Chronic wasting disease - Wikipedia

Chronic wasting disease (CWD), sometimes called zombie deer disease, is a transmissible spongiform encephalopathy (TSE) affecting deer. Chronicwastingdisease FromWikipedia,thefreeencyclopedia Jumptonavigation Jumptosearch Priondiseaseaffectingthedeerfamily MedicalconditionChronicwastingdiseaseOthernamesZombiedeerdiseaseDeerwithsignsofchronicwastingdiseaseSpecialtyInfectiousdisease,Neurology,VeterinarymedicineSymptomsBehavioralchanges,weightloss,decreasedinteractionswithotheranimals,tremors,repetitivewalkinginsetpatterns,increaseddrinkingandurination,excessivesalivationandgrindingoftheteeth,Lossoffearofhumans,confusionUsualonset18–24monthsafterinitialexposureCausesAtypeofprionDiagnosticmethodSuspectedbasedonsymptoms,confirmedbyexaminationofthebrainPreventionExterminatingInfecteddeer,IncinerationanddisposalofInfecteddeercarcassesTreatmentnonePrognosisUniversallyfatal Chronicwastingdisease(CWD),sometimescalledzombiedeerdisease,isatransmissiblespongiformencephalopathy(TSE)affectingdeer.TSEsareafamilyofdiseasesthoughttobecausedbymisfoldedproteinscalledprionsandincludesimilardiseasessuchasBSE(madcowdisease)incattle,Creutzfeldt-Jakobdisease(CJD)inhumansandscrapieinsheep.[1]IntheUS,CWDaffectsmuledeer,white-taileddeer,reddeer,sikadeer,elk,caribou,andmoose.[2]NaturalinfectioncausingCWDaffectsmembersofthedeerfamily.[2]ExperimentaltransmissionofCWDtootherspeciessuchassquirrelmonkeys,andgeneticallymodifiedmicehasbeenshown.[3] In1967,CWDwasfirstidentifiedinmuledeeratagovernmentresearchfacilityinnorthernColorado,UnitedStates.[2]Itwasinitiallyrecognizedasaclinical"wasting"syndromeandthenin1978,itwasidentifiedmorespecificallyasaTSEdisease.Sincethen,CWDhasbeenfoundinfree-rangingandcaptiveanimalpopulationsin26USstatesandthreeCanadianprovinces.[4]Inaddition,CWDhasbeenfoundinoneMinnesotareddeerfarm,onewildreindeerherdinNorway(March2016)aswellasinwildmoose.SinglecasesofCWDinmoosehavebeenfoundinFinland(March2018)andinSweden(MarchandMay2019,September2020).CWDwasfoundinSouthKoreainsomedeerimportedfromCanada.[5]CWDistypifiedbychronicweightlossandclinicalsignscompatiblewithbrainlesions,aggravatedovertime,alwaysleadingtodeath.NorelationshipisknownbetweenCWDandanyotherTSEsofanimalsorpeople. AlthoughreportsinthepopularpresshavebeenmadeofhumansbeingaffectedbyCWD,by2004astudyfortheCentersforDiseaseControlandPrevention(CDC)suggested,"[m]oreepidemiologicandlaboratorystudiesareneededtomonitorthepossibilityofsuchtransmissions".[6] Theepidemiologicalstudyfurtherconcluded,"[a]saprecaution,huntersshouldavoideatingdeerandelktissuesknowntoharbortheCWDagent(e.g.,brain,spinalcord,eyes,spleen,tonsils,lymphnodes)fromareaswhereCWDhasbeenidentified".[6] Contents 1History 1.1Quebecfarmoutbreak 2Signsandsymptoms 3Cause 3.1Genetics 3.2Spread 3.2.1Direct 3.2.2Experimentaltransmission 3.2.3Indirect 4Prevention 5Diagnosis 6Epidemiology 6.1NorthAmerica 6.2Europe 7Research 8References 9Externallinks History[edit] ChronicwastingdiseasewasfirstdiscoveredbyAmericanwildlifeveterinarianBethS.Williams.Williamsperformednecropsiesondeerandelkthathaddiedofanunknownsyndrome.Sherecognizedthatthebrainlesionsintheseanimalswereconsistentwithtransmissiblespongiformencephalopathy(TSE).[7]In1978,sheandneuropathologistStuartYoungcowrotethefirstscientificpaperthatnamedthediseaseanddescribeditasaTSE.