Now, Mad Deer
Platoni, Kara, Sierra
"Eww, gross!" thought many Americans as they read about the United Kingdom's mad-cow epidemic--all the while contentedly chewing their own hamburgers. The gruesome, incurable disease, which causes dementia and motor-skill loss, has led to 79 human deaths and the preemptive slaughter of hundreds of thousands of cattle. Now a similar condition is making an appearance among game animals in the Rocky Mountain West. Dubbed "mad-deer disease," it may already be responsible for the deaths of three people who are believed to have eaten infected venison.
Both mad-cow and mad-deer disease are transmissible spongiform encephalopathies, in which brain proteins called prions deform, forcing other brain cells to degenerate along with them. Cows get a version called bovine spongiform encephalopathy; sheep get a similar disease called scrapie; and humans contract, very rarely and by an unknown natural process, Creutzfeldt-Jakob disease. Those thought to have been infected through the consumption of tainted beef have what is called "new-variant CJD." The course of the disease is similar in all species, starting with a little wobbliness or memory loss, then progressing to full dementia and death, usually in the space of a few months.
Mad-deer disease, more formally known as chronic wasting disease (CWD), is found mostly in northeast and central Colorado and southeastern Wyoming, where it infects about 5 percent of mule deer on game farms and 1 percent of free-ranging deer. Infected animals have also been found on game farms in Nebraska, Montana, South Dakota, and Oklahoma. Game farms sell meat and the velvet from antlers (marketed as a health supplement or aphrodisiac), or sometimes ship live animals to other states to bulk up their supply of huntable wildlife. Thus one farm with infected animals could potentially spread the disease far and wide. In Larimer County, Colorado, the seeming epicenter of the outbreak, some reports put the infection rate of wild deer as high as 15 percent. By way of comparison, says John Stauber, coauthor of Mad Cow U.S.A., "At the height of mad-cow disease in Britain, only one to two percent of cows on any given farm were showing symptoms of the disease." Given the lack of a vaccine and the growing interstate commerce in farmed deer and elk, he says, "the eventual spread of chronic wasting disease across North America seems inevitable."
Mad-deer disease is apparently passed from doe to fawn, as well as through shared feeding facilities, salt licks, and touching noses. It is not yet clear how--and even whether--the disease can spread to humans. …