AIDS (acquired immune deficiency syndrome): the symptoms and sicknesses that people infected with human immunodeficiency virus (HIV) eventually develop because of their weakened immune systems. The immune system ordinarily defends the body against illness.

AIDS diagnostic criteria: the Centers for Disease Control and Prevention (CDC) has two different sets of criteria for diagnosing AIDS. If a person has both of the conditions listed in either the first or second set, he or she is said to have AIDS.
The first set of conditions includes:
HIV infection, confirmed by testing, and
a CD4+ T-cell count of less than 200 per cubic millimeter of blood. (Healthy adults usually have CD4+ T-cell counts of 1,000 or more.)
The second set of conditions includes:
HIV infection, confirmed by testing, and
infection with one or more of the 26 opportunistic diseases associated with

Antiretroviral therapy: treatments for HIV that include three or more drugs. The drugs target different stages of the HIV replication cycle, making the HIV less likely to multiply and mutate.

Asymptomatic period: a period of time in the course of HIV disease when the infected person does not have any symptoms; can last for a few months to over ten years; also called “clinical latency.”

AZT (azidothymidine): the first anti-HIV drug approved for use in the United States; belongs to the class of antiretroviral drugs known as nucleoside reverse transcriptase inhibitors; generic name is zidovudine, and brand name is Retrovir.


Beneficial disclosure: voluntary and often confidential disclosure of a person’s HIV status to others and organizations so that the person gets proper care and so that HIV becomes less stigmatizing.

Blood products: the parts of blood, including plasma (the liquid in which cells, nutrients, hormones, and enzymes are suspended), platelets (small cells that control bleeding and clotting), and red blood cells (cells that carry oxygen throughout the body)

Blood transfusion: the transfer of blood or any of its parts to a person who has lost blood due to an injury, disease, or operation.


Capsid: the bullet-shaped core of an HIV particle, where the HIV particle’s genetic material is contained.

Case: one instance of a particular disease, health disorder, or condition in a population; sometimes, an individual with the particular disease.

CD4+ cells: the cells that HIV attacks and hijacks for its own replication. A CD4+ cell is a kind of T-cell that has a molecule called cluster designation 4 (CD4) on its surface. T-cells, in turn, are white blood cells that the body makes to fight off invaders.

Centers for Disease Control and Prevention (CDC): one of the major collectors and distributors of health data in the United States, including data about the HIV/AIDS epidemic. The CDC conducts two kinds of surveillance: HIV surveillance and AIDS surveillance. (Surveillance is the ongoing, systematic collection, analysis, interpretation, and sharing of health data). For the HIV surveillance, 29 states and the U.S. Virgin Islands have reported new HIV infections to the CDC since 1998, providing sufficient data to monitor HIV trends over time and to understand better the behaviors that increase HIV infection risk. For the AIDS surveillance, all U.S. states and territories report all AIDS diagnoses to the CDC.


Discrimination: unfair treatment of a person or group.

DNA (deoxyribonucleic acid): the chemical that makes up a cell’s genes, that controls the cell’s operations, and that carries traits from one generation to the next. DNA is usually made up of two strands of molecules twisted together to form a spiral, or helix.

Dry sex: sexual intercourse between a man and a woman for which the woman dries her vagina using special powders, herbs, or douches in order to increase friction. dry sex is more likely than regular sex to cause cuts and tears, through which HIV-infected fluids may easily pass.


Entry inhibitors: the newest class of anti-HIV drugs, which work by keeping the spikes on the surface of HIV from binding and fusing with host cells.

Enzyme: a protein that begins or speeds up a chemical reaction.

Epidemic: an fast-spreading outbreak of a disease that affects many people.

Epidemiology: scientific study of the incidence, distribution, risk factors, progression, and control of disease in a population.

Ethnicity: a grouping of people based on common cultural tendencies or practices, such as language, religion, ancestral origins, customs, or social viewpoint.


Female Condoms: is a thin, soft, loose-fitting polyurethane plastic pouch that lines the vagina. It has two flexible rings: a smaller inner ring at the closed end, used to insert the device inside the vagina and to hold it in place, and a larger, outer ring which remains outside the vagina and covers the external genitalia.

Fusion inhibitors: a kind of entry inhibitor that prevents HIV replication by keeping the spikes on the surface of HIV from fusing with host cells.


Gender: the socially created, shared, and institutionalized categories of thoughts, feelings, roles, and actions assigned to men and women.

Gene: a segment of DNA that contains the information necessary to make a protein. A gene is the unit of biological inheritance.

