Download the full Chronic Wasting Disease and Cervidae Regulations in North America. [PDF]
The number one objective in the management of CWD is to prevent its spread into new areas. One theoretical mode of disease transmission is via infected carcasses. Therefore, in an effort to minimize the risk of disease spread, a number of states have adopted regulations affecting the transportation of hunter-harvested deer and elk.
Since the suspected infective agent (prion) is concentrated in the brain, spinal cord and lymph glands, the most common regulation is the prohibition of the importation of whole carcasses harvested from CWD areas. Some states, like Colorado, also have established regulations addressing the transport of deer and elk out of CWD areas. Generally, states that have adopted carcass transportation regulations do not allow the importation of any brain or spinal column tissue and allow transport of only the following:
A summary of state-by-state carcass transportation regulations is provided in Column J of the regulations on each state page (accessible from the home page) or on the map. Since these regulations are continually evolving, it is recommended that before hunting you check the CWD regulations in your home state, the state in which you will be hunting and states in which you will travel through en route home from your hunting area. Most state wildlife agencies provide regulations information on their websites, and may be accessed via the clickable map on the home page.
The Carcass Transport and Disposal Working Group of the Association of Fish and Wildlife Agencies (AFWA) Fish and Wildlife Health Committee developed the following guidelines for regulatory and non-regulatory approaches to carcass transport and disposal. The intent of the working group is to encourage states to adopt policies that minimize risk; do not hinder hunting, wild cervid population management, or disease control; are easily understood; and promote compliance because they are consistent and well-justified. The recommendations are based on current knowledge of CWD and may be updated when new information becomes available. The Working Group recognizes state wildlife management agencies will tailor their approach to fit individual concerns and situations, and asks that agency directors, through AFWA, give serious and urgent consideration to this matter so that this potential risk of CWD spread can be minimized.
Senate Environment and Public Works Subcommittee on Fisheries, Wildlife and Water
April 6, 2004
U.S. House of Representatives
House Resources Committee
Subcommittees on Forests and Forest Health, and
Fisheries Conservation, Wildlife and Oceans
Thursday, June 19, 2003
To establish a National Chronic Wasting Disease Task Force, and for other purposes.
HR2431 Word document
To amend the Fish and Wildlife Coordination Act to coordinate and strengthen scientific research and monitoring, and to promote public outreach, education, and awareness, of Chronic Wasting Disease affecting free-ranging populations of deer and elk, and for other purposes.
HR2430 Word document
To authorize the Secretary of the Interior to make grants to State and tribal governments to assist State and tribal efforts to manage and control the spread of chronic wasting disease in deer and elk herds, and for other purposes.
S1366 PDF document | Word document
To authorize the Secretary of the Interior to make grants to State and tribal governments to assist State and tribal efforts to manage and control the spread of chronic wasting disease in deer and elk herds, and for other purposes.
HR2636 PDF document | Word document
24 organizations sign letter requesting funding for National CWD Plan- April 18, 2003
Letter Word document
U.S. House of Representatives
House Resources Committee
Subcommittees on Forests and Forest Health, and
Fisheries Conservation, Wildlife and Oceans
May 16, 2002
CWD Alliances’ Testimony PDF document | Word document
The rogue proteins that cause chronic wasting disease (CWD) exhibit a dramatic increase in their infectious nature when bound to common soil particles, according to a new study.
Writing in the journal Public Library of Science (PLoS) Pathogens, a group led by University of Wisconsin-Madison prion expert Judd Aiken reports that prions, the protein agents of a family of fatal brain disorders, bind tightly to a common soil mineral and significantly increase the oral transmissibility of the agent.
The finding is important because it may help explain how chronic wasting disease and scrapie persist in the environment and spread efficiently in animal populations.
“We found a huge difference between infectious agent alone and infectious agent bound to these soil particles,” says Aiken, the senior author of the new study and a professor of comparative biosciences in the UW-Madison School of Veterinary Medicine. “We observed an almost 700-fold difference” in the rate of infection.
Prions are an abnormal form of a protein produced normally by the body. Tough as nails, they can persist in the environment for long periods of time and retain their infectious capabilities. It is believed that prions may persist in the soil around the carcasses of dead animals and other locations where infected animals shed the protein in body fluids.
“These disease agents can stay out there for years and stay infectious,” Aiken explains.
And herbivores such as deer and sheep, which are susceptible to prion infection, tend to consume a fair amount of dirt daily as they graze and forage. They are also known to consume soil as a source of minerals. Mineral licks are frequented by many animals, raising the prospect that the agents may become concentrated in the soil.
Relatively little is known about the routes of prion transmission in animals, but the new Wisconsin study may help to resolve one puzzle: Oral transmission of prions, says Aiken, tends not to be very efficient.