[8] InFebruary2003,theCentersforDiseaseControlpublishedareportof"Fataldegenerativeneurologicillnessesinmenwhoparticipatedinwildgamefeasts--Wisconsin,2002".Itreadinconclusionthat"Althoughnoassociationbetween(animal)CWDand(thefeastorsinWisconsinwhohappenedtohave)CJDwasfound,continuedsurveillanceofbothdiseasesremainsimportanttoassessthepossibleriskforCWDtransmissiontohumans."[9]InSeptember2003,Hoeypointedoutthatoneofthethreepatients(the55year-old)"presentedwitha3-monthhistoryofdifficultyinwritingandunsteadinessofgait,followedbydementia,speechabnormalitiesandmyoclonicjerking.Pathologicexaminationofthebrainatautopsy3monthslaterrevealedwidespreadsubcorticalspongiformlesionsconsistentwithCJD."[10] Asof2013PatriceKleintheCWDProgramManageratUSDA/APHISrejectedthesomewhatinconclusivefindingsofHoeyandstatedthatnoevidencehadbeenfoundoftransmissiontohumansfromdeer,norbyeatinganimalsinthedeerfamily,butbothchannelsremainasubjectofpublichealthsurveillanceandresearch.[2] Quebecfarmoutbreak[edit] TheMFFPministryinQuebecpracticed9500testsintheperiodbetween2007andautumn2018beforetheydetectedaseropositivecaseinSeptember2018.[11] TheSeptember2018discoveryofCWDonamanagedoperationinGrenville-sur-la-RougeQuebecpromptedawholesaleslaughterof3500animalsintwomonthsbeforetheenterpriseshutdownpermanently.[12]TheCFIAorderedthecull,aswellasthedecontaminationof10inchesofsoilincertainplacesonthe1000-acreoperation.[11]Post-discovery,eachanimalwastestedforCWDbytheCFIAbeforeitwasreleasedontothemarket.OtherQuebecproducerslamentedtheglutofsupply.[12]A400 kmquarantineareawasdeclared,inwhichallhuntingandtrappingactivitieswerebanned.[13]Thegovernmentslaughteredhundredsofwildanimalsoveratwo-monthperiod.Theroutinecullformarketwasbetween70and100animalsperweek.Whentheproducerwasforcedtoclose,theweeklyslaughterneared500animalsperweek.[12]Oneyearlater,750wildspecimenshadbeenculledinthe45 km-radius"enhancedmonitoringarea",andnonetestedpositiveforCWD.[14] ItcametolightinAugust2019thatpriorto2014inCanada,allanimalsonCWD-infectedfarmswereburiedorincinerated.Since2014,however,theCFIAhasallowedanimalsfromCWD-infectedfarmstoenterthefoodchainbecausethereis"nonationalrequirementtohaveanimalstestedforthedisease".[citationneeded]FromoneCWD-infectedherdinAlberta,131elkweresoldforhumanconsumption.[15] Forthefall2019huntingseasoninwesternQuebec,theprovincialministryrelaxedtherulesfortheannualwhite-taileddeer(WTD)hunt,inanefforttocurbthespreadofCWD.AnyWTDcanbehuntedwithanyweaponincertainmunicipalitiesintheOutaouaisvalleyandtheLaurentides.TheMFFPhopestherebytoreceivemoresamplestotestforCWD.[14]ThequarantinearoundGrenvillewasstillinplace,andtheministryspecificallyprohibited(only)the"removal"fromthequarantine"enhancedmonitoringarea"zoneof"thehead,morespecificallyanypartofthebrain,theeyes,theretropharyngeallymphnodesandthetonsils,anypartofthespinalcolumn,theinternalorgans(includingtheliverandtheheart),andthetesticles."[16] Signsandsymptoms[edit] DuetoCWDtaking18–24monthsafterinitialexposuretoonset,mostcasesofCWDoccurinadultanimals;theyoungestanimaltoexhibitclinicalsymptomsofthediseasewas15months.