Chronic Wasting Disease
Department of Natural Resources
November 2006
Report Highlights
Chronic wasting disease (CWD) is a fatal neurological disease that affects
members of the deer family, including white-tailed deer and elk. It was
first identified among free-ranging deer within the state in February 2002.
In the past five fiscal years, four state agencies have spent $32.3 million to
address the disease and monitor its spread, both in the wild and among
farm-raised deer.
The Department of Natural Resources (DNR), which accounted for
82.9 percent of all expenditures, has attempted to eradicate CWD by
reducing the number of free-ranging deer in areas where it has been
identified. The Department of Agriculture, Trade and Consumer
Protection (DATCP), which regulates deer farms, has established
herd-monitoring programs and issues quarantines. The Wisconsin
Veterinary Diagnostic Laboratory, which is operated by the University
of Wisconsin-Madison, tests deer tissue for infection and disposes of
infected carcasses. The Department of Health and Family Services (DHFS)
monitors potential human health effects .
Legislators and hunters have raised concerns about the cost and
effectiveness of efforts to eradicate CWD. At the request of the Joint
Legislative Audit Committee, we therefore analyzed:
trends in program expenditures and staffing levels;
the effectiveness of DNR’s current approach to CWD;
DATCP’s management of the disease in farm-raised deer;
the role of the Diagnostic Laboratory in conducting CWD tests and
disposing of deer carcasses; and
activities undertaken by DHFS to address potential human
health concerns.
CWD Expenditures
DNR is the lead agency for
coordinating Wisconsin’s efforts
to address CWD and for managing
the disease in the free-ranging deer
herd. From fiscal year (FY) 2001-02
through FY 2005-06, DNR spent
$26.8 million on CWD.
Nearly two-thirds of the $32.3 million
that all state agencies spent to
address CWD, or $20.1 million,
has been provided from the Fish
and Wildlife Account of the
Conservation Fund. That account
is funded primarily through fees
paid by hunters and anglers.
In FY 2005-06, DNR, DATCP, the
Diagnostic Laboratory, and DHFS
employed 58.8 full-time equivalent
(FTE) staff to address CWD. Most
were wildlife biologists and
technicians employed by DNR.
Disease Management in
Free-Ranging Deer
Through June 2006, 651 free-ranging
deer have tested positive for CWD
in Wisconsin. All were from the
southern part of the state, and 590
were from Dane and Iowa counties.
DNR has adopted two main
strategies to limit the spread of
CWD in free-ranging deer:
surveillance to determine the
disease’s prevalence, and reducing
the deer population in areas it has
defined as CWD zones.
To reduce the number of deer and
limit the spread of CWD, DNR has:
increased the length of deer
hunting seasons;
required hunters to shoot a doe
before shooting a buck;
established and enforced a ban
on baiting and feeding deer in
26 counties; and
created incentives for hunters
that include monetary rewards,
low-cost permits, and a program
to donate venison to food
pantries.
DNR also relies on sharpshooters
who are DNR employees. Sharpshooting
efforts by DNR staff
accounted for 5.2 percent of
deer killed in the 2004 and 2005
hunting seasons.
Available data indicate that to date,
DNR’s efforts to eradicate CWD
have not been effective:
in CWD zones, the number of
deer killed has declined from
23.1 per square mile during the
2003 hunting season to 17.4 per
square mile during the 2005
hunting season;
the CWD infection rate in the
210-square-mile “core area”
DNR uses to monitor infection
rates has not declined; and
the estimated number of deer in
CWD zones has increased from
a post-hunt population of
26.4 deer per square mile in 2002
to 38.3 deer per square mile in
2005.
Disease Management in
Farm-Raised Deer
DATCP regulates farm-raised deer,
which include both native deer
and exotic species such as sika and
reindeer. Anyone who wishes to sell
live deer within Wisconsin must
enroll in DATCP’s herd monitoring
program.
The monitoring program supplements
mandatory CWD testing
for all farm-raised deer that are
16 months of age or older at the
time of death. It requires annual
reporting on the health of deer from
enrolled herds. Farm owners may
not import deer from outside of
Wisconsin unless they are from
herds that have been monitored in
their state or country of origin.
DATCP quarantines the herd of any
farm on which a deer tests positive
for CWD. It is also authorized to
quarantine farms from which a
CWD-positive deer originated and
those whose herds may have been
exposed to CWD.
Through June 2006, DATCP issued
CWD-related quarantines for
43 deer farms. A total of 95 animals
tested positive for CWD on 7 of
these farms.
CWD Testing and Disposal
We found increases in both the
number of CWD tests performed
by the Diagnostic Laboratory
during the nine-day regular gun
hunting season and the time
required to report test results.
On average, test results were not
available until 51.8 days from the
time a deer was killed in November
2005. In 2003, results were available
in 26.6 days.
Hunters who submit deer for
CWD testing typically want test
results before they eat their deer.
To assist during the peak workload
period from late November through
mid-January, DNR plans to provide
2.0 FTE staff to assist the Diagnostic
Laboratory with CWD testing.
The Diagnostic Laboratory also
operates a chemical tissue digester
to dispose of CWD-positive carcasses
and other deer testing remains.
The tissue digester destroys prions,
which are believed to be the cause
of CWD.
In FY 2005-06, the tissue digester
disposed of 370,768 pounds of deer
tissue, of which 93.9 percent was
from DNR’s surveillance program.
The remainder was from testing
farm-raised deer.
Potential Human Health Risks
DHFS assesses potential human
health risks of CWD by monitoring
cases of related human diseases,
establishing a registry of people
known to have consumed venison
from CWD-infected deer, and
informing the public of potential
risks associated with CWD.
To date, there is no evidence to
suggest that eating CWD-infected
venison can lead to human disease.
However, because a similar disease
in cows has been linked to human
illness, DHFS, the World Health
Organization, and the federal
Centers for Disease Control and
Prevention advise people not to
consume any venison from CWDinfected
deer as a precautionary
measure.
Future Considerations
Compared to other states in which
CWD has been identified, Wisconsin
has taken an aggressive approach
to addressing the disease. That
approach has also been more costly,
but it has not been effective to date.
We therefore highlight three alternative
approaches for consideration by
DNR and the Legislature: making
no changes; increasing efforts, which
would likely increase program costs;
or reducing or eliminating some
CWD-related activities.
Recommendations
Our report includes a recommendation
for the Diagnostic Laboratory
and DNR to:
report to the Joint Legislative Audit Committee by April 15, 2007, on the time required to notify hunters of CWD test results for the 2006 hunting season
(p. 73);
We also recommend that DNR, in
consultation with DATCP, DHFS,
and the Diagnostic Laboratory:
report to the Joint Legislative Audit Committee by April 15, 2007, on:
how recent changes in hunting rules in the CWD zones affected the number of deer taken from these zones during the 2006 hunting season;
the number of CWD-positive deer killed as a result of DNR sharpshooting and trapping efforts during the 2006 hunting season;
whether testing performed on deer from the 2006 hunting season indicates any changes in the spread of CWD;
plans to improve communication with hunters; and
strategies that will be employed to reduce CWD-related costs
(p. 90);