Drug Users: People who take drugs for a non-therapeutic or non-medical effect. The drugs may be legal or illegal, but their use often results in adverse medical, legal, or social consequences for the users.Substance Abuse, Intravenous: Abuse, overuse, or misuse of a substance by its injection into a vein.Needle Sharing: Usage of a single needle among two or more people for injecting drugs. Needle sharing is a high-risk behavior for contracting infectious disease.Needle-Exchange Programs: Organized services for exchange of sterile needles and syringes used for injections as a potential means of reducing the transmission of infectious diseases.Syringes: Instruments used for injecting or withdrawing fluids. (Stedman, 25th ed)HIV Infections: Includes the spectrum of human immunodeficiency virus infections that range from asymptomatic seropositivity, thru AIDS-related complex (ARC), to acquired immunodeficiency syndrome (AIDS).Risk-Taking: Undertaking a task involving a challenge for achievement or a desirable goal in which there is a lack of certainty or a fear of failure. It may also include the exhibiting of certain behaviors whose outcomes may present a risk to the individual or to those associated with him or her.Heroin Dependence: Strong dependence, both physiological and emotional, upon heroin.Substance-Related Disorders: Disorders related to substance abuse.Street Drugs: Drugs obtained and often manufactured illegally for the subjective effects they are said to produce. They are often distributed in urban areas, but are also available in suburban and rural areas, and tend to be grossly impure and may cause unexpected toxicity.Hepatitis C: INFLAMMATION of the LIVER in humans caused by HEPATITIS C VIRUS, a single-stranded RNA virus. Its incubation period is 30-90 days. Hepatitis C is transmitted primarily by contaminated blood parenterally, and is often associated with transfusion and intravenous drug abuse. However, in a significant number of cases, the source of hepatitis C infection is unknown.Harm Reduction: The application of methods designed to reduce the risk of harm associated with certain behaviors without reduction in frequency of those behaviors. The risk-associated behaviors include ongoing and active addictive behaviors.BaltimoreMethadone: A synthetic opioid that is used as the hydrochloride. It is an opioid analgesic that is primarily a mu-opioid agonist. It has actions and uses similar to those of MORPHINE. (From Martindale, The Extra Pharmacopoeia, 30th ed, p1082-3)Heroin: A narcotic analgesic that may be habit-forming. It is a controlled substance (opium derivative) listed in the U.S. Code of Federal Regulations, Title 21 Parts 329.1, 1308.11 (1987). Sale is forbidden in the United States by Federal statute. (Merck Index, 11th ed)New York CityHIV Seroprevalence: Studies of the number of cases where human immunodeficiency virus (HIV) is present in a specific population at a designated time. The presence in a given individual is determined by the finding of HIV antibodies in the serum (HIV SEROPOSITIVITY).HIV Seropositivity: Development of neutralizing antibodies in individuals who have been exposed to the human immunodeficiency virus (HIV/HTLV-III/LAV).Sexual Behavior: Sexual activities of humans.Substance Abuse Treatment Centers: Health facilities providing therapy and/or rehabilitation for substance-dependent individuals. Methadone distribution centers are included.British Columbia: A province of Canada on the Pacific coast. Its capital is Victoria. The name given in 1858 derives from the Columbia River which was named by the American captain Robert Gray for his ship Columbia which in turn was named for Columbus. (From Webster's New Geographical Dictionary, 1988, p178 & Room, Brewer's Dictionary of Names, 1992, p81-2)Drug Overdose: Accidental or deliberate use of a medication or street drug in excess of normal dosage.Crack Cocaine: The purified, alkaloidal, extra-potent form of cocaine. It is smoked (free-based), injected intravenously, and orally ingested. Use of crack results in alterations in function of the cardiovascular system, the autonomic nervous system, the central nervous system, and the gastrointestinal system. The slang term "crack" was derived from the crackling sound made upon igniting of this form of cocaine for smoking.Needles: Sharp instruments used for puncturing or suturing.Narcotics: Agents that induce NARCOSIS. Narcotics include agents that cause somnolence or induced sleep (STUPOR); natural or synthetic derivatives of OPIUM or MORPHINE or any substance that has such effects. They are potent inducers of ANALGESIA and OPIOID-RELATED DISORDERS.Prevalence: The total number of cases of a given disease in a specified population at a designated time. It is differentiated from INCIDENCE, which refers to the number of new cases in the population at a given time.San FranciscoAcquired Immunodeficiency Syndrome: An acquired