[17]Thediseaseisprogressiveandalwaysfatal.Thefirstsignsaredifficultiesinmovement.ThemostobviousandconsistentclinicalsignofCWDisweightlossovertime.Behavioralchangesalsooccurinthemajorityofcases,includingdecreasedinteractionswithotheranimals,listlessness,loweringofthehead,tremors,repetitivewalkinginsetpatterns,andnervousness.Excessivesalivationandgrindingoftheteethalsoareobserved.Mostdeershowincreaseddrinkingandurination;theincreaseddrinkingandsalivationmaycontributetothespreadofthedisease.[18]Lossoffearofhumansandappearanceofconfusionarealsocommon.[19]TheAPHISsummarizeditas:[2] Behavioralchanges,emaciation,weakness,ataxia,salivation,aspirationpneumonia,progressivedeath. Cause[edit] ThecauseofCWD(likeotherTSEs,suchasscrapieandbovinespongiformencephalopathy)isaprion,amisfoldedformofanormalprotein,knownasprionprotein(PrP),thatismostcommonlyfoundinthecentralnervoussystem(CNS)andperipheralnervoussystem(PNS).Themisfoldedformhasbeenshowntobecapableofconvertingnormallyfoldedprionprotein,PrPC("C"forcellular)intoanabnormalform,PrPSc("Sc"forscrapie),thusleadingtoachainreaction.CWDisthoughttobetransmittedbythismechanism.TheabnormalityinPrPhasitsgeneticbasisinaparticularvariantoftheprotein-codinggenePRNPthatishighlyconservedamongmammalsandhasbeenfoundandsequencedindeer.Thebuild-upofPrPdinthebrainisassociatedwithwidespreadneurodegeneration.[2][18][20] Genetics[edit] Theallelewhichencodesleucine,codon132inthefamilyofElks,iseitherhomozygousLL,homozygousMM,orheterozygousML.IndividualswiththefirstencodingseemtoresistclinicalsignsofCWD,whereasindividualswitheitheroftheothertwoencodingshavemuchshorterincubationperiods.[2] Inwhite-taileddeer,polymorphismsatcodons95(Q->H)and96(G->S)dramaticallyaffectCWDprogressionandprionstrainspecification.Deercontainingthe96Sallelehavedelayedprogressiontoclinicaldiseaseonset.[21] Whendeerwiththe95Hpolymorphismbecomeinfected,theyselectforalteredstrainsofCWD.[22] Spread[edit] ResearchersinJuly2019statedthat"withalltheresearchonthemalignityofprions,andthepermanenceofprionsinthewiderenvironment,andtheirresistancetodestructionanddegradation,itisnecessarytoreducethepotentialsourcesofexposuretoCWD."[23]InfactanAPHISscientistobservedthat,whilethelongevityofCWDprionisunknown,thescrapieprionhasbeenmeasuredtoendurefor16years.[2][24]ThePrPCWDproteinisinsolubleinallbutthestrongestsolvents,andhighlyresistanttodigestionbyproteases.[2]PrPCWDconvertsthenormalproteinPrPCintomoreofitselfuponcontact,andbindstogetherformingaggregates.[2][24]Prusinernotedin2001that[24] Inthepriondiseases,theinitialformationofPrPScleadstoanexponentialincreaseintheprotein,whichcanbereadilytransmittedtoanotherhost butitisnotedthatasof2013,althoughCWDprionsweretransmissiblewithinthecervidaefamily,CWDwasnottransmissibletohumansortocattle.[2] HowtheprionsthatcauseCWDspreadisunknown,butrecentresearchindicatesthatprionscanbeexcretedbydeerandelk,andaretransmittedbyeatinggrassgrowingincontaminatedsoil.[25]Animalsbornincaptivityandthoseborninthewildhavebeenaffectedwiththedisease.TransmissionofCWDisthoughttobelateral(fromanimaltoanimal).Maternaltransmissionmayoccur,althoughitappearstoberelativelyunimportantinmaintainingepidemics.Aninfecteddeer'ssalivaisabletospreadtheCWDprions.[26]ExposurebetweenanimalsisassociatedwithsharingfoodandwatersourcescontaminatedwithCWDprionsshedbydiseaseddeer.[27] Direct[edit] CWDmaybedirectlytransmittedbycontactwithinfectedanimals,theirbodilytissues,andtheirbodilyfluids.[28]Spreadmayresultfromcontactwithinfecteddeerregardlessofiftheyaresymptomatic.