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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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