defect of cellular immunity associated with infection by the human immunodeficiency virus (HIV), a CD4-positive T-lymphocyte count under 200 cells/microliter or less than 14% of total lymphocytes, and increased susceptibility to opportunistic infections and malignant neoplasms. Clinical manifestations also include emaciation (wasting) and dementia. These elements reflect criteria for AIDS as defined by the CDC in 1993.PrisonersOpioid-Related Disorders: Disorders related or resulting from abuse or mis-use of opioids.Law Enforcement: Organized efforts to insure obedience to the laws of a community.Cocaine-Related Disorders: Disorders related or resulting from use of cocaine.Amphetamine-Related Disorders: Disorders related or resulting from use of amphetamines.Risk Factors: An aspect of personal behavior or lifestyle, environmental exposure, or inborn or inherited characteristic, which, on the basis of epidemiologic evidence, is known to be associated with a health-related condition considered important to prevent.Opiate Substitution Treatment: Medical treatment for opioid dependence using a substitute opiate such as METHADONE or BUPRENORPHINE.Drug and Narcotic Control: Control of drug and narcotic use by international agreement, or by institutional systems for handling prescribed drugs. This includes regulations concerned with the manufacturing, dispensing, approval (DRUG APPROVAL), and marketing of drugs.RussiaCross-Sectional Studies: Studies in which the presence or absence of disease or other health-related variables are determined in each member of the study population or in a representative sample at one particular time. This contrasts with LONGITUDINAL STUDIES which are followed over a period of time.Prostitution: The practice of indulging in sexual relations for money.KentuckyPharmacies: Facilities for the preparation and dispensing of drugs.HIV Seronegativity: Immune status consisting of non-production of HIV antibodies, as determined by various serological tests.Methamphetamine: A central nervous system stimulant and sympathomimetic with actions and uses similar to DEXTROAMPHETAMINE. The smokable form is a drug of abuse and is referred to as crank, crystal, crystal meth, ice, and speed.Sexual Partners: Married or single individuals who share sexual relations.Blood-Borne Pathogens: Infectious organisms in the BLOOD, of which the predominant medical interest is their contamination of blood-soiled linens, towels, gowns, BANDAGES, other items from individuals in risk categories, NEEDLES and other sharp objects, MEDICAL WASTE and DENTAL WASTE, all of which health workers are exposed to. This concept is differentiated from the clinical conditions of BACTEREMIA; VIREMIA; and FUNGEMIA where the organism is present in the blood of a patient as the result of a natural infectious process.Cohort Studies: Studies in which subsets of a defined population are identified. These groups may or may not be exposed to factors hypothesized to influence the probability of the occurrence of a particular disease or other outcome. Cohorts are defined populations which, as a whole, are followed in an attempt to determine distinguishing subgroup characteristics.Hepatitis C Antibodies: Antibodies to the HEPATITIS C ANTIGENS including antibodies to envelope, core, and non-structural proteins.Urban Population: The inhabitants of a city or town, including metropolitan areas and suburban areas.Hepacivirus: A genus of FLAVIVIRIDAE causing parenterally-transmitted HEPATITIS C which is associated with transfusions and drug abuse. Hepatitis C virus is the type species.Interviews as Topic: Conversations with an individual or individuals held in order to obtain information about their background and other personal biographical data, their attitudes and opinions, etc. It includes school admission or job interviews.Prisons: Penal institutions, or places of confinement for war prisoners.Questionnaires: Predetermined sets of questions used to collect data - clinical data, social status, occupational group, etc. The term is often applied to a self-completed survey instrument.EstoniaInternet: A loose confederation of computer communication networks around the world. The networks that make up the Internet are connected through several backbone networks. The Internet grew out of the US Government ARPAnet project and was designed to facilitate information exchange.Tattooing: The indelible marking of TISSUES, primarily SKIN, by pricking it with NEEDLES to imbed various COLORING AGENTS. Tattooing of the CORNEA is done to colorize LEUKOMA spots.Hepatitis B: INFLAMMATION of the LIVER in humans caused by a member of the ORTHOHEPADNAVIRUS genus, HEPATITIS B VIRUS. It is primarily transmitted by parenteral exposure, such as transfusion of contaminated blood or blood products, but can also be transmitted via sexual or intimate personal contact.United StatesUrban Health: The status of health in