[29] RecentresearchonRockyMountainelkfoundthatwithCWD-infectedcows,manysubclinical,ahighrate(80%)ofmaternal-to-offspringtransmissionofCWDprionsoccurred,regardlessofgestationalperiod.[29]Whilenotdispositiverelativetodiseasedevelopmentinthefetus,thisdoessuggestthatmaternaltransmissionmaybeyetanotherimportantrouteofdirectCWDtransmission. ModernnewsstoriesandanecdotalevidencefromtreatingphysicianssuggestthatahumanmayhavecontractedCreutzfeldt-JakobdiseaseviatheconsumptionofsquirrelbrainsinfectedwithCWD.[30] Experimentaltransmission[edit] InadditiontothecervidspeciesinwhichCWDisknowntonaturallyoccur,black-taileddeerandEuropeanreddeerhavebeendemonstratedtobenaturallysusceptibletoCWD.[31]Othercervidspecies,includingcaribou,arealsosuspectedtobenaturallyvulnerabletothisdisease.[28]ManyothernoncervidmammalianspecieshavebeenexperimentallyinfectedwithCWD,eitherorallyorbyintracerebralinoculation.[28]Thesespeciesincludemonkeys,sheep,cattle,prairievoles,mice,andferrets.[32] AnexperimentalcasestudyoforaltransmissionofCWDtoreindeershowscertainreindeerbreedsmaybesusceptibletoCWD,whileothersubpopulationsmaybeprotectiveagainstCWDinfree-rangingpopulations.NoneofthereindeerinthestudyshowedsymptomsofCWD,potentiallysignifyingresistancetodifferentCWDstrains.[33] Indirect[edit] Environmentaltransmissionhasbeenlinkedtocontactwithinfectedbodilyfluidsandtissues,aswellascontactwithcontaminatedenvironments.Onceintheenvironment,CWDprionsmayremaininfectiousformanyyears.Thus,decompositionofdiseasedcarcasses,infected"gutpiles"fromhunterswhofielddresstheircervidharvests,andtheurine,saliva,feces,andantlervelvetofinfectedindividualsthataredepositedintheenvironment,allhavethepotentialtocreateinfectiousenvironmentalreservoirsofCWD.[18] In2013,researchersattheNationalWildlifeResearchCenterinFortCollins,Coloradosuccessfullyinoculatedwhite-taileddeerwiththemisfoldedprionviathenasalpassage,whentheprionsweremixedwithclay.[34]Thiswasimportantbecausetheprionshadalreadybeenshownby2006tobindwithsandyquartzclayminerals.[2] Oneavianscavenger,theAmericancrow,wasrecentlyevaluatedasapotentialvectorforCWD.[35]AsCWDprionsremainviableafterpassingthroughthebird'sdigestivetract,crowsrepresentapossiblemechanismforthecreationofenvironmentalreservoirsofCWD.[35][36]Additionally,thecrows'extensivegeographicrangepresentsampleopportunitiesforthemtocomeincontactwithCWD.This,coupledwiththepopulationdensityandlongevityofcommunalroostingsitesinbothurbanandrurallocations,suggeststhatthefecaldepositsatroostingsitesmayrepresentaCWDenvironmentalreservoir.[35]Conservativeestimatesforcrows'fecaldepositsatonewinterroostingsiteforonewinterseasonrangedfrom391,552to599,032 kg.[35] CWDprionsadheresotightlytosoilsurfaceparticlesthatthegroundbecomesasourceofinfectionandmaybeamajorrouteoftransmissionduetofrequentgroundcontactwhenanimalsinthedeerfamilygraze.[18] Prevention[edit] Thissectionismissinginformationaboutpredation.Pleaseexpandthesectiontoincludethisinformation.Furtherdetailsmayexistonthetalkpage.(December2020) By2012,avoluntarysystemofcontrolwaspublishedbyAPHISintheUSFederalRegister.Itdependedonvoluntaryminimumstandardsmethodology,andherdcertificationprogramstoavoidinterstatemovementofthediseasevector.Itwasbasedonariskmanagementframework.