ChickenAnemiaVirus

epartmentofAnimalandFoodSciences,UniversityofDelaware,Newark,Delaware19717-1303ABSTRACTChickenanemiavirusiscommonlyfficulttoinactivatethermallyorwithcommondisinfectants,usisimportantbecauseofthediseaseitproducesfollowingtransovariantransmissionandbecauseofitspotentialforinducinglmeasuresaredirectedatlimitingverticaltransmissionandpreventingcoinfectionswithotherlymphocidalagents.(Keywords:chicken,chickenanemiavirus,immunosuppression,anemia,disease)1998PoultryScience77:1190–1192INTRODUCTIONThechickenanemiavirus(CAV)wasfirstdescribedin1979byYuasaetal.(1979)hattime,thevirushasbeendetectedbyisolationorserologyinmostothercountriesinbothlayingandbroilerchickens(vonBulowandSchat,1997).osenbergerandCloud(1989a).Itisclear,however,basedonretrospectivus,whentransmittedbythetransovarianroute,canresultinseverediseaseinprogenycharacter-izedbyanemia,subcutaneoushemorrhage,andadecreasedredbirds,ifcoinfectedwithinfectiousbursaldiseasevirus,maydevelopaprofoundimmunosuppressionwithenhancedsuscepti-bilitytoawiderangeofviralandbacterialpathogens(RosenbergerandCloud,1989b;Cloudetal.,1992).InfectionswithCAVareconsideredtobeeconomi-callysignificantbecauseoftheclinicaldiseaseassociatedwithverticaltransmissionandbecauseofitspotentialforiyetal.(1988)reportedthatapparentsubclinicalinfectionsofcommer-ciallNANEMIAVIRUSTheCAVisasmallnonenvelopedvirusresistanttothermalinactivationandtreatmentwithlipidsolventsandmanyofthecommondisinfectants(vonBulowandSchat,1997).Theviralgenomeisasingle-strandedDNAthatiscircularandcovalentlylinkedandconsistsofapproximately2,actvirionisicosahedralwithanaveragediameterofapproximately25nmandabuoyantdensityincesiumchlorideof1.33to1.34g/mL(vonBulowandSchat,1997).ThephysicalandcheEDiseaseusuallyoccursduringthefirst3wkoflifnsatanyagearesusceptibletoinfectionbytheoralorrespiratoryroutes,butdonotshowapparentsignsofdiseasebecauseofanage-associatedresistaiodofsusceptibilitytodiseasemaybeextendedbyearlyexposuretoinfectiousbursaldiseasevirus,Marek’sdiseasevirus,orselectedavianreovirusesthatinterferewithnormalimmunesystemdevelopment(Engstrometal.,1988;vonBulowandSchat,1997).LesionsofuncomplicatedCAVinfectioninyoungchickenstypicallyconsistofbonemarrowaplasiawithreductioninhematocritvalues(≤25%).Chickensareanorexic,depressed,hagescanbeReceivedforpublicationAugust3,edforpublicationFebruary17,1998.1Towhomcorrespondenceshould*************************.edubeaddressed:AbbreviationKey:CAV=ChickenAnemiaVirus.1190

SYMPOSIUM:INFECTIOUSPOULTRYDISEASES1191observedinthemusculatureandsubcutaneously,atrophyandcongestioniscommonandiscoatrophyisgenerallymodestandtransitory,heaforementionedlesionsareexacerbatedandmorepersistentinchickenscoilyaffecteoftheimmunosuppression,affectedchickensfrequentlyde-velopsecondaryinfectionswithClostridiumperfringensandStaphylococcusaureusinthesubcutaneoustisayalsobeanincreasedsusceptibilitytoacopically,thebonemarrowofCAV-infectedchickensisdepletedoferythrocytes,thrombocytes,andgranulocytesandtheirprecursorcells,asaofFabriciusandspleenmayalsobedepletedoflymphoidcells,borsofCAVinfectionusuallyreturntonormalbyapproxi-mately4wkofage,TORYDIAGNOSISAffectedflocksexhibitingpathognomonicsignsandlesionsarerelativelyeasytoidentifyandadiagnosiscanusuallybemadebasedonclinicalpreseirmationisrequired,theviruscanbeisolatedfrombuffycoats,liver,uscanbepropagatevethatthebesthostsystemforinitialisolationsofCAVmaybethechicken,asanumberofrecentlychadytoCAVcanbeassessedbyindirectimmunofluorescenceihasalsobeenusedtoidentifyCAV,butappropriateprimershavenotbeenpreparedforallTIONANDCONTROLChickenAnemiaVirusisgenerallyethevirusisveryresistanttoinactivationandeasilytransmitted,itisprobablyunrealistictoassumethatexpionsofbreederflocksnaturallyorbytheintroductionofCAVpriortotheonsetofeggproduc-tionwillrendertnsero-logicalevaluations,r,itisnotuncommon,particularlyinnewproductionfacilities,tofindpulletflocks,thatareserologicallynegativebutthatbecomeinfectedwithisoccurs,verticaltransmission,onaflockbasis,genlldocumentedthatimmdemonstratedinourlaboratorythatdayofageinfectionwithinfectiousbursaldctionsaslateas2wkofagecanaffectserologicalresponsestocommonrespiratorypathogens(Cloudetal.,1992).Accordingly,itisessentialthatinfectiousbursaldiseasevirusinfectionsbecontrolledwithbreederflockvaccinationprogramsdesignedtoprovideprogenywithproachisvsoimportanttocontrolMarek’sdiseasebecauseCAVinfectionscanexacerbatetheeffectofvirulentstrainsofMarek’earistheeconomicimportanceofhorizontalorcontacttransmissionofCAVthatoccursinyoungbroilers,whichisuncomnlimitedstudiesdoneattheUniversityofDelaware,itappearsthathyperimmunizationofbreederswedperformancemaybetheresultoflongerandmoreconsistentmaternalanti,ghitisnotfeasibletototallypreventexposuretoCAV,itisimportanttominimizeitseffectsbypropersanitizationandbyoptimizingthecontrolofotherfactorsthatcanconNCESCloud,S.S.,erger,oj,dysfunctionfollowintionsofinvitrolymphoproliferationandinvivo

is.33:707–erger,J.K.,,ectsofage,routeofexposureandcoinfectionswithinfectiousbursaldiseasevirusonthepathogenicityandtransmissibilityofchickenanemiaagent(CAA).AvianDis.33:753–ow,V.,,739–756in:ateUniversityPress;Ames,,N.,chi,a,is.23:366–pathol.34:353–om,B.E.,,n,ngdiseaseofchickens:Experimentalinfathol.17:33–y,M.S.,,ly,trick,an,ogicalsurveyofdathol.17:315–erger,J.K.,,lationandcharacterizationofchickenanemiaagent(CAA)