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From: TSS ()
June 15, 2005 USDA takes steps to battle CWD Chronic wasting disease survey and certification program in the works Dr. Randy Pritchard, a veterinary medical officer with USDA-APHIS Veterinary Services who focuses on CWD, says he hopes the certification program and survey will be approved by fall 2005. "There is not a lot of information available for this industry," he said. First detected in 1967, CWD has been found in members of the deer family, which include white-tailed deer, mule deer, and elk. To date, the disease has been identified in 13 states (see map) and two Canadian provinces. In April, APHIS announced it was seeking OMB approval for a study that would collect information, through the National Animal Health Monitoring System, on the health and management practices of up to 5,600 cervid producers. "All indications are that it will be approved," Dr. Pritchard said. If given the green light, the study will describe the farmed/captive cervid industry and identify the most efficient ways to contact producers for outreach purposes. In addition to other information, APHIS will track how long particular herds have been monitored for CWD. "It is really important that people know that this is a voluntary study and that it is completely confidential," Dr. Pritchard said. "They won't be giving us any identification information. There will be no way to tie this back to an individual." The agency will also use the collected information to prepare descriptive reports and information sheets that will be disseminated to cervid producers, stakeholders, academia, and other interested parties. Dr. Pritchard says APHIS hopes to tie the survey to the national herd certification program, which is also awaiting approval from the OMB. The proposed rule on this certification program was published in the Federal Register on Dec. 24, 2003. "There were numerous comments from that, and it has taken awhile to sort through all of those," Dr. Pritchard said. Dr. Dean Goeldner, APHIS CWD program coordinator, says that the agency has reviewed the comments and made some changes to the proposed rule. He says the final rule is still a few months away from being published. Jurisdiction over captive deer and elk varies from state to state, and several states already enroll deer and elk herd owners in voluntary state certification programs. The proposed national herd certification program will recognize state programs that meet equivalent requirements, and allow cervid owners who reside in states without equivalent certification programs to directly enroll in the national certification program. The goal is to ensure that interstate movement of captive deer and elk does not spread CWD. The national program will focus primarily on animal identification, regular CWD herd surveillance, testing of animals that die in monitored herds or are sent for slaughter, and limiting of new acquisitions to animals from herds that are also enrolled in the program. State and federal agencies will work together to trace the movements of animals with CWD and identify animals and herds that were exposed to them. "I think this national program is very important, and the reason it is important is it would help standardize the approach taken by individuals states. It offers states a blueprint on which to build their programs," said Dr. William Hueston, director of the Center for Animal Health and Food Safety at the University of Minnesota. "It would really facilitate the whole interstate movement of these animals." The proposed national program would not apply to animals being held for CWD research purposes, but to all other types of captive deer and elk. Most captive deer and elk are farmed, raised either for sale as meat, for sale as breeding animals, for harvest of antler velvet, or for hunting on private game facilities. A smaller number of captive deer and elk are maintained in zoos, other exhibitions, or research facilities. Linking the CWD survey and herd certification program is commonsense, according to Dr. Pritchard. "The national certification program would be an ideal time to do this survey," he said. "Most of the time, the questionnaire is going to be administered by a field veterinarian, so our hope was that they would already be on the farm for the certification program." Producers will be able to go through the certification process but skip the survey, if they so desire, and vice versa. Although APHIS expects both the certification program and study to be given the go-ahead, it may move forward with the study if that is approved first. Staff at APHIS' CWD program have received a barrage of questions from the public, many of which they have not been able to answer because of a lack of data. "We searched for answers