Genetic material: molecules (like DNA and RNA) that carry hereditary information.

Glycoprotein 41 (gp41): molecules that make up the stems on the spikes of HIV particles.

Glycoprotein 120 (gp120): molecules that make up the caps on the spikes of HIV particles.


HAART (highly active antiretroviral therapy): the use of three or more anti-HIV drugs in the treatment of HIV/AIDS. Combinations of drugs are more effective than individual drugs because HIV’s genetic material mutates very quickly and becomes resistant to individual drugs. Combinations of drugs overwhelm HIV, keeping it from multiplying and mutating as quickly.

Hemophiliac: a person with hemophilia, which is an inherited blood disease that causes people to bleed easily and uncontrollably, due to a lack of a particular coagulation factor in the blood.

HIV (human immunodeficiency virus): the virus that causes AIDS. Infecting only humans, HIV attacks and weakens the body’s immune system. The immune system normally protects the body against illness.

HIV antibodies: proteins produced by the body in response to HIV. Most tests for HIV are actually tests for HIV antibodies in body fluids or tissues.

HIV antibody testing: tests for the presence of HIV antibodies in a person’s body fluids or tissues.

HIV-associated dementia (HAD): a progressive neurological disorder that can affect HIV+ people, and that is characterized by cognitive, motor, and behavioral impairments.

HIV particles: individual human immunodeficiency viruses.

HIV-positive (HIV+): a term used to describe people who are infected with HIV.


Immune system: a collection of organs, cells, and proteins that works to protect the body from foreign substances and cancerous cells.

Incidence: the number of new instances of a disease in a population for a specified period of time, usually expressed as the proportion of new cases relative to the total population.

IDUs: injection drug users; injection drug use.

Integrase: an enzyme that HIV uses to splice its newly formed strands of DNA with host cell DNA.


Lymphocyte: cells that the body’s immune system makes to fight off invaders; also called white blood cells.


Microbicides: creams, gels, or foams that can be inserted into the vagina or rectum to help prevent sexual transmission of HIV and other STI/STDs.

Molecule: the smallest unit of a substance that retains all the physical and chemical properties of that substance, consisting of a single atom or a group of atoms bonded together.

Morbidity: a diseased state; also, the proportion of diseased people in a population, expressed as either incidence or prevalence.

Mortality: the death rate, usually expressed as the proportion of deaths relative to the total population.

Mucous membrane: the linings of certain cavities (such as the nose, mouth, vagina, and anus) that produce a protective layer of mucus.

Mucus: a slippery substance produced by mucous membranes for lubrication and protection.

Mutate: to change. HIV’s genetic material mutates through mistakes in replication, giving rise to new strains of HIV that are resistant to antiretroviral therapy.


Non-nucleoside reverse transcriptase inhibitors (NNRTIs): anti-HIV drugs that slow down HIV replication by chemically binding to reverse transcriptase, making it unable to convert the HIV RNA into DNA.

Norm: a rule or standard for behavior that each member of a social group is expected to follow.

Nucleoside reverse transcriptase inhibitors (NRTIs or “nukes”): anti-HIV drugs that are faulty versions of reverse transcriptase. When the HIV attempts to turn its RNA into DNA, NRTIs replace real reverse transcriptase, resulting in the creation of incomplete DNA and, in turn, inactive HIV particles.

Nucleus: the part of the cell that contains DNA and RNA and that is responsible for cell growth and reproduction.


Opportunistic infections (OIs): infections that do not ordinarily affect people with healthy immune systems, or that become much more severe than they do in people with healthy immune systems. A hallmark of AIDS is the presence of one or more opportunistic infections.


Pandemic: a widespread outbreak of a disease that affects many people over a large area.

Pathogen: things that cause disease, including viruses, bacteria, fungi, and protozoa.

Plasma: the watery, liquid part of the blood in which the red blood cells, white blood cells, and platelets are suspended.

Population: the total number of inhabitants at a given time in a given area (usually a city, county, state/province, or country).

Positive prevention: HIV prevention efforts targeted at HIV+ people.

Post-exposure prophylaxis (PEP): the giving of antiretroviral therapy to people after they have been exposed to HIV, in an attempt to prevent HIV infection.

Prevalence: the total number of people in a population with a particular disease at a particular time; usually expressed as the proportion of infected people relative to the total population.

Prevention intervention: a program designed to reduce rates of disease transmission, such as HIV transmission.

