endemic in a tricorner area of Colorado Wyoming andother parts of t - PDF document

endemic in a tri-corner area of Colorado, Wyoming, andother parts of the United States. Although detection in someencephalopathy to humans indicates that the species bar- and bovine spongiform encephalopathy. The only knownand other TSEs are believed to be caused by a pathogeniceffect on neurons of an abnormal isoform of a host-encod-ed glycoprotein, the prion protein. The pathogenic form ofports its own amplification in the host. TSEs in animalsmutations of the prion protein gene (3). Anotable excep-tion among the human TSEs is the variant form ofin Colorado and was recognized as a TSE in 1978 (6,7).Subsequently, this wasting disease was identified in muledeer in a research facility in Wyoming and in captive elkin both the Colorado and Wyoming facilities (6–8). TheColorado and southeastern Wyoming, where subsequentbasis of hunter-harvested animal surveillance, the overall1999 was estimated at approximately 5% in mule deer,2% in white-tailed deer, and ()extended eastward into adjacent areas of Nebraska (1,11),vation, difficulty swallowing, polydipsia, and polyuriaoccur. Most animals with the disease die within several 1 year. In cap-however, the disease has been reported in cervids as young�as 17 months and as old as 15 years of age (1). This dis-elk populations. A�prevalence of 90% was reported�endemic for 2 years (2,6,7,12). The mo

de of transmissionamong deer and elk is not fully understood; however, Chronic Wasting Disease andPotential Transmission to HumansErmias D. Belay,* Ryan A. Maddox,* Elizabeth S. Williams,† Michael W. Miller,‡ Emerging Infectious Diseases • www.cdc.gov/eid • Vol. 10, No. 6, June 2004977 *Centers for Disease Control and Prevention, Atlanta, Georgia,USA; †University of Wyoming, Laramie, Wyoming, USA;§Case Western Reserve University, Cleveland, Ohio, USA Chronic Wasting Diseasecally since 1996 (2). Two largely independent and simulta-another in the captive elk and deer industry, appear to rep-resent the main framework for explaining the disease’sWyoming (Figure). The observed distribution seems to beease foci documented to date. Given the disease’s insidioustry. However, our current knowledge cannot explain some(e.g., in New Mexico and Utah). Thus, unidentified riskChronic Wasting Disease in In 2000, surveillance of hunter-harvested deer firstof Colorado and Wyoming that are endemic for this dis-ease (Figure) (1,11). It was reported subsequently in othercommercial, large enclosure surrounded by a fence in�was 50% (11). Free-ranging deer from areas surroundingthe Mississippi River in Wisconsin among white-tailedregion of Wisconsin, although a second focus spanning theIllinois border was also detected (15). The absence of evi-Wisconsin. Because the dis

tance from the CWD-endemicarea of Colorado-Wyoming effectively precludes eastwardin Wisconsin was more likely introduced by an importedinfected cervid or some other unidentified source (14). Theproximity of the Wisconsin-Illinois focus to a white-tailedafter it escaped into the wild in southern Wisconsin (14).white-tailed deer escaped was demonstrated earlier, whena still-captive deer tested positive for the disease. The cap-free-ranging deer (16). In 2002, the Wisconsin Departmentwhere it was detected (15,17). Whether such aggressive 978Emerging Infectious Diseases • www.cdc.gov/eid • Vol. 10, No. 6, June 2004 PERSPECTIVES by county, United States. western part of the state. However, in 2002, the diseaseed positive for CWD. Aggressive culling of deer and elkColorado (18). This northwestern focus appears to be dis-wider than previously believed. The ultimate source ofdeer found in White Sands, New Mexico, tested positiveidentified in Wyoming to the west over the Continental(Figure). These cases provide additional evidence for theChronic Wasting Disease in and Alberta, Canada, and the Republic of Koreawhite-tailed deer on farms in Alberta and Wisconsinof the disease in this industry.depopulated both in Canada and the United States.and animal feed supply.Transmission to Other Animalstransmissions were to occur, they would potentiallyhumans. This phenomenon

may have occurred with BSEhumans after infecting cattle. However, the exact origin ofside the cervid family, it has been transmitted experimen-keys, and goats (1,26). In an experimental study, the CWD11 cattle orally challenged with the CWD agent or 24 cat-tle living with infected deer herds (E.S. Williams andM.W. Miller, unpub. data) (1). In addition, domestic cat-and lymphoreticular tissues (Table 1) (29,30). Distribution Emerging Infectious Diseases • www.cdc.gov/eid • Vol. 10, No. 6, June 2004979 Chronic Wasting Disease of Deer and Elk showed prion deposition consistent with GSS. Aprion pro-priate samples were lacking. However, prion protein geneanalysis of a blood sample from one of the patient’s par-ents indicated a GSS P102Lmutation. The patient did notwhen he was 1–2 years old. The GSS diagnosis greatlyRecently, rare neurologic disorders resulting in the(Table 2) (37). Two of the patients reportedly died of CJD,and the third died from Pick’s disease. More than 50 per-ed to have died of a degenerative neurologic disorder.common sporadic CJD subtype (MM1/MV1) (35). ThisColorado and Wyoming. years of age) was reported (38). The report implied that theprion diseases. Athird patient (63 years of age), who wasalso purported to have been a big game hunter, was subse-quently reported from the same area. However, none of theCWD-endemic areas of the west