“This is a dichotomy in our field, and maybe (the new research) is part of the answer.”
In their studies, the Wisconsin researchers looked at the ability of prions to bind to different types of common soil minerals. One, known as montmorillonite, is a type of clay and prions seem to have a special affinity for latching onto the microscopic particles.
“We expected the binding of the montmorillonite to be the highest among the minerals we examined. However, we were surprised by the strength of the binding,” notes Joel Pedersen, a UW-Madison professor of soil science who helped direct the new study.
The Wisconsin team also looked at the ability of the prion to bind to two other common soil minerals: quartz and kaolinite, another common clay mineral.
“We found binding of the abnormal protein to all three,” says Aiken, “but the binding to montmorillonite was very avid, very tight. We found it very difficult to remove the prions from the montmorillonite.”
Feeding the prion-mineral mix to hamsters, a common animal model for prion disease, Aiken’s team expected to see a lower rate of infection than animals dosed with pure agent. Surprisingly, prions bound to montmorillonite were significantly more infectious than prions alone.
“We thought the binding might decrease infectivity,” Aiken explains. “In each case, you add montmorillonite and we get more animals sicker and quicker than in the absence of montmorillonite clay.”
What is occurring in soils in the woods and on the farm is unknown, says Pedersen, but the new findings may help begin to answer some key questions about how prions survive in the soil and retain their infectious nature, sometimes for years.
In the case of scrapie, the prion disease of sheep, observations of sheep pastures in the United Kingdom and Iceland have shown that animals introduced into pastures that once held infected animals could become infected. Infectivity of prions was also enhanced when they were bound to whole soil.
“Since the 1940s it’s been known that ‘infected pastures’ have the ability to infect new animals,” according to Aiken.
Pedersen notes that soils are a complex mixture of organic and inorganic components that vary across the landscape and that scientists are just beginning to tease out factors in soils that may contribute to transmissibility. The new study implies, he says, “that some soils may promote the transmission of the prion agent more readily than others.”
Why that’s the case is unknown, Pedersen explains, but the Wisconsin team is exploring several hypotheses: that the soil particles might somehow protect the prion from degradation in the digestive system, that prions bound to clay might change the route or degree of uptake of the agent, or that the mineral somehow alters the size of prion aggregates, which have been shown to be more infectious than prions alone.
Aiken emphasizes there’s still much to learn about routes of prion transmission, and the role of soil is just beginning to be explored.
“Soil is a very complex medium and we don’t know what the agent is binding to” in natural or agricultural settings, Aiken says. “We do know that soil is not the only way it transmits. Animal-to-animal transmission is important, too.”
In addition to Aiken and Pedersen, authors of the PLoS Pathogens paper include Christopher J. Johnson, Rick J. Chappell and Debbie McKenzie. The work was supported by a grant from the U.S. Department of Defense.
CWD Update 87 July 6, 2007
State and Provincial Updates
Illinois: Paul Shelton, Illinois Department of Natural Resources provides the following: Illinois Department of Natural Resources staff collected 6,733 usable CWD surveillance samples during the period beginning July 1, 2006. A few additional samples from suspect deer remain untested at this time. Testing yielded 41 CWD-positive deer and 6,692 ‘not detected’. Forty-one positives were detected in four counties in northern Illinois: Winnebago (18), Boone (13), DeKalb (6), and McHenry (4). No new counties were identified as having CWD, and no disease was detected in Ogle County, in which CWD was first identified during the 2005-2006 sampling season. However, CWD was identified in southeastern DeKalb County, more than 20 miles southeast of previously-identified locations. Samples were collected from a variety of sources, including deer check stations in high-risk counties (3,097), sample drop-off locations for archery hunters (175), cooperating meat processors (1,778), suspect deer (25), roadkills in CWD counties (16), and culling efforts (1,642). Cooperating meat lockers were added as a sampling source this year to provide a statewide sampling base outside the identified CWD area. Hunter-harvested deer accounted for 17 (41%) of the positives identified, with the remainder coming from suspect deer (4; 10%); roadkills (1; 2%); and sharpshooting (19; 46%). Illinois DNR CWD information is available at: https://www.dnr.illinois.gov/programs/CWD/Pages/default.aspx.
