Chronic Wasting Disease: Management of chronic wasting disease in ranched elk: conclusions from a longitudinal three-year study

Research Paper

Management of chronic wasting disease in ranched elk: conclusions from a longitudinal three-year study

N.J. Haley,D.M. Henderson,R. Donner,S. Wyckoff,K. Merrett,J Tennant,

Pages 76-87 | Received 09 Oct 2019, Accepted 28 Jan 2020, Published online: 07 Feb 2020

Download citation https://doi.org/10.1080/19336896.2020.1724754

ABSTRACT

Chronic wasting disease is a fatal, horizontally transmissible prion disease of cervid species that has been reported in free-ranging and farmed animals in North America, Scandinavia, and Korea. Like other prion diseases, CWD susceptibility is partly dependent on the sequence of the prion protein encoded by the host’s PRNP gene; it is unknown if variations in PRNP have any meaningful effects on other aspects of health. Conventional diagnosis of CWD relies on ELISA or IHC testing of samples collected post-mortem, with recent efforts focused on antemortem testing approaches. We report on the conclusions of a study evaluating the role of antemortem testing of rectal biopsies collected from over 570 elk in a privately managed herd, and the results of both an amplification assay (RT-QuIC) and conventional IHC among animals with a several PRNP genotypes. Links between PRNP genotype and potential markers of evolutionary fitness, including pregnancy rates, body condition, and annual return rates were also examined. We found that the RT-QuIC assay identified significantly more CWD positive animals than conventional IHC across the course of the study, and was less affected by factors known to influence IHC sensitivity – including follicle count and PRNP genotype. We also found that several evolutionary markers of fitness were not adversely correlated with specific PRNP genotypes. While the financial burden of the disease in this herd was ultimately unsustainable for the herd owners, our scientific findings and the hurdles encountered will assist future CWD management strategies in both wild and farmed elk and deer.

KEYWORDS: Prion, elk, RAMALT, RT-QuIC, antemortem

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This manuscript describes one such property, a herd of over 570 elk maintained on 3500 acres of fenced habitat in northwestern Colorado.

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Return rate of CWD positive animals In the 2017 sampling period, 315 animals were tested for CWD antemortem. Of those, 71 tested positive by IHC, RT-QuIC, or both. Thirty-four infected animals (thirty-three cows and one bull) were euthanized and confirmed CWD positive post-mortem, with the remaining thirty-seven animals (Twenty-six bulls and eleven cows) released back onto the property. Of those animals which were released, four were harvested in the fall of 2017 and were found to be CWD positive post-mortem. Three of the remaining thirty (10%) returned for the 2018 sampling period, the remainder were lost in the field and went untested. All three were 132ML heterozygous animals, each positive again on antemortem testing in year three. In contrast, 120 of the 329 animals negative by antemortem testing were harvested in the fall of 2017, with 26 found to be CWD positive (21.7%). Of the remaining 209 animals, 141 returned for the 2018 sampling period (67.5%), with the remaining animals presumed lost in the field, untested. (Table 1 and Figure 1)

Over the course of the entire study, four of forty-nine CWD positive 132MM animals released back onto the property (8.2%) returned for a second year of sampling. Nine of thirty-three 132ML animals positive for CWD returned for a second year of sampling (27%), a return rate that was significantly greater than that of CWD positive 132MM animals (risk ratio: 3.34, p = 0.03). The lone 132LL cow identified during the course of antemortem testing in year two did not return for sampling in year three. Cumulatively, just 13 of 82 animals identified as CWD positive and released onto the property returned the following year (15.9%). These low rates of yearly return are in stark contrast to the cumulative return rate for CWD negative animals. For animals homozygous for the 132M allele, 107/144 returned in year two, and 28/69 returned in year three (63% overall). For 132ML heterozygous animals, 170/221 returned in year two, with 62/181 returning in year three (58% overall). Twenty-five of thirty-five animals homozygous for the 132L allele returned in year two, with fifteen of thirty-five returning in year three (57% overall). Cumulatively, 60% of animals negative for CWD returned the following year – a yearly return rate nearly over 3.5 times that of CWD positive animals (risk ratio: 3.62, p < 0.001; 95% confidence interval 1.96–6.69).

