OIE手册中对蛙病毒介绍

NB:VersionadoptedbytheWorldAssemblyofDelegatesoftheOIEinMay2011ManualofDiagnosticTestsforAquaticAnimals201271CHAPTER2.1.2.INFECTIONWITHRANAVIRUS1.ScopeForthepurposeofthischapter,ranavirusdiseaseisconsideredtobesystemicclinicalorsubclinicalinfection,inthemajorfamiliesofAnuraandCaudata,withamemberofthegenusRanavirus.Itdoesnotincludeepizootichaematopoieticnecrosisvirus,whichistheaetiologicalagentforepizootichaematopoieticnecrosis(EHN).2.Diseaseinformation2.1.Agentfactors2.1.1.Aetiologicalagent,agentstrainsRanavirusesbelongtothegenusRanavirusoftheFamilyIridoviridae.ThetypespeciesisFrogvirus3(FV3)(Chincharetal.,2005).OtherspeciesincludeBohlevirus(BIV),Epizootichaematopoieticnecrosisvirus(EHNV),Europeancatfishvirus(ECV),Europeansheatfishvirus(ESV)andSantee-Cooperranavirus.Therearemanyothertentativespeciesinthisgenus.SincetherecognitionofdiseasecausedbyEHNVinfinfishinAustraliain1986,similarsystemicnecrotisingiridovirussyndromeshavebeenreportedinamphibians.Ranaviruseshavebeenisolatedfromhealthyordiseasedfrogs,salamandersandreptilesinAmerica,Europe,AsiaandAustralia(Chinchar,2002;Druryetal.,1995;Fijanetal.,1991;Hyattetal.,2002;Speare&Smith,1992;Wolfetal.,1968;Xiaetal.,2009;Zupanovicetal.,1998b).Ranaviruseshavelarge(150–170nm),icosahedralvirions,adouble-strandedDNAgenome150–170kb,andreplicateinboththenucleusandcytoplasmwithcytoplasmicassembly(Chincharetal.,2005).Theypossesscommonantigensthatcanbedetectedbyseveraltechniques.SpeciesNo.isolatesExamplesGeographicsourceAmbystomatigrinumvirus2Ambystomatigrinumvirus,ReginaranavirusNorthAmericaBohleiridovirus1BohleiridovirusAustraliaFrogvirus312Frogvirus3Europe,North&SouthAmericaBoxturtlevirus3Europe,North&SouthAmericaBufobufoUnitedKingdomvirusEurope,North&SouthAmericaBufomarinusVenezuelaniridovirus1Europe,North&SouthAmericaLuckétriturusvirus1Europe,North&SouthAmericaRanatemporariaUnitedKingdomvirusEurope,North&SouthAmericaRedwoodParkvirusEurope,North&SouthAmericaSticklebackvirusEurope,North&SouthAmericaTadpoleedemavirusEurope,North&SouthAmericaTadpolevirus2Europe,North&SouthAmericaTigerfrogvirusEurope,North&SouthAmericaTortoisevirus5Europe,North&SouthAmericaTentativespecies3RanaesculentairidovirusEurope,North&SouthAmericaTestudoiridovirusEurope,North&SouthAmerica2.1.2.SurvivaloutsidethehostAllranavirusesareprobablyextremelyresistanttodrying;EHNVcansurviveformonthsinwater,infrozenfishtissuesformorethan2years(Langdon,1989),andinfrozenfishcarcasesforatleastaChapter2.1.2.—Infectionwithranavirus72ManualofDiagnosticTestsforAquaticAnimals2012year(Whittingtonetal.,1996).Santee-Cooperranavirusremainsviableinfrozenfishtissuesforatleast155days(Plumb&Zilbert,1999).Lessisknownaboutotherranaviruses,butgiventheirsimilaritytoEHNVtheyarepresumedtohavecomparablestability.ATVwasinfectiousforsalamandersifpresentinmoistbutnotdrypondsediment,butthedurationofinfectivityisunknown.2.1.3.Stabilityoftheagent(effectiveinactivationmethods)Ranaviruses(asexemplifiedviaEHNV)aresusceptibleto70%ethanol,200mglitre–1sodiumhypochloriteorheatingto60°Cfor15minutes(19).Ifdesiccatedfirst,EHNVmaysurviveheatingto60°Cfor15minutes(unpublishedobservations).107plaque-formingunitspermlofaranavirusofamphibianoriginwasinactivatedwithin1minuteinasolutionof150mglitre–1chlorhexidine(0.75%Nolvasan®),180mglitre–1sodiumhypochlorite(3%bleach)or200mglitre–1potassiumperoxymonosulfate(1%Virkon®)(Bryanetal.,2009).2.1.4.LifecycleTherouteofinfectionisunknownbutamphibiansaresusceptibleexperimentallyfollowingbathexposureinjectionandorexposurefollowinglaboratoryinducedabrasions.(Cunninghametal.,2007;2008).2.2.Hostfactors2.2.1.SusceptiblehostspeciesNaturalranavirusinfectionsareknownfrommostofthemajorfamiliesofAnuraandCaudata(Careyetal.2003a;2003b;Cullen&Owens,2002;Daszaketal.,2003).2.2.2.SusceptiblestagesofthehostSusceptiblestagesofthehostareallageclasses,larvae,metamorphsandadults.2.2.3.Speciesorsubpopulationpredilection(probabilityofdetection)Notknown.2.2.4.TargetorgansandinfectedtissueAmphibiantargetorgansandtissuesinfectedwithranavirusesmayvary.Threeexamplesaregiven:i)BIV:liver,kidney,spleen,lungandotherparenchymaltissues(Cullen&Owens,2002).ii)FV3infectsproximaltubularepithelialcellsinthekidney,theliver,andthegastrointestinaltract(Robertetal.,2005).iii)UnitedKingdomranavirus(RUK)infectsepithelialcells,fibroblasts,lymphocytes,melanomacrophagesandasmallproportionofendothelialcellsinmanytissues,aswellashepatocytesandKuppfercellsintheliver,theepidermisanddermis(Cunninghametal.,2008).Ambystomatigrinumvirusisfoundinskin,spleen,liver,renaltubularepithelialcells,andlymphoidandhaematopoietictissuesofsalmanders.2.2.5.PersistentinfectionwithlifelongcarriersNotknown.2.2.6.VectorsAmphibianscanbecomeinfectedinthesamewayasfishand,assuch,detailsassociatedwithEHNVareincludedhere.Possiblevectorsincludenets,boatsandotherequipment,orinamphibiansusedforbaitbyrecreationalfishers.Birdsarepotentialmechanicalvectors,asranavirusescanbecarriedinthegut,onfeathers,feetandthebill.Itshouldbenotedthatranavirusesarelikelytobeinactivatedattypicalavianbodytemperatures(40