Bad Brains
Death of deer hunters points to frightening new killer
by Brit Griffin HighGrader Magazine March / April 2000

When an elk or deer contracts chronic wasting disease (CWD), it isn't pretty. The animals drool, stagger and relentlessly lose weight. Their brains turn to sponge. They always die. Sound familiar? It should. The last batch of critters to start dropping off in this fashion were British cows and we all know what happened next: tens of thousands of dead heifers, mass slaughtering of infected herds, the devastation of the British beef industry and the emergence of a new variant of the grim brain disease Creutzfeldt-Jakob disease (nvCJD).
CWD is a sister disease of mad cow disease. Both diseases are part of a group of diseases called transmissable spongiform encephalopathy (TSEs). CWD was first noticed in Colorado in the 1960s. While the disease has moved relatively slowly through herds in the wild, it has spread hydra-like across North America via game farms where diseased animals have, in the words of one expert, been "traded like baseball cards."
Even more worrying has been the appearance of Creutzfeldt-Jakob disease (CJD) among some American hunters. Last December, the United States Department of Agriculture (USDA) landed in Maine to sample the brains of some 300 deer heads bagged in the fall hunt. They were looking for a link between infected deer and the death of a 28-year-old woman from Creutzfeldt-Jakob disease (CJD). She was known to have eaten venison.
Other hunters have died as well --- a 60 year old Michigan deer hunter, a 53-year-old female hunter from Kansas. But cases of CJD in older people do not tend to set off epidemiological alarm bell as the disease is known to strike one in a million in the over 50 category. (There are growing concerns, however, that some patients are misdiagnosed with Alzheimers when in fact they are suffering from CJD).
But when young hunters Jay Whitlock and Doug McEwen were diagnosed with CJD, the picture dramatically changed. The chances of the disease hitting in this younger population are more like one in a billion. Add in the case of the young woman from Maine and the spectre of " mad deer" disease was on the table.
As well, it appears that another case may have surfaced,in a 24-year-old hunter from Virginia.
Dr. Michael Hansen is with the Washington-based Consumer's Union. "Four cases in the last couple of years of people 30 or younger, with a disease that hits people in their 60s,this is not good, this is not good at all." Hansen says that although a direct link between CWD and CJD has yet to be established, there is enough indirect evidence to be worried.
At this stage, a number of risk factors have been identified for CJD including: eating venison, animal brains or pork, and contact with cattle or fertilizer.
Ron Cummins of the Organic Consumer's Union agrees that more research is needed and says it could easily be a couple more years before it is known if the hunters have a new variant of CJD.
But he maintains that the extent of the outbreak in deer populations is a worry in itself. In England, cattle had to be fed significant amounts of rendered protein to develop BSE but with CWD the animals seem to be picking it up from ordinary contact, like sharing feed or fighting.
"In some areas of the Rocky Mountains the animals are showing between a 6 - 8% infection rate. At the height of the mad cow epidemic, only 1-2% of the cows in England were infected. So why isn't this 8% cause for alarm?"
Wildlife officials have been quick to downplay worries of a deer epidemic but their actions may be speaking louder than words. Just this past summer, Mike Miller of the Colorado Veterinary Services said it would be politically impossible to curb the spread of the disease by culling deer herds. Colorado is now singing a radically different tune. The state is planning a major cull, looking at 50% of the herd.
Montana wildlife officials, who until recently thought their state was CWD-free, have launched an active surveillance program. They aren't alone. South Dakota, Nevada, Maine, and Michigan have also initiated surveillance programs. In Canada, Saskatchewan and Alberta (which presently allows no out of province or international imports of deer or elk whatsoever) are maintaining their own surveillance programs.
Imports of elk to Canada were banned in 1990, do to fears of spreading tuberculosis. The ban was lifted last year. So far, the vast majority of elk imported into the country are headed for Ontario,which does not have its own surveillance program. It relies on the federal Canadian Food Inspection Agency (CFIA). The CFIA enforces a 60-day quarantine period to screen out the disease, even though critics point out that the incubation period is more like 18 months to two years).Because there is no live test for CWD yet (one is under development) officials must rely on game records to ensure the animals come from clean herds. Record-keeping can be haphazard and the tracking of animals only a recent practice in some states. But the CFIA says that it is working on a comprehensive import protocol with some "sense of urgency".

