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CHRONIC WASTING DISEASE, CERVIDS - USA (06): (COLORADO)

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CHRONIC WASTING DISEASE, CERVIDS - USA (06): (COLORADO)
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[1]
Date: 10 Dec 2008
Source: City of Boulder [edited]
http://www.bouldercolorado.gov/files/openspace/pdf_osbtmemos/memo.pdf

CITY OF BOULDER OPEN SPACE BOARD OF TRUSTEES AGENDA ITEM
--------------------------------------------------------
MEETING DATE: 10 Dec 2008

TITLE: Chronic Wasting Disease Study Results

PRESENTERS: Open Space and Mountain Parks Michael D. Patton, Director
Heather M. Swanson, Wildlife Ecologist Colorado Division of Wildlife
Michael W. Miller, Senior Wildlife Veterinarian

EXECUTIVE SUMMARY:
Chronic wasting disease (CWD) is a fatal prion disease occurring in
mule deer inhabiting Open Space and Mountain Parks (OSMP) properties.
Beginning in 2005, OSMP and the Colorado Division of Wildlife (CDOW)
undertook a 3-year research project to examine CWD on OSMP and
private property in the Table Mesa area to increase the understanding
of CWD and possibly CWD management. During the course of the study,
131 mule deer were captured and collared and 115 adult deer were
monitored. Each deer was tested for CWD status once per year using
either tonsil or rectal mucosa biopsy (both techniques developed for
testing live animals). In addition, a mark-resight census was
performed (visual counts of collared and un-collared deer within the
study area are analyzed using a population census model to estimate
overall population size) annually to estimate the population of mule
deer residing in the study area.

OSMP and CDOW staff participants found CWD prevalence within the
study area (south Boulder between Baseline, Eldorado Springs Drive,
Broadway and the Flatirons mountain front) to be surprisingly high --
overall approximately 29 percent of the deer sampled were infected.
Staff also found that average survival time for infected deer was
significantly lower than for uninfected deer. Cause of death varied
somewhat between years, but the most common mortality causes were
mountain lion predation, clinical CWD and vehicle collisions.
Mark-resight inventory estimations of the deer population within the
study area showed a decrease in local deer numbers over estimates
derived from census efforts in the late 1980s. The high prevalence,
low survivorship, and decreasing population numbers suggest that CWD
is having a measurable effect on the mule deer herd living in south
Boulder. High prevalence makes previously discussed management
actions such as test-and-cull control unlikely to be feasible.

--
Communicated by
Terry Singletary

[For details, please see the full report. - Mod.MHJ]

******
[2]
Date: 16 Dec 2008
Source: ColoradoDaily.Com [edited]

One-third of Boulder's deer infected
------------------------------------
The depth of chronic wasting disease means culling is no longer an
option, experts say. A new study shows one out of 3 mule deer in
south Boulder suffers from chronic wasting disease -- and those
results mean the traditional approach of killing infected animals to
fight the disease probably won't work, researchers say. "Everything
that's been tried to control chronic wasting disease really fails in
the face of that kind of infection rate," said Heather Swanson, a
wildlife ecologist for Boulder's Open Space and Mountain Parks Department.

In a memo to city leaders, Boulder's open space officials said they
no longer favor killing to deal with chronic wasting disease. The
Boulder City Council, which can also set land-management policies for
the city's open space properties, hasn't yet weighed in on the matter.

Researchers from the Colorado Division of Wildlife and the city
teamed up starting in 2005 to study the mule deer population - the
1st study of its kind to take place in Boulder, Swanson said. The
study focused on deer in an area bordered by Baseline Road on the
north, Eldorado Springs Drive on the south, Broadway on the east and
the Flatirons on the west. During the study, ecologists tranquilized
115 mule deer, affixed them with radio collars and tested them for
chronic wasting disease, an affliction similar to "mad cow disease,"
in which misfolded proteins riddle an animal's brain with holes,
eventually killing it. They found that overall, 29 percent of the
deer tested had the disease. Those animals on average died much
sooner than non-infected deer, and they often fell prey to mountain
lions. Swanson said many of the infected deer preyed upon by cougars
didn't show symptoms that were obvious to human researchers.

"The mountain lions seem to be much better at detecting it," she
said. 41 percent of male mule deer were infected, compared with 20
percent of females, because males cover more territory, which puts
them at higher risk of being exposed to the disease, Swanson said.

Scientists still don't know exactly how chronic wasting disease is
transmitted, although researchers suspect it's passed on from the
urine, feces or saliva of infected animals. Swanson said some
research suggests that the prions may stick to clay soils as well.
For the past several years, land managers have consistently said the
best way to curb the spread of chronic wasting disease is to find
infected animals and kill them. But killing one-third of any deer
population isn't a realistic approach, Swanson said, and could do
more harm than good. Diseased animals can still reproduce, thereby
contributing to the health of the population, she said -- something
they wouldn't be able to do if they were killed as soon as they were
shown to be infected. "With a population that's in a precipitous
decline, removing that large of a number of animals probably isn't a
good idea," she said. "They may still be contributing to the
population" before dying of the disease.

In the memo to the Boulder City Council, open space scientists said
the disease has resulted in fewer deer in and around Boulder. "The
occurrence of chronic wasting disease in this population over the
last 2 decades ... has coincided with a measurable decline in
estimated deer abundance in this area since the late 1980s,"
according to the memo.

Swanson said scientists are hoping ever-increasing numbers of deer
don't get infected, and she said some models of the disease predict
the infection rate should level off soon. That's because chronic
wasting disease is thought to require a certain level of deer density
to spread quickly -- once sufficient numbers of deer die, that
density is depleted and the rate of infection slows. That's the hope,
anyway. Swanson said there's really only one way to know for sure.
"At this point, we're just recommending that we watch the population
and see what happens," she said.

[Byline: Ryan Morgan]

--
Communicated by
Terry Singletary

[A map of the state of Colorado is available at:

- CopyEd.EJP]

[see also:
Chronic wasting disease, cervids - USA (03)(CO): live test 20080411.1333
2006
-----
Chronic wasting disease, cervids - USA (CO): moose 20061110.3229
2005
-----
Chronic wasting disease, moose - USA (CO) 20050930.2865
2004
-----
Chronic wasting disease, cervids - USA (CO, WY) (02) 20040124.0279
Chronic wasting disease, cervids - USA (CO, WY) 20040121.0240
2002
-----
Chronic wasting disease, cervids - USA (CO) (07) 20021012.5536
Chronic wasting disease, cervids - USA (CO) (06) 20021003.5452
Chronic wasting disease - USA (Colo, Neb, Wis) 20020405.3888
Chronic wasting disease, cervids - USA (Colo.) (04) 20020401.3859
Chronic wasting disease, cervids - USA (Colorado) (03) 20020316.3755
Chronic wasting disease, cervids - USA (Colorado) (02) 20020314.3747
Chronic wasting disease, cervids - USA (Colorado) 20020131.3452
2001
-----
Chronic wasting disease, cervids - USA (Colorado) (04) 20011029.2670
Chronic wasting disease, cervids - USA (Colorado) (03) 20011025.2635
Chronic wasting disease, cervids - USA (Colorado) (02) 20010924.2317
Chronic wasting disease, cervids - USA (Colorado) 20010217.0314
1997
-----
Chronic wasting disease, deer & elk - USA (Colorado) (02) 19971113.2296
Chronic wasting disease, deer & elk - USA (Colorado) 19970601.1122]
.........................................dk/mhj/ejp/dk

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