Primary stage: the first stage of HIV disease, when HIV establishes itself in the body. At the beginning of the primary stage, most people have a short, flu-like illness. People are very contagious during the primary stage, because there is a large amount of HIV in bodily fluids. However, HIV-infected people may not test positive for HIV during the primary stage, because the body may not yet be producing antibodies to the virus.

Prognosis: the probable outcome or course of a disease.

Protease: an enzyme that cleaves proteins. Near the end of HIV’s replication cycle, protease finalizes the creation of mature HIV particles by cutting up the long strands of proteins that replication has so far produced.

Protease inhibitors: anti-HIV drugs that chemically bind to protease to so that it cannot cleave the HIV proteins into mature viral particles.

Protein: a large, complex molecule made up of chains of amino acids. The sequence of the amino acids--and thus the function of the protein--is determined by the DNA of the gene that encodes it. Proteins are required for the structure, function, and regulation of cells, tissues, and organs.

Provirus: the name for HIV’s form when it has combined its DNA with the host cell’s DNA.


Race: a classification of people, often based on physical traits.

Resistance, drug-resistance: the state of HIV when drugs no longer stop or slow its replication. HIV reproduces and mutates quickly, and in so doing evolves new forms that are not affected by drugs.

Retroviruses: viruses that carry RNA instead of DNA as their genetic material. Retroviruses do not “proofread” their genetic material during replication, and therefore mutate more quickly than do DNA-based viruses.

Reverse transcriptase: an enzyme that allows HIV RNA to change into DNA, so that it can pass into a host cell's nucleus, commandeer the host cell, and begin reproducing itself.

Reverse transcriptase inhibitors: anti-HIV drugs that interfere with reverse transciptase’s ability to change HIV RNA into DNA, either by replacing the HIV’s reverse transcriptase with a faulty decoy (nucleoside reverse transcriptase inhibitors) or by chemically binding with the HIV’s reverse transcriptase (non-nucleoside reverse transcriptase inhibitors). Most anti-HIV drugs are reverse transcriptase inhibitors, and include AZT, ddC, ddI, d4T, 3TC, nevirapine, delavirdine, abacavir and efavirenz.

RNA (ribonucleic acid): the genetic material in retroviruses. RNA is a chemical that is similar to DNA, but different in structure. Whereas DNA has two strands of molecules, RNA has only one. Because RNA does not “proofread” itself as it replicates, it mutates more quickly than does DNA.


Safer sex: sex that reduces the likelihood of transmitting HIV and other STI/STDs by preventing contact with bodily fluids, including blood, semen, pre-ejaculate, vaginal fluids, anal fluids, and the discharge from sores caused by STI/STDs. Using condoms, dental dams, and adequate lubrication all contribute to safer sex.

Self-efficacy: belief in one’s own ability to perform a task.

Serodiscordant: describes couples in which one person has tested positive for HIV and the other has not.

Seroprevalence: the proportion of people in a given population at a given time who are infected with a given virus, such as HIV.

Serostatus: positive or negative results of a test for certain antibodies in the blood, such as the antibodies that form in response to HIV infection.

Sex: either of the two biological categories (male or female) into which most organisms are divided, based on their reproductive roles.

Socioeconomic status (SES): a person’s relative rank in society, based on his or her education, income, or occupation.

Spikes: the complex proteins that protrude through HIV’s surface. Spikes attach the virus to a host cell and fuse the two together.

STI/STD: sexually transmitted infections and sexually transmitted diseases.

Stigma: qualities or conditions, such as being a racial/ethnic minority or having HIV, that decrease a person’s worth in society’s eyes.

Stigmatization: the association of a quality or condition with lower social worth.

Stress: a state of mental or physical strain or suspense.

Stressor: an activity, experience, condition, or situation that causes stress.

Superinfection: infection with two or more different strains of HIV at the same time.

Surveillance: the ongoing, systematic collection, analysis, interpretation, and sharing of health data.


T-cell: a kind of lymphocyte, or white blood cell, that the body's immune system makes to fight off infections.

Transfusion: the transfer of blood or any of its parts to a person who has lost blood due to an injury, disease, or operation.

Transplant: transferring a healthy tissue or organ to replace a damaged tissue or organ.


Viral load: the amount of HIV RNA per unit of blood plasma. Viral load indicates how much HIV there is in the blood, how quickly it is replicating, and how quickly a patient is progressing towards AIDS and subsequent death.

Virus: a tiny, relatively simple, non-living substance, usually made up of little more than a few strands of genetic material and a protein shell, that enters cells and causes disease.

© Sociometrics Corporation, 2004