Chronic wasting disease (CWD)
Chronic wasting disease (CWD) is a disease of the nervous system in deer and elk that results in distinctive brain lesions. It continues to be a major issue for wildlife scientists throughout the Nation.
Weekly CWD Status Update – Updated 12/6/2017— 30 wild deer tested positive for or are suspected of having CWD
Kits to detect chronic wasting disease in Michigan deer in short supply, Detroit Free Press, Dec 1, 2017
Why this deer disease could change the way Americans hunt forever, USA Today, Nov 27, 2017
Letting the disease spread is not an option. There’s increasing concern CWD, a prion disease similar to mad cow, eventually could cross the species barrier and spread to humans. Many scientists think it’s not a matter of if, but a matter of when. The Centers for Disease Control and Prevention warns not to eat the meat of contaminated deer. It’s possible CWD already has made the leap — comparable prion diseases have incubated for decades before dementia-like symptoms were recognized.
A fatal disease is spreading among U.S. deer, but there may be a new way to detect it, Popular Science, Nov 16, 2017
Confirmed deer with chronic wasting disease leads to well-attended meeting, MLink, Oct 26, 2017
Federal lab confirms Montcalm County deer had chronic wasting disease, Statewide DNR News, Oct 6, 2017
Money, Power, and Deer Urine, New Yorker, Sept 25, 2017
2017 Deer Regulations Changes, Michigan Department of Natural Resources, Sept 11, 2017
Concerns keep rising that chronic wasting disease could jump from deer to humans, Duluth News Tribune, July 14, 2017
Diseased deer discovered in new spot in Pennsylvania, PennLive, July 13, 2017
Researchers Look To Fire To Combat Chronic Wasting Disease, WPR, July 5, 2017
Fire May Be the Only Remedy for a Plague Killing Deer and Elk, New York Times, June 26, 2017
Supreme Court rules law allows quarantine of CWD deer, not land, Radio Iowa, June 16, 2017
2017 North American Deer Summit: CWD Is Worse Than We Thought, Realtree.com, June 9, 2017
The Ecology of Prions, Microbiology and Molecular Biolology Review, May 31, 2017
Can Michigan save deer from this deadly disease?, Lansing State Journal, May 25, 2017
Elk and deer herds in danger decades after disease discovery, Billings Gazette, May 17, 2017
25 wild deer test positive for chronic wasting disease, 27News.com, May 15, 2017
Study Shows How Chronic Wasting Disease Spreads in Wisconsin, USNews, April 21, 2017
Chronic Wasting Disease, Texas A&M, April 11, 2017
Showcasing the DNR: Task force working on CWD prevention efforts in UP, DNR, March 2, 2017
Molecular Mechanisms of Chronic Wasting Disease Prion Propagation [abstract], Perspectives in Medicine, Feb 13, 2017
State says Mecosta County deer cull could begin by end of the week, MLive, Feb 2, 2017
Chronic wasting turns up in another SE Minnesota deer, MPR News, Jan 23, 2017
Chronic Wasting Disease found at Mecosta County deer farm, Lansing State Journal, Jan 20, 2017
The deer farm where the infected animals lived will be quarantined and depopulated, state officials said. There also will be testing, fence inspections and audits of all deer farms within a 15-mile radius, as well as testing of free-ranging deer in the area.