urban populations.N-Methyl-3,4-methylenedioxyamphetamine: An N-substituted amphetamine analog. It is a widely abused drug classified as a hallucinogen and causes marked, long-lasting changes in brain serotonergic systems. It is commonly referred to as MDMA or ecstasy.HTLV-II InfectionsLogistic Models: Statistical models which describe the relationship between a qualitative dependent variable (that is, one which can take only certain discrete values, such as the presence or absence of a disease) and an independent variable. A common application is in epidemiology for estimating an individual's risk (probability of a disease) as a function of a given risk factor.Software: Sequential operating programs and data which instruct the functioning of a digital computer.Homosexuality, Male: Sexual attraction or relationship between males.Seroepidemiologic Studies: EPIDEMIOLOGIC STUDIES based on the detection through serological testing of characteristic change in the serum level of specific ANTIBODIES. Latent subclinical infections and carrier states can thus be detected in addition to clinically overt cases.MexicoUnsafe Sex: Sexual behaviors which are high-risk for contracting SEXUALLY TRANSMITTED DISEASES or for producing PREGNANCY.Risk Reduction Behavior: Reduction of high-risk choices and adoption of low-risk quantity and frequency alternatives.ArkansasHomosexuality: The sexual attraction or relationship between members of the same SEX.Socioeconomic Factors: Social and economic factors that characterize the individual or group within the social structure.Sampling Studies: Studies in which a number of subjects are selected from all subjects in a defined population. Conclusions based on sample results may be attributed only to the population sampled.HIV-1: The type species of LENTIVIRUS and the etiologic agent of AIDS. It is characterized by its cytopathic effect and affinity for the T4-lymphocyte.VietnamSexually Transmitted Diseases: Diseases due to or propagated by sexual contact.Incidence: The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from PREVALENCE, which refers to all cases, new or old, in the population at a given time.AIDS Serodiagnosis: Immunologic tests for identification of HIV (HTLV-III/LAV) antibodies. They include assays for HIV SEROPOSITIVITY and HIV SERONEGATIVITY that have been developed for screening persons carrying the viral antibody from patients with overt symptoms of AIDS or AIDS-RELATED COMPLEX.ConnecticutContraceptive Devices, Male: Contraceptive devices used by males.Antiretroviral Therapy, Highly Active: Drug regimens, for patients with HIV INFECTIONS, that aggressively suppress HIV replication. The regimens usually involve administration of three or more different drugs including a protease inhibitor.Condoms: A sheath that is worn over the penis during sexual behavior in order to prevent pregnancy or spread of sexually transmitted disease.Police: Agents of the law charged with the responsibility of maintaining and enforcing law and order among the citizenry.Marijuana Abuse: The excessive use of marijuana with associated psychological symptoms and impairment in social or occupational functioning.Crime: A violation of the criminal law, i.e., a breach of the conduct code specifically sanctioned by the state, which through its administrative agencies prosecutes offenders and imposes and administers punishments. The concept includes unacceptable actions whether prosecuted or going unpunished.China: A country spanning from central Asia to the Pacific Ocean.Appalachian Region: A geographical area of the United States with no definite boundaries but comprising northeastern Alabama, northwestern Georgia, northwestern South Carolina, western North Carolina, eastern Kentucky, eastern Tennessee, western Virginia, West Virginia, western Maryland, southwestern Pennsylvania, southern Ohio, and southern New York.Bacillaceae Infections: Infections with bacteria of the family BACILLACEAE.HungaryHIV: Human immunodeficiency virus. A non-taxonomic and historical term referring to any of two species, specifically HIV-1 and/or HIV-2. Prior to 1986, this was called human T-lymphotropic virus type III/lymphadenopathy-associated virus (HTLV-III/LAV). From 1986-1990, it was an official species called HIV. Since 1991, HIV was no longer considered an official species name; the two species were designated HIV-1 and HIV-2.Medication Adherence: Voluntary cooperation of the patient in taking drugs or medicine as prescribed. This includes timing, dosage, and frequency.Health Knowledge, Attitudes, Practice: Knowledge, attitudes, and associated behaviors which pertain to health-related topics such as PATHOLOGIC PROCESSES or diseases, their prevention, and treatment. This term refers to non-health workers and health workers (HEALTH PERSONNEL).Social Support: Support systems that provide assistance and encouragement to individuals with physical or emotional