AIDS (acquired immunodeficiency syndrome): An HIV-infected person receives a diagnosis of AIDS after the development of 1 of the CDC-defined AIDS indicator illnesses (see opportunistic infection) or on the basis of the results of specific blood tests (i.e., a CD4+ count of less than 200 cells/microliter or a CD4+ percentage of less than 14). A positive HIV test result does not mean that a person has AIDS.

antiretroviral therapy (ART): Anti-HIV treatments designed to reduce the levels of HIV in a person’s body.

ASD (Adult/Adolescent Spectrum of Disease): Study funded by the CDC and conducted in Louisiana since 1990. (For additional details on the study’s purpose and methods, see Appendix A.)

bias: Refers to results that do not represent true findings because of a systematic error in the data. For example, if persons feel uncomfortable reporting that they have engaged in high-risk behaviors, these behaviors will be systematically underreported. Consequently, conclusions about the occurrence of such behaviors would be considered biased.

CDC: The Centers for Disease Control and Prevention, in the U.S. Department of Health and Human Services, is the lead federal agency for protecting the health and safety of the people of the United States. CDC accomplishes its mission through developing and applying disease prevention and control, environmental health, and health promotion and education activities designed to improve public health in the United States. The CDC provides most of the funding for HIV prevention and HIV surveillance activities in Louisiana.

denominator: Divisor; the term of a fraction, usually written under or after the line that indicates the number of equal parts into which the unit is divided; used to calculate a rate or ratio. For example, in the fraction ¾, four is the denominator.

epidemiology: Study of how diseases or health conditions are distributed in a population. Consequently, an epidemiologist may analyze public health data to determine how a disease is transmitted and to recommend interventions, to identify segments of a population at risk of acquiring a disease, or to monitor disease trends and predict the course and effect of a disease.

exposure categories: To monitor how HIV is being transmitted, HIV/AIDS cases are classified as one of several exposure (risk) categories developed by the CDC.

• Male-male sexual contact refers to men who have sex with men (MSM); that is, homosexual or bisexual contact.
• Injection drug use refers to the use of forms of drugs that require injection. Although it may be valuable to know that a person has used illicit drugs through other routes, this information would not be enough to classify a case as an exposure through injection drug use.
• High-risk heterosexual contact refers to heterosexual contact with a partner who is at increased risk for HIV infection, i.e., a homosexual or bisexual man, an injection drug user, or a person with documented HIV infection.
• Hemophilia/transfusion/transplant cases are those resulting from a transfusion of blood or blood products before 1985.
• Perinatal HIV cases are cases of HIV infection in children resulting from transmission from an HIV-positive mother.
• Unspecified, or no identified risk (NIR), cases are those in persons who have no reported history of exposure at the time of the report date. This category includes persons for whom the surveillance protocols to document risk behavior information have not yet been completed, persons whose exposure history is incomplete because they have died, persons who have declined to disclose their risk behavior or who deny any risk behavior, and persons who do not know the HIV status or risk behaviors of their sex partners.

HAART (highly active antiretroviral therapy): Aggressive anti-HIV treatments that usually include a combination of protease and reverse transcriptase inhibitors, which interrupt the HIV life cycle and whose purpose is to reduce a person’s viral load to undetectable levels.

HITS (HIV Testing Survey): Study funded by the CDC and conducted in Louisiana in 2001. (For additional details on the study’s purpose and methods, see Appendix A.)

HIV (human immunodeficiency virus): The virus that causes AIDS. A person who has contracted the virus is said to be HIV-positive or HIV infected.

incidence: Refers to the number of new cases of a disease that occur in a population during a specified time, usually a year. Even though HIV data are often presented as “new cases of HIV,” these data do not represent new infections (true HIV incidence) because a person may not be tested for HIV during the same period that he or she became infected. On the other hand, incidence can be calculated for diseases (e.g., some STDs). These diseases have clear symptoms that are detectable when a person becomes infected and that cause a person to be tested or to seek treatment shortly after infection.

numerator: Dividend, the term of a fraction, usually written above or before the line that indicates the number of parts that are to be divided; used to calculate a rate or ratio. For example, in the fraction ¾, three is the numerator.