2 More Deer Found With CWD, 5 County Feeding Ban In Place, CBS Local.com, Jan 10, 2017
Third CWD-infected deer found in SE MN; special hunt starts Saturday, Kare11News, Dec 28, 2016
Suspect CWD deer harvested in Eagle Township, Clinton County, Statewide DNR News, Nov 22, 2016
Video: Testing Deer for CWD, MDNR, Nov 10, 2016
Michigan continues to battle chronic wasting disease, MDNR, Nov 3, 2016
Eighth Michigan deer likely to test positive for chronic wasting disease, MLink, Sept 12, 2016
Suspect deer for chronic wasting disease identified in Ingham County, Statewide DNR News, Sept 12, 2016
Court says Missouri can’t ban deer imports over fears of disease, LakeExpo.com, Sept 17, 2016
Researchers document first-ever evidence of white-tailed deer declines from CWD, Phys.org, Sept 2, 2016
Chronic Wasting Disease in White-tailed Deer: Infection, Mortality, and Implications for Heterogeneous Transmission, Ecology, July 2016
Southwest Colorado gets first deer infected with wasting disease, The Journal, July 12, 2016
Fatal deer disease impacts Ionia County, Sentinel Standard, July 5, 2016
Female deer disperse farther than males, present disease-control challenge, Science Daily, June 28, 2016
Illinois is shining star in fight against deer disease, rrstar.com, June 19, 2016
TPWD merits support in fight against chronic wasting disease, MySA.com, June 19, 2016
Pa. Game Commission looks into targeted removal for diseased deer, Citizen’s Voice, June 7, 2016
AGFC Needs Hunters To Hunt To Manage Spread Of Deadly Deer Disease, KFSM, May 26, 2016
Michigan expands deer chronic wasting disease test zone, Detroit Free Press, May 20, 2016
Decision time nears for CWD outbreak in wild Pennsylvania deer, Outdoor Newd, May 16, 2016
Seven new cases of chronic wasting disease found in Missouri deer, KY3.com, April 23, 2016
A contagious brain disease has hit Norway’s reindeer, and scientists are afraid of it spreading, Quartz, April 23, 2016
Wisconsin loses ground against fatal deer disease, Daily News, April 22, 2016
Deadly animal prion disease appears in Europe, Nature, April 18, 2016
The first detection of Chronic Wasting Disease (CWD) in Europe, CWD-Info.org, April 5, 2016
The sick female reindeer (Rangifer tarandus tarandus) was detected in the middle of March 2016 in connection with capture for GPS-collaring using helicopter performed by the Norwegian Institute for Nature Research (NINA. It died and the carcass was submitted to the Norwegian Veterinary Institute in Oslo for necropsy and laboratory examinations. It was an adult animal, says wildlife pathologist Turid Vikøren at Norwegian Veterinary Institute, who performed the necropsy.
Six more cases of CWD found in Newton County, CWD-Info.org, April 5, 2015
Outdoors: To fight chronic wasting disease among deer, we must act now, Detroit Free Press, April 3, 2016
Chronic Wasting Disease Cases Keep Rising In Newton Co. Deer Population, KFSM News, April 1, 2016
More deer with chronic wasting disease reported, with one outside of a CWD management area, PA Live, March 26, 2016
Wisconsin leaders are ignoring the risk of chronic wasting disease, Isthmus, March 28, 2016
Five Deer Test Positive for Chronic Wasting Disease, CSD-Info.org, March 28, 2016
Michigan confirms new CWD-positive findings; total is now seven deer, Michigan DNR Bulletin, March 18, 2016
The intensive removal of deer in these areas has a two-part benefit. One, it helps us understand prevalence rates and spread so we can make informed decisions on disease management moving forward; and two, by removing individual deer around areas with known disease occurrence, it reduces the potential for spread and accumulation in our deer herd, which has benefits not only locally, but on the periphery of the management zone as well.
News On Deer Chronic Wasting Disease Gets Worse, Grand View Outdoors, March 1, 2016
Deer disease confirmed in Hartley Co., WALB, Feb 28, 2016
DNR lauds partners in continuing battle against chronic wasting disease, Statewide DNR News, Dec 30, 2015
- Occurance of Chronic Wasting Disease (CWD), CDC, Jan 2016
As of January 8, 2016, there were 150 counties in 20 states with reported CWD in free-ranging cervids.
- Deer Killed In Clinton County May Have CWD, WILX.com, Dec 31, 2015
Watertown Twp., Clinton Co. – The Michigan Department of Natural Resources says a deer killed by a bow hunter earlier this month may have Chronic Wasting Disease.
- Weekly CWD Status Update – Updated 12/4/2015
4th deer tested positive for chronic wasting disease in Eaton County.
- Deer disease has food banks on edge, Lansing State Journal, Nov 13, 2015
All deer harvested within a nine-township core area around Meridian Township must be taken to a check station for testing. And processors who accept deer from the core area are required to isolate those carcasses from other meat.
- DNR: Deer killed in DeWitt Township may have chronic wasting disease, Lansing STate Journal, Nov 13, 2015
While DeWitt Township is one of nine townships that make up what the DNR has designated as the CWD Core Area, until now, no wild deer with the disease had been found outside Meridian Township.