ern United States. The 66-year-old patient hunted most of his life in WashingtonState. Although information about the 54-year-old patientCWD-endemic areas. The third patient was not a hunterWashington. The neuropathologic changes, Western bloteach fit the MM1, VV1, or VV2 sporadic CJD subtype,To date, only two nonfamilial CJD cases with a positivepatients was a 61-year-old woman who grew up in an areavenison harvested locally. She died in 2000, and analysisof autopsy brain specimens confirmed that the patient’sropathologic features. The second patient was a 66-year-negative for CWD, and the patient’s illness was consistentColorado and Wyoming, the incidence of CJD and the agesimilar to those seen in other parts of the United States. Emerging Infectious Diseases • www.cdc.gov/eid • Vol. 10, No. 6, June 2004981 Chronic Wasting Disease of Deer and Elk Table 2. Creutzfeldt-Jakob disease investigated for possible causal link with chronic wasting disease of deer and elk, United States Case no. Age at death (y) Year of death Codon 129 Western blot Final diagnosis Eating of venison from CWD-endemic area 1 25 2001 M/V Type 1 GSS 102 Yes 2 26 2001 M/M Type 2 CJD No 3b 28 2002 nd nd GSS 102 No 4 28 1997 M/M nd CJD No 5 28 2000 M/V Type 1 CJD No 6 30 1999 V/V Type 1 CJD No 7 54 2002 V/V Type 2 CJD No 8c 55 1

999 M/M Type 1 CJD No 9d 61 2000 M/M Type 1 CJD Yes 10 63 2002 V/V Type 1 CJD No 11 64 2002 M/M Type 1 CJD Yes 12 66 2001 M/M Type 1 CJD No CWD, chronic wasting disease; GSS, Gerstmann-Sträussler-Scheinker syndrome; CJD, Creutzfeldt-Jakob disease; nd, not done. Immunohistochemical analysis of postmortem brain tissue was consistent with GSS, and a GSS 102 mutation was confirmed in the family.Investigated as part of a cluster of three case-patients who participated in “wild game feasts” in a cabin owned by one of the decedents.Patient grew up in an area known to be endemic for CWD and ate venison harvested locally; however, the CJD phenotype fits the most common form of sporadic CJD. Patient may have been successful in harvesting two deer since 1996 from a CWD-endemic area, but both deer tested negative for CWD. incidence in Colorado and Wyoming suggest that the risk,if any, of transmission of CWD to humans is low. Althoughthe in vitro studies indicating inefficient conversion oflink with CWD have been identified. However, the trans-that, provided sufficient exposure, the species barrier mayrecognizable human disease. The level and frequency ofspread of CWD in the United States. Because the numbersuch transmissions. Studies involving transgenic miceed, remains important to effectively monitor the possibledeer and elk tha

t look sick or test positive for CWD. Theybrain and spinal cord tissues. As a precaution, huntersAcknowledgmentsWe thank Claudia Chesley for editorial assistance and stateDr. Belay is a medical epidemiologist in the Division ofViral and Rickettsial Diseases, Centers for Disease Control and1.Williams ES, Miller MW, Kreeger TJ, Khan RH, Thorne ET. Chronicmanagement. J Wildl Manage. 2002;66:551–63.2.Williams ES, Miller MW. Chronic wasting disease in deer and elk inNorth America. Rev Sci Tech. 2002;21:305–16.3.Belay ED. Transmissible spongiform encephalopathies in humans.4.Will RG, Ironside JW, Zeidler M,Cousens SN, Estibeiro K,Alperovitch A,et al. Anew variant of Creutzfeldt-Jakob disease in the5.Belay ED, Schonberger SB. Variant Creutzfeldt-Jakob disease andbovine spongiform encephalopathy. Clin Lab Med. 2002;22:849–62.6.Williams ES, Young S. Chronic wasting disease of captive mule deer:a spongiform encephalopathy. J Wildl Dis. 1980;16:89–98.7.Williams ES, Young S. Spongiform encephalopathies in Cervidae.Rev Sci Tech. 1992;11:551–67.8.Williams ES, Young S. Spongiform encephalopathy of RockyMountain elk. J Wildl Dis. 1982;18:465–71.9.Spraker TR, Miller MW, Williams ES, Getzy DM, Adrian WJ,Schoonveld GG, et al. Spongiform encephalopathy in free-ranging)and Rocky Mountain elk (central Colorado. J Wildl Dis. 1997;33:1–6.10.Miller MW, Williams ES, McCarty CW, S

praker TR, Kreeger TJ,Larsen CT,et al. Epizootiology of chronic wasting disease in free-ranging cervids in Colorado and Wyoming. J Wildl Dis.11.Nebraska Game and Parks Commission. Chronic wasting diseaseNebraska Game and Parks Commission. Chronic wasting disease2003 Nov 7]. Available from: http://www.ngpc.state.ne.us/wildlife/12.Miller MW, Williams ES. Horizontal prion transmission in mule deer.13.South Dakota Department of Game, Fish and Parks. South Dakota:South Dakota Department of Game, Fish and Parks. South Dakota:Nov 7]. Available from: http://www.state.sd.us/gfp/divisionwildlife/14.Joly DO, Ribic CA, Langenberg JA, Beheler K, Batha CA, Dhuey BJ,et al. Chronic wasting disease in free-ranging Wisconsin white-taileddeer. Emerg Infect Dis. 2003;9:599–601.15.Wisconsin Department of Natural Resources. Chronic wasting dis-ease and Wisconsin deer [monograph on the Internet]. [cited 2003Nov 7]. Available from: http://www.dnr.state.wi.us/org/land/16.Illinois Department of Natural Resources. Illinois CWD surveillanceIllinois Department of Natural Resources. Illinois CWD surveillanceAvailable from: http://dnr.state.il.us/cwd/cwd_locations.jpg17.Nolen RS. Wisconsin mobilizes to battle chronic wasting disease. JAm Vet Med Assoc. 2002;220:1769–70. Emerging Infectious Diseases • www.cdc.gov/eid • Vol. 10, No. 6, June 2004983 Chronic Wasting Disease of Deer and El