to some of those questions and found out pretty quickly that those answers are not available, at least on an national level," Dr. Pritchard said. "We don't have a lot of knowledge about this industry." Information collected through the survey should help. –Kate O'Rourke http://www.avma.org/onlnews/javma/jun05/050615d.asp CWD found in New York wildlife The wildlife cases were discovered through the New York State Department of Environmental Conservation's intensive monitoring efforts that were put into place after the disease was identified in captive herds. In response to the wildlife cases, the DEC filed emergency regulations regarding the handling, transport, and management of deer in the state to prevent further spread of the disease in the wild. For example, the regulations prohibit the movement of certain animal parts out of a containment area established in and around Oneida County, and establish mandatory checkpoints for deer hunters in this area. They also include a number of provisions to be followed by individuals and facilities across the state. Implemented on April 29, the emergency regulations will be effective for 90 days. The DEC is in the process of developing permanent regulations. At press time, the DEC, along with the Department of Agriculture's Wildlife Services program, had tested 317 wild deer in central New York as part of its investigation and had not identified any further cases of CWD in the wild. Investigators were still trying to determine the source or sources of the disease in the state. Since 2002, the DEC has collected more than 3,700 samples from wild white-tailed deer. http://www.avma.org/onlnews/javma/jun05/050615p.asp May 15, 2005 Until now, CWD had been identified only in Colorado, Illinois, Kansas, Minnesota, Montana, Nebraska, New Mexico, Oklahoma, South Dakota, Utah, Wisconsin, and Wyoming. Saskatchewan and Alberta in Canada have also reported CWD infections. The disease has been found in captive animals in some states and provinces and in the wild in others. In some areas, the disease is found in both captive and wild animals. Chronic wasting disease, first detected in 1967, has been found in members of the deer family, which include white-tailed deer, mule deer, and elk. Researchers hypothesize that prions, infectious proteins, cause the disease, but more research is needed into the fatal neurologic illness. Responding to the positive cases in New York, Dr. William Hueston, director of the Center for Animal Health and Food Safety at the University of Minnesota, says he won't be surprised if the disease is found in additional states. States that have experienced CWD have taken steps to regulate the movement of farmed deer and elk, but not all states have followed suit. The Department of Agriculture's Animal and Plant Health Inspection Service provides support for CWD prevention and surveillance for farmed and wild elk and deer as well as indemnification dollars for captive herds that must be destroyed. Many states, however, still struggle to fund state surveillance programs. "The challenge is that most of the states are stretched very thin in their animal health resources," Dr. Hueston said. "Largely, legislators and legislatures have the attitude, which I perfectly understand, that if we don't have a problem, why should we pay for additional veterinary services or animal health programs? That is all well and good, as long as you don't get a new problem emerging." The political climate is also a factor. "We are in an era where, in general, the majority of the people would like to see a smaller government and less laws, and that creates a window of opportunity for emerging diseases," Dr. Hueston said. In New York, the responsibility for controlling CWD is shared by the USDA and two state departments. The Department of Environmental Conservation issues licenses to individuals who possess, import, or sell white-tailed deer, and also routinely tests New York's wild deer. The Department of Agriculture and Markets monitors the health and movement of all captive deer and elk for the presence of CWD. In July 2004, this department initiated the CWD Enhanced Surveillance and Monitoring Program. This program requires captive deer and elk herd owners to take various actions, including routine sampling and testing, animal identification, and an annual herd inventory. On March 31, 2005, the NYSDAM announced they had confirmed the first case of CWD in the state. The animal, a six-year-old, white-tailed doe, was slaughtered from a captive herd as part of the state's mandatory surveillance. Preliminary tests performed at the New York State Veterinary Diagnostic Laboratory at Cornell University determined the presumptive positive, which was confirmed by the National Veterinary Services Laboratories in Ames, Iowa. Nathan