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Chronic Wasting Disease: America's Homegrown Contagion That Lumbers On Four Hooves
April 12, 2020
Chronic Wasting Disease: America's Homegrown Contagion That Lumbers On Four Hooves
Forget, for a moment, Covid-19 and bats. Epidemiologists say we need to take seriously this wildlife version of Mad Cow rapidly spreading across the country. First in a new investigative series
an exhaustive multi-part series on Chronic Wasting Disease. With Covid-19 elevating public awareness about transmittable diseases originating in wildlife and and its relationship to ecological and public health, we are launching this new series CWD in America featuring the most up-to-date information. The spread of CWD has huge implications, scientists say, for not only the Greater Yellowstone Ecosystem but now and in the future for every corner of the continental US. Epizootic diseases are not problems that begin only with bats in some far-flung other corner of the world. CWD is a serious home-grown problem that epidemiologists say is being exacerbated in the US by those in charge of stewarding our wildlife.
By Todd Wilkinson
Considering the Context
Once Obscure, Why CWD is a Zootic Threat for Our Time
In short order, Americans have become educated, in ways we never were before, about the thinking that goes into containment of zoonotic disease—i.e. a disease that originates in animals and can be passed to humans.
Think now of the concepts firmly embedded in public consciousness with a purpose generally understood: Social distancing. Sheltering in place. Orders issued from on high directing humans not to gather in large groups.
Protocols, based on science, were devised by public health officials as a response to the deadly Covid-19 pandemic—the point being that in the face of a spreading communicable contagion the worst possible action is herding large numbers of humans together and concentrating us in single locations.
At first, the appropriate limit set for massing was no more than 1,000 people, then dialed down to 500, then later reduced to 100, 50, and 10. Now the strategy, informed by epidemiology, is that we stay at home, or move about sparingly at no closer than six feet; if we grocery shop or order take out from a restaurant, it is smart to do so wearing a mask.
Young spring breakers, crowding together on beaches, were chastised for demonstrating irresponsible behavior, especially after some later tested positive for novel coronavirus. A similar outcome happened with congregationists who flouted established distancing precautions and went to church. The very same strategies for preventing disease transmission from human to human and animal to human apply for animal to animal, be it pets, livestock or wildlife, experts say.
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Dr. Thomas Roffe for many years worked as the equivalent of Dr. Anthony Fauci in his own field. Fauci is director of the National Institute of Allergy and Infectious Diseases and is currently advising President Trump and The White House on how to deal with novel coronavirus. Roffe spent his career with the US Fish and Wildlife Service, rising to the rank of chief veterinarian for animal health. His post was a prestigious and influential one, hard earned.
The Fish and Wildlife Service touts itself as representing the vanguard of professional wildlife management, being the exemplar for other agencies. But is it? While on the job and now in retirement at his small horse farm in Montana, Dr. Roffe has been an outspoken critic of his former federal employer as well as the Wyoming Game and Fish Department for operating 23 elk “feedgrounds.” Visualize these facilities as benign-looking chow lines established to nourish wild, free-ranging elk in winter.
The largest public feedground in America is the National Elk Refuge in Jackson Hole, Wyoming where since the first decade of the early 20th century thousands of elk have been fed every winter. What started as a benevolent purpose—to keep more wapiti alive in winter— has, in our more enlightened age of better understanding transmittable diseases, become highly controversial and widely condemned.
At the Elk Refuge and the 22 other facilities operated by the state of Wyoming, huge numbers of elk are attracted to, and congregate in close quarters around artificial alfalfa pellets and hay laid down on the ground by the agencies mentioned above. See an example, below.
Elk bunched up around feed at the National Elk Refuge in Jackson Hole. Epidemiologists say that this wildlife management practice in the face of approaching Chronic Wasting Disease is no different than having spring breakers gathered on a beach as Covid-19 is bearing down. Image courtesy Daniel Schmidt/Feeding the Problem (https://feedingtheproblem.wordpress.com)
Wildlife disease experts like Roffe and others say it is the worst possible management practice when a suspected infectious disease is present. Were the feedgrounds instead set up for people or livestock, those in charge of operating them would be vilified, accused of committing malpractice for violating tenets of disease prevention that are irrefutable, Roffe says, calling the practice an anachronism.
