HIV SeropositivityHIV SeroprevalenceSchistosoma haematobiumHIV InfectionsSchistosomiasis haematobiaSubstance Abuse, IntravenousNematode InfectionsAquacultureFish DiseasesParasite Egg CountSexual BehaviorHost-Parasite InteractionsRisk FactorsDisease ProgressionSeroepidemiologic StudiesAntibodies, ViralAntibodies, BacterialChlamydophila pneumoniaeImmunoglobulin GChlamydophila InfectionsEnzyme-Linked Immunosorbent AssaySerologic TestsHIV SeronegativityPrevalenceHelicobacter pyloriHelicobacter InfectionsAcquired Immunodeficiency SyndromeToxocariasisHIV-1Antibodies, ProtozoanCytomegalovirus InfectionsCross-Sectional StudiesCase-Control StudiesToxoplasmosisHepatitis CHerpesvirus 2, HumanToxocaraAIDS SerodiagnosisBlood DonorsCohort StudiesPapillomavirus InfectionsProspective StudiesNeosporaCD4 Lymphocyte CountAge FactorsTime FactorsCytomegalovirusRural PopulationHerpes GenitalisSyphilisImmunoglobulin AHuman papillomavirus 16BrazilToxoplasmaHomosexualityCell CycleOdds RatioImmunoglobulin MHomosexuality, Male