[2]AsofAugust2019,APHISlawin9CFRPart55-CONTROLOFCHRONICWASTINGDISEASEdealtwiththisproblem. Introducedforthe2019Minnesotahuntingseason,ano-costdeercarcass-incinerationprogramwasrolledoutbyCrowWingCountyofficialshopingtostemthespreadofCWDintheregion.CWDwasfoundamongwilddeerinCrowWingCountyforthefirsttimeinJanuary2019.ThevoluntaryprogramencouragesbothresidentsandvisitinghunterstobringharvesteddeercarcassestothecountylandfilleastofBrainerd,Minnesotaforincinerationanddisposal.[19] Diagnosis[edit] Diagnosisisbasedonpostmortemexamination(necropsy)andtesting;examinationofthedeadbodyisnotdefinitive,asmanyanimalsdieearlyinthecourseofthediseaseandconditionsfoundarenonspecific;generalsignsofpoorhealthandaspirationpneumonia,whichmaybetheactualcauseofdeath,arecommon.Onmicroscopicexamination,lesionsofCWDintheCNSresemblethoseofotherTSEs.Inaddition,scientistsuseimmunohistochemistrytotestbrain,lymph,andneuroendocrinetissuesforthepresenceoftheabnormalprionproteintodiagnoseCWD;positiveIHCfindingsintheobexisconsideredthegoldstandard.[18]ConventionalCWDdiagnosticstrategiesandseededamplificationmethodsforamplifyingCWDprionsinvitroinclude:immunohistochemistry(IHC),westernblotting(WB),enzymeimmunoassay(EIA),proteinmisfoldingcyclicamplification(PMCA),andrealtimequaking-inducedconversion(RT-QuIC).[37] Availabletests,asofJuly2019,attheCFIAwerenotsensitiveenoughtodetecttheprioninspecimensfromanimalsyoungerthanayearold.[23]Strategiesarebeingdevelopedtoallowforthequantificationofprionburdeninatissue,bodyfluid,orenvironmentalsample.[37] Asof2015,nocommerciallyfeasiblediagnostictestscouldbeusedonliveanimals.[18]Asearlyas2001anantemortemtestwasdeemedurgent.[38]Runningabioassay,takingfluidsfromanimalsinthedeerfamilysuspectedofinfectionandincubatingthemintransgenicmicethatexpressthecervidprionprotein,canbeusedtodeterminewhetherthecervidisinfected,butethicalissuesexistwiththis,anditisnotscalable.[18] AtonsillarbiopsytechniquehasbeenareliablemethodoftestingforCWDinlivedeer,[39]butitonlyseemstobeeffectiveonmuledeerandwhite-taileddeer,notelk.[40]BiopsiesoftherectalmucosahavealsobeeneffectiveatdetectingCWDinlivemuledeer,white-taileddeer,andelk,thoughdetectionefficacymaybeinfluencedbynumerousfactorsincludinganimalage,genotype,anddiseasestage.[41][42][43][44] ItispossibleforCWDprionstosurvivesterilizationproceduresinvolvinganautoclave. Epidemiology[edit] ReportedcasesofchronicwastingdiseaseinNorthAmerica,asof2018 NorthAmerica[edit] Thediseasewasfirstidentifiedin1967inaclosedherdofcaptivemuledeerincontiguousportionsofnortheasternColorado.In1980,thediseasewasdeterminedtobeaTSE.Itwasfirstidentifiedinwildelkandmuledeerandwhite-taileddeerintheearly1980sinColoradoandWyoming,andinfarmedelkin1997.[2][18][20]ThediseasedidnotaffectCanadauntil1996.[23] InMay2001,CWDwasalsofoundinfree-rangingdeerinthesouthwesterncornerofNebraska(adjacenttoColoradoandWyoming)andlaterinadditionalareasinwesternNebraska.ThelimitedareaofnorthernColorado,southernWyoming,andwesternNebraskainwhichfree-rangingdeer,moose,and/orelkpositiveforCWDhavebeenfoundisreferredtoastheendemicarea.Theareain2006hasexpandedtosixstates,includingpartsofeasternUtah,southwesternSouthDakota,andnorthwesternKansas.Also,areasnotcontiguous(totheendemicarea)areasincentralUtahandcentralNebraskahavebeenfound.Thelimitsoftheaffectedareasarenotwelldefined,sincethediseaseisatalowincidenceandtheamountofsamplingmaynotbeadequatetodetectit.In2002,CWDwasdetectedinwilddeerinsouth-centralWisconsinandnorthernIllinoisandinanisolatedareaofsouthernNewMexico.In2005,itwasfoundinwildwhite-taileddeerinNewYorkandinHampshireCounty,WestVirginia.