HIV SeropositivityHIV SeroprevalenceHIV InfectionsDisease ProgressionAcquired Immunodeficiency SyndromeSubstance Abuse, IntravenousSexual BehaviorHIV-1Risk FactorsCohort StudiesSeroepidemiologic StudiesViral LoadSimian Acquired Immunodeficiency SyndromeSimian immunodeficiency virusnef Gene Products, Human Immunodeficiency VirusMacaca mulattaCD4-Positive T-LymphocytesAntibodies, ViralAntibodies, BacterialChlamydophila pneumoniaeImmunoglobulin GPrevalenceChlamydophila InfectionsEnzyme-Linked Immunosorbent AssaySerologic TestsProspective StudiesHIV SeronegativityCase-Control StudiesHelicobacter pyloriHelicobacter InfectionsFollow-Up StudiesCross-Sectional StudiesTime FactorsAge FactorsRetrospective StudiesToxocariasisIncidenceCytomegalovirus InfectionsAntibodies, ProtozoanAIDS SerodiagnosisCD4 Lymphocyte CountHepatitis CToxoplasmosisOdds RatioHerpesvirus 2, HumanMultivariate AnalysisTreatment OutcomeBlood DonorsBrazilToxocaraPapillomavirus InfectionsAnti-HIV AgentsLogistic ModelsHomosexualityRural PopulationLongitudinal StudiesAIDS-Related Opportunistic InfectionsUnited StatesPregnancyPrognosisCytomegalovirusNeosporaSyphilisHerpes GenitalisImmunoglobulin AQuestionnairesHuman papillomavirus 16Biological MarkersToxoplasmaRisk-TakingHomosexuality, MaleCell CycleImmunoglobulin MInfant, NewbornSexual PartnersSex FactorsHIV AntigensHepatitis BAge Distribution