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Also on May 16, sharpshooters began shooting deer in Blue Mounds State Park near Mt. Horeb. If the Wisconsin Department of Natural Resources has its way, they will eradicate all the deer in a 247-square-mile zone around Mt. Horeb to try to control the spread of CWD. Is there cause for concern? Well, here's the background (and an acronym alert). CWD is one type of a broad group of neurological diseases called transmissible spongiform encephalopathies (TSE), the most famous of which is bovine spongiform encephalopathy (BSE), or "mad cow" disease. TSEs are always fatal, and the discovery of mad cow disease in Europe, you may recall, led to the killing and cremation of five-million head of livestock. U.K. scientists also believe that some people who ate BSE-infected beef may have contracted a new variant of a rare fatal brain disorder — with symptoms like BSE — called Creutzfeldt-Jakob disease. This is very significant as usually there is a "species barrier" in the transmission of TSEs. This discovery made BSE a public-health issue, as well as an agricultural nightmare. Creutzfeldt-Jakob disease (CJD) is found worldwide at approximately one case per million people per year. The symptoms are similar to Alzheimer's and dementia. CJD is almost always fatal. Its cause is not well understood. It appears to be infectious, but not transmissible like the flu or the plague. Sometimes it appears to be inherited. CJD normally occurs in older people. The name "new-variant Creutzfeld-Jakob disease" arose when it started appearing in younger people, which led to the theory that BSE had jumped the species barrier to become NVCJD. TSEs get their name from the postmortem appearance of the brain, which has large cavities, like a sponge. Most mammalian species, including humans, get species-specific TSE diseases. Examples include: Scrapie (sheep); transmissible mink encephalopathy (mink); bovine spongiform encephalopathy (cows); Creutzfeld-Jacob disease (humans); and kuru (humans). Some species and individuals appear to have immunity to TSEs, including some Suffolk sheep and 12 percent of the Japanese population. TSEs are believed to be caused by a "protein acetous infection particle," or prion. Some scientists consider prions viruses, but others say they are abnormal non-living particles. Unlike a virus, a prion contains no nucleic acid, does not trigger an immune response, and is highly resistant to extreme heat or cold. So, we've seen the link between mad cow disease and Creutzfeld-Jacob disease in humans, and people are starting to worry that this new mad deer disease will also find its way to the human brain. Congress is holding emergency meetings on this right now, and the National Park Service is preparing to spend millions on CWD control. This is just the beginning of the potential economic impact of CWD. Hunters spend $20 billion a year on equipment and trips, and deer hunting is more popular now than ever before. Wisconsin is considered by many to be the deer-hunting capital of North America. If CWD continues to spread, it could effect all deer and elk and related economies in the U.S., Canada, and Mexico, and devastate many rural communities. THE
DEER DETAILS CWD is now known to infect elk, mule deer, whitetail deer, and blacktail deer. It has been found in 14 captive elk herds in Colorado, Montana, Nebraska, Oklahoma, South Dakota, and Saskatchewan. Federal agriculture officials already have spent nearly $15 million to clean up CWD in the Colorado elk industry by eradicating ranched herds. Additional preventive strategies include double-fencing to keep wild deer and elk from physical contact with tame ones, and prohibiting shipment of farmed deer and elk across state boundaries. In 1981 CWD made the jump to a herd of about 62,000 wild deer and elk that live between southeastern Wyoming, northeastern Colorado, and southwestern Nebraska. Between 4 percent and 8 percent of that herd are known to have it, but some biologists believe that 15 percent may in fact be infected. CWD has also been found in wild deer in Saskatchewan and the western slope of Colorado. The discovery of CWD in Wisconsin, over 900 miles east of known cases in Nebraska, raises the question of just how widespread the disease may be in the wild. Frankly, no one knows. Until recently, few were even looking for it. A significant amount of the money being requested for Wisconsin is to set up a program to test deer killed by hunters, who annually harvest 300,000 whitetails in that state. At present, the only conclusive test for CWD is an autopsy of the animal's brain. Blood and urine tests are expected to be available soon. They will enable live testing and offer quicker and cheaper ways to detect CWD in deer killed by hunters. CWD is thought to be spread through contact with bodily fluids and tissues, but according to Dr. Dave Samuel, former chair of wildlife biology at the University of West Virginia, "the method of transmission is unknown." The disease lies dormant for a long time, and may be persistent for two years or more. Prions concentrate in the bones, spinal chord, brain, and spleen. (Deer and elk typically feed on shed antlers and bones to get minerals.) Dr. Valerius Geist of the University of Calgary has suggested organizing teams with specially trained dogs to find dead animals in the woods and/or recover shed antlers as a way to stop or slow the spread of CWD. As for Wisconsin, any hunter knows you cannot eradicate a herd of wild, unfenced deer unless you set off a nuclear bomb. It's hard enough shooting them when the snow is on the ground and foliage is down. Now the cover is thick and just finding them is extremely difficult. Some will hide or escape. Shooting in one area will drive some out into another area. Many hunters say they won't shoot deer they can't eat. If the state has to hire