- DNR: Deer killed in Clinton Co. may have wasting disease, Detroit Free Press, Jan 4, 2016
State wildlife officials say a deer killed by a bow hunter in Watertown Township this month might have been carrying chronic wasting disease. Samples of the deer — a 11/2-year-old doe — were sent to a federal laboratory in Iowa on Monday for more detailed testing.
- Hunters in affected areas encouraged to have deer checked for CWD, Michigan DNR bulletin,11/13/2015
The DNR strongly encourages hunters in a broader CWD Management Zone – consisting of Clinton, Ingham and Shiawassee counties – to check their deer and have them tested for CWD as well.
- DNR video: Wasting disease prompts tighter deer hunt rules, MLive, Sept 30, 2015
Three deer have been discovered with the disease this year, all in the Lansing area. The neurological disease, which also kills elk and moose, was first found in wild deer in western states in 1985. The first Michigan infection was discovered in Kent County in 2008. The DNR developed a disease response plan in 2002.
Stricter rules are meant to stem the spread of the disease.
- CWD is an always-fatal brain disease. Once deer contract it, their life expectancy is about 18 to 20 months. They typically look healthy the first 16 months before showing its effects. Those signs include tremors, heavy drool, staggering and stark ribs and spinal bones outlined beneath a ratty hide. In advanced stages, they lose their fear of humans.
Map of CWD as of April 2015
Will CWD wipe out deer for future hunters?, Green Bay Press Gazette, Sept 4, 2015
Like it or not, the odds of a sickly Wisconsin deer herd in 2071 are looking more likely each year. CWD prevalence in southern Wisconsin has doubled across all ages in both sexes of deer the past 13 years. In at least one area, four of every 10 adult bucks carries the disease, and in at least two other areas one in four mature bucks are infected.
- Follow Illinois, not Wisconsin, to slow spreading CWD, Journal-Sentinel, Aug 19, 2015
Although the Wisconsin DNR initially attempted to eradicate the disease with aggressive measures, including sharpshooters and longer hunting seasons, it now uses only monitoring and surveillance. Rates of the disease have increased substantially since Wisconsin abandoned targeted deer reduction efforts.
The difference in CWD prevalance rates in the two states is due mostly to management strategy, according to University of Illinois researchers Jan Novakofski and Michelle Green. Illinois has remained committed to reducing deer in areas with known CWD-positive animals. The IDNR also is testing deer for CWD in a wide area, hoping to find any new disease sites.
For the sampling year ending June 30, the CWD prevalence rate in Illinois was 1.2%, according to Paul Shelton, forest wildlife manager for the Illinois Department of Natural Resources. “This is a very challenging issue,” Shelton said. “We can’t declare victory, but we can say that the work we’ve been doing has helped keep the rates lower than they otherwise would be.”
- DNR confirms third deer positive for CWD; hunter participation critical this fall, Aug 6 2015
- Two new deer were found this week, testing positive for Chronic Wasting Disease, Michigan Emerging Disease Issues, Chronic Wasting Disease (CWD)
Weekly CWD Status Update – Updated 7/17/2015
- Michigan confirms CWD in second free-ranging white-tailed deer, Michigan DNR sent this bulletin at 07/17/2015
The Michigan departments of Natural Resources (DNR) and Agriculture and Rural Development (MDARD) have confirmed a second free-ranging deer in Meridian Township (Ingham County) has tested positive for chronic wasting disease (CWD), a fatal neurological disease that affects white-tailed deer, mule deer, elk and moose. This second case is a 2-year-old male found less than a mile from the initial positive female deer, confirmed this past May. Genetic testing is being conducted to see if the two deer are related.
- Ten Deer Test Positive for CWD in 2014-2015Kansas Wildlife, Parks and Tourism, July 16, 2015
A total of 640 deer were tested for chronic wasting disease (CWD) during the 2014-2015 seasons, and 10 of those were confirmed positive. Samples were obtained from deer killed by hunters in southcentral and southwest parts of Kansas and from sick and/or suspect deer observed in the eastern, northcentral and northwest parts of the state.
- ‘Surprising’ Discovery Made About Chronic Wasting Disease , Food and Safety News, June 2015
According to researchers at The University of Texas Health Science Center at Houston (UTHealth), grass plants can bind, uptake and transport infectious prions. Why this is so important takes some understanding of what prions are. Much smaller than bacteria, prions are single proteins that cannot be destroyed by typical “kill strategies” such as extreme heat or ultraviolet light.
