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1. What is Chronic Wasting Disease?
Chronic Wasting Disease (CWD) is a new disease threat to North American deer
and elk populations. CWD is a brain disease related to Bovine Spongiform Encephalopathy,
also known as "Mad Cow Disease." CWD affects elk, mule and white-tailed deer. It has been
diagnosed in free-ranging deer and elk primarily in Northeastern Colorado/Southeastern
Wyoming and adjacent Nebraska, but also has been found in captive elk in Colorado, Kansas,
Montana, Nebraska, Oklahoma, Saskatchewan, and South Dakota.
Researchers are just beginning to understand CWD. The disease appears to be caused by
an abnormal protein called a prion. CWD can be spread by close contact between animals.
Animals exposed to a CWD-contaminated environment also may become infected. Usually, months
to years pass before an infected animal shows signs of the disease. Classic CWD signs in
deer and elk, age18 months or older, include poor body condition, tremors, stumbling,
increased salivation, difficulty swallowing, and excessive thirst or urination. There has
been no way to test a live animal for CWD. Scientists must microscopically examine the
brain from a recently dead animal to detect credible signs of the disease. Researchers in
Colorado are developing a live animal test for deer using tonsil biopsies.
2. How common is CWD?
It is thought to be relatively uncommon, but is likely more common where deer or
elk densities are high. Examinations of wild deer and elk where CWD has been found
indicate about 1% to 5% of the animals are infected. Under captive circumstances, where
animals tend to be in physically closer living conditions, the infection rate is as
high as 15%.
3. Has CWD been found in Vermont?
CWD has not been found in Vermont or any of the Northeastern states
or provinces. The following states and Canadian provinces had found
CWD in their wild deer or elk populations: Colorado, Wyoming, Nebraska,
South Dakota, Utah, New Mexico, Wisconsin, Illinois, and Saskatchewan.
These states and Canadian provinces had found CWD in captive herds of
deer or elk: New York, Colorado, Nebraska, South Dakota, Kansas, Oklahoma, Wisconsin,
Minnesota, Montana, and Alberta.
It has been thought that game farms and elk ranches were responsible for the spread of the disease. However, upon the discovery of CWD in wild white-tails in Wisconsin in 2002, scientists are re-examing biological information to detect other risk factors for spread of the disease.
4. What is the Vermont Fish and Wildlife Department doing to protect the deer herd from CWD?
The Fish and Wildlife Department, in cooperation with the state’s Department of
Agriculture, has issued a moratorium effective May 1, 2002 on the importation into
Vermont of all deer family (deer and elk) animals used for farming, exhibitions, and
shooting purpose. The moratorium will be reviewed every six months and adjusted should
new developments warrant. The Fish and Wildlife Department will begin testing all
white-tailed deer that display the classic symptoms of CWD described above. Also,
a predetermined number of hunter-killed deer will be sampled at various check stations
in November 2002.
5. Is venison safe to eat?
The World Health Organization (WHO) has said there is no scientific evidence CWD
can infect humans. However, WHO also says no part of a deer or elk with evidence of
CWD should be eaten by people or other animals. Over 16 years of monitoring in the
infected area in Colorado has found no disease in people or cattle living there. In
states where CWD is found, hunters are asked to dress the carcass without cutting the
spinal cord, brain, eyes, lymph nodes, and tonsils.
Until a reliable conclusion can be drawn, the safest approach would be to not eat
deer or elk meat from regions of the country where CWD is known to occur.
6. Can people get CWD?
According to public health (Centers for Disease Control, World Health Organization)
and animal health officials, data available to date indicate that chronic wasting disease
is not currently known to be naturally transmitted to humans, or to animals other than
deer and elk. Data from recent molecular studies provide quantitative evidence of the
apparent difficulty of cross-species transmission. As a general precaution, however,
public health officials recommend that people avoid contact with deer, elk, or any other
wild animal that appears sick. Although there’s no evidence that chronic wasting disease
can be naturally transmitted to domestic livestock, chronic wasting disease is similar
in some respects to two livestock diseases: scrapie, which affects domestic sheep and
goats worldwide and has been recognized for over 200 years, and bovine spongiform
encephalopathy (BSE), which is a more recent disease of cattle in the United Kingdom
and Europe. Despite some similarities, there is no evidence suggesting either scrapie
or BSE are caused by contact with wild deer or elk, or that wild deer or elk can contract
either scrapie or BSE in countries where these diseases occur.
7. How do you test for CWD?
To test for CWD a small piece of brain tissue is examined under a microscope for
the presence of the causative prions. A list of Laboratories that can test for CWD may
be found in the Library section of the Vermont Fish and Wildlife Webpage..
8. Will the Vermont Fish and Wildlife Department pay to test my deer?
No. You will have to cover that cost yourself. However, the department will be
testing a predetermined number of hunter-killed deer to estimate the probability of
CWD occurring in Vermont.
9. How can CWD be prevented?
There is no know vaccine nor is there a cure for infected animals. Researchers
believe that CWD is transmitted by direct contact between animals. Preventing direct
contact can be accomplished in several ways. First, prevent animals of an unknown
health background from entering the state. Second, eliminate artificial feeding sites
and other circumstances that lead to high densities of deer (e.g. uncontrolled
population growth).
10. Where can I learn more about Chronic Wasting Disease?
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