Duty to WarnJurisprudenceLegislation, MedicalEthicsEthics, MedicalBiological Specimen BanksInformed ConsentUnited StatesDisabled PersonsHomeless PersonsMentally Ill PersonsRisk FactorsBioethical IssuesVisually Impaired PersonsMentally Disabled PersonsHIV InfectionsQuestionnairesPrevalenceIncidenceAge FactorsCross-Sectional StudiesCohort StudiesTime FactorsSex FactorsDisease OutbreaksPopulation Surveillance