HIV SeropositivityHIV SeroprevalenceHIV InfectionsSubstance Abuse, IntravenousSexual BehaviorRisk FactorsDisease ProgressionSeroepidemiologic StudiesAntiretroviral Therapy, Highly ActiveCD4 Lymphocyte CountAnti-HIV AgentsAntibodies, ViralHIV-1Antibodies, BacterialAcquired Immunodeficiency SyndromeViral LoadChlamydophila pneumoniaeImmunoglobulin GChlamydophila InfectionsHIV SeronegativityEnzyme-Linked Immunosorbent AssayPrevalenceSerologic TestsCohort StudiesHelicobacter pyloriHelicobacter InfectionsAIDS-Related Opportunistic InfectionsCross-Sectional StudiesToxocariasisProspective StudiesCytomegalovirus InfectionsHepatitis CCase-Control StudiesAntibodies, ProtozoanTime FactorsHerpesvirus 2, HumanToxoplasmosisPapillomavirus InfectionsTreatment OutcomeToxocaraAIDS SerodiagnosisBrazilFollow-Up StudiesAge FactorsBlood DonorsRetrospective StudiesCytomegalovirusIncidenceHomosexuality, MaleNeosporaMultivariate AnalysisHomosexualityRural PopulationUgandaOdds RatioHIVHerpes GenitalisSyphilisImmunoglobulin ARNA, ViralCD4-Positive T-LymphocytesHuman papillomavirus 16Hepatitis BToxoplasmaSouth AfricaHIV AntigensRisk-TakingCell CycleSexual PartnersCoinfectionInfectious Disease Transmission, VerticalImmunoglobulin MLogistic Models