Somebody at the Montana Department of Livestock needs to be very worried about the spread of this disease into the cattle industry. Elk and deer are closely related to cattle, and CWD has already made a least one shift from mule deer to elk....Who is to say CWD cannot make the shift to cattle."
-Bruce Chesebro, Rocky Mountain Laboratories, September 1999

Crap Shoot
As wildlife officials tackle the spread the disease in deer and elk, health officials are offering the public reassurances. In a carefully worded September 1999 release from the Colorado and Wyoming veterinary services, CWD is described as a disease with no known relationship "to any other spongiform encephalopathy of animals or human."
Translation: calm down because what's killing the deer and elk doesn't have anything to do with mad cow disease or the new variant of Creutzfeldt-Jakob disease appearing in the United Kingdom.
This optimism stems from the belief that CWD will not breach the species barrier. Experiments attempting to transmit the disease from deer into cows have so far failed, and this has led officials to proclaim that elk and deer are "dead-end" hosts.
John Stauber is co-author of Mad Cow USA: Could the Nightmare Happen Here? He maintains the notion of a dead-end host isn't convincing. He points out that back in the late 1980s, British researchers made the dangerous mistake of assuming that British beef was safe because cows were purported to be dead-end hosts.
But already the evidence of CWD's dead-end host seems to be unravelling. The disease has clearly shown its ability to jump from mule deer to elk. Some have also speculated that the disease originated because domesticated deer were sharing pens with scrapie-infected sheep (scrapie is the form the disease takes in sheep).
Says Stauber, "The fact that we have a strain that apparently has already made one jump, doesn't that make it logical that it might be able to jump to another species? I would say the answer is yes, but unfortunately the official attitude and opinions that we are seeing in North America relative to this epidemic of CWD is reminiscent of the way the British handled the emergence of mad cow disease."
In fact, British officials and scientists wavered on the connection between BSE and CJD even until recently. Only a year ago, Stanley Prusnier, Nobel award winning scientist (credited with the theory that TSEs are caused not by conventional bacteria or viruses, but by 'rogue proteins'), was still waffling on the connection between mad cow disease and nvCJD. But at the end of 1999, Prusnier published findings in new research which provided compelling evidence of the link.
Conservative estimates now suggest that at least 14,000 people will be afflicted with the fatal nvCJD.
This kind of dramatic turnaround in opinion is fairly typical in the controversial world of TSEs. The fundamental problem with any official assurances about CWD or any of the sister illnesses related to TSE's is that scientists don't really know what they are up against.
The progress of TSEs is hard to predict because of their highly unpredictable nature. For example, mink have become infected (the disease becoming known as TME) after being fed downer (sick) cows. Experiments succeeded in transmitting the new variant TME back to the cows, as well as to other mink, squirrel monkeys and ferrets. Mice, interestingly, seemed unaffected. The sister illness, BSE, however, affected mice, goats, monkeys and pigs, but not hamsters. Sheep Scrapie took care of that, being easily transferable to hamsters. It goes on and on in a confusing but deadly cycle.
Stauber puts it in perspective. "Once the species barrier has been broken by a particular strain of TSE, where that strain will go, what species it will infect, is a wide-open question. And because this is such an bizarre disease, so invisible and it progresses so slowly, it's not all that reassuring to say we haven't seen it happen yet."
In light of the British experience, many folks believe that it's better to adopt a 'better safe than sorry, approach. John Kober of the Montana Wildlife Federation says the possible spread of CWD to humans is a "huge concern with the Montana hunting public."
"There are mountains of evidence to suggest that it's a big possibility but there is virtually no evidence that suggests that it's not a possibility."

"Without a live test, we have no way of knowing what our rate of infection is. It could be zero, it could be 100%. We're not even sure how long it takes to show up."
- Tom Cline, veterinarian, South Dakota Animal Husbandry Board

One Shot
Right now it appears that deer hunters are in the front line of possible infection. And just as British farmers were assured that common sense would keep everything in check, hunters are being pacified with similar lists of reasonable do's and don'ts - if an animal looks sick don't shoot it, wear gloves, be careful, don't eat the brains.
Yet traditional safeguards have proven woefully inadequate with prion infections. Prions can survive heat, sterilization, rendering and extended time periods without a host. They can survive on cutting tables and in cattle pens or fields despite rigorous efforts.
Morticians are now becoming increasingly skittish about dealing with patients who have died from CJD because of the possibility of contamination of medical instruments. Should hunters be worried that their gear - knives, trucks etc., that could be contaminated by CWD?
"They're having hunters cut off the heads of deer in some states but they aren't telling them why," says Cummins, "In Michigan they're saying 'there is this disease in deer that could spread to cattle.' They aren't saying 'you better wear gloves, you better wear a facial mask, you better be careful not to cut yourself or get any of the blood of that animal into a cut.' I mean, when you are cutting off the head of an animal you are severing the spinal cord, one of the most dangerous parts of the body if that animal is infected."