Soto’s team analyzed the retention of CWD and other infectious prion proteins and their infectivity in wheat grass roots and leaves that had been incubated with prion-contaminated material. They discovered that even highly diluted amounts of the material can bind to the roots and leaves. From there, they fed the wheat grass to hamsters, which became infected with the disease. The team also found the infectious prion proteins in plants that had been exposed to urine and feces from prion-infected hamsters and deer.
- Chronic wasting disease spreading among deer in Michigan, KTTC News, June 17, 2015
MICHIGAN – Two dozen deer have been collected in the first week of a targeted deer kill in Meridan Township, in Michigan, after chronic wasting disease killed animals in the area. According to the Lansing State Journal, experts estimate 59 deer in the township are infected. The disease is fatal and causes a mutated protein to multiply, and attack the animal’s immune system.
- DNR works to contain chronic wasting disease found in Meridian Township deer, Great Lakes Echo, June 5, 2015
The Michigan Department of Natural Resources says it’s found a deer in Meridian Township that’s tested positive for chronic wasting disease. It’s the first reported case of the disease in the state since 2008, and the very first time it has occurred in a wild deer population. Chronic wasting disease is not harmful to humans, but is always fatal to deer.
- Deer kill under way in Meridian Township, Lansing State Journal, June 4, 2015
The hunt “certainly will” continue through a lot of the summer, Stewart said, but he doesn’t anticipate it extending into hunting season. Bow season begins Oct.1. “We are in this for the long haul, unfortunately,” he added.
It’s thought that chronic wasting disease — which is not transmittable to humans — is more common in larger populations. The fatal neurological disease affects white-tailed deer, mule deer, moose and elk.
- Midnight Snipers Fighting CWD, WJIMAM.com, May 27, 2015
In the wake of Chronic Wasting Disease or CWD being confirmed in a wild Michigan deer, the Department of Natural Resources is moving quickly to implement an emergency plan it’s had for in place years but hoped to never use. The emergency management plan is aggressive and will likely change the dynamics of the deer population in the state for generations to come.
- CWD in Michigan, Deer Michigan, May 26,2015
The Michigan Department of Natural Resources has an emergency response plan for CWD, which it originally created in 2002, deployed in 2008 after a Kent County deer at a captive cervid facility tested positive for CWD, and updated in 2012 based on what it learned from that experience and from more recent science on CWD. So what is the DNR doing? What can we expect? What can we do to help? What are hunters required to do? What can’t we do? What should we do? Use the resources below to find out!
- Michigan confirms first case of CWD in free-ranging white-tailed deer, Michigan DNR sent this bulletin at 05/26/2015 02:01 PM EDT:Press Release
The Michigan departments of Natural Resources (DNR) and Agriculture and Rural Development (MDARD) today confirmed that a free-ranging deer in Meridian Township (Ingham County) has tested positive for chronic wasting disease (CWD), a fatal neurological disease that affects white-tailed deer, mule deer, elk and moose. This is the first time the disease has been found in Michigan’s free-ranging deer population.
The disease is caused by the transmission of infectious, self-multiplying proteins (prions) contained in saliva and other body fluids of infected animals. Susceptible animals can acquire CWD by direct exposure to these fluids or from environments contaminated with these fluids or the carcass of a diseased animal. Once contaminated, research shows that soil can remain a source of infection for long periods of time, making CWD a particularly difficult disease to eradicate. Some chronically CWD-infected animals will display abnormal behaviors, progressive weight loss and physical debilitation. There is no cure; once a deer is infected with CWD, it will die.
- Emerging Disease Issues > Chronic Wasting Disease (CWD), Michigan Emerging Disease Issues, 2015
Links to reports, documents, pictures
- DNR > Wildlife & Habitat > Wildlife Disease > Chronic Wasting Disease and Hunting, Michigan DNR, 2015
Disease information, How it affects Hunters, other resources
- Grass plants can transport infectious prions, Science Daily, May 15 2015
“There is no proof of transmission from wild animals and plants to humans,” said lead author Claudio Soto, Ph.D., professor of neurology at UTHealth Medical School and director of the UTHealth George and Cynthia W. Mitchell Center for Alzheimer’s Disease and Other Brain Related Illnesses. “But it’s a possibility that needs to be explored and people need to be aware of it. Prions have a long incubation period.”
