GLOSSARY OF HIV/AIDS-RELATED TERMS

ACQUIRED IMMUNODEFICIENCY SYNDROME (AIDS): The most severe manifestation of infection with the human immunodeficiency virus (HIV). The period between infection with HIV and the onset of AIDS averages 10 years in the United States. People with AIDS often suffer infections of the lungs, brain, eyes and other organs, and frequently suffer debilitating weight loss, diarrhea and a type of cancer called Kaposi's sarcoma. Even with treatment, most people with AIDS die within two years of developing infections or cancers that take advantage of their weakened immune systems.

ACUTE INFECTION: An infection causing disease with a sudden onset, severity and (often) short course. Once the virus enters the body, HIV infects a large number of CD4+ T cells and replicates rapidly. During this acute or primary phase of infection, the blood contains many viral particles that spread throughout the body, seeding themselves in various organs, particularly the lymphoid tissues.

ACUTE RETROVIRAL SYNDROME: The acute or primary HIV infection often passes unrecognized, but may be present as a mononucleosis-like syndrome within three months of the infection. The diagnosis is made by demonstrating HIV antibody seroconversion.

AFFECTED COMMUNITY: This includes HIV-positive people, persons living with AIDS and other individuals, including their families, friends and advocates, directly impacted by HIV infection and its physical, psychological and sociological ramifications.

AIDS-RELATED COMPLEX (ARC): A term that has been used to describe a variety of symptoms and signs found in some persons infected with HIV. These may include recurrent fevers, unexplained weight loss, swollen lymph nodes, and/or fungus infection of the mouth and throat.

AIDS SERVICE ORGANIZATION (ASO): A health association, support agency or other service active in the prevention and treatment of AIDS. (AIDS Response Effort, Inc. is an ASO.)

AIDS WASTING SYNDROME: Involuntary weight loss of 10 percent of baseline body weight plus either chronic diarrhea or chronic weakness, and documented fever for 30 days or more, in the absence of a concurrent illness or condition other than HIV infection that would explain the findings.

ALTERNATIVE THERAPY: In Western countries, alternative therapy refers to any type of medicine that supplements or is used in lieu of conventional medical practices.

ANEMIA: A lower than normal number of red blood cells.

ANTIBIOTIC: An antimicrobial agent, derived from cultures of a microorganism or produced semisynthetically, used to treat infections.

ANTIBODIES: Molecules in the blood or secretory fluids that tag, destroy or neutralize bacteria, viruses or other harmful toxins.

ANTIGEN: A substance that, when introduced into the body, is capable of inducing the production of a specific antibody.

ANTIRETROVIRAL AGENTS: Substances used against retroviruses such as HIV. See also Retrovirus.

ANTIVIRAL: A substance or process that destroys a virus or suppresses its replication.

AZT (Azidothymidine, also called zidovudine, Retrovir, or ZDV): One of the first drugs used against HIV infection by suppressing replication of the HIV virus.

BACTERIUM: A microscopic organism composed of a single cell. Many bacteria can cause disease in humans. It is larger than a virus and can usually be treated with antibiotics.

BIOPSY: The surgical removal of a piece of tissue from a living subject for microscopic examination to make a diagnosis (for example, to determine whether abnormal cells such as cancer cells are present).

BODY FLUIDS: Any fluid in the human body, such as blood, urine, saliva, sputum (spit), tears, semen, mother's milk or vaginal secretions. Only blood, semen, mother's milk and vaginal secretions have been linked directly to the transmission of the HIV virus.

CANDIDA: Yeast-like fungi commonly found in the normal flora of the mouth, skin, intestinal tract and vagina, but can become clinically infectious in immune compromised people.

CD4 (T4) or CD4+ CELLS: White blood cells killed or disabled during HIV infection. These cells normally orchestrate the immune response, signaling other cells in the immune system to perform their special functions. Also known as T helper cells, these cells have a docking molecule called cluster designation 4 (CD4) on their surfaces. Cells with this molecule are known as CD4-positive (or CD4+) cells. Destruction of CD4+ lymphocytes is the major cause of the immunodeficiency observed in AIDS.

CENTERS FOR DISEASE CONTROL AND PREVENTION (CDC): The federal agency most responsible for assessing the status and characteristics of the AIDS epidemic and the prevalence of HIV infections.

CHEMOTHERAPY: The treatment, mostly of cancer, by the use of a series of drugs that attack cancerous cells. This treatment commonly has adverse side effects that may include the temporary loss of the body's natural immunity to infections, loss of hair, digestive upset and a general feeling of illness.

COMMUNITY-BASED ORGANIZATION (CBO): A locally based service organization that provides social services, such as the Salvation Army, at the community level. (AIDS Response Effort, Inc. makes referrals to CBOs.)