Besides pondering the communicable disease brucellosis that is already present in elk at the feedgrounds, and fearing that a potential outbreak of bovid tuberculosis could someday arrive and sweep through the herds, the lethal pathogen that keeps Roffe up at night—a zoonotic malady considered one of the most rapidly spreading in North America, is Chronic Wasting Disease.
Chronic Wasting, or CWD as it is more commonly referenced as an acronym, afflicts members of the deer family (deer, elk, moose and reindeer) and as an equivalent of Mad Cow Disease, is grouped in a family of sickness known as “prion diseases” or transmissible spongiform encephalopathies. Always fatal when contracted, prion diseases, which involve abnormal folding of cellular proteins that multiply, attack the host’s central nervous system and turn brains of the afflicted essentially to mush, causing them to drool, stagger and exhibit symptoms much like a human beset with severe dementia.
There has, as of yet, never been a confirmed case of CWD being passed to people by animals, namely hunters and their families eating infected game meat, but CWD is proliferating. Now present in 26 states among wild, free-ranging herds of deer and elk, it has been found, too in some private domestic game farms. It is also present in three Canadian provinces as well as Finland, Norway, Sweden and South Korea.
For many citizens, CWD remains an obscure plague about which they know little. If you don't hunt, you don't think about it. However, some scientists worry about potential implications for the food supply and expanding environmental contamination. The disconnect between scientific reality, intervention needed to blunt disease in Wyoming and the larger consequences provides a lens for pondering what is, more broadly, at stake with CWD, say those whom we interviewed.
The management of elk feedgrounds in northwest Wyoming has attracted international focus, closely watched with disbelief by epidemiologists and professional wildlife managers because the herds represent the largest complex of artificial wildlife feeding in the West.
They are located among one of the most famous concentrations of big game animals in the world—those inhabiting the Greater Yellowstone Ecosystem, the region venerated as “the cradle of American wildlife conservation.” Elk and deer follow ancient migration pathways that take them between lower elevations in winter and mountains in summer where they trail emerging green-ups of grass.
Elsewhere in the Lower 48, such epic migrations no longer exist because the corridors have become fragmented by various kinds of human development—be it towns and suburbs, busy highways or industrial activity such as natural resource extraction.
Healthy wildlife in Greater Yellowstone is the foundation of a thriving multi-billion-dollar annual nature tourism economy (wildlife watching and hunting) and is a biological cornerstone for the survival of a larger suite of species that includes iconic grizzly bears and wolves.
Wyoming’s feedgrounds, Roffe says, represent known reservoirs of disease, as has already been proven with the persistence of brucellosis and failures to eradicate it. Attracting migratory animals that move vast distances seasonally, bunching up elk at feedgrounds hastens the likelihood of disease spread as infected animals move and come in contact with herds from other areas in Greater Yellowstone’s three-state region.
With novel coronavirus as a parallel reference point, fear over long-distance spread of Covid-19 from a source of infected individuals is why the Trump Administration banned flights from China as the pathogen moved behind its place of origin in Wuhan and turned into a pandemic.
Artificial feeding of elk has trained the animals to expect they will be fed. At the National Elk Refuge between 8000 and 10,000 elk have converged there in recent winters and an equal number or more at the feedgrounds run by the state.
In 2018, following claims made by Wyoming Game and Fish officials that it could take years for CWD to reach the heart of Greater Yellowstone, a mule deer tested positive in Grand Teton National Park, within miles of the Elk Refuge. It was just the latest example in which assertions made by the state to downplay the perceived threat of CWD proved to be refuted by reality on the ground. A year earlier, a different mule deer that inhabited the Shoshone National Forest just east of Yellowstone Park was found to be CWD-positive.
Roffe says the sentinel event in Grand Teton should have caused red alarms to flash, but both the US Fish and Wildlife Service and Wyoming Game and Fish did not respond with haste. By continuing to feed wapiti, wildlife health officials and conservationists say it is tantamount to operating a mega soup kitchen in New York City during this Covid-19 outbreak.