sharpshooters and hunt from helicopters the price tag will go up astronomically. And, to make matters worse, Wisconsin has at least two million wild whitetails, which multiply like rabbits. Even if all the deer around Mt. Horeb are shot, the method for safe disposal of the carcasses is not clear. Landfills have been proposed, but residents worry about contamination of groundwater. Incineration is possible: Prions can be destroyed at1000-degrees Fahrenheit, and 600 degrees probably works if the prion is contained at that temperature until all organic material is burned. If CWD does cross the species barrier to cattle or even humans, it would immediately place the matter in the hands of the FDA, and even the Center for Disease Control, which have authority to implement procedures like those used for infectious diseases like Ebola, according to the l999 TSE Law. Anyone seen the movie Outbreak, or The Andromeda Strain? There is hot debate over what to do right now in Wisconsin. Feeding wild deer and moving captive deer and elk across state lines have been banned. No one is sure how CWD got there. No ranched animals in Wisconsin have contracted CWD. Some are calling for a ban on bird feeders, as deer congregate around the seed that drops to the ground. There are 33 million whitetail deer in the U.S., mostly east of the Rockies. In many areas, like Mt. Horeb, the population densities are very high. According to Dr. Robert Wegner, there are 150 to 180 deer per section around Mt. Horeb. Wildlife biologists in Wyoming say CWD is spreading at a rate of about 50 miles per year. Considering the density of deer in many areas, the potential for an epidemic that could devastate deer and elk is clearly there. The potential for human panic associated with this outbreak seems almost as serious as the disease itself. A
SILVER (ER, COPPER) BULLET? If mutated prions are the cause, couldn't they occur naturally? They could, but McDonnell believes there is a second factor involved in the spread of CWD, whatever its cause: low levels of copper in animal diets. McDonnell says that there are low copper levels in the soils in northeastern Colorado, where CWD got started, and low copper levels in every place where an outbreak has occurred. But regardless of the copper levels in the soil, where the herds are too large, they overbrowse certain species of plants that normally are rich in copper, such as buck bush. This results in a copper-deficient diet, regardless of copper levels in soil. That dietary deficiency makes the deer and elk more susceptible to CWD. Here's how McDonnell describes the lethal cycle: Imagine a prion as a screen-door spring: a long length with a curling structure like DNA. At each end of the prion are hooks that carry copper to various body tissues. The prion then goes to the liver to pick up more copper. When copper is low or manganese is high, manganese gets stuck on these hooks. Manganese has a different shape than copper, causing the screen-door spring to bend with both ends coming together. These "fish-hook-shaped" prions stick to normal prions and knock off copper ions. Manganese replaces the copper and the cycle starts all over. The fish hooks latch onto each other and form chains. These chains with the fish hooks sticking out tear holes in the brain that are the trademark of TSEs. McDonnell cites studies that show that when 300 mg of supplemental copper were fed to farmed-elk herds, which were subsequently slaughtered as part of the USDA control program, CWD was stopped almost completely. When 300 mg were fed from copper sulfate, 5-7 percent of the herd still tested positive for CWD. When no copper was fed, 33-55 percent of the elk tested positive for CWD. What about air-dropping salt blocks laced with copper into areas like southwestern Wisconsin? In theory, it could help, McDonnell says. It would be safer than shooting and wouldn't risk dispersing the deer from the area and spread the disease more rapidly, because deer would be drawn to the salt licks. While not a solution, it could at least slow down the spread of the disease until we can get a better handle on what is going on and how serious the problem is. McDonnell doubts if CWD could cause extinction of a species. CWD might devastate a herd, but it could not cause extinction because some animals have a natural immunity to CWD. In time, the resistant animals would interbreed and the herd would be immune. But the bottom line, he emphasizes, is that there are too many deer. They are overbrowsing the range, which depletes natural vegetation that would normally carry copper to the deer or elk. With all predators gone except man (and his automobiles), the deer population is out of control in many areas. If we don't increase the harvest, other diseases will eventually reduce the population, if starvation doesn't occur first. And if those diseases can skip species, we may find that those nice deer in the front yard that already carry Lyme disease and bovine tuberculosis may be carriers of something much worse for man and beast. Poised on the verge of large-scale eradication of wild deer and elk herds, Dr. Michael McDonnell's copper bullet theory seems worthy of serious consideration. MAD
DEER DIRECTORY
— Mr.
Swan is the “Media Watch” columnist for North American Hunter
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November, 14 free-ranging whitetail deer have been infected with chronic
wasting disease (CWD), a mysterious illness related to mad cow disease
that attacks deer and elk. They have been found in the vicinity of Mt.
Horeb, Wisconsin. On May 16, the Wisconsin legislature voted to spend
$4 million to fight the disease, and Wisconsin Gov. Scott McCallum has
requested an additional $18.5 million in federal money over the next four
years to aid in the effort. (President Bush's budget request for 2003
calls for $7.2 million to combat CWD nationwide.)
