NelfinavirHIV SeropositivityHIV SeroprevalenceHIV InfectionsSubstance Abuse, IntravenousHIV Protease InhibitorsSexual BehaviorRisk FactorsSeroepidemiologic StudiesSaquinavirOxazinesRitonavirIndinavirAnti-HIV AgentsBenzoxazinesHIV-1StavudineAntibodies, ViralHIV SeronegativityAntibodies, BacterialChlamydophila pneumoniaeReverse Transcriptase InhibitorsChlamydophila InfectionsPyrimidinonesHIV ProteaseImmunoglobulin GSerologic TestsLopinavirEnzyme-Linked Immunosorbent AssayPrevalenceCD4 Lymphocyte CountCarbamatesViral LoadDrug InteractionsAspartic Acid ProteasesHelicobacter pyloriDibenzocycloheptenesHelicobacter InfectionsDrug Resistance, ViralLamivudineToxocariasisArea Under CurveAntibodies, ProtozoanDrug Therapy, CombinationCytomegalovirus InfectionsAnti-Retroviral AgentsToxoplasmosisAcquired Immunodeficiency SyndromeCross-Sectional StudiesToxocaraHerpesvirus 2, HumanRNA, ViralAIDS SerodiagnosisBlood DonorsHepatitis CCytochrome P-450 CYP3A