CONTAGIOUS: Any infectious disease capable of being transmitted by casual contact from one person to another. Casual contact can be defined as normal day-to-day contact between people at home, school, work or in the community. A contagious infection (e.g., a common cold) can be communicable by casual contact; an infectious infection, on the other hand, is communicable by intimate contact such as sex. AIDS is infectious, not contagious.

DEMENTIA: Chronic intellectual impairment (i.e., loss of mental capacity) with organic origins that affects a person's ability to function in a social or occupational setting.

DNA (Deoxyribonucleic Acid): The principal constituent of chromosomes, the structures that transmit hereditary characteristics.

ELISA (Enzyme-Linked Immunosorbent Assay): A laboratory test to determine the presence of antibodies to HIV in the blood. A positive ELISA test generally is confirmed by the Western Blot test.

END-STAGE DISEASE: Final period or phase in the course of a disease leading to a person's death.

GENE: A unit of DNA in the cell that carries inheritable characteristics to succeeding generations in all living organisms. Genes are contained by, and arranged along the length of, the chromosome. The gene is composed of deoxyribonucleic acid (DNA).

HEMOPHILIA: An inherited disease that prevents the normal clotting of blood.

HEPATITIS: An inflammation of the liver caused by certain viruses and other factors such as alcohol abuse, some medications and trauma. Although many cases of hepatitis are not a serious threat to health, the disease can become chronic and can sometimes lead to liver failure and death. There are four major types of viral hepatitis: (1) Hepatitis A; (2) Hepatitis B, which is most commonly passed on to a partner during intercourse, especially during anal sex, as well as through sharing drug needles; (3) Hepatitis C, which appears to be spread through sexual contact as well as through sharing drug needles; and (4) Delta hepatitis, which occurs among people who are frequently exposed to blood and blood products such as people with hemophilia. A fifth type is caused by the hepatitis E virus, principally spread through contaminated water.

HERPES SIMPLEX VIRUS I (HSV-I): A virus that causes cold sores or fever blisters on the mouth or around the eyes, and can be transmitted to the genital region. The latent virus can be reactivated by stress, trauma, other infections or suppression of the immune system.

HIV DISEASE: Characterized by a gradual deterioration of immune function. During the course of infection, crucial immune cells called CD4+ T cells are disabled and killed, and their numbers progressively decline. CD4+ T cells play a crucial role in the immune response, signaling other cells in the immune system to perform their special functions.

HUMAN IMMUNODEFICIENCY VIRUS TYPE 1 (HIV-1): The retrovirus isolated and recognized as the causing, or contributing to the cause, of AIDS. Most viruses and all bacteria, plants and animals have genetic codes made up of DNA, which uses RNA to build specific proteins. The genetic material of a retrovirus such as HIV is the RNA itself. HIV inserts its own RNA into the host cell's DNA, preventing the host cell from carrying out its natural functions and turning it into an HIV virus factory.

HUMAN IMMUNODEFICIENCY VIRUS TYPE 2 (HIV-2): A virus closely related to HIV-1 that has been found to cause immune suppression. Most common in Africa.

IMMUNE DEFICIENCY: A breakdown or inability of certain parts of the immune system to function, thus making a person susceptible to certain diseases that they would not ordinarily develop.

IMMUNE SYSTEM: The complex functions of the body that recognize foreign agents or substances, neutralize them and recall the response later when confronted with the same challenge.

IMMUNOSUPPRESSION: A state of the body in which the immune system is damaged and does not perform its normal functions. Immunosuppression may be induced by drugs or result from certain disease processes, such as HIV infection.

INCUBATION PERIOD: The time interval between the initial exposure to infection and appearance of the first symptom or sign of disease.

INFECTION: The state or condition in which the body (or part of the body) is invaded by an infectious agent (e.g., a bacterium, fungus or virus), which multiplies and produces an injurious effect (active infection). As related to HIV: Infection typically begins when HIV encounters a CD4+ cell. The HIV surface protein binds tightly to the CD4+ cell's surface. The membranes of the virus and the cell fuse.

INFECTIOUS: Capable of being transmitted by infection, with or without actual contact.

INOCULATION: The introduction of a substance into the body to produce or to increase immunity to the disease or condition associated with the substance.

KAPOSI'S SARCOMA: A previously uncommon form of cancer that attacks the connective tissue, bones, cartilage and muscles of the body. The cancer may spread and also attack the eyes. If the cancerous area is near the surface of the skin, purple or brown lesions inches in length may develop.

LATENCY: The period when an organism (i.e., a virus or a bacterium) is in the body and not producing any ill effects.

LESION: A general term to describe an area of altered tissue (e.g., the infected patch or sore in a skin disease).