Montana: Neil Anderson, Montana Fish, Wildlife and Parks provides the following: Cases of CWD in wild elk or deer have been found within 100 miles of the Montana border in Wyoming and the Black Hills of South Dakota and within 150 miles of the border with the Canadian providences of Saskatchewan and Alberta. Montana Fish, Wildlife and Parks (FWP) began surveillance activities in 1998 following a directive from the Governor’s office to work with the Department of Livestock to survey for and manage CWD in Montana. Initially, FWP activities focused on obtaining a broad geographical survey from across the state using existing game check stations. In 1999 surveillance efforts were expanded to include targeted surveillance of symptomatic animals, special collections of wild elk and deer near alternative livestock operations, and broad geographical surveillance of hunter killed deer and elk. The geographical survey area changed in 2000 concentrating on areas bordering Saskatchewan (region 6) and Wyoming and South Dakota (regions 5 and 7) where CWD had been detected in wild populations. This selected geographical survey has been followed through the 2006 big game hunting season.
Since 1998 over 10,600 moose, deer and elk have been tested for CWD. Hunter-harvested animals remain the bulk of samples collected but efforts to enhance collections of targeted and road-killed animals resulted in an increase in the numbers of samples collected in these groups. To date, all tests have produced no evidence of CWD in wild populations. Surveillance efforts have shifted in priority since 1998 when the first statewide geographical survey was conducted. The majority of samples have been collected near the borders of regions 5, 6 and 7 and in areas surrounding the only alternative livestock operation to test positive for CWD near Philipsburg, MT. The number of samples collected during 2003 was nearly double that of previous efforts and has remained consistent through 2005 declining slightly in 2006. Although surveillance efforts have changed, mule deer have consistently comprised the majority of wild Cervids tested for CWD in Montana. To date, a total of 1342 samples have been tested in the 2006 surveillance period which will continues until June 30, 2007. The hunting district could not be determined for 18 samples but were included in the regional summaries. Montana FWP CWD information is available at: fwp.mt.gov/hunting/chronicWD.html.
West Virginia: Paul Johansen, West Virginia Department of Natural Resources provides the following: Three additional free-ranging white-tailed deer in Hampshire County, West Virginia, tested positive for Chronic Wasting Disease (CWD). This brings the total number of CWD-positive deer found in Hampshire County to 13. These most recent samples were collected from a total of 101 adult deer taken in March and April 2007 by DNR personnel as part of an ongoing and intensive CWD surveillance effort. The three CWD-positive deer were collected within the CWD Containment Area located north of U.S. Route 50 in Hampshire County.
When CWD was first confirmed in Hampshire County in September 2005, the DNR immediately implemented its CWD – Incident Response Plan. As part of that plan, the DNR has been engaged in intensive CWD surveillance efforts designed to determine the distribution and prevalence of the disease. These surveillance efforts have included carefully planned and coordinated deer collections within Hampshire County by CWD deer collection teams comprised of Wildlife Biologists, Wildlife Managers and Conservation Officers within the DNR.
The following disease management strategies have been implemented by the DNR within the affected area of Hampshire County.
West Virginia DNR CWD information is available at: wvdnr.gov/Hunting/ChronicWaste.
Third International Chronic Wasting Disease Symposium The Utah Division of Wildlife Resources has announced their intent to host the 3rd International CWD Symposium in Park City, Utah during July of 2009. The initial CWD Symposium was held in Denver, Colorado in 2002; the second was held in Madison, Wisconsin in 2005. Details on the 2009 conference will be forthcoming. Many thanks to our colleagues in Utah for their willingness to arrange and host this event.
Oral Transmissibility of Prion Disease Is Enhanced by Binding to Soil Particles Christopher J. Johnson, Joel A. Pedersen, Rick J. Chappell, Debbie McKenzie and Judd M. Aiken PLoS Pathogens Vol. 3, No. 7, e93 doi:10.1371/journal.ppat.0030093.
Abstract: Soil may serve as an environmental reservoir for prion infectivity and contribute to the horizontal transmission of prion diseases (transmissible spongiform encephalopathies [TSEs]) of sheep, deer and elk. TSE infectivity can persist in soil for years, and we previously demonstrated that the disease-associated form of the prion protein (PrPTSE) binds to soil particles and that prions adsorbed to the common soil mineral montmorillonite (Mte) retain infectivity following intracerebral inoculation. Here, we assess the oral infectivity of Mte- and soil-bound prions. We establish that prions bound to Mte are orally bioavailable and that, unexpectedly, binding to Mte significantly enhances disease penetrance and reduces incubation period relative to unbound agent. Cox proportional hazards modelling revealed that across the doses of TSE agent tested, Mte increased the effective infectious titer by a factor of 680 relative to unbound agent. Oral exposure to Mte-associated prions led to TSE development in experimental animals even at doses too low to produce clinical symptoms in the absence of the mineral. We tested the oral infectivity of prions bound to three whole soils differing in texture, mineralogy and organic carbon content, and found soil-bound prions to be orally infectious. Two of the three soils increased oral transmission of disease, and the infectivity of agent bound to the third soil was equivalent to that of unbound agent. Enhanced transmissibility of soil-bound prions may explain the environmental spread of some TSEs despite the presumably low levels shed into the environment. Association of prions with inorganic microparticles represents a novel means by which their oral transmission is enhanced relative to unbound agent. pathogens.plosjournals.org/perlserv/?request=get-document&doi=10.1371/journal.ppat.0030093.
