FT, chronic wasting disease is front page news in the WSJ today. I think this will become epidemic in short order, because the incubation period is 2-3 years, and may be spread like the flu, which is very, very alarming!
An excerpt>
Meanwhile, scientists in Fort Collins and elsewhere are conducting federally funded tests to figure out how the animals are becoming infected. In mad-cow, the disease source was traced to cattle feed containing bone meal from contaminated livestock. But no one knows how CWD moves from animal to animal. One thing is clear: The infectious agents are hard to kill off. The grounds at the 35-acre Foothills facility have been dug up, disinfected and even temporarily closed. Still, when the animals return, they invariably lose weight, salivate copiously, behave oddly, and die.
"We know very, very little. We don't understand the transmission, we don't understand the origin, we don't understand any of this," says Stanley Prusiner, the University of California, San Francisco neurologist who won a Nobel Prize for developing the prion hypothesis.
Chronic wasting disease has been around for at least 35 years, but until the mad-cow outbreak, it was of interest to only a handful of wildlife biologists. Elizabeth Williams was one of them. Just out of veterinary school in 1977, she learned about the trouble researchers had been having since the mid-60s at the animal research pens on the edge of Fort Collins. The deer there were doing poorly in captivity, mysteriously losing weight and dying. Biologists suspected a nutritional problem, or perhaps poisoning, and termed the syndrome "chronic wasting."
Dr. Williams soon found the problem. Peering at thin slices of the animals' brains through a microscope, she recalls seeing "a lot of lesions." The sponge-like patterns of decay she found reminded her of a video she'd seen as a student about the human cannibals of Papua New Guinea. An adventurous scientist named D. Carleton Gajdusek had won a Nobel Prize for showing that the ritual acts of eating human brains were causing a rare condition, called spongiform encephalopathy, that was killing the islanders.
The deer were dying of something similar. Dr. William's classification of CWD as a spongiform disease in 1977 was a career-making finding, although CWD remained an obscure wildlife problem.
Initially, CWD had been spreading slowly, since wildlife in the main infection area of about 20,000 square miles between Fort Collins and Laramie were contained by natural barriers, such as the slopes of the Rocky Mountains. But CWD's jump from deer into local elk gave the disease an unpredictable new way to spread: via man-made transport as part of the trade in elk. In 1996, CWD turned up on a commercial elk farm on Saskatchewan, Canada. Three years later, elk-breeding operations in four U.S. states had found sick animals as well.
At the time, commercial elk farming was booming among small ranchers looking for new income. Elk require little food or space to thrive, and ranchers can make money from their meat and antlers, which are sawed off in the spring, then ground and sold as nutritional supplements. So-called velvet antler is exported to Asia where it is considered an aphrodisiac, and is also sold in U.S. chains such as General Nutrition Centers, where it retails for about $17 an ounce.
Since 2000, only 259 farmed elk have died or been diagnosed with CWD, according to the North American Elk Breeders Association. This is just a small percentage of the 160,000 elk it estimates are in captivity on 2,300 U.S. and Canadian elk ranches. But the disease has an incubation period of two to three years. Since 1998, elk farmers have destroyed 4,432 elk known to be exposed to the sickness.
Some researchers speculate that the elk trade brought the disease to wild deer in Wisconsin. Discovery of those infected animals sharply escalated CWD concerns nationwide, because the new region of infection is so far from where the disease was first identified. But the truth is, nobody knows.
Scientists in Colorado and Wyoming are now urgently trying to determine just how CWD is spread, partly funded by a $2.2 million grant from the National Science Foundation. At Sybille Canyon, researchers have infected three young deer with CWD by feeding them the brains of deer that died of the disease. Blood, saliva, feces and urine collected from the animals every six months will be injected into the brains of laboratory mice to see if they cause infection.
A separate set of experiments will confirm whether prions can lurk in the environment, as the team suspects. At the Fort Collins pens, Michael Miller, a Colorado Division of Wildlife biologist, has overseen the construction of isolation rooms to test different theories. In one room, two fawns are living alongside the decomposed carcass of a CWD deer. Others are being reared in rooms that previously housed animals with CWD.
The unknowns worry some consumer advocates. "I think that we have to assume the worst of CWD -- that it could be even more dangerous and costly than mad cow because of its unique ability to spread through the environment and animal to animal," says John Stauber, the author of "Mad Cow U.S.A.," a book arguing the U.S. hasn't done enough to keep bovine spongiform encephalopathy, as the disease is known formally, out of the country. "With BSE there was a feeding loop that could be shut down. Here, it seems to spread like a cold or the flu."
Some laboratory studies suggest CWD could theoretically infect people. Byron Caughey, a prion researcher at the National Institutes of Health's Rocky Mountain Laboratory in Hamilton, Mont., found that CWD prions could convert human prion proteins to their deadly form in a lab dish. However, the efficiency of such "conversion" was extremely low, evidence of a substantial species barrier.
So far, few steps have been taken to reduce people's exposure to CWD prions. In Colorado, where hunting and wildlife sightseeing generate nearly as much economic activity as skiing, there are no special regulations governing how deer carcasses are handled. Hunters in Fort Collins have been asked to sever the head of any deer they bag and deposit it in a steel drum outside the Division of Wildlife's offices across from the Holiday Inn. A couple of weeks later, a state lab reports whether the kill was infected.
This could run into the $10's of $billions of lost dollars, hunting $$, research $$, and if a link to human infection can be proved, turn out the lights..
Add in the possibility of a spread to domestic cattle, and you can easily go into $100 billion. The US economy could not handle something this big. |
