HIV SeropositivityHIV SeroprevalenceHIV InfectionsSubstance Abuse, IntravenousSexual BehaviorRisk FactorsSeroepidemiologic StudiesBehavior, AnimalFeeding BehaviorAntibodies, ViralAntibodies, BacterialChlamydophila pneumoniaeHealth BehaviorImmunoglobulin GChlamydophila InfectionsSocial BehaviorSerologic TestsPrevalenceBehaviorEnzyme-Linked Immunosorbent AssayHIV SeronegativityRisk-TakingSexual Behavior, AnimalHelicobacter pyloriHelicobacter InfectionsCross-Sectional StudiesToxocariasisChild BehaviorAdolescent BehaviorExploratory BehaviorAntibodies, ProtozoanCytomegalovirus InfectionsAcquired Immunodeficiency SyndromeToxoplasmosisAIDS SerodiagnosisChild Behavior DisordersHerpesvirus 2, HumanMaternal BehaviorSexual PartnersHIV-1ToxocaraBehavior TherapyRural PopulationAge FactorsCase-Control StudiesBlood DonorsHepatitis CHomosexuality, MaleQuestionnairesStereotyped BehaviorPapillomavirus InfectionsNeosporaHomosexualityBrazilSyphilisHerpes GenitalisCytomegalovirusOdds RatioToxoplasmaCohort StudiesImmunoglobulin ALogistic ModelsProstitutionHuman papillomavirus 16