Abstract: Chronic wasting disease (CWD) was diagnosed in a free-ranging moose (Alces alces shirasi) killed by a hunter in Jackson County, Colorado, USA, in September 2005. The diagnosis was based upon immunohistochemistry (IHC) demonstrating the presence of accumulations of CWD-associated prion protein (PrPCWD) in tissue sections of medulla oblongata at the level of the obex (dorsal motor nucleus of the vagus) and in retropharyngeal lymph node (RPLN); additional testing by IHC revealed deposits of PrPCWD in multiple sections of medulla oblongata and cervical spinal cord as well as palatine tonsil and submandibular lymph node tissues. Western blot confirmed the presence of PrPCWD in RPLN and tonsil tissue. The PrPCWD also was detected via enzyme-linked immunosorbent assay of RPLN tissue. Spongiform encephalopathy was observed in sections of the brainstem and cervical spinal cord, although no clinical signs were noted by the hunter who killed the animal. The affected moose was homozygous for methionine at codon 209 of the prion protein coding region. In October 2006, two additional free-ranging moose were diagnosed with CWD. Epidemiology and implications of CWD in moose remain to be determined. jwildlifedis.org/cgi/content/abstract/43/2/309.
Abstract: Fourteen, 3-month-old calves were intracerebrally inoculated with the agent of chronic wasting disease (CWD) from white-tailed deer (CWDwtd) to compare the clinical signs and neuropathologic findings with those of certain other transmissible spongiform encephalopathies (TSE, prion diseases) that have been shown to be experimentally transmissible to cattle (sheep scrapie, CWD of mule deer [CWDmd], bovine spongiform encephalopathy [BSE], and transmissible mink encephalopathy). Two uninoculated calves served as controls. Within 26 months postinoculation (MPI), 12 inoculated calves had lost considerable weight and eventually became recumbent. Of the 12 inoculated calves, 11 (92%) developed clinical signs. Although spongiform encephalopathy (SE) was not observed, abnormal prion protein (PrPd) was detected by immunohistochemistry (IHC) and Western blot (WB) in central nervous system tissues. The absence of SE with presence of PrPd has also been observed when other TSE agents (scrapie and CWDmd) were similarly inoculated into cattle. The IHC and WB findings suggest that the diagnostic techniques currently used to confirm BSE would detect CWDwtd in cattle, should it occur naturally. Also, the absence of SE and a distinctive IHC pattern of CWDwtd and CWDmd in cattle suggests that it should be possible to distinguish these conditions from other TSEs that have been experimentally transmitted to cattle. vetpathology.org/cgi/content/abstract/44/4/487.
An e-book is now available on the CWD Alliance website. The emphasis of this e-book is on modeling approaches to describe and gain insight of the spatial epidemiology of CWD.
Contributing Authors: Mary M. Conner – Utah Division of Wildlife Resources John E. Gross – National Park Service Paul C. Cross – United States Geological Survey Michael R. Ebinger – Utah State University Robert R. Gillies – Utah State University Michael D. Samuel – United States Geological Survey Michael W. Miller – Colorado Division of Wildlife
CWD Update 86 May 3, 2007
State and Provincial Updates
Lloyd Fox, Kansas Department of Wildlife & Parks provides the following: Kansas Dept. Wildlife and Parks has collected 10,737 samples for CWD testing since 1996. The only known positive cases of CWD in Kansas occurred in November 2001 at a captive elk facility and in December 2005 from an adult female white-tailed deer killed by a hunter in Cheyenne County. Usable tissues were obtained from 2,970 animals during 2006 and the recent hunting seasons. CWD prions were not detected from any of those samples. The species breakdown for the sample was 2,724 white-tailed deer, 225 mule deer, 15 elk, and 6 animals where the species was not recorded. The majority of the specimens were obtained from animals killed by hunters (n = 2,342 plus n = 400 on animals killed by hunters and taken to taxidermists). Animals killed by vehicles accounted for 185 specimens, while 28 specimens were collected from animals considered CWD suspects. Other source types, such as animals confiscated for law enforcement purposes, accounted for the remaining 15 specimens. For more information on CWD in Kansas, phone Ruby Mosher at 620-342-0658 or email her at [email protected]. Kansas Department of Wildlife & Parks press release is available at: kdwp.state.ks.us/news/kdwp_info/news/weekly_news/4_26_07/chronic_wasting_disease_not_found_in_2006_deer_season.