Rudgers, New York State commissioner of agriculture, said the identification demonstrated that the state control program is working. "Our control program achieves what it's intended to do, and that's to rapidly detect disease, if it's out there, and provide the proper protocols to quickly respond," he said. The subsequent investigation revealed that one of the herds associated with the index animal had recently sent another sample to New York's veterinary diagnostic laboratory to be tested for CWD. The white-tailed deer had died from aspiration pneumonia, which is often associated with the disease. Because of the direct connection with the index herd, the department expedited the testing procedure by rerouting the sample to the NVSL, which announced the sample was positive. The NYSDAM quarantined and depopulated the two herds in which the positive deer were found, and testing revealed three more deer with CWD from the index herd. Herds associated with the infected herds were also quarantined and, at press time, an investigation had been initiated to find and test any susceptible deer that came into contact with the index herd. Investigators were attempting to determine the source of the infection, and the NYSDEC was also conducting surveillance in surrounding wild deer populations. The DEC is implementing precautionary regulations limiting transportation and possession of whole carcasses and some parts of wild deer taken near the location of the infected captive herds. The regulations will be similar to those currently in place for importation of carcasses and parts of deer into New York. For the latest on the investigation, visit www.agmkt.state.ny.us/AI/cwd.html. – Kate O'Rourke http://www.avma.org/onlnews/javma/may05/050515h.asp some studies worth noting...TSS Authors Hamir, Amirali Technical Abstract: Raccoons (Procyon lotor) are omnivorous and their diet may include carrion. It is therefore possible that in the wild they may get exposed to carcasses of animals with transmissible spongiform encephalopathies (TSEs). To determine the susceptibility of raccoons to transmissible mink encephalopathy (TME), scrapie, and chronic wasting disease (CWD), each of these agents was inoculated intracerebrally into a group of 4 kits. Three uninoculated kits served as controls. All raccoons in the TME-inoculated group developed neurologic signs and were euthanized within 6 months post inoculation (PI). In the scrapie-inoculated group, 3 animals became sick and were euthanized between 18 - 22 months PI. Although the fourth raccoon in this group did not show any clinical signs, it was euthanized at 24 months PI. At necropsy all clinically affected raccoons had extensive microscopic lesions of spongiform encephalopathy and protease-resistant prion protein (PrP**res) was detected in the CNS by immunohistochemistry and Western blot. In the CWD-inoculated group, 1 raccoon was euthanized at 39 months PI because of severe cystitis. Its brain was negative for PrP**res. At present, 4 years PI, the 3 remaining CWD-inoculated raccoons are alive and apparently healthy. These preliminary findings demonstrate that TME and scrapie can be transmitted to raccoons within 6 months and 2 years, respectively, whereas CWD cannot. Based on these incubation periods, it may be possible to differentiate these 3 TSEs should they occur in non-host species. Such a laboratory model would be relatively simple and inexpensive for characterization of unknown TSEs in the United States. Title: Experimental Inoculation of Tme, Scrapie, and Cwd to Raccoons (Procyon Lotor) and the Unilization of Raccoons for Strain-Typing of Unknown Tses in the United States Technical Abstract: Raccoons (Procyon lotor) are omnivorous and their diet may include carrion. It is therefore possible that in the wild they may get exposed to carcasses of animals with transmissible spongiform encephalopathies (TSEs). To determine the susceptibility of raccoons to transmissible mink encephalopathy (TME), scrapie, and chronic wasting disease (CWD), each of these agents was inoculated intracerebrally into a group of 4 kits. Three uninoculated kits served as controls. All raccoons in the TME-inoculated group developed neurologic signs and were euthanized within 6 months post inoculation (PI). In the scrapie-inoculated group, 3 animals became sick and were euthanized between 18 - 22 months PI. Although the fourth raccoon in this group did not show any clinical signs, it was euthanized at 24 months PI. At necropsy all clinically affected raccoons had extensive microscopic lesions of spongiform encephalopathy and protease-resistant prion protein (PrP**res) was detected in the CNS by immunohistochemistry and Western blot. In the CWD-inoculated group, 1 raccoon was euthanized at 39 months PI because of severe cystitis. Its brain