HIV SeropositivityHIV SeroprevalenceHIV InfectionsSubstance Abuse, IntravenousSexual BehaviorRisk FactorsDisease ProgressionSeroepidemiologic StudiesCD4 Lymphocyte CountLeukocyte CountPlatelet CountAntibodies, ViralAntibodies, BacterialChlamydophila pneumoniaeImmunoglobulin GCell CountChlamydophila InfectionsEnzyme-Linked Immunosorbent AssayBlood Cell CountSerologic TestsHIV SeronegativityPrevalenceHIV-1Acquired Immunodeficiency SyndromeHelicobacter pyloriHelicobacter InfectionsLymphocyte CountColony Count, MicrobialTime FactorsToxocariasisCross-Sectional StudiesCohort StudiesCase-Control StudiesViral LoadProspective StudiesCytomegalovirus InfectionsErythrocyte CountAntibodies, ProtozoanAnti-HIV AgentsHepatitis CSperm CountToxoplasmosisHerpesvirus 2, HumanToxocaraAge FactorsAIDS SerodiagnosisBlood DonorsFollow-Up StudiesPapillomavirus InfectionsRetrospective StudiesAIDS-Related Opportunistic InfectionsTreatment OutcomeRural PopulationCytomegalovirusNeosporaBrazilBiological MarkersImmunoglobulin AHerpes GenitalisMultivariate AnalysisHomosexualitySyphilisOdds RatioPrognosisImmunoglobulin MToxoplasmaCell CycleHuman papillomavirus 16Homosexuality, MaleAnti-Retroviral AgentsIncidenceAntibodies, Helminth