LONG-TERM NON-PROGRESSORS: Individuals who are HIV-infected for seven or more years, have stable CD4+ T cell counts of 600 or more cells per cubic millimeter of blood, no HIV-related diseases and no previous antiretroviral therapy.

LYMPH NODES: Small, bean-sized organs of the immune system, distributed widely throughout the body. Lymph fluid is filtered through the lymph nodes in which all types of lymphocytes take up temporary residence. Antigens that enter the body find their way into lymph or blood and are filtered out by the lymph nodes or spleen respectively, for attack by the immune system.

LYMPHOMA: Cancer of the lymphoid tissues. The different types often have different prognoses (i.e., prospect of survival or recovery. The types of lymphomas most commonly associated with HIV infection are called non- Hodgkin's lymphomas or B cell lymphomas. In these types of cancers, certain cells of the lymphatic system grow abnormally. They divide rapidly, growing into tumors.

MALAISE: A generalized, nonspecific feeling of discomfort.

METASTASIS: Transfer of a disease-producing agent (e.g., cancer cells or bacteria) from an original site of disease to another part of the body with development of a similar lesion in the new location (e.g., spread of cancer from an original site to other sites in the body).

MUCOUS MEMBRANE: A moist layer of tissue that lines body cavities or passages that have an opening to the external world (e.g., the lining of the mouth, nostrils or vagina).

MUTATION: During the course of HIV disease, viral strains may emerge in an infected individual that differ widely in their ability to infect and kill different cell types, as well as in their rate of replication. Strains of HIV from patients with advanced disease appear to be more virulent and infect more cell types than strains obtained earlier from the same individual.

NEONATAL: Concerning the first four weeks of life after birth.

OPPORTUNISTIC INFECTION: An illness caused by an organism that usually does not cause disease in a person with a normal immune system. People with advanced HIV infection suffer opportunistic infections of the lungs, brain, eyes and other organs. 2. Opportunistic infections common in AIDS patients include Pneumocystis carinii pneumonia, Kaposi's sarcoma, shigellosis, histoplasmosis and other parasitic, viral, and fungal infections, and some types of cancers.

PALLIATIVE: A treatment that provides symptomatic relief, but not a cure.

PATHOGEN: Any disease-producing microorganism or material.

PERINATAL: Events that occur at or around the time of birth.

PLASMA: That 10 percent of the blood that contains nutrients, electrolytes (dissolved salts), gases, albumin, clotting factors, wastes and hormones.

PNEUMOCYSTIS CARINII PNEUMONIA (PCP): A life-threatening lung infection that can affect people with weakened immune systems, such as those infected with HIV. More than three-quarters of all people with HIV disease will develop PCP if they do not receive treatment to prevent it.

PROPHYLAXIS: Treatment that helps to prevent a disease or condition before it occurs or recurs.

PROTEASE INHIBITORS: HIV protease is an enzyme essential to the replicative life cycle of HIV. The molecular structure of the HIV protease has been fully determined, so pharmaceutical developers have been able to design compounds to inhibit it and interfere with replication of the virus

PULMONARY: Pertaining to the lungs.

RECEPTOR: A molecule on the surface of a cell that serves as a recognition or binding site for antigens, antibodies or other cellular or immunological components.

REGULATORY T CELLS: T cells that direct other immune cells to perform special functions. The chief regulatory cell, the CD4+ T cell or T helper cell, is HIV's chief target.

REMISSIONS: The lessening of the severity or duration of outbreaks of a disease, or the abatement (diminution in degree or intensity) of symptoms altogether over a period of time.

RENAL: Pertaining to the kidneys.

RETROVIRUS: HIV and other viruses that carry their genetic material in the form of RNA and that have the enzyme reverse transcriptase. Like all viruses, HIV can replicate only inside cells, commandeering the cell's machinery to reproduce. Like other retroviruses, HIV uses the enzyme called reverse transcriptase to convert its RNA into DNA, which is then integrated into the host cell DNA.

RIBONUCLEIC ACID (RNA): A nucleic acid, found mostly in the cytoplasm of cells, that is important in the synthesis of proteins. Most forms of RNA consist of a single nucleotide strand, but a few forms of viral RNA that function as carriers of genetic information (instead of DNA) are double-stranded. Some viruses (e.g., HIV) carry RNA instead of the more usual genetic material DNA.

RYAN WHITE CARE ACT: The Ryan White Comprehensive AIDS Resources Emergency (CARE) Act of 1990 represents the largest dollar investment made by Congress to date specifically for the provision of services for people with HIV infection. The purpose of the Act is "to improve the quality and availability of care for individuals and families with HIV disease."

