HIV SeropositivityHIV SeroprevalenceHIV InfectionsSubstance Abuse, IntravenousSexual BehaviorRisk FactorsSeroepidemiologic StudiesAntibodies, ViralAntibodies, BacterialImmunoglobulin GChlamydophila pneumoniaeEnzyme-Linked Immunosorbent AssayChlamydophila InfectionsPrevalenceSerologic TestsHIV SeronegativityDelayed DiagnosisSensitivity and SpecificityHelicobacter pyloriHelicobacter InfectionsToxocariasisPrenatal DiagnosisAntibodies, ProtozoanEarly DiagnosisCross-Sectional StudiesCytomegalovirus InfectionsCase-Control StudiesAcquired Immunodeficiency SyndromeToxoplasmosisRetrospective StudiesProspective StudiesAge FactorsToxocaraHerpesvirus 2, HumanHIV-1Cohort StudiesAIDS SerodiagnosisBlood DonorsHepatitis CBrazilPapillomavirus InfectionsRural PopulationNeosporaPregnancyImmunoglobulin MSyphilisIncidenceImmunoglobulin AToxoplasmaCytomegalovirusDiagnosisOdds RatioHerpes GenitalisAntibodies, HelminthInfant, NewbornHomosexualityHomosexuality, MaleAntigens, BacterialHuman papillomavirus 16Logistic ModelsHepatitis ATime Factors