was negative for PrP**res. At present, 4 years PI, the 3 remaining CWD-inoculated raccoons are alive and apparently healthy. These preliminary findings demonstrate that TME and scrapie can be transmitted to raccoons within 6 months and 2 years, respectively, whereas CWD cannot. Based on these incubation periods, it may be possible to differentiate these 3 TSEs should they occur in non-host species. Such a laboratory model would be relatively simple and inexpensive for characterization of unknown TSEs in the United States. Author Hamir, Amirali hello Dr. Miller, thank you so much for this update! if CWD transmits to sheep, and it is; ''indistinguishable from scrapie'' then what do we have here? if CWD transmits to sheep and is the same those Vermont sheep are looking more and more what a mess! i don't mean for this to be a trick question, this is more fuel for the fire to rapid TSE test thank you, I am happy to provide an update on the experimental inoculation of Experimental Transmission of Chronic Wasting Disease (CWD) to Cattle Experimental Transmission to Cattle Background: Update: Summary of findings on all necropsied animals to date: Ear tag Date of Survival Disease Clinical Summary: Experimental Transmission of CWD to sheep Eight Suffolk sheep from the NADC scrapie-free flock were inoculated Summary: ########### http://mailhost.rz.uni-karlsruhe.de/warc/bse-l.html ############ Department of Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523- 1671, USA1 snip... full text; http://vir.sgmjournals.org/cgi/content/full/80/10/2757?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&titleabstract=Oral+Transmission+And+Early+Lymphoid+Tropism+Of+Chronic+Wasting+Disease&fulltext=Oral+Transmission+And+Early+Lymphoid+Tropism+Of+Chronic+Wasting+Disease&searchid=1056118413058_454&stored_search=&FIRSTINDEX=0&search_url=http%3A%2F%2Fvir.sgmjournals.org%2Fcgi%2Fsearch&journalcode=vir Oral transmission of kuru, Creutzfeldt-Jakob disease, and scrapie to Gibbs CJ Jr, Amyx HL, Bacote A, Masters CL, Gajdusek DC. Kuru and Creutzfeldt-Jakob disease of humans and scrapie disease of http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=6997404&dopt=Abstract Transmission of human spongiform encephalopathies to experimental Asher DM, Gibbs CJ Jr, Sulima MP, Bacote A, Amyx H, Gajdusek DC. Laboratory of Central Nervous System Studies, National Institute of The agents of kuru and Creutzfeldt-Jakob disease have been consistently http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8270119&dopt=Abstract Aguzzi warns of CWD danger The TSE family of diseases also includes chronic wasting disease (CWD) "For more than a decade, the US has by-and-large considered mad cows "Its horizontal spread among the wild population is exceedingly This quote from Dr. Gambetti is especially significant since he is the Pierluigi Gambetti, director of the National Prion Disease Pathology "There is no way around it," he said. "Nobody should touch that meat http://www.ledger-enquirer.com/mld/...ion/3954298.htm SEWING THE SEEDS OF MAD COW (CWD) THROUGH ANIMAL PROTEIN $ snip... DEPARTMENT OF HEALTH & HUMAN SERVICES PUBLIC HEALTH SERVICE FOOD AND DRUG ADMINISTRATION April 9, 2001 WARNING LETTER 01-PHI-12 CERTIFIED MAIL RETURN RECEIPT REQUESTED Brian J. Raymond, Owner Sandy Lake Mills 26 Mill Street P.O. Box 117 Sandy Lake, PA 16145 PHILADELPHIA DISTRICT Tel: 215-597-4390 Dear Mr. Raymond: Food and Drug Administration Investigator Gregory E. Beichner conducted an inspection of your animal feed manufacturing operation, located in Sandy Lake, Pennsylvania, on March 23, 2001, and determined that your firm manufactures animal feeds including feeds containing prohibited materials. The inspection found significant deviations from the requirements set forth in Title 21, code of Federal Regulations, part 589.2000 - Animal Proteins Prohibited in Ruminant Feed. The regulation is intended to prevent the establishment and amplification of Bovine Spongiform Encephalopathy (BSE) . Such deviations cause products being manufactured at this facility to be misbranded within the meaning of Section 403(f), of the Federal Food, Drug, and Cosmetic Act (the Act). Our investigation found failure to label your swine feed with the required cautionary statement "Do Not Feed to cattle or other Ruminants" The FDA suggests that the statement be distinguished by different type-size or color or other means of highlighting the statement so that it is easily noticed by a purchaser. In addition, we note that you are using approximately 140 pounds of cracked corn to flush your mixer used in the manufacture of animal feeds containing prohibited material. This flushed material is fed to wild game including deer, a ruminant animal. Feed material which may potentially contain prohibited material should not be fed to