Soto’s team analyzed the retention of infectious prion protein and infectivity in wheat grass roots and leaves incubated with prion-contaminated brain material and discovered that even highly diluted amounts can bind to the roots and leaves. When the wheat grass was consumed by hamsters, the animals were infected with the disease. The team also learned that infectious prion proteins could be detected in plants exposed to urine and feces from prion-infected hamsters and deer.
- Can DEER droppings transmit CHRONIC WASTING DISEASE to HUMANS?, Natural Unseen Hazards Blog, April 2, 2015
The biggest potential problem you face in having so many deer droppings in your garden is the potential for the transmission of E. coli and chronic wasting disease (CWD), a deer and elk disease similar to mad cow disease. The Pennsylvania Game Commission’s website notes that CWD has been detected in several Pennsylvania locations since it was first found in the state in 2012. After a bit of investigating, I discovered that the jury is still out on whether and how chronic wasting disease can be transmitted to humans. That being said, both the Pennsylvania Game Commission’s website and the Center for Disease Control’s website note that there’s no evidence that CWD is transmissible to humans. But they do not recommend eating meat from a deer that has tested positive for CWD. From what I found, fecal-to-oral transmission from deer to humans has not been completely ruled out, meaning the disease could possibly be transmitted to a human if she were to touch contaminated deer excrement and then inadvertently introduce it into her mouth, but no cases of this type of transmission have ever been recorded.
- Is chronic wasting disease a threat to humans?, Virology Blog, March 11, 2015
Another concern is that prions of chronic wasting disease could be transmitted to cows grazing in pastures contaminated by cervids. Prions can be detected in deer saliva and feces, and contamination of grass could pass the agent on to cows. In the laboratory, brain homogenates from infected deer can transmit the disease to cows. Therefore it is possible that cervid prions could enter the human food chain through cows.
Although the risk of human infection with CWD prions appears to be low, hunters should not shoot or consume an elk or deer that is acting abnormally or appears to be sick, to avoid the brain and spinal cord when field dressing game, and not to consume brain, spinal cord, eyes, spleen, or lymph nodes. No case of transmission of chronic wasting disease prions to deer hunters has yet been reported.
- 10 Reasons You Don’t Want CWD in Your Woods, QDMA, Feb 17, 2015
There is much confusion between CWD and hemorrhagic disease (EHD and bluetongue virus). EHD and bluetongue are serious matters in their own right, and their impact is more rapid, more visible and more dramatic. Deer carcasses pile up quickly in outbreak areas. By contrast, CWD is a slow poison, building over time, taking months or years to kill individual deer that are spreading the infection as they slowly die. Unlike the EHD and bluetongue viruses transmitted by insects, the CWD blight is steadily growing with no breaks, no recovery periods, no survivors, and no resulting immunity. The known impact sites for CWD in wild deer or elk currently include 19 states and two Canadian provinces, a list that has been growing recently. Minnesota and Maryland discovered CWD in free-roaming deer in 2011; Missouri in 2012; Pennsyvlania in 2013; and last year, Iowa. We should be concered about both EHD and CWD, but an important difference is that CWD can still be prevented from spreading to new areas. If you don’t hunt in or near regions with CWD, be very happy, and support all efforts to prevent the disease’s arrival near you. If it hits, the biological damage to the deer herd will be slow to build, but the impact on you and your hunting will likely be immediate and significant.
- First successful vaccination against ‘mad cow’-like wasting disease in deer, Science Daily, Dec 21, 2014
The study, to be published in Vaccine online Dec. 21, documents a scientific milestone: The first successful vaccination of deer against chronic wasting disease (CWD), a fatal brain disorder caused by unusual infectious proteins known as prions. Prions propagate by converting otherwise healthy proteins into a disease state.
