication Type: Abstract Only Publication Acceptance Date: August 12, 2015
Publication Date: N/A Technical Abstract: The purpose of this work was to
determine susceptibility of white-tailed deer (WTD) to the agent of sheep
scrapie and to compare the resultant PrPSc to that of the original inoculum and
chronic wasting disease (CWD). We inoculated WTD by a natural route of exposure
(concurrent oral and intranasal (IN); n=5) with a US scrapie isolate. All
scrapie-inoculated deer had evidence of PrPSc accumulation. PrPSc was detected
in lymphoid tissues at preclinical time points, and deer necropsied after 28
months post-inoculation had clinical signs, spongiform encephalopathy, and
widespread distribution of PrPSc in neural and lymphoid tissues. Western
blotting (WB) revealed PrPSc with 2 distinct molecular profiles. WB on cerebral
cortex had a profile similar to the original scrapie inoculum, whereas WB of
brainstem, cerebellum, or lymph nodes revealed PrPSc with a higher profile
resembling CWD. Homogenates with the 2 distinct profiles from WTD with clinical
scrapie were further passaged to mice expressing cervid prion protein and
intranasally to sheep and WTD. In cervidized mice, the two inocula have distinct
incubation times. Sheep inoculated intranasally with WTD derived scrapie
developed disease, but only after inoculation with the inoculum that had a
scrapie-like profile. The WTD study is ongoing, but deer in both inoculation
groups are positive for PrPSc by rectal mucosal biopsy. In summary, this work
demonstrates that WTD are susceptible to the agent of scrapie, two distinct
molecular profiles of PrPSc are present in the tissues of affected deer, and
inoculum of either profile readily passes to deer.
White-tailed Deer are Susceptible to Scrapie by Natural Route of Infection
Jodi D. Smith, Justin J. Greenlee, and Robert A. Kunkle; Virus and Prion
Research Unit, National Animal Disease Center, USDA-ARS
Interspecies transmission studies afford the opportunity to better
understand the potential host range and origins of prion diseases. Previous
experiments demonstrated that white-tailed deer are susceptible to sheep-derived
scrapie by intracranial inoculation. The purpose of this study was to determine
susceptibility of white-tailed deer to scrapie after a natural route of
exposure. Deer (n=5) were inoculated by concurrent oral (30 ml) and intranasal
(1 ml) instillation of a 10% (wt/vol) brain homogenate derived from a sheep
clinically affected with scrapie. Non-inoculated deer were maintained as
negative controls. All deer were observed daily for clinical signs. Deer were
euthanized and necropsied when neurologic disease was evident, and tissues were
examined for abnormal prion protein (PrPSc) by immunohistochemistry (IHC) and
western blot (WB). One animal was euthanized 15 months post-inoculation (MPI)
due to an injury. At that time, examination of obex and lymphoid tissues by IHC
was positive, but WB of obex and colliculus were negative. Remaining deer
developed clinical signs of wasting and mental depression and were necropsied
from 28 to 33 MPI. Tissues from these deer were positive for scrapie by IHC and
WB. Tissues with PrPSc immunoreactivity included brain, tonsil, retropharyngeal
and mesenteric lymph nodes, hemal node, Peyer’s patches, and spleen. This work
demonstrates for the first time that white-tailed deer are susceptible to sheep
scrapie by potential natural routes of inoculation. In-depth analysis of tissues
will be done to determine similarities between scrapie in deer after
intracranial and oral/intranasal inoculation and chronic wasting disease
resulting from similar routes of inoculation.
see full text ;
PO-039: A comparison of scrapie and chronic wasting disease in white-tailed
deer
Justin Greenlee, Jodi Smith, Eric Nicholson US Dept. Agriculture;
Agricultural Research Service, National Animal Disease Center; Ames, IA USA
White-tailed deer are susceptible to the agent of sheep scrapie by
intracerebral inoculation
snip...
It is unlikely that CWD will be eradicated from free-ranging cervids, and
the disease is likely to continue to spread geographically [10]. However, the
potential that white-tailed deer may be susceptible to sheep scrapie by a
natural route presents an additional confounding factor to halting the spread of
CWD. This leads to the additional speculations that
1) infected deer could serve as a reservoir to infect sheep with scrapie
offering challenges to scrapie eradication efforts and
2) CWD spread need not remain geographically confined to current endemic
areas, but could occur anywhere that sheep with scrapie and susceptible cervids
cohabitate.
This work demonstrates for the first time that white-tailed deer are
susceptible to sheep scrapie by intracerebral inoculation with a high attack
rate and that the disease that results has similarities to CWD. These
experiments will be repeated with a more natural route of inoculation to
determine the likelihood of the potential transmission of sheep scrapie to
white-tailed deer. If scrapie were to occur in white-tailed deer, results of
this study indicate that it would be detected as a TSE, but may be difficult to
differentiate from CWD without in-depth biochemical analysis.
2012
PO-039: A comparison of scrapie and chronic wasting disease in white-tailed
deer
Justin Greenlee, Jodi Smith, Eric Nicholson US Dept. Agriculture;
Agricultural Research Service, National Animal Disease Center; Ames, IA USA
snip...
