HIV SeropositivityHIV SeroprevalenceHIV InfectionsDisease ProgressionAcquired Immunodeficiency SyndromeSubstance Abuse, IntravenousSexual BehaviorHIV-1Risk FactorsSeroepidemiologic StudiesViral LoadSimian Acquired Immunodeficiency SyndromeSimian immunodeficiency virusnef Gene Products, Human Immunodeficiency VirusEpidemiologyCohort StudiesMacaca mulattaMolecular EpidemiologyCD4-Positive T-LymphocytesAntibodies, ViralPrevalenceAntibodies, BacterialChlamydophila pneumoniaeImmunoglobulin GChlamydophila InfectionsEnzyme-Linked Immunosorbent AssaySerologic TestsIncidenceHIV SeronegativityHelicobacter pyloriHelicobacter InfectionsCross-Sectional StudiesAge FactorsCase-Control StudiesUnited StatesToxocariasisCytomegalovirus InfectionsAntibodies, ProtozoanProspective StudiesTime FactorsAIDS SerodiagnosisHepatitis CBrazilRural PopulationAge DistributionToxoplasmosisBlood DonorsHerpesvirus 2, HumanRetrospective StudiesToxocaraCD4 Lymphocyte CountPapillomavirus InfectionsHomosexualityAIDS-Related Opportunistic InfectionsDisease OutbreaksPopulation SurveillanceOdds RatioInfant, NewbornEpidemiologic MethodsSyphilisFollow-Up StudiesIndiaPolymerase Chain ReactionNeosporaCytomegalovirusAnti-HIV AgentsHerpes GenitalisHepatitis AMultivariate AnalysisLogistic ModelsGenotypeToxoplasmaHepatitis BChinaImmunoglobulin AHomosexuality, MaleHepatitis A Virus, HumanHuman papillomavirus 16Sex FactorsImmunoglobulin MZoonosesRisk-TakingTreatment OutcomeSexual PartnersCell CycleUrban PopulationSEER ProgramPrognosisAntibodies, HelminthHIV Antigens