[45]In2008,thefirstconfirmedcaseofCWDinMichiganwasdiscoveredinaninfecteddeeronanencloseddeer-breedingfacility.ItisalsofoundintheCanadianprovincesofAlbertaandSaskatchewan. InFebruary2011,theMarylandDepartmentofNaturalResourcesreportedthefirstconfirmedcaseofthediseaseinthatstate.Theaffectedanimalwasawhite-taileddeerkilledbyahunter.[46] CWDhasalsobeendiagnosedinfarmedelkanddeerherdsinanumberofstatesandintwoCanadianprovinces.Thefirstpositivefarmed-elkherdintheUnitedStateswasdetectedin1997inSouthDakota. Sincethen,additionalpositiveelkherdsandfarmedwhite-taileddeerherdshavebeenfoundinSouthDakota(7),Nebraska(4),Colorado(10),Oklahoma(1),Kansas(1),Minnesota(3),Montana(1),Wisconsin(6),andNewYork(2).Asoffallof2006,fourpositiveelkherdsinColoradoandapositivewhite-taileddeerherdinWisconsinremainunderstatequarantine.Alloftheotherherdshavebeendepopulatedorhavebeenslaughteredandtested,andthequarantinehasbeenliftedfromoneherdthatunderwentrigoroussurveillancewithnofurtherevidenceofdisease.CWDalsohasbeenfoundinfarmedelkintheCanadianprovincesofSaskatchewanandAlberta.AretrospectivestudyalsoshowedmuledeerexportedfromDenvertotheTorontoZoointhe1980swereaffected.InJune2015,thediseasewasdetectedinamalewhite-taileddeeronabreedingranchinMedinaCounty,Texas.Stateofficialseuthanized34deerinanefforttocontainapossibleoutbreak. InFebruary2018,theMississippiDepartmentofWildlife,Fisheries,andParksannouncedthataMississippideertestedpositiveforchronicwastingdisease.[47]AnotherMississippiwhitetaileuthanizedinPontotocCountyon8October2018testedpositiveforCWD.ThediseasewasconfirmedbytheNationalVeterinaryServicesLaboratoryinAmes,Iowaon30October2018.[48] SpeciesthathavebeenaffectedwithCWDincludeelk,muledeer,white-taileddeer,black-taileddeer,andmoose.Otherruminantspecies,includingwildruminantsanddomesticcattle,sheep,andgoats,havebeenhousedinwildlifefacilitiesindirectorindirectcontactwithCWD-affecteddeerandelk,withnoevidenceofdiseasetransmission.However,experimentaltransmissionofCWDintootherruminantsbyintracranialinoculationdoesresultindisease,suggestingonlyaweakmolecularspeciesbarrierexists.ResearchisongoingtofurtherexplorethepossibilityoftransmissionofCWDtootherspecies. ByApril2016,CWDhadbeenfoundincaptiveanimalsinSouthKorea;thediseasearrivedtherewithliveelkthatwereimportedfromCanadaforfarminginthelate1990s.[2][49] Inthesummerof2018,caseswerediscoveredintheHarpurFarmherdinGrenville-sur-la-Rouge,Quebec.[11] Overthecourseof2018fully12%ofthemuledeerthatweretestedinAlberta,hadapositiveresult.Morethan8%ofAlbertadeerweredeemedseropositive.[15] Europe[edit] In2016,thefirstcaseofCWDinEuropewasfromtheNordfjellawildreindeerherdinsouthernNorway.Scientistsfoundthediseasedfemalereindeerasitwasdying,androutineCWDscreeningatnecropsywasunexpectedlypositive.TheoriginofCWDinNorwayisunknown,whereasimportofinfecteddeerfromCanadawasthesourceofCWDcasesinSouthKorea.Norwayhasstrictlegislationandrulesnotallowingimportationofliveanimalsanddeerintothecountry.Norwayhasascrapiesurveillanceprogramsince1997;whilenoreportsofscrapiewithintherangeofNordfjellareindeerpopulationhavebeenidentified,sheepareherdedthroughthatregionandareapotentialsourceofinfection.