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CWD is already viewed as a grave long-term threat to deer-family species in North America. This series will show what other states are doing. More sobering is that several prominent epidemiologists believe that CWD becoming transmissible to humans is inevitable. In addition to worries about humans in the Lower 48 and southern Canada, there are potential implications for indigenous people in the Far North who depend upon reindeer (called caribou in North America) for subsistence.
Deer, elk, moose and caribou suffering from CWD may not initially exhibit symptoms, giving the superficial impression based on appearance they are perfectly healthy. The only way to determine if CWD is present is to test after the animal is dead.
There are other insidious aspects of CWD, Roffe and researchers note. Prions shed from living infected animals via their urine, feces and saliva can remain infectious in soils. Studies have shown that prions can also be uptaken in the tissue of plants growing from prion-contaminated soils, potentially making them sources for further snowballing infection. "Prion-contaminated soil and plants, such as corn and other crops that deer feed on, may facilitate CWD transmission," researchers with the US Geological Survey National Wildlife Health Center in Madison, Wisconsin say, raising the question of whether human ingestion of plants that have prion uptake could also increase the odds of the disease reaching people. Further, how might prion update in alfalfa or corn or other cash crops affect the movement and trade of those commodities?
Those are many open questions now being more rigorously investigated.
Prions can survive on metal surfaces whether in meat processing plants or hospital operating rooms. These non-organic entities can also remain active in dead animals and only through techniques like carcass incineration can they be destroyed.
CWD is thought to be a slow-moving disease and not virulent. Yet over time, as its presence deepens among social animals, incidence of disease rises. That trend has been demonstrated in most areas where CWD has spread, despite some extreme measures taken to try to slow its progression such as herd depopulation. In nearly half a century, after originating in the state of Colorado at a state research facility (thus making it a “new” disease”) in 1967, it is now present in more than half of all US states.
After CWD was first confirmed to have arrived in Montana in 2017 via mule deer crossing into the state from Wyoming, and also in northern parts of Montana from infected wildlife in Canada, the disease has rapidly turned up in white-tailed and mule deer, elk and moose with blazing speed across the huge state.
The federal Centers for Disease Control recommends that humans should not ingest an animal that looks sick, but more and more veteran hunters are deciding not to eat game animals from areas where CWD is known to exist in wildlife because they might be asymptomatic. Roffe happens to be one of those.
Again, Greater Yellowstone is home to hundreds of thousands of elk and deer, plus moose, including some of the most famous elk herds on earth. Despite CWD rapidly spreading in mostly deer herds across Wyoming, from the southeast portion of the state fanning out toward Greater Yellowstone in the northwest part of the state, both the Fish and Wildlife Service and Wyoming Game and Fish, even when prodded by the courts, have refused to heed calls to phase out feeding.
Wyoming claims that removing feeding stations would cause a devastating crash in elk numbers and it reasons that feedlots keep animals concentrated on federal land so they do not wander onto private ranches, mingle with cattle possibly infecting them with brucellosis, and eat hay put out for domestic animals.
As Roffe notes, the feedgrounds themselves have paradoxically fueled the brucellosis problem. They are going to do the same with CWD, he says. While phasing out feeding would result in a reduction of elk, it is unlikely to be devastating, given that a number of large wild elk herds in Greater Yellowstone are not nourished on alfalfa pellets.
Further, it should be noted, Wyoming today has liberal hunting quotas because there are perceived to be too many elk, not too few. Three autumns ago, after CWD turned up in Montana, the Montana Fish Wildlife and Parks Commission wrote a letter asking Wyoming to curtail feeding. The request was largely ignored.
Mountain Journal's first series, which devoted more than 80,000 words to the topic, was widely read coast to coast and elicited engagement from one of America’s foremost epidemiologists, Dr. Michael Osterholm headquartered at the University of Minnesota in Minneapolis/St. Paul.
Osterholm and Roffe are hardly alone in their concerns. In Greater Yellowstone, they are joined by Bruce Smith who spent more than two decades as a senior biologist at the Elk Refuge in Jackson and who wrote a critically acclaimed book, Where Elk Roam: Conservation and Biopolitics of Our National Elk Herd.
