HIV InfectionsHIV SeropositivityHIV SeroprevalenceHIV-1Acquired Immunodeficiency SyndromeHIV SeronegativityAnti-HIV AgentsHIVAIDS SerodiagnosisSexual BehaviorCD4 Lymphocyte CountHomosexuality, MaleDelayed DiagnosisPrevalenceAnti-Retroviral AgentsRisk-TakingRisk FactorsEarly DiagnosisViral LoadAIDS-Related Opportunistic InfectionsSubstance Abuse, IntravenousSensitivity and SpecificitySouth AfricaPrenatal DiagnosisAntiretroviral Therapy, Highly ActiveSexual PartnersHIV AntigensRetrospective StudiesCross-Sectional StudiesCohort StudiesCD4-Positive T-LymphocytesPregnancyAIDS Dementia ComplexZimbabweProstitutionUnited StatesCondomsHIV Protease InhibitorsIncidenceInfectious Disease Transmission, VerticalHIV Core Protein p24Prospective StudiesHomosexualityUgandaUnsafe SexPregnancy Complications, InfectiousSyphilisDiagnosisTime FactorsInfant, NewbornHeterosexualityHIV AntibodiesAfrica South of the SaharaCoinfectionMalawiHIV Envelope Protein gp120Mass ScreeningTreatment OutcomeDiagnostic ErrorsHealth Knowledge, Attitudes, PracticeTuberculosisPopulation SurveillanceCounselingAIDS-Related ComplexRNA, ViralFollow-Up StudiesHIV Wasting SyndromeSexually Transmitted DiseasesCircumcision, MaleSafe SexReceptors, HIVDisease ProgressionVirus ReplicationAge FactorsCase-Control StudiesReceptors, CCR5QuestionnairesPredictive Value of TestsPolymerase Chain ReactionLogistic ModelsSubstance-Related DisordersIndiaEpidemicsVoluntary ProgramsTuberculosis, PulmonaryZidovudineBiopsyHIV-2TanzaniaHIV Long-Term SurvivorsTomography, X-Ray ComputedHIV Reverse TranscriptaseZambiaEnzyme-Linked Immunosorbent AssayMultivariate AnalysisComorbidityReproducibility of ResultsSocioeconomic FactorsHepatitis CRural Population