ruminant animals which may become part of the food chain. The above is not intended to be an all-inclusive list of deviations from the regulations. As a manufacturer of materials intended for animal feed use, you are responsible for assuring that your overall operation and the products you manufacture and distribute are in compliance with the law. We have enclosed a copy of FDA's Small Entity Compliance Guide to assist you with complying with the regulation... blah, blah, blah... http://www.fda.gov/foi/warning_letters/g1115d.pdf Suggested citation for this article: Belay ED, Maddox RA, Williams ES, Miller MW, Gambetti P, Schonberger LB. Chronic wasting disease and potential transmission to humans. Emerg Infect Dis [serial on the Internet]. 2004 Jun [date cited]. Available from: http://www.cdc.gov/ncidod/EID/vol10no6/03-1082.htm Chronic wasting disease (CWD) of deer and elk is endemic in a tri-corner area of Colorado, Wyoming, and Nebraska, and new foci of CWD have been detected in other parts of the United States. Although detection in some areas may be related to increased surveillance, introduction of CWD due to translocation or natural migration of animals may account for some new foci of infection. 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. In 2001, the case of a 25-year-old man who reportedly died of a prion disease after an illness lasting ≈22 months was investigated (Table 2). Although this man had hunted deer only rarely, his grandfather hunted deer and elk throughout much of the 1980s and 1990s and regularly shared the venison with the case-patient's family. The grandfather primarily hunted in southeastern Wyoming, around the known CWD-endemic area. The case-patient's illness began with a seizure and progressed to fatigue, poor concentration, and depression. Memory loss, ataxia, speech abnormalities, combative behavior, and recurrent seizures also developed. Histopathologic, immunohistochemical, and Western blot testing of brain autopsy samples confirmed a prion disease diagnosis. Analysis of the prion protein gene indicated a P102L mutation coupled with valine at the polymorphic codon 129 in the mutant allele, confirming a diagnosis of Gerstmann-Sträussler-Scheinker syndrome (GSS). This case-patient was unusually young even for a person with a GSS P102L mutation. It remains unknown whether the possible exposure of the case-patient to CWD-infected venison potentially contributed to the early onset of his prion disease. In 2001, two additional CJD patients 26 and 28 years of age were reported from a single state (Table 2) (34). The patients grew up in adjacent counties and had illness onset within several months of each other. As a result of this fact and their unusually young age, a possible environmental source of infection, including exposure to CWD-infected venison, was considered. One of the patients died after an illness lasting 5–6 months that was characterized by progressive aphasia, memory loss, social withdrawal, vision disturbances, and seizure activity leading to status epilepticus and induced coma. Histopathologic, immunohistochemical, and Western blot testing of brain biopsy and autopsy samples confirmed a CJD diagnosis. The patient's disease phenotype corresponded to the MM2 sporadic CJD subtype reported by Parchi et al. (35). This patient did not hunt, and family members provided no history of regularly eating venison. The patient may have occasionally eaten venison originating from the Upper Peninsula of Michigan while away from home during his college years. However, ongoing surveillance has not detected CWD in Michigan deer (36). The second patient died from an illness lasting <16 months. The patient's illness began with behavioral changes, including unusual outbursts of anger and depression. Confusion, memory loss, gait disturbances, incontinence, headaches, and photophobia also developed. Western blot analysis of frozen brain biopsy tissue confirmed a prion disease diagnosis. Immunohistochemical analysis of brain tissue obtained after the patient's death showed prion deposition consistent with GSS. A prion protein gene analysis could not be performed because appropriate samples were lacking. However, prion protein gene analysis of a blood sample from one of the patient's parents indicated a GSS P102L mutation. The patient did not hunt but may have eaten venison from Michigan once when he was 1–2 years old. The GSS diagnosis greatly reduced the likelihood that the two patients reported from adjacent counties had disease with a common origin. Recently, rare neurologic disorders resulting in the deaths of three men who participated in "wild game feasts" in a cabin owned by one of the decedents created concern about the possible relationship of their illnesses with CWD (Table 2) (37). Two of the patients reportedly