Besides them, every top manager of the Elk Refuge going back a quarter of a century, including Brian Glaspell who was there until 2019, has expressed worries and supported discontinuation of feeding because of worries about CWD. They, in turn, are joined by a wide range of professional wildlife management societies, conservationists and more epidemiologists.
“The preponderance of science, every major wildlife organization in the nation and our neighboring states in the Greater Yellowstone Ecosystem have all come out, if not outright condemning feeding, saying it is likely to exacerbate the effects of Chronic Wasting Disease,” Glaspell said at the Northern Rockies Conservation Cooperative’s Biennial Wildlife Symposium in 2019. “Feeding only occurs in a handful of counties in northwest Wyoming. Everybody else thinks it’s a bad idea; let’s just be honest about that.”
In a position paper circulated a few years ago, The Wildlife Society (motto: "leaders in wildlife science, management and conservation") pointed out how artificial feeding increases disease risk. "The future of wildlife management within North America depends on wild places to naturally support diverse, healthy, and sustainable populations of wildlife compatible with human interests and desires. Public policies that allow or promote baiting and supplemental feeding by the general public may convey the erroneous concept that such practices are suitable replacements for adequate habitat and scientific management of wildlife. A public that associates illegal baiting and/or supplemental feeding with stewardship may be unprepared to understand and act on the real and substantive threats to wildlife sustainability."
Meanwhile, in a technical report on CWD, the Association of Fish and Wildlife Agencies that set guidelines adopted by state wildlife departments, the authors said artificial feeding should be eliminated.
A group that has not pushed for feedground closure is the Rocky Mountain Elk Foundation which touts itself as being in the vanguard of promoting the best science-based management of elk. Some of its board members and former staff say that while the organization is well aware of the problems posed by feedgrounds for CWD, its leadership has not wanted to alienate Wyoming, though the state increasingly finds itself standing alone.
In Wyoming, politicians, civil servants and those affiliated with the Game and Fish Commission have downplayed the likely spread of CWD. Just as President Trump initially said that concern about Covid-19 was overblown, former Wyoming State Wildlife Veterinarian Dr. Terry Kreeger once appeared before an audience gathered for a CWD conference in Minnesota and said, “Forgive me if I’m somewhat nonchalant about this...I consider this a media-driven disease.”
Just as President Trump initially said that concern about Covid-19 was overblown, former Wyoming State Wildlife Veterinarian Dr. Terry Kreeger once appeared before an audience gathered for a CWD conference in Minnesota and said, “Forgive me if I’m somewhat nonchalant about this...I consider this a media-driven disease.”
Dr. Kreeger and others claimed that CWD doesn't represent a major threat to elk at the feedgrounds because wapiti somehow have genetic advantages preventing their infection compared to mule deer.
He said it would not cause population-level declines of wildlife; it has. Others in Wyoming have claimed production of an effective CWD vaccine could soon arrive thus blunting the need to close down the feedgrounds; it hasn’t.
As the US Geological Survey notes, "in areas of Colorado, Wisconsin, and Wyoming heavily affected by CWD, more than 40 percent of free-ranging cervids are infected." One study in Wyoming suggested that elk with a certain genotype might go extinct. Another showed how mule deer herds in southeastern Wyoming are in steady decline, dying faster than they can be replaced.
Kreeger, before he moved to Minnesota from Wyoming, also dismissed the threat of CWD crossing the species barrier from cervids to people. "If I thought it could infect me, I wouldn’t live here," he said.
These days, emerging facts, contradicting earlier assertions made by officials in the state, have forced Wyoming to re-posture. Not long ago, Mountain Journal spoke with an upper tier employee of the Wyoming Game and Fish Department. (We won’t reveal whether it was a retired or active civil servant because the individual was worried about retaliation). The person said: “I can’t say this on the record using my name but some of us have wanted to take action and phase out the feedgrounds for a long time but preventing us has been politics. Our hands have been tied by various governors and a Game and Fish Commission that pretty much answers to outfitters and guides.”
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Mountain Journal has interviewed several notable experts familiar with zoonotic diseases, including Dr. Osterhom who recently has been touted for his prescient predictions about the need to confront novel coronavirus. Notably, Osterhom and colleagues recently established the Center for Infectious Disease Research and Policy (CIDRAP) based at the University of Minnesota. The two diseases today featured most prominently on the CIDRAP site: Covid-19 and CWD.