Box Insert:
Blood Scare
"He (Doug McEwen) contaminated the whole western world's blood supply, the way I see it. The scope of this is breath-taking. You've got a time bomb ticking in millions and million of people."
- Dr. Tom Pringle, TSE expert
Hunter Doug McEwen was a generous blood plasma donor. His death was only recognized as a case of CJD after his wife, who had seen a program on mad cow disease, insisted he be tested. When the tests came back positive an attempt was made to track McEwen's plasma donations.
By then the blood had been shipped out for use in the US and Canada. After a one week quarantine period, Health Canada officials decided there was nothing to worry about. Officials said they were confident that McEwen had succumbed to classical CJD whereas the cases in England were nvCJD. Since McEwen's illness varied from the British illness, they reasoned it was not tied to an outbreak of mad cow, or in this case, mad deer disease.
Canadian hemophiliacs at the time were not impressed with the reasoning behind the lifting of the quarantine. Author John Stauber says they have reason to be concerned.
"There is no reason to expect these new cases should be nvCJD because they are not transmitted from cows. It's like apples and oranges --both are fruits and nvCJD and CWD are both TSEs (Transmissable Spongiform Encephalopathy), but apples and oranges don't look alike and I don't think most scientists would expect that if CWD jumped into people it would resemble nvCJD. "
John Stauber wonders if we have learnt anything from the British experience. He says there are too many unknowns to be certain about anything. " I think perhaps these diseases should be called Dumb Human Diseases. We could end up in the same boat as the British unless we get to the bottom of this and straighten it out."

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Tracking an Elusive Killer
A quick examination of the history of C WD raises serious questions about the role played by the game farm industry in the spread of the disease. CWD was first noticed in 1967 among deer being held at the Colorado Division of Wildlife's research facilities. Over the next decade the strange wasting illness continued to stalk through the herd. During one five year period, 57 of 67 animals died. When some of these animals were traded with a Wyoming research station, the disease moved into Wyoming.
The illness had researchers baffled. They knew the disease had a high level of lateral transmission, that it was hard to shake from contaminated pens, and that it was always fatal. It wasn't until 1978 that Beth Williams, a researcher in Wyoming, discovered that the brains of the affected animals were peppered with tiny holes. Like other spongiform diseases, the brain eventually resembles a sponge.
In 1981, it turned up in the wild in Colorado. Five years later, it was also present in free ranging deer and elk in neighbouring Wyoming. Researchers, however, have been reluctant to admit that the disease may have spread from the research facility.
"Of course it came from the research facility. They had scrapie infected sheep there," says John Kober of the Montana Wildlife Federation, "and somehow the disease crossed the species line, and what did they do? Well, they turned some of those animals lose. There's no actual proof but all of sudden they release these animals that they have diagnosed with the disease and they then start seeing it in the wild. There is an obvious parallel there."
The sheep scrapie theory is one theory. Another one is that the domesticated deer were feed rendered protein at the game facilities, essentially repeating the mad cow experience. Another expert maintains that deer could have contracted CWD by chewing on the bones of scrapie infected sheep that share their range.
Whatever the cause, the disease is slowly spreading. If the American experience is any indication, game farms could well be the infrastructure for the transmission of CWD. John Kober says his organization has always advocated against game farms, but now it's reaching a boiling point.
"Almost every case of CWD that I know of can be traced directly back to the importation of an animal," says John Kober, "We don't have herds that migrate from state to state. In captivity we have animals in unnatural settings, more prone to disease, and then we artificially transport the disease from state to state through direct shipments. It's a double whammy. "
Dr. Val Geist, Professor Emeritus of Environmental Science out on Canada's west coast, is very concerned about the effect game farms may be having on the spread of CWD. "You must remember that in game farms one of the greatest loss of animals is that they jump fences and are gone back into the wild. The escape rate is quite high."
As well, it is not uncommon to have wild animals coming into the pens during rutting season. The high lateral transmission of CWD (some captive herds have been decimated up to 70%) means it's only a matter of time before the disease is carried into wild populations in states other than Colorado and Wyoming.
Says Dr. Geist, "There should be a complete abolition on game farming. Policies that would make game farms successful are completely antithetical to the policies that allowed wildlife populations to recover from their decimation 100 years ago in the first place."

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