John Major, New York Department of Environmental Conservation (DEC), provides the following: In New York State, efforts continued with CWD surveillance through sampling of hunter killed deer statewide and mandatory check of hunter killed deer and collection of vehicle killed deer in the Oneida-Madison County CWD Containment Area. Despite testing over 7,900 deer, including 1,800 deer from the CWD Containment Area from April 1, 2006 through March 31, 2007, no new cases were detected. CWD surveillance began in New York in 2002, with increased efforts in 2005 after the disease was detected in 5 captive and 2 wild deer in Oneida County. Since 2002, over 18,700 samples have been collected throughout the state, including 3,900 samples from the Oneida-Madison County CWD Containment Area, with no additional positives found. The involved captive facilities were depopulated within weeks of the initial discovery. Regulations prohibiting the feeding of wild deer and restricting the import and movement of live animals and carcasses remain in effect. Surveillance will continue at the same level of effort in the coming year. The NY DEC maintains CWD information at: www.dec.state.ny.us/website/dfwmr/wildlife/deer/cwd.html.
The following press release was issued by the North Dakota Game & Fish Department of April 16, 2007: CWD Test Results All Negative. North Dakota deer and elk populations remain free of chronic wasting disease, according to test results recently received by the state Game and Fish Department. Last fall, North Dakota hunters submitted samples for testing from 2,993 wild deer, 37 elk and four moose collected during the 2006 hunting season. All those samples tested negative, said Erika Butler, Game and Fish Department wildlife veterinarian. Samples for CWD testing were sent to the Wyoming State Veterinary Lab last December. “We are always hopeful that this will be the outcome,” Butler said. “We will continue to be aggressive. In addition to testing any suspect animals throughout the year, we plan to continue our hunter-harvest surveillance in the fall.” Samples in 2006 were collected from hunter-harvested deer taken from all deer hunting units in the state. “Our volunteer cooperation is overwhelming,” Butler said. “We couldn’t achieve our goals without their help. Hunters, meat processors, taxidermists, and the assistance from other agencies are vital in this process.” Since 2002, nearly 8,500 North Dakota deer and 147 elk have tested negative for CWD. To date, CWD has not been diagnosed in wild or farmed deer or elk in North Dakota. Chronic wasting disease affects the nervous system of members of the deer family and is always fatal. Scientists have found no evidence that CWD can be transmitted naturally to humans or livestock. Press release is at: gf.nd.gov/multimedia/news/2007/04/070406.html. North Dakota Game & Fish Department maintains CWD information at: www.gf.nd.gov/hunting/cwd-q-and-a.html.
Leslie McFarlane, Utah Division of Wildlife Resources, provides the following: The Utah Veterinary Diagnostic Laboratory in Logan has completed testing 1,934 mule deer samples collected during the 2006 hunting season by the Utah Division of Wildlife Resources. The positive samples include one deer taken during last fall’s archery season, two harvested during the muzzleloader season, and the remaining four were collected during the rifle hunt. The animals were all harvested in areas where CWD has previously been detected, with 6 from the La Sal Mountains and 1 from Vernal. No positive animals were detected from the central portion of the state. In addition to the deer that were tested, nearly 500 samples from elk were collected and none of these tested positive for the disease. To date, CWD has not been detected in elk from Utah. Since the fall of 2002, nearly 12,000 deer samples have been collected in Utah and tested for CWD. Distribution of CWD in Utah occurs in three distinct geographical areas including central and northeastern Utah, where it is estimated that less than 1 percent of the buck population is affected by CWD. In the LaSal Mountains of southeastern Utah, prevalence rates are estimated to be near 2%. To date, 33 samples collected from mule deer have tested positive for CWD. Twenty-four of the 33 positive samples came from the LaSal Mountains, five from the Vernal area, one near the south end of Flaming Gorge, one near Fountain Green, and two 20 miles north of Fountain Green. The Utah Division of Wildlife Resources maintains CWD information at: wildlife.utah.gov/diseases/cwd.
Levels of Abnormal Prion Protein in Deer and Elk with Chronic Wasting Disease. Brent L. Race, Kimberly D. Meade-White, Anne Ward, Jean Jewell, Michael W. Miller, Elizabeth S. Williams, Bruce Chesebro, and Richard E. Race Emerg Infect Dis. 2007 Jun; [Epub ahead of print].
