Serial PassageSeasonsVirus CultivationDefective VirusesVirus ReplicationVirulenceViral InterferenceCell LineMutationCytopathogenic Effect, ViralGenome, ViralRNA, ViralBase SequenceMolecular Sequence DataViral Plaque AssayGenes, vpuCallitrichinaeAdaptation, BiologicalCercopithecus aethiopsGenetic VariationHelper VirusesCells, CulturedTime FactorsNeoplasm TransplantationCulture MediaDNA, ViralCricetinaeReassortant VirusesFoot-and-Mouth Disease VirusPhenotypeVero CellsOrthomyxoviridaeHepatovirusCulture TechniquesMicrobial Sensitivity TestsHaplorhiniSerial LearningViral ProteinsDrug Resistance, MicrobialAdaptation, PhysiologicalRepliconVaccines, AttenuatedCattleViral VaccinesFoot-and-Mouth DiseaseTransplantation, HeterologousAnti-Bacterial AgentsSheepAphthovirusInfluenza, HumanSpecies SpecificityPrPSc ProteinsAmino Acid SequenceAntigens, ViralTemperatureSequence Analysis, DNAPoliovirusGenes, ViralDrug Resistance, BacterialSelection, GeneticMesocricetusAmino Acid SubstitutionRecombination, GeneticDrug Resistance, ViralPolymerase Chain ReactionDogsRainScrapieReproductionKidneyDNA PrimersCapsidChick EmbryoClone CellsNeoplasms, ExperimentalNucleopolyhedrovirusHIV-1RNA, Ribosomal, 23SDisease Models, AnimalCapsid ProteinsSimian virus 40SwineCell DivisionBrainMicroscopy, ElectronInfluenza VaccinesCloning, MolecularStaphylococcus aureusInfluenza B virusViral Envelope ProteinsL Cells (Cell Line)Reverse Transcriptase Polymerase Chain ReactionGenetic VectorsFibroblastsVirionVirus AssemblyMutagenesisFluorescent Antibody TechniqueSimian immunodeficiency virusBreeding