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Discussion

While reports on the management of chronic wasting disease in wild deer and elk are many and varied [33–43], rare is the case presented for managing the disease in farmed cervids. Almost without exception, farmed cervids are immediately placed under quarantine and eventually depopulated when CWD is discovered on site [12]. This manuscript reports our efforts to manage CWD in a large elk herd, in a controlled setting with endemic CWD, through the use of annual live animal testing and targeted culling of CWD positive cows. Although the herd owners were presented with additional management directives, including culling of CWD positive bulls and those animals positive by an amplification assay (RT-QuIC), they were not implemented due to concern regarding its potential impact on hunting revenue. Ultimately, we could not completely evaluate our management practices, as the herd was slowly depopulated after the final sampling period due to the financial burden brought by the disease.

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https://www.tandfonline.com/doi/full/10.1080/19336896.2020.1724754

1999

Oklahoma:

-- In June,1998 CW) was diagnosed in a captive elk in Oklahoma.

-- The Oklahoma herd received more than 80 elk from commercial sources in Montana and Idaho.

-- Animals from the same origins as the Oklahoma herd went to 13 other ranches in Colorado, Idaho, Iowa, Montana, Nebraska, Alberta, and Saskatchewan in the past 11 years, plus many secondary movements. [8]

-- no control or surveillance program.

Utah:

-- one trace-back zoo in Salt Lake City from elk possibly associated to Oklahoma game farm.

-- One 30 year old hunter dying of CJD of unknown origin (not familial or iatrogenic).

-- 135 deer sampled in 1998, 90 tested, all negative so far, pathology done in-state. Unpublished UF&G.

Montana:

-- Single trace-back elk game farm under quarantine from Oklahoma case, though importer destroyed ear tag.

-- Single trace-forward elk game farm that had bought elk from trace-back game farm connected to Oklahoma

Montana to Survey for Chronic Wasting Disease

Montana FWP web site

During the upcoming fall big game hunting season, Fish, Wildlife & Parks' Wildlife Laboratory will be conducting surveys for Chronic Wasting Disease (CWD) in FWP administrative regions 2, 3, 4, 5 and 7. The surveys will include collection of heads from mule deer, white-tailed deer and elk. Sampled animals will be tagged at check stations to indicate that the head was removed for the CWD survey to prevent enforcement problems with evidence of sex. Specific brain tissues and tonsils will be extracted from the heads. Laboratory technicians will be assisting at several check stations to collect the tissues and these will be forwarded to a laboratory where histologic sections will be examined by a pathologist to look for lesions typical of CWD.

CWD has been identified in wild deer and elk in Colorado and Wyoming and in seven game farms in South Dakota, Nebraska, Oklahoma and Saskatchewan. For the past several years, Montana FWP monitored a limited number of big game animals for CWD and has found no evidence of the disease in free ranging wildlife. CWD was not believed to be present in Montana game farms until late June of this year, when the Department of Livestock notified FWP that a game farm elk reportedly shipped from Montana to Oklahoma was confirmed with CWD.

FWP has proposed increasing the surveillance for this disease in wild elk and deer. The surveillance will provide monitoring the southern perimeters of the state where the disease is most likely to naturally spread from Wyoming and Colorado. Emphasis will be placed on animals that are 1.5 years old and older of both sexes.

Tom Palmer of Montana FWP writes us about concerning a leaked "secret memo" circulating on the Internet:

"We don't have "internal" memos and this notion of something being "leaked" is odd. All of FWP's communications are open, public, and straight forward. The .memo released to the press by FWP and Gov. Marc Racicot. FWP is taking the CWD threat to wildlife very seriously.

Karen Zachheim, our Game Farm Coordinator, will send you any material requested .Should you want to talk to Karen about the CWD issue, call 406-444-4039, or Paul Sihler in the Director's office at 406-444-5620. If the material doesn't arrive early next week, please call me (406-444-3051)."

Montana has 93 game farms with 4,000 animals; 12 further facilities approved. Elk hunters pend an estimate $75 million per year for 22,000 elk, deer hunters $68 million to kill 75,000 mule deer and 60,000 white-tailed deer.

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Montana to Survey for Chronic Wasting Disease

For Montanans, ultimately, the choice looms between the competing visions offered by Bob Spoklie and our Western neighbors. Montana lawmakers should follow Wyoming's lead and remove our wildlife heritage from the private marketplace.

