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By Patrick O'Driscoll USA TODAY
DENVER
-- Although mad cow disease has yet to show up in America,
a similar disorder exists in some herds of wild and captive
deer and elk here in the West.
Chronic
wasting disease (CWD) does not appear to transfer to cattle
or to humans -- at least, not easily. So far, researchers
have been able to infect cattle only by injecting the brains
of test animals with the protein molecules, or prions, that
trigger the affliction.
CWD,
first noted in the late '60s, attacks the brain and is always
fatal, just like its infamous cattle-killing cousin, bovine
spongiform encephalopathy, better known as mad cow disease.
CWD-infected
wildlife, mostly mule deer, have been found in pockets of
northeastern Colorado, southeastern Wyoming and western
Nebraska. The disease also has struck some elk on game farms
in South Dakota, Nebraska, Montana, Colorado, Oklahoma and
the Canadian province of Saskatchewan.
This
month, Colorado wildlife officials said that testing of
deer shot by hunters around the state confirms that the
disorder hasn't spread. But Tom Thorne, wildlife veterinarian
for the Wyoming Game and Fish Department, says, ''There
is every reason to expect that, over time, (the range) will
expand.''
Colorado
is trying to reduce CWD's occurrence in its most disease-infested
game management area by holding a special deer hunt from
December through February this season and again in 2002
and 2003.
As many
as 15% of deer killed in that zone north of Fort Collins
in previous seasons tested positive for chronic wasting.
Biologists think that reducing the density of the wild herd
may slow the disease's spread.
Thorne
bristles at popular media descriptions of CWD as ''mad deer''
disease. Given the behavior of animals afflicted with it,
''they ought to call it 'sleepy deer' or 'slobbery deer,'
'' he says. CWD causes animals to lose weight and conditioning,
eventually leading to death.
Nor
is Thorne alarmed about an epidemic, saying it is highly
unlikely the malady can spread to humans, whether by eating
venison or through other contact. He says a recent study
at the National Institutes of Health's Rocky Mountain Laboratory
in Montana came to the same conclusion.
But
given how little is yet known about CWD, state wildlife
agencies are cautioning hunters to wear rubber gloves when
field-dressing deer carcasses and to avoid handling brain
or spinal tissues, which are thought to harbor the disease
pathogens.
''Now,
you can never say 'never,' but I have probably been exposed
to this disease over a longer period of time than almost
anybody,'' says Thorne, who has studied chronic wasting
for more than three decades. ''I guess if there's an ongoing
experiment, it's me.'' In fact, he jokes, ''I'm certain
that if I die of (CWD), I will be written up extensively.''
His
wife, Elizabeth Williams, is a leading CWD researcher at
the state lab at the University of Wyoming. She has autopsied
and handled ''more material than anybody,'' Thorne says.
In addition, he and his wife regularly hunt and consume
venison at their hunting cabin in the Laramie Peak area,
where Wyoming's largest concentration of infected deer is
found.
''We're
the experiment, and we're not worried,'' Thorne says. ''Now,
I wouldn't inject it into my brain, but beyond that, we're
really not concerned.''
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