[50] InMayandJune2016,twoinfectedwildmoose(Alcesalces)werefoundaround300 kmnorthfromthefirstcase,inSelbu.[51][52]BytheendofAugust,afourthcasehadbeenconfirmedinawildreindeershotinthesameareaasthefirstcaseinMarch.[53] In2017,theEnvironmentAgencyoftheNorwegiangovernmentreleasedguidelinesforhuntershuntingreindeerintheNordfjellaareas.TheguidelinescontaininformationonidentifyinganimalswithCWDsymptomsandinstructionsforminimizingtheriskofcontamination,aswellasalistofsuppliesgiventohunterstobeusedfortakingandsubmittingsamplesfromshotreindeer.[54] InMarch2018,FinnishFoodSafetyAuthorityEVIRAstatedthatthefirstcaseofCWDinFinlandhadbeendiagnosedina15-year-oldmoose(Alcesalces)thathaddiednaturallyinthemunicipalityofKuhmointheKainuuregion.BeforethiscaseinKuhmo,NorwaywastheonlycountryintheEuropeanEconomicAreawhereCWDhasbeendiagnosed.ThemoosedidnothavethetransmissibleNorthAmericanformofthedisease,butsimilartotheNorwegianvariantofCWD,anatypicalorsporadicformwhichoccursincidentallyinindividualanimalsofthedeerfamily.InFinland,CWDscreeningoffallenwilddeerhasbeendonesince2003.Noneoftheroughly2,500samplesanalyzedsofarhavetestedpositiveforthedisease.TheexportofliveanimalsofthedeerfamilytoothercountrieshasbeentemporarilybannedasaprecautionarymeasuretostopthespreadoftheCWD,andmoosehuntersaregoingtobeprovidedwithmoreinstructionsbeforethestartofthenexthuntingseason,ifappropriate.Theexportandsalesofmeatfromdeerwillnotberestrictedandmoosemeatisconsideredsafetoeatasonlythebrainandnervoustissueofinfectedmoosecontainsprions.[55] InMarch2019,theSwedishNationalVeterinaryInstitute(SVA)diagnosedthefirstcaseofCWDinSweden.A16-yearoldemaciatedfemalemoosewasfoundinthemunicipalityofArjeploginthecountyofNorrbotten,circlingandwithlossofshynesstowardshumans,possiblyblind.ThemoosewaseuthanizedandtheheadwassentforCWDscreeninginthenationalCWDsurveillanceprogram.Thebrainstemtissue,butnotlymphnodes,waspositiveforCWD(confirmedwithWesternBlot).AsecondcaseofCWDwasdiagnosedinMay2019,withverysimilarcasehistory,about70 kmeastofthefirstcase.Thissecondcase,inthemunicipalityofArvidsjaur,wasalsoanemaciatedandapathic16-year-oldfemalemoosethatwaseuthanized.ThecircumstancesoftheseSwedishcasesaresimilartotheCWDcasesinmooseinbothNorwayandFinland.TheEUregulatedCWDsurveillancerunsbetween2018-2020.Aminimumof6000deeraretobetested,bothfree-ranginganimalsinthedeerfamily,farmedreddeer,andsemi-domesticatedreindeer.[56]ThefindingofCWD-positivemooseinitiatedanintensifiedsurveillanceintheaffectedmunicipalities.Adulthunter-harvestedmooseandslaughteredsemi-domesticatedreindeerfromtheareaaretestedforCWD.InSeptember2019,athirdmoosewasfoundpositiveforCWD,ahunter-harvested10-year-oldapparentlyhealthyfemalemoosefromArjeplog.[57]AfourthcaseofCWDinmoosewasverifiedinSeptember2020,inaeuthanized14-year-oldlameandunshyfemalemooseinthemunicipalityofRobertsfors,inthecountyofVästerbotten,approximately200 kmfromthepreviousmoosecasesintheneighboringcountyofNorrbotten.[58] Research[edit] ScholiahasatopicprofileforChronicwastingdisease. Researchisfocusedonbetterwaystomonitordiseaseinthewild,liveanimaldiagnostictests,developingvaccines,betterwaystodisposeofanimalsthatdiedfromthediseaseandtodecontaminatetheenvironment,whereprionscanpersistinsoils,andbetterwaystomonitorthefoodsupply.Deerharvestingandmanagementissuesareintertwined.