***> For the sake of both the hunter and the hunted, private elk farms should be banned."

http://www.mad-cow.org/99feb_cwd_special.html#eee

Trace-back: A game farm, zoo, or research facility that sold an elk or deer to a second facility where CWD was later positively diagnosed for the first time. The trace-back farm is presumed to be contaminated even if it has never reported CWD. Examples: Colorado has numerous trace-back game farms among the 11 in the Ft. Collins disease epicenter; improbably, none of these have ever reported CWD. Ear tags had been discarded in the Oklahoma CWD elk case, causing uncertainty in trace-back (limited to Montana, Idaho, or Utah).

http://www.mad-cow.org/99feb_cwd_special.html#eee

-- The Oklahoma herd received more than 80 elk from commercial sources in Montana and Idaho.

Montana:

-- Single trace-back elk game farm under quarantine from Oklahoma case, though importer destroyed ear tag.

-- Single trace-forward elk game farm that had bought elk from trace-back game farm connected to Oklahoma

Montana to Survey for Chronic Wasting Disease Montana FWP web site During the upcoming fall big game hunting season, Fish, Wildlife & Parks' Wildlife Laboratory will be conducting surveys for Chronic Wasting Disease (CWD) in FWP administrative regions 2, 3, 4, 5 and 7. The surveys will include collection of heads from mule deer, white-tailed deer and elk. Sampled animals will be tagged at check stations to indicate that the head was removed for the CWD survey to prevent enforcement problems with evidence of sex. Specific brain tissues and tonsils will be extracted from the heads. Laboratory technicians will be assisting at several check stations to collect the tissues and these will be forwarded to a laboratory where histologic sections will be examined by a pathologist to look for lesions typical of CWD. CWD has been identified in wild deer and elk in Colorado and Wyoming and in seven game farms in South Dakota, Nebraska, Oklahoma and Saskatchewan. For the past several years, Montana FWP monitored a limited number of big game animals for CWD and has found no evidence of the disease in free ranging wildlife. CWD was not believed to be present in Montana game farms until late June of this year, when the Department of Livestock notified FWP that a game farm elk reportedly shipped from Montana to Oklahoma was confirmed with CWD.

Tom Palmer of Montana FWP writes us about concerning a leaked "secret memo" circulating on the Internet:

MONTANA

Karen Zachiem with Montana Parks and Wildlife reported that Montana allows game farming. Initial regulations were inadequate to protect the state's wildlife resources. The state has tried to tighten up regulations related to game farming, resulting in a series of lawsuits against the state from elk ranchers. Zachiem reported that the tightening of regulations was in response to the discovery of TB in wildlife (elk, deer, and coyotes) surrounding a TB infected game farm. TB has been found on several game farms in Montana. Also, they have had problems with wildlife entering game farms as well as game farm animals escaping the farms. Finally, there has been a growth in shooting ranches in Montana. Game farmers allow hunters to come into enclosures to kill trophy game farm animals, raising the issues of fair chase and hunting ethics.

Keep 'em wild: Montana should ban canned hunts. Whitefish elk farm draws fire from hunters, biologists By STEVE THOMPSON Missoula Independent, also the Whitefish Pilot 13 Sep 1998 Ph: 406/862-3795 Fax: 406/862-5344 "Although not everyone sees it the same way, Kalispell legislator Bob Spoklie says his controversial plan to develop an elk shooting gallery on 160 acres near Whitefish is rooted in the richest of Montana traditions-private property, pleasure and profit. Flaring like a bull elk in rut, Spoklie rages against those who disagree with his intentions. "These are not public wildlife," Spoklie told me angrily. "These are our animals and not anyone else's. We'll do as we please." If his political opponents succeed in banning canned elk hunts, Spoklie warns, the next step will be to eliminate all public hunting. "That's the real agenda here," he said.

By contrast, next door in Wyoming, the suggestion that Rocky Mountain elk can be penned, hand-fed and then shot is more than a disgusting notion. It's illegal. In fact, the Cowboy State has gone so far as to prohibit all private game farms. Utah also prohibits canned elk hunts. Listening to Spoklie, one might be convinced that Utah and Wyoming are governed by a bunch of socialist, animal-rights activists. But the truth is those states are hardly run by left-wing zealots. Rather, lawmakers there have chosen to honor a Western tradition as deeply rooted as Spoklie's rather crass libertarianism.