Abstract: Chronic wasting disease (CWD) of deer and elk is a widespread health concern because its potential for cross-species transmission is undetermined. CWD prevalence in wild elk is much lower than its prevalence in wild deer, and whether CWD-infected deer and elk differ in ability to infect other species is unknown. Because lymphoid tissues are important in the pathogenesis of some transmissible spongiform encephalopathies such as sheep scrapie, we investigated whether CWD-affected elk and deer differ in distribution or quantity of disease-associated prion protein (PrPres) in lymphoid tissues. Immunoblot quantification of PrPres from tonsil and retropharyngeal lymph nodes showed much higher levels of PrPres in deer than in elk. This difference correlated with the natural prevalence of CWD in these species and suggested that CWD-infected deer may be more likely than elk to transmit the disease to other cervids and have a greater potential to transmit CWD to noncervids. www.cdc.gov/eid/content/13/6/pdfs/07-0186.pdf?s_cid=eid07_0186_x.
Abstract: Advances in acquiring and analyzing the spatial attributes of data have greatly enhanced the potential utility of wildlife disease surveillance data for addressing problems of ecological or economic importance. We present an approach for using wildlife disease surveillance data to identify areas for (or of) intervention, to spatially delineate paired treatment and control areas, and then to analyze these nonrandomly selected sites in a meta-analysis framework via before–after–control–impact (BACI) estimates of effect size. We apply these methods to evaluate the effectiveness of attempts to reduce chronic wasting disease (CWD) prevalence through intensive localized culling of mule deer (Odocoileus hemionus) in north-central Colorado, USA. Areas where surveillance data revealed high prevalence or case clusters were targeted by state wildlife management agency personnel for focal scale (on average <17 km2) culling, primarily via agency sharpshooters. Each area of sustained culling that we could also identify as unique by cluster analysis was considered a potential treatment area. Treatment areas, along with spatially paired control areas that we constructed post hoc in a case-control design (collectively called “management evaluation sites”), were then delineated using home range estimators. Using meta-BACI analysis of CWD prevalence data for all management evaluation sites, the mean effect size (change of prevalence on treatment areas minus change in prevalence on their paired control areas) was 0.03 (SE = 0.03); mean effect size on treatment areas was not greater than on paired control areas. Excluding cull samples from prevalence estimates or allowing for an equal or greater two-year lag in system responses to management did not change this outcome. We concluded that management benefits were not evident, although whether this represented true ineffectiveness or was a result of lack of data or insufficient duration of treatment could not be discerned. Based on our observations, we offer recommendations for designing a management experiment with 80% power to detect a 0.10 drop in prevalence over a 6–12-year period. www.esajournals.org/esaonline/?request=get-abstract&issn=1051-0761&volume=017&issue=01&page=0140.
Abstract: Animals that naturally acquire the prion diseases have a well-developed olfactory sense that they utilize for a variety of basic behaviors. To assess the potential for the nasal cavity to serve as a point of entry for prion diseases, a small amount of prion-infected brain homogenate was placed inferior to the nostrils of hamsters, where it was immediately sniffed into the nasal cavity. Hamsters extranasally inoculated with the HY strain of transmissible mink encephalopathy (TME) agent had an incubation period that was not significantly different from per os inoculation of the same dose of the HY TME agent. However, the efficiency of the nasal route of inoculation was determined to be 10 to 100 times greater based on endpoint dilution analysis. Immunohistochemistry on tissues from hamsters killed at 2-week intervals after inoculation was used to identify the disease-associated form of the prion protein (PrPd) to determine the route of prion neuroinvasion. Nasal mucosa-associated lymphoid tissue and submandibular lymph nodes initially accumulated PrPd as early as 4 weeks postinfection. PrPd was first identified in cervical lymph nodes at 8 weeks, in the mesenteric lymph nodes, spleen, and Peyer’s patches at 14 weeks, and in the tongue 20 weeks after inoculation. Surprisingly, there was no evidence of PrPd in olfactory epithelium or olfactory nerve fascicles at any time after inoculation. Therefore, the HY TME agent did not enter the central nervous system via the olfactory nerve; instead, PrPd accumulated in elements of the cranial lymphoreticular system prior to neuroinvasion. jvi.asm.org/cgi/content/abstract/81/9/4482.
Abstract: Transmissible spongiform encephalopathies are fatal neurodegenerative diseases that are caused by unconventional pathogens and affect the central nervous system of animals and humans. Several different forms of these diseases result from natural infection (i.e. exposure to transmissible spongiform encephalopathy agents or prions, present in the natural environment of the respective host). This holds true also for scrapie in sheep, bovine spongiform encephalopathy in cattle, chronic wasting disease in elk and deer, or variant Creutzfeldt–Jakob disease in humans, all of which are assumed to originate predominantly from peroral prion infection. This article intends to provide an overview of the current state of knowledge on the spread of scrapie, chronic wasting disease, bovine spongiform encephalopathy and variant Creutzfeldt–Jakob disease agents through the body in naturally affected hosts, and in model animals experimentally challenged via the alimentary tract. Special attention is given to the tissue components and spreading pathways involved in the key stages of prion routing through the body, such as intestinal uptake, neuroinvasion of nerves and the central nervous system, and centrifugal spread from the brain and spinal cord to peripheral sites (e.g. sensory ganglia or muscles). The elucidation of the pathways and mechanisms by which prions invade a host and spread through the organism can contribute to efficient infection control strategies and the improvement of transmissible spongiform encephalopathy diagnostics. It may also help to identify prophylactic or therapeutic approaches that would impede naturally acquired transmissible spongiform encephalopathy infections. content.febsjournal.org/cgi/content/abstract/274/3/588.