opportunistic infection (OI): HIV infection can weaken a person’s immune system to the point that it has difficulty fighting off certain infections. These types of infections are known as opportunistic infections because they take the opportunity a weakened immune system gives to cause illness. Some examples of opportunistic infections are Pneumocystis carinii pneumonia (PCP) and Kaposi’s sarcoma (KS). Opportunistic infections are CDC-defined AIDS indicator illnesses, which means that an HIV-infected person receives a diagnosis of AIDS after the development of 1 of them.

parish: A civil division of the state of Louisiana corresponding to a county in other states.

perinatal: The word means “around birth” and is used to describe events that occur during labor and birth, and immediately after delivery. When used to describe HIV transmission, however, this word applies more broadly and describes any time that a mother may transmit HIV to her child―while she is pregnant, during birth, or through breast-feeding.

prevalence: Refers to the total number of persons with a specific disease or condition at a given time. HIV prevalence data are generally presented as “persons living with HIV.” HIV prevalence data provided by HIV surveillance programs underestimate the true HIV prevalence because HIV-infected persons who have not yet been tested or reported to the health department are not included.

proportion (percentage): A proportion is a type of ratio in which the numerator is included in the denominator. Because the numerator is a subset of the denominator, a proportion can be thought of as a ratio of a part to the whole. A proportion is usually expressed as a percentage.

rate: Type of ratio that includes a specification of time. In epidemiology, rates express the probability of, or risk for, disease or other events in a defined population during a specified period, often 1 year.

ratio: The value obtained by dividing one quantity by another. For example, the fraction ¾ is a ratio and can be expressed verbally as “three divided by four.” Both rates and proportions are specific examples of ratios.

reporting delay: The time lag between the diagnosis of a new case of HIV or AIDS and the report to the health department. Currently in Louisiana, 86% of HIV cases and 87% of AIDS cases are reported to the HIV/AIDS Surveillance Program within 6 months of diagnosis. Because of reporting delays, surveillance estimates of cases diagnosed in recent periods underestimate the actual number of cases diagnosed in those periods. Consequently, data for recent periods are adjusted to account for the anticipated number of cases diagnosed, but not yet reported. For AIDS cases, the HIV/AIDS Reporting System (HARS) was used to generate reporting delay fractions. For HIV cases, multiple years of data were reviewed to calculate the estimated percentage of cases in persons reported within specified periods (e.g., 1 year, 2 years) after the diagnosis of HIV infection. The estimates were then adjusted upward to account for the reporting delay.

Ryan White CARE Act: The Ryan White Comprehensive AIDS Resources Emergency Act was created to provide federal assistance to increase the availability of primary health care and support services for persons living with HIV disease, to increase access to care for underserved populations, and to improve the quality of life of those affected by HIV infection. The CARE Act was first enacted by Congress in 1990 and was reauthorized in 1996 and 2000. HRSA implements the CARE Act and directs assistance through the following channels:

• Title I provides support to eligible metropolitan areas (EMAs) with the largest numbers of reported AIDS cases, to meet emergency service needs of persons living with HIV.
• Title II provides support to all states and territories to improve the quality, availability, and organization of health care and support services for persons living with HIV and their families.
• Title III supports early-intervention outpatient HIV services through funding to public and private nonprofit entities.
• Title IV funds public and private nonprofit entities to conduct projects to coordinate services to children, youth, women, and families with HIV/AIDS.
• Part F provides support for Special Projects of National Significance (SPNS) to develop and evaluate innovative models of HIV/AIDS care, for AIDS Education and Training Centers (AETCs) to conduct education and training for health care providers, and for the HIV/AIDS Dental Reimbursement Program to assist with providing oral health services to HIV-infected patients.

surveillance: In a public health context, refers to the intentional collection of data on diseases or other important health conditions in order to monitor where the condition occurs and to determine the risk factors associated with the condition.

testing (anonymous, confidential): In Louisiana, a person can choose to be tested anonymously or confidentially for HIV infection. Positive results of anonymous and confidential HIV tests are reported to the health department, where the information is maintained under the strictest security and confidentiality measures. Persons who are tested anonymously do not provide their names when they are tested. Persons who are tested confidentially do provide their names when they are tested.

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