[59] References[edit] ^"ChronicWastingDisease(CWD)".USDA.APHIS.1August2017. ^abcdefghijklmnoPatriceNKlein,CWDProgramManagerUSDA/APHIS."ChronicWastingDisease-APHISProposedRuletoAlignBSEImportRegulationstoOIE"(PDF).WHHCCMeeting–5–6February2013.Archivedfromtheoriginal(PDF)on26September2014.{{citeweb}}:CS1maint:location(link) ^"Transmission|ChronicWastingDisease(CWD)|PrionDisease|CDC".www.cdc.gov.3December2018.Retrieved21February2019. ^ "DistributionofChronicWastingDiseaseinNorthAmerica".USGS.gov.31January2019.Retrieved7January2019. ^"Occurrence|ChronicWastingDisease(CWD)|PrionDisease|CDC".www.cdc.gov.25February2019.Retrieved5March2019. ^ab 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Externallinks[edit] WikimediaCommonshasmediarelatedtoChronicwastingdisease. ThisentryincorporatespublicdomaintextoriginallyatWhatischronicwastingdisease?AnimalandPlantHealthInspectionService ChronicWastingDiseaseAlliance ChronicwastingdiseaseCentersforDiseaseControlandPrevention Chronicwastingdisease(CWD)ofdeerandelk,CanadianFoodInspectionAgency Chronicwastingdisease(CWD)USGSNationalWildlifeHealthCenter CWDinformation&testingColoradoParksandWildlife [https://www.dnr.illinois.gov/programs/CWD/Pages/default.aspxChronicwastingdiseasIllinoisDepartmentofNaturalResources ChronicwastingdiseasemanagementMinnesotaDepartmentofNaturalResources Chronicwastingdisease(CWD)NebraskaGameandParksCommission ChronicwastingdiseaseNewYorkStateDepartmentofEnvironmentalConservation ChronicwastingdiseaseProgramPennsylvaniaDepartmentofAgriculture ChronicwastingdiseasePennsylvaniaGameCommission ChronicwastingdiseaseWisconsinDepartmentofNaturalResources Chronicwastingdisease(CWD)WyomingWildlife,WyomingGameandFish vtePriondiseasesandtransmissiblespongiformencephalopathyPriondiseasesinhumansinherited/PRNP: fCJD Gerstmann–Sträussler–Scheinkersyndrome Fatalfamilialinsomnia sporadic: sCJD Sporadicfatalinsomnia Variablyprotease-sensitiveprionopathy acquired/transmissible: iCJD vCJD Kuru Priondiseasesinotheranimals Bovinespongiformencephalopathy Camelspongiformencephalopathy Scrapie Chronicwastingdisease Transmissibleminkencephalopathy Felinespongiformencephalopathy Exoticungulateencephalopathy Retrievedfrom"https://en.wikipedia.org/w/index.php?title=Chronic_wasting_disease&oldid=1068276944" Categories:TransmissiblespongiformencephalopathiesRuminantdiseasesAnimaldiseasesHiddencategories:CS1maint:locationCS1Norwegian-languagesources(no)ArticleswithshortdescriptionShortdescriptionisdifferentfromWikidataUsedmydatesfromJuly2021AllarticleswithunsourcedstatementsArticleswithunsourcedstatementsfromNovember2021ArticlestobeexpandedfromDecember2020CommonscategorylinkfromWikidata Navigationmenu Personaltools NotloggedinTalkContributionsCreateaccountLogin Namespaces ArticleTalk English expanded collapsed Views ReadEditViewhistory More expanded collapsed Search Navigation MainpageContentsCurrenteventsRandomarticleAboutWikipediaContactusDonate Contribute HelpLearntoeditCommunityportalRecentchangesUploadfile Tools WhatlinkshereRelatedchangesUploadfileSpecialpagesPermanentlinkPageinformationCitethispageWikidataitem Print/export DownloadasPDFPrintableversion Inotherprojects WikimediaCommons Languages العربيةБългарскиČeštinaDanskDeutschEspañolFrançais한국어Italiano日本語NorskbokmålPolskiSvenskaไทย中文 Editlinks