USDA FY08 Budget Request for Chronic Wasting Disease The United States Department of Agriculture’s 2008 budget summary is posted at: www.obpa.usda.gov/budsum/fy08budsum.pdf. Page 76 of this document (Pest and Disease Management Programs) identifies that “Decreased funding is also proposed for brucellosis, chronic wasting disease, pseudorabies, and other efforts.” The line item for CWD in the FY08 President’s Budget Request for USDA is $12.3M, down $6.2M from the FY07 budget estimate of $18.5M. USDA utilizes this funding to provide fiscal support to the states for CWD surveillance activities (both captive and free-ranging). The President’s Budget Request is the initial portion of the federal appropriations process. Congress ultimately determines the level of funding that will be made available to USDA for CWD and other programs.
CWD Update 85 March 24, 2007
State and Provincial Updates
Ontario: John Dungavell, Ontario Ministry of Natural Resources, provides the following: Since 2002, Ontario has conducted CWD surveillance of hunter-harvested deer. The program has tested more than 3500 deer with all negative results to date. Ontario will continue to conduct surveillance activities in the 2007 hunting season. In 2005, the Government of Ontario developed the Ontario CWD Surveillance and Response Plan which outlines the province’s actions with regards to CWD. In November 2005, Ontario passed a regulation restricting the importation of high risk cervid parts (head, spinal column etc.) from other jurisdictions. For more information on the Ontario plan, the regulation, or our surveillance program, please see our CWD website at http://www.mnr.gov.on.ca/MNR/hunting/cwd.
Additionally, if an Ontarian harvests a CWD positive cervid in your jurisdiction, please contact John Dungavell at 705-755-1573.
Pennsylvania: Bob Boyd, Pennsylvania Game Commission, provides the following on their recent CWD exercise: On Nov. 11, 2006, Pennsylvania Game Commission (PGC) Executive Director Carl G. Roe announced that the agency would conduct a CWD response simulation exercise in the first quarter of 2007. To more fully evaluate their preparedness, the Pennsylvania Game Commission developed different scenarios for each of the six region offices and the Harrisburg headquarters. Each scenario had a different set of constructs, variables and challenges that staff had to work through. One week after the exercise commenced, each team reported on their efforts to respond to the simulated discovery of CWD. Details of each response will be incorporated into the agency’s Operational Plan. The decision to hold the drill was a product of two meetings to review and update the state’s CWD response plan, as well as the agency’s internal operational plan. “Currently, there are no confirmed or suspected cases of CWD-infected deer or elk in Pennsylvania, and we are working to ensure that it stays that way,” Roe said. “While there always is room for improvement, I believe that, having gone through this planning exercise, our agency response plan provides a solid foundation should CWD be identified within our borders.
Pennsylvania Game Commission CWD information is at: http://www.pgc.state.pa.us/pgc/cwp/view.asp?a=458&q=163873.
South Dakota: Steve Griffin, South Dakota Game, Fish, and Parks, provides the following: In the South Dakota CWD Surveillance period of July 1, 2006 to February 28, 2007 a total of 2,515 samples were collected for CWD surveillance. Breakdown of the sampling is as follows:
Below is a listing of the positive cervids that have been found in South Dakota during the surveillance period of July 1, 2006 to February, 2007.
In Summary: To date, South Dakota has found 57 cases of CWD (39 deer and 18 elk) in free ranging deer and elk since testing began in 1997. Wind Cave National Park accounts for 16 of these animals (8 elk, 8 deer). Three elk have been found in Custer State Park. A total of 14,817 wild deer and elk have been tested for CWD since 1997.
South Dakota Game, Fish, and Parks CWD information is at: http://www.sdgfp.info/Wildlife/hunting/BigGame/CWD.htm.