died of CJD, and the third died from Pick's disease. More than 50 persons were identified as possibly participating in these feasts; the three patients were the only participants reported to have died of a degenerative neurologic disorder. Reanalysis of autopsy brain tissues from the three patients at the National Prion Disease Pathology Surveillance Center indicated that two of them had no evidence of a prion disease by immunohistochemical analysis. CJD was confirmed in the third patient, who had clinicopathologic, codon 129, and prion characteristics similar to the most common sporadic CJD subtype (MM1/MV1) (35). This patient participated in the feasts only once, perhaps in the mid-1980s. In addition, the investigation found no evidence that the deer and elk meat served during the feasts originated from the known CWD-endemic areas of Colorado and Wyoming. In 2003, CJD in two deer and elk hunters (54 and 66 years of age) was reported (38). The report implied that the patients had striking neuropathologic similarities and that their illness may represent a new entity in the spectrum of prion diseases. A third patient (63 years of age), who was also purported to have been a big game hunter, was subsequently reported from the same area. However, none of the three patients were reported to have eaten venison from the CWD-endemic areas of the western United States. The 66-year-old patient hunted most of his life in Washington State. Although information about the 54-year-old patient was limited, there was no evidence that he hunted in CWD-endemic areas. The third patient was not a hunter but ate venison harvested from Pennsylvania and Washington. The neuropathologic changes, Western blot profile, and genotype at codon 129 of the three patients each fit the MM1, VV1, or VV2 sporadic CJD subtype, indicating absence of phenotypic similarity among the cases or atypical neuropathologic features (35). To date, only two nonfamilial CJD cases with a positive history of exposure to venison obtained from the known CWD-endemic areas have been reported. One of the patients was a 61-year-old woman who grew up in an area where this disease is known to be endemic, and she ate venison harvested locally. She died in 2000, and analysis of autopsy brain specimens confirmed that the patient's CJD phenotype fit the MM1 subtype, with no atypical neuropathologic features. The second patient was a 66-year-old man who was reported to have eaten venison from two deer harvested in a CWD-endemic area. Both deer tested negative for CWD, and the patient's illness was consistent with the MM1 CJD phenotype. Despite the decades-long endemicity of CWD in Colorado and Wyoming, the incidence of CJD and the age distribution of CJD case-patients in these two states are similar to those seen in other parts of the United States. From 1979 to 2000, 67 CJD cases from Colorado and 7 from Wyoming were reported to the national multiple cause-of-death database. The average annual age-adjusted CJD death rate was 1.2 per million persons in Colorado and 0.8 in Wyoming. The proportion of CJD patients who died before age 55 in Colorado (13.4%) was similar to that of the national (10.2%). The only CJD case-patient <30 years of age in Colorado had iatrogenic CJD linked to receipt of human growth hormone injections. CJD was not reported in persons <55 years of age in Wyoming during the 22-year surveillance period. snip... Acknowledgments http://www.cdc.gov/ncidod/EID/vol10no6/03-1082.htm -------------------------------------------------------------------------------- Position statement - Chronic wasting disease in UK deer 1. The Food Standards Agency asked SEAC to consider the possible public and animal health implications of chronic wasting disease (CWD), in particular the level of risk posed to consumers of meat from infected animals. The committee also considered the possibility that BSE may be present in UK deer. Background 2. CWD has emerged as an endemic transmissible spongiform encephalopathy (TSE) in certain captive and free-ranging species of cervid (deer) in some areas of North America. The disease is characterised by weight loss and behavioural changes in infected animals, usually over a period of weeks or months leading to death. CWD has not been found in the UK or elsewhere in Europe. No definitive or suspected cases of transmission of CWD to humans have been reported. 3. SEAC considered a review of the published, and some unpublished, research on CWD, together with surveillance data on TSEs in European cervids and information on UK cervid populations (1). Origins 4. The origins of CWD are unknown. On the basis of epidemiological data, it is highly improbable that CWD originated from the recycling of mammalian protein in processed feed. It has been suggested that CWD may have arisen from transmission and adaptation of scrapie from sheep to cervids, as a result of a spontaneous change of endogenous prion protein (PrP) to an abnormal disease-associated form, or from an unknown source. 