disabilities in order that they may better cope. Informal social support is usually provided by friends, relatives, or peers, while formal assistance is provided by churches, groups, etc.Data Collection: Systematic gathering of data for a particular purpose from various sources, including questionnaires, interviews, observation, existing records, and electronic devices. The process is usually preliminary to statistical analysis of the data.Health Services Accessibility: The degree to which individuals are inhibited or facilitated in their ability to gain entry to and to receive care and services from the health care system. Factors influencing this ability include geographic, architectural, transportational, and financial considerations, among others.Legislation, Pharmacy: Laws and regulations, pertaining to the field of pharmacy, proposed for enactment or enacted by a legislative body.Rhode IslandRomeProspective Studies: Observation of a population for a sufficient number of persons over a sufficient number of years to generate incidence or mortality rates subsequent to the selection of the study group.Anthropology, Cultural: It is the study of social phenomena which characterize the learned, shared, and transmitted social activities of particular ethnic groups with focus on the causes, consequences, and complexities of human social and cultural variability.Preventive Health Services: Services designed for HEALTH PROMOTION and prevention of disease.Heterosexuality: The sexual attraction or relationship between members of the opposite SEX.Longitudinal Studies: Studies in which variables relating to an individual or group of individuals are assessed over a period of time.Patient Acceptance of Health Care: The seeking and acceptance by patients of health service.WashingtonPeer Group: Group composed of associates of same species, approximately the same age, and usually of similar rank or social status.Syphilis: A contagious venereal disease caused by the spirochete TREPONEMA PALLIDUM.Self Disclosure: A willingness to reveal information about oneself to others.Anti-HIV Agents: Agents used to treat AIDS and/or stop the spread of the HIV infection. These do not include drugs used to treat symptoms or opportunistic infections associated with AIDS.Soft Tissue Infections: Infections of non-skeletal tissue, i.e., exclusive of bone, ligaments, cartilage, and fibrous tissue. The concept is usually referred to as skin and soft tissue infections and usually subcutaneous and muscle tissue are involved. The predisposing factors in anaerobic infections are trauma, ischemia, and surgery. The organisms often derive from the fecal or oral flora, particularly in wounds associated with intestinal surgery, decubitus ulcer, and human bites. (From Cecil Textbook of Medicine, 19th ed, p1688)Thailand: Formerly known as Siam, this is a Southeast Asian nation at the center of the Indochina peninsula. Bangkok is the capital city.Disease Outbreaks: Sudden increase in the incidence of a disease. The concept includes EPIDEMICS and PANDEMICS.Puerto Rico: An island in the Greater Antilles in the West Indies. Its capital is San Juan. It is a self-governing commonwealth in union with the United States. It was discovered by Columbus in 1493 but no colonization was attempted until 1508. It belonged to Spain until ceded to the United States in 1898. It became a commonwealth with autonomy in internal affairs in 1952. Columbus named the island San Juan for St. John's Day, the Monday he arrived, and the bay Puerto Rico, rich harbor. The island became Puerto Rico officially in 1932. (From Webster's New Geographical Dictionary, 1988, p987 & Room, Brewer's Dictionary of Names, 1992, p436)Patient Compliance: Voluntary cooperation of the patient in following a prescribed regimen.Buprenorphine: A derivative of the opioid alkaloid THEBAINE that is a more potent and longer lasting analgesic than MORPHINE. It appears to act as a partial agonist at mu and kappa opioid receptors and as an antagonist at delta receptors. The lack of delta-agonist activity has been suggested to account for the observation that buprenorphine tolerance may not develop with chronic use.Opium: The air-dried exudate from the unripe seed capsule of the opium poppy, Papaver somniferum, or its variant, P. album. It contains a number of alkaloids, but only a few - MORPHINE; CODEINE; and PAPAVERINE - have clinical significance. Opium has been used as an analgesic, antitussive, antidiarrheal, and antispasmodic.Population Surveillance: Ongoing scrutiny of a population (general population, study population, target population, etc.), generally using methods distinguished by their practicability, uniformity, and frequently their rapidity, rather than by complete accuracy.Human Rights Abuses: Deliberate maltreatment of groups of humans beings including violations of generally-accepted fundamental rights as stated by the Universal Declaration