Virginia: After extensive testing, the Virginia Department of Game and Inland Fisheries (VDGIF) has not found any evidence of chronic wasting disease (CWD) in Virginia’s white-tailed deer population. In 2006, over 800 samples were collected from white-tailed deer throughout the state. Approximately 500 samples were collected from the active surveillance area, which includes the western and northern parts of Shenandoah, Frederick, Clarke and Loudoun Counties, the area of Virginia closest to where CWD has been detected in West Virginia. All hunters and members of the public are asked to keep a look out for any deer showing symptoms consistent with the disease. These clinical suspects are defined as adult (16 months or older) deer or elk that have poor body condition with neurological signs such as abnormal behavior, tremors, stumbling, incoordination, poor posture including droopy ears and a lowered head, drooling, and excessive thirst, and urination. Anyone who sees a CWD suspect deer should not attempt to contact, disturb or kill the animal. Instead, accurately document the location and immediately contact the Department of Game and Inland Fisheries by calling 1-804-367-1258.
Press Release is at: http://www.dgif.virginia.gov/news/release.asp?id=119.
Virginia Department of Game and Inland Fisheries CWD information is at: http://www.dgif.virginia.gov/cwd.
Wisconsin: Donna Gilson, Wisconsin Department of Agriculture, Trade and Consumer Protection, provides the following:
The Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP) has confirmed a second CWD-positive white-tailed deer at a Crawford County captive cervid facility. The first positive on this farm was discovered in January 2005, in a 19-month-old buck that died from respiratory causes and was routinely sampled as required for deer that die or are killed at 16 months and older. Subsequent to the initial positive, the State Veterinarian ordered the herd depopulated for testing. However, the owner challenged the USDA’s test results (the USDA’s National Veterinary Services Laboratories in Ames, Iowa, conducts Wisconsin’s captive cervid testing for regulatory purposes). That case is in federal court and therefore the depopulation order is on hold. The second positive was a male born in June 2004. It was found dead Jan. 4, 2007, after an apparent fight with another buck. Again, it was sampled as required under rule. The State Veterinarian was notified by the USDA Area Veterinarian in Charge on Feb. 5 that it was positive for CWD.
Detection of PrPCWD in postmortem rectal lymphoid tissues in Rocky mountain elk (Cervus elaphus nelsoni) infected with chronic wasting disease. Terry R. Spraker, Thomas L. Gidlewski, Aru Balachandran, Kurt C. VerCauteren, Lynn Creekmore and Randy D. Munger Journal of Veterinary Diagnostic Investigation Vol. 18 Issue 6, 553-557.
Abstract: Preclinical diagnostic tests for transmissible spongiform encephalopathies have been described for mule deer (Odocoileus hemionus), using biopsy tissues of palatine tonsil, and for sheep, using lymphoid tissues from palatine tonsil, third eyelid, and rectal mucosa. The utility of examining the rectal mucosal lymphoid tissues to detect chronic wasting disease (CWD) was investigated in Rocky Mountain elk (Cervus elaphus nelsoni), a species for which there is not a live-animal diagnostic test. Postmortem rectal mucosal sections were examined from 308 elk from two privately owned herds that were depopulated. The results of the postmortem rectal mucosal sections were compared to immunohistochemical staining of the brainstem, retropharyngeal lymph nodes, and palatine tonsil. Seven elk were found positive using the brainstem (dorsal motor nucleus of the vagus nerve), retropharyngeal lymph nodes, and palatine tonsil. Six of these elk were also found positive using postmortem rectal mucosal sections. The remaining 301 elk in which CWD-associated abnormal isoform of the prion protein (PrPCWD) was not detected in the brainstem and cranial lymphoid tissues were also found to be free of PrPCWD when postmortem rectal mucosal sections were examined. The use of rectal mucosal lymphoid tissues may be suitable for a live-animal diagnostic test as part of an integrated management strategy to limit CWD in elk. http://jvdi.org/cgi/content/abstract/18/6/553.
UK Red Deer Surveillance for CWD Following agreement between the EU Commission and Member States, a one year Transmissible Spongiform Encephalopathy (TSE) surveillance programme which targets farmed and wild red deer will be undertaken across the Community. The Scottish Executive has announced details of how the surveillance protocols will apply in Scotland. With the assistance of the Deer Commission for Scotland and Forestry Commission Scotland, the sample target of 598 wild red deer animals over 18 months of age will be achieved by taking a percentage of deer culled as part of the normal stock management arrangement, with a further smaller number of animals uplifted following road kills. The sample target is expected to be collected over one hunting season. A further 598 farmed deer are also to be collected under the surveillance target. This part of the sample will be collected through a specialist deer abattoir in England. All animals collected for surveillance purposes will be subject to screening for the presence of TSEs. The sale of venison for public consumption is not under investigation and trade in venison should be unaffected.
Scotland press release at: http://www.scotland.gov.uk/News/Releases/2007/01/23140934.
More information on the UK program: http://www.defra.gov.uk/animalh/bse/pdf/comms_strat.pdf.