| Emerging
Wildlife Diseases, An Update
Briggs Hall DVM
Chronic
Wasting Disease
With nearly 2000 deer and elk brain stems having been sampled
from around the state, the Washington Department of Fish and
Wildlife continues to believe our state is free of Chronic
Wasting Disease (CWD). Since first recognized as a clinical
Awasting" condition in 1967 in mule deer in a wildlife
research facility in Colorado, CWD has become a major threat
to free ranging wildlife. As of March 1, 2003 CWD has been
detected in free-ranging cervids in Colorado, Illinois, Nebraska,
New Mexico, South Dakota, Utah, Wisconsin, and Wyoming. Prior
to movement restrictions initiated by various state agricultural
departments and the United States Department of Agriculture,
the movement of farmed cervids facilitated the spread of CWD.
While
controversial at the time, the Washington Department of Fish
and Wildlife took aggressive action in the early nineties
to closely regulate the movement of farmed cervids. This action
may well have prevented CWD from entering the state at a time
when the disease was poorly understood.
In 1996, before most hunters had heard of CWD, the department
began conducting "targeted surveillance" for the
disease. "Targeted surveillance" consists of testing
those animals showing clinical signs which could be considered
consistent with CWD. The past two years the pace of testing
has increased dramatically. Using brain stems collected at
hunter check stations and meat processing facilities, approximately
900 deer and elk have been sampled per year. Dependent upon
funding, it is our intent to continue the testing activity
until 5000 animals have been evaluated.
To date,
the cost of collecting, processing, and testing samples has
been born by the Washington Department of Fish and Wildlife.
In April 2003 the U.S. Department of Agriculture announced
that it was making funding available to assist wildlife agencies
in addressing CWD concerns. The costs of conducting past CWD
survey work would have been nearly prohibitive were it not
for the volunteer assistance which has been provided by various
hunter and outdoor organizations.
At this
time WDFW Director Jeff Koenings has completely closed the
door on the movement of live cervids into Washington State.
The one remaining avenue by which CWD could cross our state
border is via carcasses brought into the state by Washington
hunters harvesting animals in states in which CWD occurs.
We strongly urge that Washington hunters, who harvest deer
or elk in states where CWD occurs, have the meat cut and wrapped
prior to bringing it into Washington. Since the infective
agent causing CWD occurs in greatest concentrations in the
brain and nerve tissues, these tissues should not be brought
into Washington, and skullcaps should be cleansed with Clorox
solution before traveling back to Washington.
West
Nile Virus
State agencies, including the Washington Department of Fish
and Wildlife (WDFW), are working together to minimize public
health risks from the disease. The mosquito-borne West Nile
virus was first found in North America in 1999 and has since
spread to most U.S. states. In rare cases it can cause a form
of encephalitis in humans and be fatal. There were 4,156 U.S.
instances of the virus in humans, and 284 people died in the
United States in 2002, according to the Centers for Disease
Control and Prevention.
To date
(April 2003), there have been no cases of humans acquiring
the disease in Washington state. The
Washington Department of Health offers more information
on WNV human health issues on its website and on its toll-free
telephone line: 1-866-78VIRUS (1-866-788-4787).
Horses
also can be affected by the virus. Horse owners can visit
the state Department
of Agriculture’s website for information
West Nile
Virus was confirmed to be present on both sides of Washington
State by the end of last summer. Based on the information
regarding the rapid spread of this infection in other states,
we expect to see West Nile infections manifest in many parts
of Washington as the summer of 2003 progresses. The lead agency
for dealing with the West Nile virus problem in Washington
State is the Department of Health
The presence
of dead birds in an area may be an indicator that WNV is present.
Public health workers in Washington conduct dead bird surveillance
from late spring to fall, when mosquitoes are most active.
If you find a dead bird, or if you notice more dead birds
in an area than you consider normal, please take the following
actions:
- Report
the information promptly to your local health department.
Birds that have been dead less than 48 hours provide the
best samples for testing.
- Be
prepared to share information about the bird(s) such as
the specific location it was found, including the distance
to the nearest town, road or other landmark. Also provide
your name and phone number.
- It
is best to leave the bird in place on the ground and report
its location. If you choose to collect the specimen, use
a shovel or wear gloves to place it in two plastic bags.
Keep the specimen in an ice chest or refrigerator that is
not used for food or place plastic bags of ice or cool packs
over the bird and cover it with a bucket. Do not handle
wildlife with bare hands.
Birds
serve as the host for West Nile virus, which is spread by
mosquitoes to other birds and animals. According to the Centers
for Disease Control, West Nile virus has been identified in
138 species of birds. Blue jays, crows, and raptors seem to
be especially susceptible. West Nile does not seem to be a
serious threat to pheasant, quail, chukar, waterfowl, or other
hunted game bird species.
There
have been reports of West Nile virus causing infections in
both bighorn sheep and mountain goats in zoo’s and wildlife
parks. Department biologists will be closely monitoring our
big horn sheep and mountain goat populations this summer in
an attempt detect to any unusual mortalities. Hunters and
back packers are asked to report dead big horn sheep and mountain
goats to the Washington Department of Fish and Wildlife. There
have been no reports of West Nile virus related mortalities
in deer or elk.
The best
way to protect yourself is to avoid mosquito bites and reduce
the places mosquito live and breed around your home.
- Stay
indoors at dawn and dusk if possible.
- Wear
long sleeve shirt, long pants and a hat.
- Use
mosquito repellant when necessary. Repellents that contain
DEET are the most effective.
- Empty
any standing water around your home.
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