of Human Rights, adopted and proclaimed by the United Nations General Assembly resolution 217 A (III) of 10 December 1948.Directly Observed Therapy: A treatment method in which patients are under direct observation when they take their medication or receive their treatment. This method is designed to reduce the risk of treatment interruption and to ensure patient compliance.MoscowSex Factors: Maleness or femaleness as a constituent element or influence contributing to the production of a result. It may be applicable to the cause or effect of a circumstance. It is used with human or animal concepts but should be differentiated from SEX CHARACTERISTICS, anatomical or physiological manifestations of sex, and from SEX DISTRIBUTION, the number of males and females in given circumstances.Disease Transmission, Infectious: The transmission of infectious disease or pathogens. When transmission is within the same species, the mode can be horizontal or vertical (INFECTIOUS DISEASE TRANSMISSION, VERTICAL).Georgia (Republic)Computer Graphics: The process of pictorial communication, between human and computers, in which the computer input and output have the form of charts, drawings, or other appropriate pictorial representation.Opiate Alkaloids: Alkaloids found in OPIUM from PAPAVER that induce analgesic and narcotic effects by action upon OPIOID RECEPTORS.Marijuana Smoking: Inhaling and exhaling the smoke from CANNABIS.Counseling: The giving of advice and assistance to individuals with educational or personal problems.CD4 Lymphocyte Count: The number of CD4-POSITIVE T-LYMPHOCYTES per unit volume of BLOOD. Determination requires the use of a fluorescence-activated flow cytometer.Demography: Statistical interpretation and description of a population with reference to distribution, composition, or structure.Motivation: Those factors which cause an organism to behave or act in either a goal-seeking or satisfying manner. They may be influenced by physiological drives or by external stimuli.Endocarditis, Bacterial: Inflammation of the ENDOCARDIUM caused by BACTERIA that entered the bloodstream. The strains of bacteria vary with predisposing factors, such as CONGENITAL HEART DEFECTS; HEART VALVE DISEASES; HEART VALVE PROSTHESIS IMPLANTATION; or intravenous drug use.ArgentinaMobile Health Units: Movable or portable facilities in which diagnostic and therapeutic services are provided to the community.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Residential Treatment: A specialized residential treatment program for behavior disorders including substance abuse. It may include therapeutically planned group living and learning situations including teaching of adaptive skills to help patient functioning in the community. (From Kahn, A. P. and Fawcett, J. Encyclopedia of Mental Health, 1993, p320.)RNA, Viral: Ribonucleic acid that makes up the genetic material of viruses.Canada: The largest country in North America, comprising 10 provinces and three territories. Its capital is Ottawa.Los AngelesClostridium Infections: Infections with bacteria of the genus CLOSTRIDIUM.Netherlands: Country located in EUROPE. It is bordered by the NORTH SEA, BELGIUM, and GERMANY. Constituent areas are Aruba, Curacao, Sint Maarten, formerly included in the NETHERLANDS ANTILLES.Safe Sex: Sexual behavior that prevents or reduces the spread of SEXUALLY TRANSMITTED DISEASES or PREGNANCY.Attitude to Health: Public attitudes toward health, disease, and the medical care system.Amyl Nitrite: A vasodilator that is administered by inhalation. It is also used recreationally due to its supposed ability to induce euphoria and act as an aphrodisiac.Community-Institutional Relations: The interactions between members of a community and representatives of the institutions within that community.Hepatitis, Viral, Human: INFLAMMATION of the LIVER in humans due to infection by VIRUSES. There are several significant types of human viral hepatitis with infection caused by enteric-transmission (HEPATITIS A; HEPATITIS E) or blood transfusion (HEPATITIS B; HEPATITIS C; and HEPATITIS D).Hepatitis D: INFLAMMATION of the LIVER in humans caused by HEPATITIS DELTA VIRUS, a defective RNA virus that can only infect HEPATITIS B patients. For its viral coating, hepatitis delta virus requires the HEPATITIS B SURFACE ANTIGENS produced by these patients. Hepatitis D can occur either concomitantly with (coinfection) or subsequent to (superinfection) hepatitis B infection. Similar to hepatitis B, it is primarily transmitted by parenteral exposure, such as transfusion of contaminated blood or blood products, but can also be transmitted via sexual or intimate personal contact.Prescription Drug Misuse: Improper use of drugs or medications outside the intended purpose, scope, or guidelines for use. This is in contrast to MEDICATION ADHERENCE, and distinguished from DRUG ABUSE, which is a deliberate or willful action.Hallucinogens: Drugs capable of inducing illusions, hallucinations, delusions, paranoid ideations, and other alterations of mood and thinking. Despite the name, the feature that distinguishes these agents from other classes of drugs is their capacity to induce states of altered perception, thought, and feeling that are not experienced otherwise.ScotlandCaliforniaHealth Education: Education that increases the awareness and favorably influences the attitudes and knowledge relating to the improvement of health on a personal or community basis.Urban Health Services: Health services, public or private, in urban areas. The services include the promotion of health and the delivery of health care.Substance Abuse Detection: Detection of drugs that have been abused, overused, or misused, including legal and illegal drugs. Urine screening is the usual method of detection.Qualitative Research: Any type of research that employs nonnumeric information to explore individual or group characteristics, producing findings not arrived at by statistical procedures or other quantitative means. (Qualitative Inquiry: A Dictionary of Terms Thousand Oaks, CA: Sage Publications, 1997)Pilot Projects: Small-scale tests of methods and procedures to be used on a larger scale if the pilot study demonstrates that these methods and procedures can work.FloridaMultivariate Analysis: A set of techniques used when variation in several variables has to be studied simultaneously. In statistics, multivariate analysis is interpreted as any analytic method that allows simultaneous study of two or more dependent variables.Databases, Factual: Extensive collections, reputedly complete, of facts and data garnered from material of a specialized subject area and made available for analysis and application. The collection can be automated by various contemporary methods for retrieval. The concept should be differentiated from DATABASES, BIBLIOGRAPHIC which is restricted to collections of bibliographic references.Viral Load: The quantity of measurable virus in a body fluid. Change in viral load, measured in plasma, is sometimes used as a SURROGATE MARKER in disease progression.Hepatitis C, Chronic: INFLAMMATION of the LIVER in humans that is caused by HEPATITIS C VIRUS lasting six months or more. Chronic hepatitis C can lead to LIVER CIRRHOSIS.Homeless Youth: Runaway and homeless children and adolescents living on the streets of cities and having no fixed place of residence.Equipment Contamination: The presence of an infectious agent on instruments, prostheses, or other inanimate articles.Epidemiologic Research Design: The form and structure of analytic studies in epidemiologic and clinical research.Central Nervous System Stimulants: A loosely defined group of drugs that tend to increase behavioral alertness, agitation, or excitation. They work by a variety of mechanisms, but usually not by direct excitation of neurons. The many drugs that have such actions as side effects to their main therapeutic use are not included here.Epidemics: Sudden outbreaks of a disease in a country or region not previously recognized in that area, or a rapid increase in the number of new cases of a previous existing endemic disease. Epidemics can also refer to outbreaks of disease in animal or plant populations.Comorbidity: The presence of co-existing or additional diseases with reference to an initial diagnosis or with reference to the index condition that is the subject of study. Comorbidity may affect the ability of affected individuals to function and also their survival; it may be used as a prognostic indicator for length of hospital stay, cost factors, and outcome or survival.PhiladelphiaHuman T-lymphotropic virus 2: A strain of PRIMATE T-LYMPHOTROPIC VIRUS 2 that can transform normal T-lymphocytes and can replicate in both T- and B-cell lines. The virus is related to but distinct from HTLV-1.Analgesics, Opioid: Compounds with activity like OPIATE ALKALOIDS, acting at OPIOID RECEPTORS. Properties include induction of ANALGESIA or NARCOSIS.Residence Characteristics: Elements of residence that characterize a population. They are applicable in determining need for and utilization of health services.Narcotic Antagonists: Agents inhibiting the effect of narcotics on the central nervous system.UkraineDenial (Psychology): Refusal to admit the truth or reality of a situation or experience.Odds Ratio: The ratio of two odds. The exposure-odds ratio for case control data is the ratio of the odds in favor of exposure among cases to the odds in favor of exposure among noncases. The disease-odds ratio for a cohort or cross section is the ratio of the odds in favor of disease among the exposed to the odds in favor of disease among the unexposed. The prevalence-odds ratio refers to an odds ratio derived cross-sectionally from studies of prevalent cases.Focus Groups: A method of data collection and a QUALITATIVE RESEARCH tool in which a small