HIV SeropositivityHIV SeroprevalenceHIV InfectionsSubstance Abuse, IntravenousSexual BehaviorRisk FactorsDisease ProgressionSeroepidemiologic StudiesRNA VirusesSynaptic TransmissionVaccinia virusAntibodies, ViralVirus ReplicationDisease Transmission, InfectiousVirus SheddingReceptors, VirusVirus CultivationInfectious Disease Transmission, VerticalEnzyme-Linked Immunosorbent AssayImmunoglobulin GVirus DiseasesInfluenza A Virus, H1N1 SubtypeSimian virus 40HIV-1Antibodies, BacterialPlant VirusesPrevalenceVirus AssemblySerologic TestsDNA VirusesChlamydophila pneumoniaeDefective VirusesRNA, ViralMeasles virusHIV SeronegativityChlamydophila InfectionsSindbis VirusInfluenza A Virus, H5N1 SubtypeHepatitis CHepatitis B virusAcquired Immunodeficiency SyndromeRabies virusTime FactorsMolecular Sequence DataVirus ActivationWest Nile virusInfluenza A Virus, H3N2 SubtypeMicroscopy, Electron, TransmissionDNA, ViralPolymerase Chain ReactionAntigens, ViralHepatitis A virusTumor Virus InfectionsViral LoadHerpesvirus 2, HumanRespiratory Syncytial VirusesSimian immunodeficiency virusHelicobacter pyloriPhylogenyHelicobacter InfectionsGenes, ViralDisease OutbreaksViral ProteinsCell LineCytomegalovirus InfectionsHepatitis BVirus LatencyAnti-HIV AgentsAntiviral AgentsAntibodies, ProtozoanHemagglutinin Glycoproteins, Influenza VirusVesicular stomatitis Indiana virusNeutralization TestsBlood DonorsCase-Control StudiesToxocariasisCD4 Lymphocyte CountCercopithecus aethiopsHepacivirusVirionCross-Sectional StudiesCells, CulturedCohort StudiesVero CellsCytomegalovirusHerpes GenitalisInfluenza, HumanBrazilJC VirusOncogenic VirusesAIDS SerodiagnosisHepatitis A Virus, HumanProspective StudiesGenotypeToxoplasmosisPregnancyAge FactorsVirus AttachmentMumps virusAmino Acid Sequence