Follow Ups | Post Followup | Back to Discussion Board | VegSource
See spam or
inappropriate posts?
Please let us know.

From: TSS ()
Date: April 12, 2008 at 7:34 pm PST

Preliminary Results for Research on Live Chronic Wasting Disease Test for
Elk in Rocky Mountain National Park

Date: April 10, 2008
Contact: Kyle Patterson, 970-586-1363

In January, research began in Rocky Mountain National Park to evaluate
procedures for testing live elk for chronic wasting disease (CWD). This is
the first time free ranging elk have been tested for CWD using this live
procedure. This study is being done at the park to take advantage of the
implementation of the recently announced Rocky Mountain National Park Elk
and Vegetation Management Plan.

Elk were captured from early January through mid March. The majority of
captures took place in Moraine Park and near Beaver Meadows Visitor Center.
Out of 136 female elk captured, (there were 117 usable biopsies), 13 tested
CWD positive and were removed. Complete necropsies were performed and
confirmed those results. Based on those results there was an 11 percent
estimated CWD prevalence rate in this sample population. At the time of
capture there was no obvious evidence of clinical CWD.

Researchers indicated they were not surprised at the results since previous
research in the park has shown that the elk herd in Rocky Mountain National
Park and the Estes Valley, is larger, less migratory and more concentrated
than it would be under natural conditions. Research has also shown that elk
densities on the core winter range are the highest concentrations ever
documented for a free-ranging population in the Rocky Mountains.

Over the next several years, in conjunction with the proposed lethal
reduction of elk, researchers will continue to conduct studies to evaluate
procedures for testing live elk for CWD. Currently, there is a live CWD test
effective for deer, but CWD diagnosis in live elk has received limited
evaluation to date. Until now, the disease could only be reliably diagnosed
after death in elk. Any elk which tests positive for CWD will be lethally
removed from the population, thereby contributing to annual population
reduction targets. These targets will be developed each year based on annual
population surveys and hunter success outside the park. Over the next three
years elk population reduction will gradually remove study elk and the CWD
status will be evaluated.

Chronic wasting disease (CWD) was first reported in free-ranging wildlife in
1981. It is a member of the transmissible spongiform encephalopathy (TSE)
disease family which also includes bovine spongiform encephalopathy in
cattle (BSE, also known as Mad Cow disease) and scrapie in domestic sheep
and goats. CWD is fatal in deer and elk. Northeastern Colorado (including
the eastside of Rocky Mountain National Park), southeastern Wyoming and
western Nebraska are considered the endemic area for the disease.

Participants in the studies include scientists from the Colorado State
University Department of Biomedical Sciences, the National Park Service,
USDA National Wildlife Research Center, Colorado State University Department
of Microbiology, Immunology and Pathology; USDA Agricultural Research
Service. The Colorado Division of Wildlife is participating in the study on
the live CWD test.


April 2, 2008
New Scrapie Live-Animal
Test Approved
On Jan. 11, 2008, Veterinary Services (VS), a unit
within the U.S. Department of Agriculture's Animal
and Plant Health Inspection Service, approved a new
live-animal test for detecting scrapie in sheep and
goats. Similar to the currently used third eyelid test,
the test involves collecting lymphoid tissue. The new
test, however, uses rectal mucosa biopsy, as opposed
to third eyelid biopsy. Both tests can be conducted on
live animals using local anesthetic.

Brief Communications

Adaptation and evaluation of a rapid test for the diagnosis of sheep scrapie
in samples of rectal mucosa
Lorenzo González1, Robert Horton, Drew Ramsay, Reet Toomik, Valerie
Leathers, Quentin Tonelli, Mark P. Dagleish, Martin Jeffrey and Linda Terry
Correspondence: 1Corresponding Author: Lorenzo González, Veterinary
Laboratories Agency, Pentlands Science Park, Bush Loan, PENICUIK, Midlothian
EH26 0PZ, UK, e-mail:

In recent publications, it was shown that disease-associated prion protein
(PrPd) accumulates in the lymphoid tissue of the rectal mucosa of a high
proportion of scrapie-infected sheep at clinical and preclinical stages,
regardless of several host factors; PrPd can also be detected in biopsy
specimens of rectal mucosa, with an increased probability proportional to
age or incubation period and with an efficiency almost identical to that of
tonsil biopsies. Rectal biopsies have the advantages of providing higher
numbers of lymphoid follicles and of being simpler to perform, which makes
them suitable for scrapie screening in the field. In biopsy samples, PrPd
could be demonstrated by immunohistochemical (IHC) and Western
immunoblotting methods, and the purpose of the present study was to optimize
and evaluate a "rapid test" for the diagnosis of scrapie in rectal biopsy
samples. The HerdChek CWD (chronic wasting disease) antigen EIA (enzyme
immunoassay) test was chosen and, once optimized, provided specificity and
sensitivity figures of 99.2% and 93.5%, respectively, compared with IHC
results in the same samples obtained at a postmortem. The sensitivity of the
assay increased from 82.1%, when a single rectal mucosa sample was tested to
99.4% for those sheep in which 3 or more samples were analyzed. Similarly,
sensitivity values of the HerdChek CWD antigen EIA test on biopsy samples
increased from 95% to 100% for sheep subjected to 1 or 2 sequential biopsies
4 months apart, respectively. Thus, a preclinical diagnosis of scrapie in
live sheep can be achieved by a combination of a simple sampling procedure,
which can be repeated several times with no detrimental effect for the
animals, and a rapid and efficient laboratory method.

Key Words: Rectal biopsy . scrapie . sheep


PrPCWD in rectal lymphoid tissue of deer (Odocoileus spp.)
Lisa L. Wolfe1, Terry R. Spraker2, Lorenzo González3, Mark P. Dagleish4,
Tracey M. Sirochman1,5, Jeremy C. Brown6, Martin Jeffrey3 and Michael W.

1 Colorado Division of Wildlife, Wildlife Research Center, 317 West Prospect
Road, Fort Collins, CO 80526-2097, USA
2 Colorado State University Veterinary Diagnostic Laboratory, Colorado State
University, Fort Collins, CO 80523, USA
3 Veterinary Laboratories Agency - Lasswade, Pentlands Science Park,
Penicuik EH26 0PZ, UK
4 Moredun Research Institute, Pentlands Science Park, Penicuik EH26 0PZ, UK
5 Department of Molecular Biology, University of Wyoming, 1000 E. University
Avenue, Laramie, WY 82071, USA
6 Department of Veterinary Sciences, University of Wyoming, 1174 Snowy Range
Road, Laramie, WY 82070, USA

Lisa L. Wolfe

The utility of rectal lymphoid tissue sampling for the diagnosis of chronic
wasting disease (CWD) infections in mule deer (Odocoileus hemionus) and
white-tailed deer (Odocoileus virginianus) was evaluated. CWD-associated
prion protein (PrPCWD) deposits were observed in the rectal mucosa from 19
orally inoculated mule deer by 381 days post-inoculation (p.i.); similarly,
45 out of 50 naturally infected mule deer had PrPCWD in their rectal mucosa.
In orally inoculated white-tailed deer, the presence of glycine (G) or
serine (S) at codon 96 of the native PrP (denoted 96GG, 96GS or 96SS)
appeared to influence the temporal patterns of PrPCWD deposition: nine out
of 11 infected 96GG individuals had PrPCWD in their rectal mucosa by 342
days p.i., whereas only three out of seven infected 96GS individuals had
PrPCWD in their rectal mucosa by 381 days p.i. and none of three 96SS
individuals had PrPCWD in their rectal mucosa by 751 days p.i. These
findings support further evaluation of rectal mucosa sampling in CWD

APHIS received approximately $18.5 million in appropriated CWD funding in FY
2006 ...

He then shared preliminary data on use of rectal mucosa biopsy to ...


animals were tested in 2007 with the identification and removal of positive
elk from infected herds. Eighty percent of the positive animals in a highly
infected white-tailed deer herd were identified with *** rectal biopsy. The
lower incidence of CWD in most infected elk herds complicates the evaluation
of this test in elk. It appears that in deer, rectal lymphoid tissue becomes
positive later than lymphoid tissue of the head suggesting that early cases
may be missed with rectal biopsy. Positive rectal biopsy is indicative of
disease but a negative rectal biopsy test does not rule out CWD in an
individual or herd.


Title: Detection of PrP**CWD in retinal tissues in white-tailed deer
(Odocoileus virginianus) and Rocky Mountain elk (Cervus elaphus nelsoni)
with CWD


Follow Ups:

Post a Followup

E-mail: (optional)


Optional Link URL:
Link Title:
Optional Image URL: