by Brian McCombie
from: [email protected]
Suspicion that a fatal, incurable illness can spread
from infected deer to humans is increasing. Here, a special report on
chronic wasting disease and how one hunter may have lost his life from
it.
Jay Dee Whitlock was a husband and father, a sportsman
from Oklahoma with a passion for deer hunting. But in January 1999, his
wife, Julie, noticed he was forgetting phone numbers and seemed confused
while driving. When Julie voiced her concerns, Jay Dee said it was
nothing, and Julie told herself she was overreacting. Everyone forgets
something, right?
But a few weeks later, two of Jay Dee's coworkers called
on her. "They said he was more and more withdrawn at work," Julie
Whitlock remembers, "that he wouldn't eat lunch with people." A truck
driver for six years, Jay Dee was also having problems delivering his
loads. Before, "You'd give him an address and directions, and he'd find
it 400 miles away," Whitlock says. But now, said his coworkers, Jay Dee
couldn't locate places he'd delivered to in the past. "It just made me
sick when they told me that," Whitlock says.
Over the next 15 terrible months, in and out of various
hospitals and, at the last, a nursing home, Julie watched helplessly as
Jay Dee deteriorated physically, mentally, and emotionally from
Creutzfeldt-Jakob (pronounced CROYTS-felt YAH-kob) disease, or CJD. It
is untreatable, incurable, and always fatal. While Whitlock says doctors
have no idea how her husband contracted this dreadful disease, no one
can rule out the venison Jay Dee regularly ate.
"I'll never touch another deer," says Whitlock, "or eat
deer meat ever again."
Mad Cows and Englishmen
CJD is a form of transmissible spongiform encephalopathy (TSE).
According to research, TSE appears to alter proteins in the brain called
prions (PREE-ons). The transformation leads to a series of microscopic
holes in and around brain cells. Prior to this damage, behavioral
changes become apparent, as with Jay Dee.
A second form of TSE is mad cow disease, which affects
cattle. It is so named because the animals become agitated, shake with
tremors, and kick violently when touched.
In Great Britain, a rash of human deaths from CJD
occurred in the early 1990s. Some suspected that cattle feed containing
protein and bone meal processed from diseased or injured cattle was to
blame; the practice had been halted in 1988, but by then mad cow disease
was apparently distributed throughout Great Britain. Initially, the
British government insisted there was no connection between cattle with
mad cow disease and humans with CJD. But after much research and
political wrangling, officials announced it was indeed possible to
contract CJD by eating infected beef. A spokesperson for a British
government advisory committee recently confirmed a total of 76 cases of
CJD in Great Britain attributable to mad cow disease.
A third version of TSE is chronic wasting disease (CWD),
which is currently afflicting Western deer and elk. So, the obvious
question for hunters is, Can humans contract CJD from eating CWD-infected
venison?
The answer: It's possible. Research has shown that CWD-infected
materials can transfer to human matter in test tubes. "CWD may not
transmit that easily," says Dr. Thomas Pringle, a molecular biologist
who tracks CWD-type diseases for the Sperling Biomedical Foundation in
Eugene, Oregon, "but the rate isn't zero." Pringle points out that it
was tests like this that helped convince the British that CJD could
result from people eating infected cattle.
When the Deer Began Dying
The Foothills Wildlife Research Facility in Fort Collins, Colorado, is
believed by many to be where CWD first appeared and then spread into the
wild. It's also a good example of how tough CWD is to eradicate.
According to Michael Miller of Colorado's Division of Wildlife, mule
deer at Foothills began dying in 1967 of a strange disease. In 1980, CWD
was determined as the cause.
Attempts to rid the facility of the disease by culling
out sick deer failed, so all animals were killed in 1985. Then,
everything the animals had contacted (water troughs, feed bins, etc.)
was cleaned with a powerful disinfectant. The ground was sprayed with
the same disinfectant, plowed to a depth of about a foot, and resprayed.
Paddocks went unused for up to a year, and double fencing was installed
to eliminate any nose-to-nose contact with possibly infected wildlife.
Eventually, new deer and elk were introduced, but within the year they
began contracting CWD.
No one is completely sure how it spreads. Blood
transmission seems likely, as from doe to fawn. But CWD has transferred
between adult animals at game farms, leading Miller and other wildlife
professionals to believe simple contact can pass it. This could include
nose-to-nose touching, shared saliva (as at a feed trough), or brushing
against urine or feces from an infected animal.
In 1981, CWD was discovered in a wild elk in southwest
Larimer County, Colorado. Today 15 percent of mule deer in this area
test positive. "Overall, the endemic area has a 3.5 to 4 percent rate of
infection," says Miller, though pockets exist where CWD is twice as
prevalent. Wyoming's southeastern corner sees similar rates for mule
deer, and in both states elk contract CWD at about 1 percent. Deer or
elk with CWD may slobber uncontrollably, appear listless, and will lose
a great deal of weight before
eventually dying.
Miller says CWD "probably should be considered an
epidemic," given that it has spread through some 14,600 square miles of
north-central and northeastern Colorado, plus parts of Wyoming, in two
decades. The fact that mule deer and elk in both states are relatively
dispersed seems to have slowed transmission. But he also notes that CWD
has been found in whitetail deer along the Platte River. Whitetail
densities are quite high there, and Miller warns, "As it moves east, CWD
could pick up momentum."
