HIV SeropositivityHIV SeroprevalenceHIV InfectionsSubstance Abuse, IntravenousSexual BehaviorRisk FactorsDisease ProgressionSeroepidemiologic StudiesRNA VirusesVaccinia virusAntibodies, ViralVirus ReplicationReceptors, VirusFocal AdhesionsVirus CultivationVirus SheddingImmunoglobulin GEnzyme-Linked Immunosorbent AssayVirus DiseasesSimian virus 40Virus AssemblyAntibodies, BacterialInfluenza A Virus, H1N1 SubtypePlant VirusesChlamydophila pneumoniaeDNA VirusesDefective VirusesSerologic TestsChlamydophila InfectionsMeasles virusSindbis VirusHIV SeronegativityPrevalenceHIV-1RNA, ViralHepatitis B virusRabies virusInfluenza A Virus, H5N1 SubtypeAcquired Immunodeficiency SyndromeHepatitis CVirus ActivationHepatitis A virusAntigens, ViralInfluenza A Virus, H3N2 SubtypeTumor Virus InfectionsTime FactorsWest Nile virusRespiratory Syncytial VirusesDNA, ViralHerpesvirus 2, HumanMolecular Sequence DataHelicobacter pyloriHelicobacter InfectionsCell LineGenes, ViralVirus LatencySimian immunodeficiency virusViral LoadCytomegalovirus InfectionsViral ProteinsPolymerase Chain ReactionVesicular stomatitis Indiana virusAntiviral AgentsHemagglutinin Glycoproteins, Influenza VirusToxocariasisNeutralization TestsHepatitis BCase-Control StudiesCells, CulturedCercopithecus aethiopsAntibodies, ProtozoanBlood DonorsJC VirusCytomegalovirusOncogenic VirusesVero CellsVirionCD4 Lymphocyte CountHepatitis A Virus, HumanHepacivirusCohort StudiesAnti-HIV AgentsHerpes GenitalisCross-Sectional StudiesProspective StudiesMumps virusToxoplasmosisParainfluenza Virus 1, HumanAIDS SerodiagnosisMosaic VirusesImmunoglobulin MPhylogenyPapillomavirus InfectionsVirus AttachmentSemliki forest virusAvian Sarcoma VirusesEpstein-Barr Virus InfectionsToxocaraHepatitis AAge Factors