This conservation heritage was pioneered by Theodore Roosevelt and others who established wildlife as a public commons. Wildlife laws in those states seek to protect hunters' fair-chase pursuit of healthy, free-ranging game. According to Dick Sadler, a long-time Democratic legislator in Wyoming now retired, elk hunting farms violate the very spirit of the West. In the 1970s, he joined forces with Republican John Turner to pass landmark legislation which banned game farms. Sadler and Turner had researched game farms in other states, and they came away with a bitter taste.

Spoklie, however, says elk and other big game have been converted to private livestock around the world. "Montana is so far behind that we think we're leading," he says. As the founder of the Montana Alternative Livestock Association, Spoklie is clearly frustrated about the clamor surrounding his attempts to domesticate elk in Whitefish. But then he has been one of the chief lobbyists for the game farm industry. Due in large part to his influence, Montana legislators have resisted attempts to copy Wyoming's game farm ban, including former Florence Senator Terry Klampe's proposed moratorium in 1995.

But Sadler, a lifelong hunter, offers the following evidence for what's wrong with canned hunting: "I saw a film of one of those canned hunts in Michigan, where the guys get up and have a big breakfast, put on their hunting clothes, walk outside, shoot the animals in an enclosure and then congratulate themselves. "That was one of the most disgusting things I've ever seen."

As the proposal to ban game farms wound through the Wyoming legislature, though, Sadler focused on more pragmatic arguments. Today, he still complains about the threat of disease transmission to wild animals, genetic pollution and loss of habitat to enclosures.

It was the Republican Turner, who later became George Bush's Fish and Wildlife Service director, who invoked the West's sporting heritage. "Turner's argument to the legislature was that you can't take a magnificent animal like an elk and allow some slob to shoot it inside a fence," Sadler says. Ultimately, most Wyoming legislators agreed that it just wasn't proper to domesticate and commercialize a wild animal like elk.

To Spoklie's dismay, the debate locally is getting louder, and his loudest opponents are sportsmen. Making the biggest waves are the Montana Wildlife Federation, the Rocky Mountain Elk Foundation, Orion: The Hunter's Institute, and a coalition of neighbors and hunters in the Whitefish area.

Orion's founder Jim Posewitz, a retired wildlife biologist, says canned hunts jeopardize public acceptance of the real thing. A leading advocate of "fair chase" hunting, which emphasizes the almost sacred relationship between hunter and prey, Posewitz argues that the majority of non-hunting Americans will tolerate hunting only if it is conducted with the highest ethics. "Game farms are an abomination," he says.

Spoklie, an appointed lawmaker who recently lost the Republican primary election, dismisses such statements as "differences of philosophy" that don't stack up against private property rights. If someone's willing to pay thousands of dollars to shoot a penned elk, then that's good both for him and Montana's economy, he says.

Karen Zackheim, game farm coordinator for the state Department of Fish, Wildlife and Parks, says the issue goes beyond philosophy. The most pressing statewide concern, she says, is chronic wasting, an elk version of mad cow disease. The little known disease, for which there is neither a test nor a cure, recently killed captive elk in several Western states and has spread to wild game in some places. Zackheim also has identified other potential problems with the Spoklie elk farm.

Spoklie makes it clear that Zackheim and others should butt out. And some Montana lawmakers seem willing to listen to him, having recently stripped state wildlife officials of some oversight responsibilities. Now, Spoklie would prefer even less state oversight, including his permit application currently under review.

http://www.mad-cow.org/99feb_cwd_special.html#eee

Governments say Mr. McEwen, 30, has the classical strain, but some scientists question that diagnosis. They say it's possible the Utah man, who was an occasional hunter, is the first known victim of a newer strain contracted by eating deer and elk -- much the same way some in Britain contracted "mad cow disease" from eating infected beef in the 1980s.

