HIV SeropositivityTularemiaFrancisella tularensisHIV SeroprevalenceHIV InfectionsSubstance Abuse, IntravenousSexual BehaviorRisk FactorsSeroepidemiologic StudiesAntibodies, ViralAntibodies, BacterialChlamydophila pneumoniaeChlamydophila InfectionsImmunoglobulin GSerologic TestsEnzyme-Linked Immunosorbent AssayHIV SeronegativityPrevalenceHelicobacter pyloriHelicobacter InfectionsSequence Analysis, DNASpecies SpecificityToxocariasisAntibodies, ProtozoanCytomegalovirus InfectionsAntigens, BacterialRNA, Ribosomal, 16SHIV-1ToxoplasmosisAcquired Immunodeficiency SyndromeCross-Sectional StudiesMice, Inbred StrainsHerpesvirus 2, HumanDNA, RibosomalPolymerase Chain ReactionToxocaraBacterial Typing TechniquesAIDS SerodiagnosisBlood DonorsHepatitis CGenes, BacterialEscherichia coliCase-Control StudiesVirulenceBrazilCytomegalovirusNeosporaToxoplasmaPapillomavirus InfectionsImmunoglobulin ARural PopulationSyphilisMutationHerpes GenitalisDNA, BacterialImmunoglobulin MHepatitis A Virus, HumanHomosexualityAge FactorsHepatitis AHuman papillomavirus 16