EnzymeimmunoassayforthequalitativedeterminationofIgG-classantibodiesagainsttheMeaslesvirusinhumanserumorplasma.MeaslesormorbillivirusbelongstotheRNAvirusesofthefamilyParamyxoviridae.Thevirionsaresphericalparticlesof150-250nmindiameterconsistingoftheribonucleoproteinwithhelicalsymmetryandanenvelopewithspikescontainingthestrain-specificandhemagglutinatingantigens.Morbilliviruseshavenoneuraminidaseactivity.Measlesisaclassicchildhooddisease.Thevirusisendemic:attheageof20about90%ofthepopulationhashadimmunologicalexperiencewithit.Newbornsareprotectedbymaternalantibodiesforthefirst3-4monthsoflife;theactivediseaseleaveslifelongimmunity.Themeaslesvirushasacontagiousityindexofabout96%,isworldwidedistributed,andcanbeserious.Bacterialsuperinfectionwasaseriousthreatinthepreantibioticera,buttheprognosisofuncomplicatedmeaslesisnowgood.CNScomplicationssuchasencephalomyelitis(0.1%)whichmayoccuraftertheacutephaseofmeaslesinfectionsubsides,howeverstillhaveahighmortality(10%).Prognosisofrecoveryinthesepatientsispoor.Between10-30%ofallcasesarefatal;20-50%developsignificantdamages.Subacutesclerosingpanencephalitis(SSPE)isarare(1:1000)degenerativediseaseoftheCNSwhichisthoughttobeaslowvirusinfection.