- The importance of localized culling in stabilizing chronic wasting disease prevalence in white-tailed deer populations, Preventive Veterinary Medicine, Jan 2014
We addressed the functional differences between hunting and government culling programs for managing chronic wasting disease (CWD) in white-tailed deer by comparing prevalence over a 10-year period in Illinois and Wisconsin. When both Illinois and Wisconsin were actively culling from 2003 – 2007, there were no statistical differences between state CWD prevalence estimates. Wisconsin government culling concluded in 2007 and average prevalence over the next five years was 3.09 ± 1.13% with an average annual increase of 0.63%. During that same time period, Illinois continued government culling and there was no change in prevalence throughout Illinois.
- New York : DEC Amends New York’s Chronic Wasting Disease (CWD) Regulation in Response to Discovery of Disease in Ohio, New York State Department of Environmental Conservation, November 03, 2014
In late October, the Ohio Department of Agriculture confirmed a case of CWD in a white-tailed deer on a deer farm in Holmes County, OH – the first positive CWD case in the state. CWD has also been confirmed in captive deer on multiple farms in Pennsylvania and in the wild deer herd in that state.
- Pat Durkin column: Study suggests shooting more bucks to reduce CWD, Green Bay Gazette, March 28, 2014
A just-released University of Wisconsin study on chronic wasting disease recommends focusing more hunting pressure on the deer most likely to carry and spread CWD in whitetails: bucks, the males of the species.
Transmission of Chronic Wasting Disease in Wisconsin White-Tailed Deer: Implications for Disease Spread and Management, PlosOne, March 2014
. Using maximum-likelihood methods to evaluate alternative multi-state deterministic models of CWD transmission, harvest data strongly supports a frequency-dependent transmission structure with sex-specific infection rates that are two times higher in males than females.
- The importance of localized culling in stabilizing chronic wasting disease prevalence in white-tailed deer populations, Preventative Veterinary Medicine, Jan 2014
Despite its unpopularity among hunters, localized culling is a disease management strategy that can maintain low disease prevalence while minimizing impacts on recreational deer harvest.
- Chronic wasting disease, Prion, Jan-March 2012
Transmissible spongiform encephalopathies (prion diseases) in animals may be associated with a zoonotic risk potential for humans as shown by the occurrence of variant Creutzfeldt-Jakob disease in the wake of the bovine spongiform encephalopathy epidemic. Thus, the increasing exposure of humans in North America to cervid prions of chronic wasting disease (CWD) in elk and deer has prompted comprehensive risk assessments. The susceptibility of humans to CWD infections is currently under investigation in different studies using macaques as primate models. The necessity for such studies was recently reinforced when disease-associated prion protein and its seeding activity were detected in muscles of clinically inconspicuous CWD-infected white-tailed deer (WTD).
- CWD: A 10-Year Retrospective, Wisconsin Dept of Natural Resources,
In February 2002, the DNR was notified that three deer harvested the previous fall from Deer Management Unit 70A in western Dane County had tested positive for CWD. This discovery launched an intensive surveillance effort in Wisconsin that continues today. As of February 2012, nearly 172,000 wild white-tailed deer have been sampled, over 1,800 of which have tested CWD-positive.
There appear to be two main areas of CWD infection in Wisconsin. One is centered in western Dane and eastern Iowa counties. The second is located in northern Illinois and extends into southeastern Wisconsin. Illinois first detected the presence of CWD in this area in the fall of 2002 and as of April 2011, 336 CWD-positive deer have been found.
- Mad Cow Disease of Deer Can be Controlled by Targeted Culling, Long-term Study Finds, Nature World News, Oct 21, 2013
- Chronic Wasting Disease (CWD), USGS National Wildlife Health Center, May 21, 2013
- Chronic Wasting Disease, An emerging threat, Humane Society, Oct 4, 2012
In order to reduce the potential of future biological threats from this and other zoonotic diseases on a larger scale, states must ban game farms and captive hunts. The high population densities that characterize captive hunt facilities greatly increase the risk of disease transmission.
The risk of CWD spreading to native populations of wildlife is taken very seriously. Thus far, testing and “depopulating” are the chosen methods of eradication.
- Deer density and disease prevalence influence transmission of chronic wasting disease in white-tailed deer, Ecosphere, Jan 2013
. We evaluated the influence of deer density,
landscape features, and soil clay content on transmission of chronic wasting disease (CWD) in young white-tailed deer in south-central Wisconsin, USA. We evaluated how frequency-dependent, density-dependent, and intermediate transmission models predicted CWD incidence rates in harvested yearling deer. An intermediate transmission model, incorporating both disease prevalence and density of infected deer, performed better than simple density- and frequency-dependent models. Our results indicate a combination of social structure, non-linear relationships between infectious contact and deer density, and distribution of disease among groups are important factors driving CWD infection in young deer.