group of individuals are brought together and allowed to interact in a discussion of their opinions about topics, issues, or questions.African Americans: Persons living in the United States having origins in any of the black groups of Africa.Coinfection: Simultaneous infection of a host organism by two or more pathogens. In virology, coinfection commonly refers to simultaneous infection of a single cell by two or more different viruses.Risk Assessment: The qualitative or quantitative estimation of the likelihood of adverse effects that may result from exposure to specified health hazards or from the absence of beneficial influences. (Last, Dictionary of Epidemiology, 1988)Drug Contamination: The presence of organisms, or any foreign material that makes a drug preparation impure.Genotype: The genetic constitution of the individual, comprising the ALLELES present at each GENETIC LOCUS.Vulnerable Populations: Groups of persons whose range of options is severely limited, who are frequently subjected to COERCION in their DECISION MAKING, or who may be compromised in their ability to give INFORMED CONSENT.Sentinel Surveillance: Monitoring of rate of occurrence of specific conditions to assess the stability or change in health levels of a population. It is also the study of disease rates in a specific cohort such as in a geographic area or population subgroup to estimate trends in a larger population. (From Last, Dictionary of Epidemiology, 2d ed)Social Discrimination: Group behavior toward others by virtue of their group membership.LatviaCocaine: An alkaloid ester extracted from the leaves of plants including coca. It is a local anesthetic and vasoconstrictor and is clinically used for that purpose, particularly in the eye, ear, nose, and throat. It also has powerful central nervous system effects similar to the amphetamines and is a drug of abuse. Cocaine, like amphetamines, acts by multiple mechanisms on brain catecholaminergic neurons; the mechanism of its reinforcing effects is thought to involve inhibition of dopamine uptake.Public Health: Branch of medicine concerned with the prevention and control of disease and disability, and the promotion of physical and mental health of the population on the international, national, state, or municipal level.Oxycodone: A semisynthetic derivative of CODEINE.Computer User Training: Process of teaching a person to interact and communicate with a computer.Centers for Disease Control and Prevention (U.S.): An agency of the UNITED STATES PUBLIC HEALTH SERVICE that conducts and supports programs for the prevention and control of disease and provides consultation and assistance to health departments and other countries.Montenegro: Montenegro was formerly part of the historic Kingdom of Yugoslavia. Following World War II, Montenegro was granted the status of a republic within YUGOSLAVIA. On May 21, 2006, the Republic of Montenegro held a successful referendum on independence and declared independence on June 3. The capital is Podgorica.BrazilWheelchairs: Chairs mounted on wheels and designed to be propelled by the occupant.HIV Antibodies: Antibodies reactive with HIV ANTIGENS.Hepatitis B Vaccines: Vaccines or candidate vaccines containing inactivated hepatitis B or some of its component antigens and designed to prevent hepatitis B. Some vaccines may be recombinantly produced.Health Services: Services for the diagnosis and treatment of disease and the maintenance of health.Confidence Intervals: A range of values for a variable of interest, e.g., a rate, constructed so that this range has a specified probability of including the true value of the variable.Criminal Law: A branch of law that defines criminal offenses, regulates the apprehension, charging and trial of suspected persons, and fixes the penalties and modes of treatment applicable to convicted offenders.Treatment Outcome: Evaluation undertaken to assess the results or consequences of management and procedures used in combating disease in order to determine the efficacy, effectiveness, safety, and practicability of these interventions in individual cases or series.SwitzerlandEpidemiologic Methods: Research techniques that focus on study designs and data gathering methods in human and animal populations.LondonEndocarditis: Inflammation of the inner lining of the heart (ENDOCARDIUM), the continuous membrane lining the four chambers and HEART VALVES. It is often caused by microorganisms including bacteria, viruses, fungi, and rickettsiae. Left untreated, endocarditis can damage heart valves and become life-threatening.Behavior, Addictive: The observable, measurable, and often pathological activity of an organism that portrays its inability to overcome a habit resulting in an insatiable craving for a substance or for performing certain acts. The addictive behavior includes the emotional and physical overdependence on the object of habit in increasing amount or frequency.