http://www.mad-cow.org/mar99_mcewen.html#aaa

Colorado Chronic Wasting Disease Response Plan December 2018

I. Executive Summary Mule deer, white-tailed deer, elk and moose are highly valued species in North America. Some of Colorado’s herds of these species are increasingly becoming infected with chronic wasting disease (CWD). As of July 2018, at least 31 of Colorado's 54 deer herds (57%), 16 of 43 elk herds (37%), and 2 of 9 moose herds (22%) are known to be infected with CWD. Four of Colorado's 5 largest deer herds and 2 of the state’s 5 largest elk herds are infected. Deer herds tend to be more heavily infected than elk and moose herds living in the same geographic area. Not only are the number of infected herds increasing, the past 15 years of disease trends generally show an increase in the proportion of infected animals within herds as well. Of most concern, greater than a 10-fold increase in CWD prevalence has been estimated in some mule deer herds since the early 2000s; CWD is now adversely affecting the performance of these herds.

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(the map on page 71, cwd marked in red, is shocking...tss)

https://cpw.state.co.us/Documents/RulesRegs/Brochure/BigGame/biggame.pdf

CWD Advisory Group

https://cpw.state.co.us/learn/Pages/CWD-Advisory-Council.aspx

Testing Waiver

A Colorado alternative livestock producer who has had no CWD positive tests in the previous 60 months and who has had at least 60 months of CWD surveillance status may apply for a waiver from the mandatory surveillance requirements. Application to Waive CWD Sample Submission for Imported Elk

https://www.colorado.gov/pacific/aganimals/chronic-wasting-disease

https://www.colorado.gov/pacific/aganimals/elk

https://www.colorado.gov/pacific/aganimals/Cervids-Moving-Within-Colorado

ORIGIN OF CHRONIC WASTING DISEASE TSE PRION?

COLORADO THE ORIGIN OF CHRONIC WASTING DISEASE CWD TSE PRION?

*** Spraker suggested an interesting explanation for the occurrence of CWD. The deer pens at the Foot Hills Campus were built some 30-40 years ago by a Dr. Bob Davis. At or abut that time, allegedly, some scrapie work was conducted at this site. When deer were introduced to the pens they occupied ground that had previously been occupied by sheep.

IN CONFIDENCE, REPORT OF AN UNCONVENTIONAL SLOW VIRUS DISEASE IN ANIMALS IN THE USA 1989

http://webarchive.nationalarchives.gov.uk/20080102193705/http://www.bseinquiry.gov.uk/files/mb/m11b/tab01.pdf

ALSO, one of the most, if not the most top TSE Prion God in Science today is Professor Adriano Aguzzi, and he recently commented on just this, on a cwd post on my facebook page August 20 at 1:44pm, quote;

''it pains me to no end to even contemplate the possibility, but it seems entirely plausible that CWD originated from scientist-made spread of scrapie from sheep to deer in the colorado research facility. If true, a terrible burden for those involved.'' August 20 at 1:44pm ...end

”The occurrence of CWD must be viewed against the contest of the locations in which it occurred. It was an incidental and unwelcome complication of the respective wildlife research programmes. Despite it’s subsequent recognition as a new disease of cervids, therefore justifying direct investigation, no specific research funding was forthcoming. The USDA viewed it as a wildlife problem and consequently not their province!” page 26.

https://web.archive.org/web/20060307063531/http://www.bseinquiry.gov.uk/files/mb/m11b/tab01.pdf

SATURDAY, FEBRUARY 01, 2020

Colorado confirmed CWD TSE Prion in 24 game management units in the state where it previously hadn’t been found

https://chronic-wasting-disease.blogspot.com/2020/02/colorado-confirmed-cwd-tse-prion-in-24.html

MONDAY, MAY 21, 2018

Colorado Chronic Wasting disease CWD TSE Prion hits 16 percent of male deer, elk, moose tested in some parts of state

http://chronic-wasting-disease.blogspot.com/2018/05/colorado-chronic-wasting-disease-cwd.html

FRIDAY, FEBRUARY 07, 2020

Montana 142 animals tested positive for CWD thus far during 2019/20 sampling

https://chronic-wasting-disease.blogspot.com/2020/02/montana-142-animals-tested-positive-for.html

TUESDAY, JANUARY 07, 2020

Oklahoma Farmed Elk Lincoln County CWD Depopulation 3 Positive Elk with 1 Additional Dead Trace Out Confirmed Positive