Serial PassageVirus CultivationDefective VirusesVirus ReplicationVirulenceViral InterferenceCell LineMutationCytopathogenic Effect, ViralGenome, ViralBase SequenceRNA, ViralMolecular Sequence DataViral Plaque AssayGenes, vpuCallitrichinaeAdaptation, BiologicalCercopithecus aethiopsHelper VirusesCells, CulturedNeoplasm TransplantationCulture MediaCricetinaeGenetic VariationDNA, ViralFoot-and-Mouth Disease VirusPhenotypeReassortant VirusesVero CellsHepatovirusCulture TechniquesMicrobial Sensitivity TestsSerial LearningHaplorhiniViral ProteinsDrug Resistance, MicrobialTime FactorsRepliconOrthomyxoviridaeViral VaccinesFoot-and-Mouth DiseaseTransplantation, HeterologousVaccines, AttenuatedAdaptation, PhysiologicalAphthovirusAnti-Bacterial AgentsPrPSc ProteinsPoliovirusAmino Acid SequenceGenes, ViralMesocricetusAntigens, ViralDrug Resistance, BacterialRecombination, GeneticAmino Acid SubstitutionSelection, GeneticScrapieSequence Analysis, DNACattleSpecies SpecificityCapsidDogsKidneyChick EmbryoDrug Resistance, ViralDNA PrimersClone CellsNeoplasms, ExperimentalNucleopolyhedrovirusHIV-1RNA, Ribosomal, 23SPolymerase Chain ReactionDisease Models, AnimalSimian virus 40Cell DivisionMicroscopy, ElectronCloning, MolecularCapsid ProteinsStaphylococcus aureusViral Envelope ProteinsBrainL Cells (Cell Line)Genetic VectorsFibroblastsVirionVirus AssemblyMutagenesisSimian immunodeficiency virusSwineGenetic EngineeringFluorescent Antibody TechniqueMice, NudeTemperatureSequence DeletionReverse Transcriptase Polymerase Chain ReactionFluoroquinolonesSheepMice, Inbred BALB CDNA Restriction EnzymesAnti-Infective Agents