- Study Spells Out Spread of Brain Illness in Animals, New York Times, Sept 9, 2009
There is no evidence to date that humans who hunt, kill and eat deer have developed chronic wasting disease. Nor does the prion that causes it pass naturally to other animal species in the wild.
Besides mad cow and chronic wasting disease, the prion diseases include Creutzfeldt-Jakob, which leads to dementia and death in humans. Each of these diseases is caused by a different strain, and all strains behave somewhat differently.
In the case of chronic wasting disease, “it turns out prions exploit the oldest trick in the book used by pathogens and parasites,” said Mike Miller, a veterinarian at the Colorado Division of Wildlife who is an expert on chronic wasting disease.
“Fecal-oral transmission is very effective,” Dr. Miller continued. Each deer excretes about two pounds of fecal pellets a day. As wild herds move around, or captive herds are trucked between states, more soil becomes infected.
- The Spread of CWD in White-tailed Deer, The BuckManager, Oct 29, 2009
The finding suggests a reasonable explanation for transmission of the disease among white-tailed deer, mule deer, and possibly elk and moose in the environment. While the study reveals that prions are shed in feces of symptomatic deer as well, the discovery that the infected deer shed prions in their feces many months before they show clinical symptoms is the most unsettling. White-tailed deer, mule deer, elk and moose inadvertently consume feces and soil in the course of their daily browsing and grazing.
- Prions found in feces of deer asymptomatic for chronic wasting disease, UCSF, Sept 9, 2009
Scientists have discovered that deer asymptomatic for a fatal brain condition known as chronic wasting disease excrete the infectious prions that cause the disease in their feces. The finding, they say, suggests a plausible explanation for transmission of the disease among deer and, possibly, elk and moose in the environment. While the study reveals that prions are shed in feces of symptomatic deer as well, the discovery that the infected deer shed prions in their feces many months before they show clinical symptoms has particularly provocative implications.
Deer, elk and moose inadvertently consume feces and soil in the course of their daily grazing. Given this, the team set out to determine whether the animals could develop chronic wasting disease through long-term consumption of contaminated feces. They did so by measuring the amount of prions contained in the feces of orally infected deer up until the time they became symptomatic and then calculated whether prolonged exposure to the concentrations of prions in these feces would be enough to cause the disease.
- Host culling as an adaptive management tool for chronic wasting disease in white-tailed deer: a modelling study, J Appl Ecol. Apr 2009; 46(2): 457–466.
- Chronic Wasting Disease and Potential Transmission to Humans, CDC, June 2004
Increasing spread of CWD has raised concerns about the potential for increasing human exposure to the CWD agent. The foodborne transmission of bovine spongiform encephalopathy to humans indicates that the species barrier may not completely protect humans from animal prion diseases. Conversion of human prion protein by CWD-associated prions has been demonstrated in an in vitro cell-free experiment, but limited investigations have not identified strong evidence for CWD transmission to humans. More epidemiologic and laboratory studies are needed to monitor the possibility of such transmissions.
- Chronic Wasting Disease: Frequently Asked Questions, Illinois DNR
- Chronic Wasting Disease: Moving On, Wyoming Game & Fish Dept
Chronic Wasting Disease Is Spreading, Can It Be Stopped?, Grand View Outdoors, Oct 8, 2015
“We call them Droolers and Shakers,” said Don Bates, former supervisor of chronic wasting disease operations for the Wisconsin Department of Natural Resources. Bates, now retired, said many people ignore CWD because most infected deer die alone and unseen. Although some huddle against a garage or near a dryer vent in winter to protect themselves from the cold, most die unseen and undocumented in thickets, wetlands or river bottoms. It’s getting worse at faster and higher rates than ever.”
Pa. expands deer CWD disease area, WITF, May 6, 2015
Four Maryland Deer Test Positive for Chronic Wasting Disease, Maryland DNR, Jan 20, 2015
Chronic Wasting Disease and Potential Transmission to Humans, CDC Emerging Infectious Diseases, June 2004