As anybody who has followed the Oprah Winfrey beef libel trial knows, mad-cow disease has never been found in American cattle. Deer and elk, though, are another matter. Chronic wasting disease, a cousin to the mad-cow plague that decimated British cattle herds, has been identified in deer and elk in three Western states.
Infected animals waste away, becoming
emaciated and listless. "A (sick deer) might have its head down,
its ears flattened, instead of up and alert," says Beth Williams, a
veterinary pathologist at the University of Wyoming Department of
Veterinary Sciences in Laramie. "It would have a spacy look in its
eyes. It would be able to see you, but wouldn't care very much."
Once symptoms emerge, death comes within weeks
as the disease destroys the animal's coordination, leaving it
unable to stand.
"Often the actual cause of death
turns out to be pneumonia," says Williams. "I wouldn't be surprised
if many are finished off by coyotes."
programs carried out over the past four years in Colorado and
Wyoming suggest that the disease infects 5 percent of the deer and
approximately 1 percent of the elk in northeastern Colorado and
Wildlife officials from
both states believe the disease is confined to this relatively
small area. South Dakota has recently identified a dozen cases in
captive elk, further complicating the
While chronic wasting disease is no
newcomer to the Rockies, the rate of infection, particularly for
deer, seems to be excessively high. Five percent is "a staggering
figure," says Clarence Gibbs, head of Transmissible Spongiform
Encephalopathies (TSE) research at the National Institutes for
Health, in Bethesda, Md. "That should be sufficient stimulus for
people to get off their suitcases and try to figure out where it's
Chronic wasting disease (CWD) was
first detected 31 years ago in captive mule deer near Fort Collins.
The disease is one member of a family of rare and mysterious brain
illnesses called TSEs that kill by eating microscopic holes in the
brains of their victims. Mad-cow disease is another form of the
illness, as is Creutzfeldt-Jakob disease in humans, and scrapie,
which has been endemic at low levels in American sheep since the
Research is stepping up. Colorado is
expanding its monitoring program for the next hunting season, while
South Dakota plans to initiate a surveillance program for wild deer
and elk herds. Last October, the U.S. Animal and Plant Health
Inspection Service initiated a modest seven-state program to
determine if the disease is present outside of Colorado, Wyoming
and South Dakota.
Currently, little is known
about how chronic wasting disease is spread among deer and elk, let
alone whether other species can be infected. Experiments are under
way at the Animal Research Service's laboratories in Ames, Iowa, to
test cattle susceptibility to the disease. Results are at least 18
months away, says Randall Cutlip with the Animal Research
There are inevitable concerns about
whether the infection can pass from game to hunters, especially
since mad-cow disease made the jump from beef to
Public health officials don't believe
that humans can contract the disease by eating infected animals,
though they acknowledge the possibility
"Is chronic wasting disease transmissible
(to humans under normal conditions)? The answer is nobody knows,"
says John Pape, an epidemiologist with the Colorado Department of
Health, "The evidence suggests it is not."
Colorado officials are asking hunters handling
deer and elk from affected areas to use precautions, including
wearing gloves when dressing out animals, avoiding the most
infectious tissues, the brain, lymph and spinal tissue, and boning
out the carcass.
Wyoming has yet to issue health
recommendations for deer and elk hunters, but "the risk is so
small, I wouldn't worry about it at all," says Tom Thorne of
Wyoming Game and Fish, who adds that he regularly hunts and eats
deer from southeastern Wyoming.
What does worry
Thorne is a possible spread of the disease to uninfected deer and
elk herds. "If, in the worst-case scenario, this disease spread
from deer to deer ... across the country, it could play a role in
limiting your (deer) population," he says.
spread of the disease among captive animals may represent a more
"This is probably going to
cause quite a bit of problem in the game-farm industry," says
Wyoming's Tom Thorne. Captive herds seem to facilitate the spread
of chronic wasting disease, just as they do other communicable
diseases like tuberculosis. Already, several cases have been linked
to game farms. The captive South Dakota elk that developed the
disease came from a source herd that included animals from the
Colorado-Wyoming infection zone as well as from Canada, according
to Sam Holland, South Dakota's state veterninarian. Additionally,
two recent Canadian casualties, a deer and an elk, both originated
from U.S. game farms.
All of which means that
either chronic wasting disease is already more widespread than
suspected, says Thomas Pringle, a molecular biologist and public
lands advocate, or game farms are allowing it to spread beyond the
Colorado-Wyoming focus area. "That's how scrapie got spread
around," says Pringle, who operates the Mad Cow Disease home page
for the Sperling Foundation. "They brought in (infected) Suffolk
sheep from England (in the 1940s). They were buying and selling
them all over, then pretty soon you have it in 39 states."
Chris Carrel freelances
from Federal Way, Wash.
* Contact the Colorado Division of
Wildlife at 303/297-1192;
* Contact Tom Thorne
at the Wyoming Department of Game and Fish at
* Contact Beth Williams, University
of Wyoming Department of Veterinary Sciences, at
* Find a comprehensive source of
news articles and scientific articles about TSEs on the Mad Cow
Disease home page at http://mad-cow.org.
two recent books, which provide excellent background information on
TSE disease: Deadly Feasts by Richard Rhodes (HarperCollins, 1997),
and Mad Cow, USA: Could the Nightmare Happen Here? by John Stauber
and Sheldon Rampton (Common Courage Press, 1997).