HIV SeropositivityHIV SeroprevalenceSexual BehaviorHIV InfectionsSubstance Abuse, IntravenousRisk-TakingRisk FactorsSeroepidemiologic StudiesRNA VirusesVaccinia virusAntibodies, ViralVirus ReplicationReceptors, VirusVirus CultivationVirus SheddingVirus DiseasesImmunoglobulin GSimian virus 40Enzyme-Linked Immunosorbent AssayVirus AssemblyAntibodies, BacterialPlant VirusesInfluenza A Virus, H1N1 SubtypeDNA VirusesChlamydophila pneumoniaeDefective VirusesSerologic TestsChlamydophila InfectionsSindbis VirusMeasles virusHIV SeronegativityRabies virusHepatitis B virusInfluenza A Virus, H5N1 SubtypeRNA, ViralPrevalenceVirus ActivationHepatitis A virusHIV-1Hepatitis CInfluenza A Virus, H3N2 SubtypeAntigens, ViralWest Nile virusTumor Virus InfectionsRespiratory Syncytial VirusesAcquired Immunodeficiency SyndromeHerpesvirus 2, HumanDNA, ViralHelicobacter pyloriHelicobacter InfectionsGenes, ViralVirus LatencyCytomegalovirus InfectionsVesicular stomatitis Indiana virusViral ProteinsSimian immunodeficiency virusHemagglutinin Glycoproteins, Influenza VirusToxocariasisNeutralization TestsAntiviral AgentsAntibodies, ProtozoanBlood DonorsHepatitis BJC VirusViral LoadOncogenic VirusesVero CellsCytomegalovirusHepatitis A Virus, HumanVirionCercopithecus aethiopsHerpes GenitalisMumps virusHepacivirusParainfluenza Virus 1, HumanToxoplasmosisAIDS SerodiagnosisMosaic VirusesPolymerase Chain ReactionMolecular Sequence DataAnti-HIV AgentsSemliki forest virusVirus AttachmentCross-Sectional StudiesToxocaraAvian Sarcoma VirusesHepatitis AImmunoglobulin MEpstein-Barr Virus InfectionsViral Plaque AssayCell LineBK VirusCase-Control StudiesPhylogenyPapillomavirus InfectionsViruses, UnclassifiedInfluenza, HumanBrazilImmunoglobulin AGene Expression Regulation, Viral