A year ago, Osterholm made national headlines when he said this, below, about CWD during testimony before the Minnesota legislature as the disease continues to spread to new whitetail deer hunting units. Deer hunting in the Upper Midwest is regarded as a sacred autumn pastime.
Osterholm's comments set off a shockwave. “It is my best professional judgment based on my public health experience and [studying the risk of Mad Cow Disease] transmission to humans in the 1980s and 1990s and my extensive review and evaluation of laboratory research studies…that it is probable that human cases [of CWD] associated with the consumption of contaminated meat will be documented in the years ahead. It is possible that that the number of human cases will be substantial and will not be isolated events.”
Osterholm says you don't judge the potential of a disease based upon where it is today; you have to understand its likely progression and years of studying the patterns of related diseases offers a good sense of where CWD is headed. "CWD is one that warrants us being overly cautious even if the unwanted outcomes never materialize because there is a lot at stake," he told Mountain Journal.
On the wildlife side of things, Roffe said CWD needs national attention. “CWD is spreading and while you cannot stop its progression completely, there are smart things you can do, including discontinuing doing the irresponsible things that are certain to make the spread and incidence of disease worse," Roffe said. "One of those things is addressing the obvious: moving to phase out elk feeding in Wyoming which should have been done decades ago."
“CWD is spreading and while you cannot stop its progression completely, there are smart things you can do, including discontinuing doing the irresponsible things that are certain to make the spread and incidence of disease worse." —Dr. Thomas Roffe, former chief of animal health for the US Fish and Wildlife Service
Over the years, Wyoming lodged complaints about the outspokenness of Roffe and his colleagues in the hope they would be muzzled or fired. It didn’t happen. Still, not a single national director of the US Fish and Wildlife Service in Washington DC working under both Democrat and Republican administrations took action even though they were well aware of dangers of clustering animals around artificial feed.
Former national Fish and Wildlife Director Jamie Rappaport Clark didn’t take steps to phase out feeding while she served in the Clinton Administration in the 1990s—something she later told Mountain Journal she regretted, citing political pressure from Wyoming. Today, she is at the helm of the conservation group, Defenders of Wildlife. Defenders has joined the Sierra Club and National Wildlife Refuge Association in bringing legal action to halt feeding in a lawsuit filed by environmental law firm EarthJustice.
Another former national director of the Fish and Wildlife Service, Jackson Hole native son John Turner, also did nothing while in his post. Turner’s family for decades has been contracted by the federal government to operate a guest dude ranch in Grand Teton National Park which also offers big game hunts on the neighboring national forest. Mr. Turner’s brother, Harold, and colleagues in the hunting and guiding industry have been vocally opposed to phasing out artificial elk feeding because it bolsters the number of huntable wapiti, which is good for their clients.
U.S. Rep. Raul Grijalva of Arizona, chairman of the House Natural Resources Committee, told Mountain Journal that he may hold public hearings on CWD and ask the Fish and Wildlife Service why it is not moving faster to prevent a potential outbreak of the disease, by phasing out feeding at the Elk Refuge as part of a promise made to a federal court.
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It was Dr. Osterholm who earlier this winter warned about the spread of coronavirus in the US as it was being downplayed by the Trump Administration. He cited research from a study in London. It showed that, without aggressive action to contain the spread, there could have been more than two million casualties in this country.
Ultimately, policy makers heeded what Osterholm and others had to say. Osterholm over the last few decades has been part of expert panels addressing Mad Cow and its human form, Variant Creutzfeldt-Jakob disease (vCJD), Ebola, and infectious zoonotic viruses kindred to Covid-19 such as Middle Eastern Respiratory Syndrome (MERS) and Severe Acute Respiratory Syndrome (SARS).
Osterholm sees parallels between CWD and Mad Cow. As the federal Centers for Disease Control notes, Variant Creutzfeldt-Jakob Disease (vCJD) was first described in 1996 in the United Kingdom. And there is today strong scientific evidence that the agent responsible for the outbreak of prion disease in cows, bovine spongiform encephalopathy (BSE, or “Mad Cow”) is the same responsible for the outbreak of vDJC in humans. Osterholm participated in the scientific investigation into BSE.
