HIV SeropositivityHIV SeroprevalenceHIV InfectionsSubstance Abuse, IntravenousSexual BehaviorRisk FactorsSeroepidemiologic StudiesAntibodies, ViralPeripheral NervesAntibodies, BacterialImmunoglobulin GChlamydophila pneumoniaeAcquired Immunodeficiency SyndromeChlamydophila InfectionsEnzyme-Linked Immunosorbent AssaySerologic TestsHIV SeronegativityPrevalenceHelicobacter pyloriHelicobacter InfectionsPeripheral Nervous SystemHIV-1Peripheral Nervous System DiseasesToxocariasisCytomegalovirus InfectionsAntibodies, ProtozoanAIDS SerodiagnosisCross-Sectional StudiesCase-Control StudiesPeripheral Vascular DiseasesToxoplasmosisBlood DonorsToxocaraHerpesvirus 2, HumanHepatitis CLeukocytes, MononuclearHomosexualityCytomegalovirusNeosporaImmunoglobulin MRural PopulationPapillomavirus InfectionsImmunoglobulin ABrazilCD4 Lymphocyte CountAge FactorsAIDS-Related Opportunistic InfectionsSyphilisAnti-HIV AgentsHerpes GenitalisToxoplasmaCohort StudiesProspective StudiesTime FactorsHIV AntigensOdds RatioPeripheral Nerve InjuriesAntibodies, HelminthHuman papillomavirus 16