5. Data supporting any of these possible origins of CWD are either absent or equivocal. Although CWD could have originated from scrapie, the differing properties of the two prion diseases in strain typing bioassays, whilst limited, do not support this hypothesis. Evidence for multiple strains of CWD is equivocal. It seems most likely that CWD arose from a spontaneous change of endogenous PrP resulting in a disease-associated and laterally-transmissible form of PrP, although direct data to support this hypothesis are lacking. Host range 6. The known natural hosts for CWD are mule deer (Odocoileus hemionus hemionus), black-tailed deer (Odocoileus hemionus columbianus), white-tailed deer (Odocoileus virginianus) and Rocky Mountain elk (Cervus elaphus nelsoni). The prevalence and geographical distribution of CWD in these species appears to be increasing in North America in a manner which is unlikely to be due simply to increased surveillance. 7. There are no direct data relating to the transmissibility of CWD to UK cervid species. However, comparison of a limited number of PrP codons indicates some homology in the endogenous PrP gene of European and North American cervid species. Thus, the possibility that UK cervids may be susceptible to CWD cannot be excluded, in particular red deer (Cervus elaphus elaphus) which are closely related to elk. 8. There is no evidence to suggest that CWD is present in UK cervids. However, because surveillance in the UK is very limited, a low level prevalence of CWD cannot be ruled out. The committee endorsed the opinion of the European Food Safety Authority on CWD surveillance in the European Union (2004) . 9. Transmission studies using parenteral routes of administration to cattle, sheep and a single goat, together with data from in vitro PrP conversion experiments, suggest that a significant barrier to CWD transmission to these species may exist. No transmission has been evident so far in an on-going oral transmission study in cattle after six years. Furthermore, no signs of infection have been observed from monitoring of cattle co-habiting areas with infected cervids, or in cattle, sheep or goats in close contact with infected cervids in research facilities. Thus, although the data are limited, there is currently no evidence to suggest that CWD can be transmitted naturally to cows, sheep or goats, and it is likely that there is a strong species barrier to such transmission. Routes of transmission 10. Epidemiological data indicate that lateral transmission between infected and susceptible cervids occurring naturally is sufficiently effective to maintain epidemics in both captive and free-living populations. There is good evidence from studies of cervids inhabiting paddocks previously inhabited by infected animals or contaminated with infected carcases, that CWD can be transmitted laterally between animals via the environment. The precise mechanism of transmission is unclear. It is possible that the infectious agent is shed in the saliva, faeces or urine or as a result of decomposition of infected carcases and transferred to other cervids grazing the contaminated areas. It is also possible that some maternal transmission occurs. 11. There have also been suggestions that the lateral transmission of CWD may be influenced by environmental factors. Pathogenesis 12. Information on the pathogenesis of CWD is limited. The data show that, following oral challenge, PrPCWD is first detected in the oral and gut-associated lymphoid tissues before spreading more widely within the lymphoid system and then to the brain. Involvement of the retropharyngeal lymph nodes or tonsils in the pathogenesis may not occur in some elk. At the microscopic level, the nature and distribution of the tissue lesions are similar to those found for scrapie. The available data suggest the pathogenesis of CWD is similar to scrapie. BSE in UK deer 13. Both captive and free-ranging cervids in the UK may have been exposed to contaminated feed prior to the reinforced mammalian meat and bone meal ban instituted in 1996. A study to look at the potential susceptibility of red deer to BSE has shown no signs of transmission of the disease by the oral route, but it is at a very preliminary stage. Although a theoretical possibility exists, there is no evidence from the very limited surveillance data to suggest that BSE is present in the UK cervid population. Human health implications 14. Epidemiological data on possible CWD infection of humans are very limited. The possibility that clinical symptoms of CWD in humans differ from those of Creutzfeldt-Jakob Disease (CJD) cannot be excluded. There is no significant difference between the prevalence of CJD in CWD endemic areas and other areas of the world. However, because CJD surveillance in the USA is relatively recent, not all CJD cases may have been identified. Additionally, detection of a small increase in prevalence of such a rare disease is very difficult. Investigation of six cases of prion disease in young people (< 30 years of age) in the USA found no definite causal link with consumption of venison from known CWD endemic areas. The disease characteristics in these cases were indistinguishable from sporadic CJD or Gerstmann-Sträussler-Scheinker syndrome. Likewise, in a study of three hunters (> 54 years of age) diagnosed with sporadic CJD, no link with consumption of venison from CWD endemic areas was found. No causal link was found in an investigation of three men with neurological illnesses who were known to partake in “wild game feasts”. Only one of these subjects was found to have a prion disease and this was also indistinguishable from sporadic CJD. 15. Preliminary results from transmission experiments in transgenic mice expressing human PrP suggest the presence of a significant species barrier to transmission of CWD to humans. However, these findings must be interpreted with caution as they may not accurately predict the human situation. Data from in vitro experiments on conversion of human PrP by disease-associated forms of PrP, including PrPCWD, are equivocal. 16. The committee concluded there is no evidence of transmission of CWD to humans from consumption of venison, and that there may be significant barriers to transmission. Nevertheless, as the data are extremely limited a risk cannot be ruled out should CWD enter UK herds. Conclusions 17. There is no evidence that CWD (or BSE) is present in the UK cervid population. However, because only limited surveillance is conducted in the cervid population, a low level prevalence of CWD cannot be ruled out. It is recommended that further surveillance of TSEs in UK cervids is conducted. 18. There is no evidence of transmission of CWD to humans from consumption of meat from infected cervids. Although epidemiological and experimental data on potential transmission of CWD are extremely limited, they suggest that there may be a significant species barrier. It would be helpful if further studies were available assessing the potential species barrier for transmission to humans. 19. Although limited, there is no evidence CWD can be transmitted to cattle, sheep or goats by natural means. 20. In summary, it appears that CWD currently poses relatively little risk to human health, or to the health of cattle, sheep or goats in the UK. Nevertheless, as a risk cannot be excluded a watching brief should be maintained. http://www.seac.gov.uk/statements/state180105.htm 10:00 Annex 1 (pdf) http://www.seac.gov.uk/papers/cwdiseaseannex1.pdf Annex 2 (pdf): http://europa.eu.int/comm/food/fs/sc/ssc/out324_en.pdf Annex 3 (incl. appendices) (pdf) http://www.seac.gov.uk/papers/munrodeerrptannex3.pdf Annex 4 (pdf) http://www.seac.gov.uk/papers/deersurvannex4.pdf Annex 5 (pdf): AS with the BSE TO HUMANS AND BSE to GOAT. IT was always it never happend under natural conditions, just in the lab, so not to worry. NOW WE HAVE TO WORRY; http://www.jarvm.com/articles/Vol2Iss1/DEBOSSCHERE.htm http://www.pnas.org/cgi/content/full/041490898v1 snip... CONCLUSION CWD is spreading and may have the potential to infect humans... FULL TEXT ; Chronic Wasting Disease in deer and elk: Scientific Facts and Findings Mo. D. SALMAN Animal Population Health Institute, College of Veterinary Medicine (Received 12 April 2003/Accepted 2 June 2003) http://www.jstage.jst.go.jp/article/jvms/65/7/761/_pdf PAGE 25 Transmission Studies Mule deer transmissions of CWD were by intracerebral inoculation and snip... The occurrence of CWD must be viewed against the context of the [figures...TSS] snip... VISIT TO USA - DR A E WRATHALL - INFO ON BSE AND SCRAPIE 1. Dr Clark lately of the Scrapie Research Unit, Mission Texas has better cut this short, you can read full text of part 2 here; snip... In Reply to: In Confidence - Perceptions of unconventional slow virus http://www.bseinquiry.gov.uk/files/mb/m11b/tab01.pdf As implied in the Inset 25, we must not _ASSUME_ that transmission snip... G A H WELLS 4 January 1991 http://www.bseinquiry.gov.uk/files/yb/1991/01/04004001.pdf http://www.bseinquiry.gov.uk/files/mb/m09a/tab01.pdf http://www.bseinquiry.gov.uk/files/mb/m09/tab05.pdf http://www.pnas.org/cgi/content/abstract/0305777101v1 Adaptation of the bovine spongiform encephalopathy agent to primates and http://www.pnas.org/cgi/content/full/041490898v1 http://vir.sgmjournals.org/cgi/content/abstract/85/8/2471 TSS
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