“Strong evidence indicates that classic BSE has been transmitted to people primarily in the United Kingdom, causing a variant form of Creutzfeldt-Jakob disease (vCJD). In the United Kingdom, where over 1 million cattle may have been infected with classic BSE, a substantial species barrier appears to protect people from widespread illness,” CDC states. “Since vCJD was first reported in 1996, a total of only 231 patients with this disease, including 3 secondary, blood transfusion-related cases, have been reported worldwide. The risk to human health from BSE in the United States is extremely low.”
Osterholm says that just as the CDC did not respond as vigorously as it should have initially to mitigating the speed of Covid-19, it is not doing enough to warn about growing numbers of prion exposures to humans caused by more game animals infected with CWD.
Prior to the Covid-19 pandemic, Osterholm warned about CWD and the likelihood it will eventually infect people. Why did he do so? Because prions associating with it continue to mutate and the number of contacts between CWD-infected animals and people eating meat or coming in contacted with contaminated areas in the environment is rising and will continue to do so.
Along the way, he says, CWD will have devastating impacts on wildlife and the public's perception of it. Osterholm has warned that if not confronted, CWD will harm the appeal of hunting, which in many states is an important wildlife management tool.
Osterholm recently noted how prion strains continue to diversify; there isn’t just one CWD strain but many—strains that spread more easily in deer and others that take hold in elk. Eventually, he says, there will likely be a prion strain that is more virulent, increasing the infection rate among deer family members. Further mutation will enhance the probability of it crossing species barriers from cervids to possibly bison, cattle, goats and sheep (wild and domestic).
The more animals that have it, and the more that humans unwittingly are consuming meat with prion contamination, the higher the chances that it will, just as Mad Cow did in Britain, cross the barrier from animal to human. Just one case of confirmed transmission will be a game changer, Osterholm says. He noted on a podcast with media personality Joe Rogan in winter 2020 that likely many thousands of people already have unknowngly eaten game animals that were infected with CWD. It could be years before anyone gets sick. See the full interview Rogan did with Osterholm on Covid-19 and CWD below.
Besides Dr. Osterhom, Mountain Journal also interviewed Dr. Andrew Dobson, a wildlife disease expert based at Princeton University. Dobson has studied pathogens in Africa in addition to being part of scientific review panels working in the Greater Yellowstone region. “CWD represents an expanding and increasingly worrying threat to elk, mule deer and cattle,” he told Mountain Journal. ”Aggregating elk on feedgrounds…with CWD looming is arguably the stupidest form of animal management I can imagine.”
Zootic diseases have received elevated attention with the arrival of Covid-19 and they take many different forms. In a report issued by the US Geological Survey titled "Why Bother About Wildlife Diseases?," the authors note Homo sapiens share the world with more than 1,400 species of infectious organisms known to be pathogenic to humans, including approximately 870 that are zoonotic
"Despite those potential threats, society goes about its business without being intimidated by the specter of infectious disease for it has no option," the authors of the USGS report write "However, because too little preemptive thought and too few associated actions are taken for combatting those more than 1,400 species of infectious organisms, infectious disease is the leading cause of human mortality."
Recognizing CWD in their report, they go on to say "the tsunami of infectious disease impacting free-ranging wildlife populations since the last half of the 20th century is unprecedented in recorded history and shows no signs of abating during the 21st century. Our changing world and the associated pressures on biological resources have greatly elevated disease as a factor that must be dealt with. As a result, the question 'Why bother?' has now been transformed to that of 'how can we do better?'"
The answer: "these challenges go far beyond considerations associated with emerging zoonoses to the more difficult task of preventing these environments from becoming foci for disease eruption and transmission among free-ranging wildlife population."
This ongoing series will explore why CWD is considered a major health risk to wildlife and potentially people and the economy, and how the politics have for years have overridden the conclusions of professional wildlife managers, epidemiologists, disease prevention and even decisions rendered by the courts.
Coming: Next Time: Lawsuit Charges Federal Government With Endangering The Famous Elk Herd It Is Supposed To Protect