SEROCONVERSION: The development of antibodies to a particular antigen. When people develop antibodies to HIV or an experimental HIV vaccine, they "seroconvert" from antibody-negative to antibody-positive.

SERUM: The clear, thin and sticky fluid portion of the blood that remains after coagulation. Serum contains no blood cells, platelets or fibrinogen.

SEXUALLY TRANSMITTED DISEASE (STD): Also called venereal disease. A contagious disease usually acquired by sexual intercourse or genital contact. Historically, the five venereal diseases were: gonorrhea, syphilis, chancroid, granuloma inguinale and lymphogranuloma venereum. To these have been added scabies, herpes genitalis and anorectal herpes and warts, pediculosis, trichomoniasis, genital candidiasis, molluscum contagiosum, nonspecific urethritis, chlamydial infections, cytomegalovirus and AIDS

STEM CELLS: Cells from which all blood cells derive. Bone marrow is rich in stem cells.

SYMPTOMS: Any perceptible, subjective change in the body or its functions that indicates disease or phases of disease, as reported by the patient.

SYNDROME: A group of symptoms and diseases that together are characteristic of a specific condition.

SYPHILIS: A disease (usually sexually transmitted) resulting from infection with the spirochete (a bacterium) Treponema pallidum.

T CELLS (T Lymphocytes): A thymus-derived white blood cell that participates in a variety of cell-mediated immune reactions.

THERAPEUTIC HIV VACCINE: A vaccine designed to boost the immune response to HIV in persons already infected with the virus.

THRUSH: Sore patches in the mouth caused by a fungus. Thrush is one of the most frequent early symptoms of an immune disorder. The fungus commonly lives in the mouth, but only causes problems when the body's resistance is reduced either by antibiotics that have reduced the number of competitive organisms in the mouth, or by an immune deficiency such as HIV disease.

TRANSMISSION: HIV is spread most commonly by sexual contact with an infected partner. The virus can enter the body through the mucosal lining of the vagina, vulva, penis, rectum or, very rarely, the mouth during sex. The likelihood of transmission is increased by factors that may damage these linings, especially other sexually transmitted diseases that cause ulcers or inflammation. HIV also is spread through contact with infected blood, most often by the sharing of drug needles or syringes contaminated with minute quantities of blood containing the virus. Children can contract HIV from their infected mothers either during pregnancy or birth, or postnatally, via breastfeeding. Current research indicates that the AIDS virus may be 100 to 1000 times more contagious during the first two months of infection, when routine AIDS tests are unable to tell whether people are infected.

TUBERCULOSIS (TB): A bacterial infection caused by Mycobacterium tuberculosis. TB bacteria are spread by airborne droplets expelled from the lungs when a person with active TB coughs, sneezes or speaks. Repeated exposure to these droplets can lead to infection in the air sacs of the lungs. The immune defenses of healthy people usually prevent TB infection from spreading beyond a very small area of the lungs. If the body's immune system is impaired because of infection with HIV, aging, malnutrition or other factors, the TB bacterium may begin to spread more widely in the lungs or to other tissues.

VACCINATION: Inoculation of a substance (vaccine) into the body for the purpose of producing active immunity against a disease. The vaccine is usually a weakened culture of the agent causing the disease.

VIRAL BURDEN (or LOAD): The amount of HIV virus in the circulating blood. Monitoring a person's viral burden is important because sicker patients generally have more virus than those with less advanced disease.

VIRUS: An organism composed mainly of nucleic acid within a protein coat, which can be seen only with an electron microscope. During the stage of their life cycle when they are free and infectious, viruses do not carry out the usual functions of living cells, such as respiration and growth; however, when they enter a living plant, animal or bacterial cell, they make use of the host cell's chemical energy and protein- and nucleic acid-synthesizing ability to replicate themselves. Viral nucleic acids are single- or double-stranded and may be DNA (deoxyribonucleic acid) or RNA (ribonucleic acid). After viral components are made by the infected host cell, virus particles are released; the host cell is often dissolved. Some viruses do not kill cells but transform them into a cancerous state; some cause illness and then seem to disappear, while remaining latent and later causing another, sometimes much more severe, form of disease.

Viruses cause measles, HIV, mumps, yellow fever, poliomyelitis, influenza and the common cold. Some viral infections can be treated with drugs. HIV is spherical in shape with a diameter of 1/10,000 of a millimeter.

WESTERN BLOT: A laboratory test for the presence of specific antibodies, more accurate than the ELISA test.

Source:

HIV/AIDS Treatment Information Service, a Department of Health and Human Services project collaboratively sponsored by the National Institutes of Health, Centers for Medicare and Medicaid Services, Health Resources and Services Administration, and the Centers for Disease Control and Prevention