The results of this study suggest that there are many similarities in the
manifestation of CWD and scrapie in WTD after IC inoculation including early and
widespread presence of PrPSc in lymphoid tissues, clinical signs of depression
and weight loss progressing to wasting, and an incubation time of 21-23 months.
Moreover, western blots (WB) done on brain material from the obex region have a
molecular profile similar to CWD and distinct from tissues of the cerebrum or
the scrapie inoculum. However, results of microscopic and IHC examination
indicate that there are differences between the lesions expected in CWD and
those that occur in deer with scrapie: amyloid plaques were not noted in any
sections of brain examined from these deer and the pattern of immunoreactivity
by IHC was diffuse rather than plaque-like.
*** After a natural route of exposure, 100% of WTD were susceptible to
scrapie.
Deer developed clinical signs of wasting and mental depression and were
necropsied from 28 to 33 months PI. Tissues from these deer were positive for
PrPSc by IHC and WB. Similar to IC inoculated deer, samples from these deer
exhibited two different molecular profiles: samples from obex resembled CWD
whereas those from cerebrum were similar to the original scrapie inoculum. On
further examination by WB using a panel of antibodies, the tissues from deer
with scrapie exhibit properties differing from tissues either from sheep with
scrapie or WTD with CWD. Samples from WTD with CWD or sheep with scrapie are
strongly immunoreactive when probed with mAb P4, however, samples from WTD with
scrapie are only weakly immunoreactive. In contrast, when probed with mAb’s 6H4
or SAF 84, samples from sheep with scrapie and WTD with CWD are weakly
immunoreactive and samples from WTD with scrapie are strongly positive. This
work demonstrates that WTD are highly susceptible to sheep scrapie, but on first
passage, scrapie in WTD is differentiable from CWD.
2011
*** After a natural route of exposure, 100% of white-tailed deer were
susceptible to scrapie.
White-tailed Deer are Susceptible to Scrapie by Natural Route of Infection
Jodi D. Smith, Justin J. Greenlee, and Robert A. Kunkle; Virus and Prion
Research Unit, National Animal Disease Center, USDA-ARS
Interspecies transmission studies afford the opportunity to better
understand the potential host range and origins of prion diseases. Previous
experiments demonstrated that white-tailed deer are susceptible to sheep-derived
scrapie by intracranial inoculation. The purpose of this study was to determine
susceptibility of white-tailed deer to scrapie after a natural route of
exposure. Deer (n=5) were inoculated by concurrent oral (30 ml) and intranasal
(1 ml) instillation of a 10% (wt/vol) brain homogenate derived from a sheep
clinically affected with scrapie. Non-inoculated deer were maintained as
negative controls. All deer were observed daily for clinical signs. Deer were
euthanized and necropsied when neurologic disease was evident, and tissues were
examined for abnormal prion protein (PrPSc) by immunohistochemistry (IHC) and
western blot (WB). One animal was euthanized 15 months post-inoculation (MPI)
due to an injury. At that time, examination of obex and lymphoid tissues by IHC
was positive, but WB of obex and colliculus were negative. Remaining deer
developed clinical signs of wasting and mental depression and were necropsied
from 28 to 33 MPI. Tissues from these deer were positive for scrapie by IHC and
WB. Tissues with PrPSc immunoreactivity included brain, tonsil, retropharyngeal
and mesenteric lymph nodes, hemal node, Peyer’s patches, and spleen. This work
demonstrates for the first time that white-tailed deer are susceptible to sheep
scrapie by potential natural routes of inoculation. In-depth analysis of tissues
will be done to determine similarities between scrapie in deer after
intracranial and oral/intranasal inoculation and chronic wasting disease
resulting from similar routes of inoculation.
see full text ;
Friday, April 22, 2016
*** Texas Scrapie Confirmed in a Hartley County Sheep where CWD was
detected in a Mule Deer
Saturday, April 02, 2016
TEXAS TAHC BREAKS IT'S SILENCE WITH TWO MORE CASES CWD CAPTIVE DEER
BRINGING TOTAL TO 10 CAPTIVES REPORTED TO DATE
Friday, February 26, 2016
TEXAS Hartley County Mule Deer Tests Positive for Chronic Wasting Disease
CWD TSE Prion
Tuesday, July 21, 2015
*** Texas CWD Medina County Herd Investigation Update July 16, 2015 ***
Thursday, July 09, 2015
TEXAS Chronic Wasting Disease (CWD) Herd Plan for Trace-Forward Exposed
Herd with Testing of Exposed Animals
Wednesday, July 01, 2015
TEXAS Chronic Wasting Disease Detected in Medina County Captive Deer
Tuesday, June 07, 2016 Comparison of two US sheep scrapie isolates supports
identification as separate strains
Research Project: TRANSMISSION, DIFFERENTIATION, AND PATHOBIOLOGY OF
TRANSMISSIBLE SPONGIFORM ENCEPHALOPATHIES
Terry S. Singeltary Sr.
posted by Terry S. Singeltary Sr. at
4:18 PM
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