There are no tests to detect CWD in living animals. The
disease can only be confirmed by examination of a dead animal. Pringle
argues that this makes the interstate transportation of animals onto
game farms a big problem.
The Game Farm Connection
CWD has been documented at deer or elk farms in Colorado, Montana,
Nebraska, Oklahoma, South Dakota, Alberta, and Saskatchewan. Between
1997 and 1998, South Dakota officials discovered animals at three game
farms with CWD and acted quickly to halt other infected animals from
entering. State veterinarian Dr. Sam Holland says a risk assessment is
now done before a game farm can import an animal. "If the [originating]
state is not actively doing CWD surveillance for captive animals -- and
that means CWD testing for all deaths of animals over 18 months of age
-- then we won't let their animals in," he says.
To test for CWD, South Dakota requires a brain necropsy
for all dead animals. Game farm herds must also be monitored and
inventoried; Nebraska and Montana have similar requirements.
But regulations vary by state. Wisconsin game farms, for
instance, can import any animal as long as it possesses an interstate
health certificate, according to state veterinarian Clarence Siroky.
It's a good preventive to keep out a detectable disease like bovine
tuberculosis but does little for an untestable one like CWD. Since 1992,
at least 370 elk have been imported there from farms having direct or
indirect contact with the disease, and two animals came from herds later
found to have CWD. These imported elk caused Wisconsin's Department of
Natural Resources to test the brains of 250 wild deer last year, and all
came back negative.
Other states apparently think there's a risk, too. As of
1999, 14 had either tested or were actively testing free-ranging deer,
antelope, and/or elk for CWD. Alberta and Saskatchewan are also looking
for it. Game farms are prime test sites.
Though they're fenced, game farms provide many
opportunities for contact between captive and wild animals. Nose-to-nose
touching occurs at fence lines, and fences are breached by storms and
accidents. Gates are left open. Even when captive animals don't escape,
such openings allow wild deer to come in, mix, and leave. After CWD was
detected at a South Dakota game farm in 1998, for example, one of the 30
free-ranging whitetails harvested outside the fence tested positive.
Steve Wolcott, past president of the North American Elk
Breeders Association, thinks this focus on game farms ignores a key
avenue for spreading CWD around the country. "People who hunt in the
Colorado and Wyoming endemic areas are free to take those carcasses
anywhere in the country,"
he points out. Once home, hunters with an elk or muley carrying a nice
rack are going to saw it off themselves or have it professionally
mounted. Either way, the brain and spinal cord -- the most infected
parts of a CWD animal -- will end up in a landfill or pitched into the
woods, he says, perhaps introducing CWD-infected materials.
What's Next?
Two officials from the Centers for Disease Control (CDC) visited Julie
Whitlock while Jay Dee was struggling to stay alive. They asked her
hundreds of questions about Jay Dee: his diet, his work, his habits. But
one of their questions sticks in her mind. "They wanted to know where he
hunted." She told them: the area around Miami, Welch, and Wyandotte in
the very northeastern corner of Oklahoma. She also offered them the two
deer in her freezer, animals Jay Dee harvested in 1998, thinking the CDC
might be able to test the meat. "They said maybe they'd be interested,"
Whitlock remembers. "But they never got back to me."
That lack of interest bothered her, especially when she
discovered that two other deer hunters had recently died from CJD: Jim
Koepke, 39, of Nevada in February 1999; and Doug McEwen, 30, of Utah in
March of the same year. In a January 1999 article in USA Today, Whitlock
read that Lawrence
Schonberger of the CDC said only five cases of CJD per billion people
are reported annually worldwide for people aged 30 and under. Given this
rarity, she couldn't help but wonder how three young deer hunters would
contract CJD so closely together in time.
Currently, the Colorado Division of Wildlife recommends
that hunters wear rubber gloves while cleaning and butchering deer and
elk, and that brains, spinal cords, and lymph nodes be handled as little
as possible. If a hunter's harvest tests CWD positive, the Colorado
Department of Public Health advises hunters to not consume the meat, as
does the World Health Organization.
In May 2000, Dr. Byron Caughey of the National
Institutes of Health announced that he had converted human prion
materials using CWD prion matter at rates roughly equal to the transfer
between cattle and humans. Commenting on Caughey's research, Dr.
Elizabeth Williams, of the University of Wyoming's veterinary science
department and a member of the state's CWD task force, says, "We were
very pleased with his work. It showed a substantial barrier" to CWD
transmission between animals and
people.
Pringle has reviewed the test data and agrees
transmission rates are very low. Yet low is not absolute. Caughey's work
provides "concrete evidence that there is a definite risk here," Pringle
contends. However, Pringle also admits there are significant chemical
differences between materials transferring in a test tube and a person
eating meat.
Jay Dee Whitlock died on April 7, 2000, six months shy
of his 31st birthday. "I guess I thank God Jay Dee never knew he was
dying," says Julie.
Go on to Horse
Slaughter
Return to 3 May 2001 Issue
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