Attention A T users. To access the menus on this page please perform the following steps. 1. Please switch auto forms mode to off. 2. Hit enter to expand a main menu option (Health, Benefits, etc). 3. To enter and activate the submenu links, hit the down arrow. You will now be able to tab or arrow up or down through the submenu options to access/activate the submenu links.



Quick Links

Veterans Crisis Line Badge
My healthevet badge

Glossary of HIV/AIDS Terms

for Health Care Providers

Glossary of HIV/AIDS Terms


Emaciation, extreme thinness. Cacexia reflects malnutrition and general ill health. It usually is associated with serious disease.

See Wasting syndrome.


Yeastlike fungi commonly found in the normal flora of the mouth, skin, intestinal tract, and vagina. It can become infectious in individuals with an abnormal immune system.

See Candidiasis; Fungus; Thrush.


An infection with a yeastlike fungus of the Candida family, generally Candida albicans. Candidiasis of the esophagus, trachea, bronchi, or lungs is an indicator disease for AIDS. Oral or recurrent vaginal candida infection is an early sign of immune system abnormalities.

See Opportunistic infection; Thrush; Vaginal candidiasis.


Any cancer-producing substance.

Casual contact

Can be defined as normal day-to-day contact among people at home, school, work, or in the community. Some contagious infectious agents (eg, chickenpox, flu) can be transmitted by casual contact, but HIV cannot.

CD4 (T4) or CD4+ cells

A type of lymphocyte involved in protecting against viral, fungal, and protozoal infections. They are also known as T helper cells or simply T cells. HIV infects and destroys CD4 lymphocytes. Destruction of CD4+ lymphocytes is the major cause of the immunodeficiency observed in AIDS, and decreasing CD4 lymphocyte levels are the best indicator of someone's risk of developing opportunistic infections.

CD4 count

A test that measures the number of CD4 lymphocytes in the blood, thus reflecting the state of the immune system. A normal count in a healthy adult is 600-1,200 cells/µL. When the CD4 count of an adult falls below 200 cells/µL, there is a high risk of opportunistic infection.

CD4, CD4 receptor

One of the protein structures on the surface of a human cell that allows HIV to attach, enter, and thus infect the cell. Present on CD4 cells (helper T lymphocytes) among others.

CD8 (T8) cells

White blood cells (lymphocytes) with the CD8 protein on their surface. These white blood cells kill some cancer cells and cells infected by bacteria and viruses. Also called cytotoxic T cells, T8 cells, cytotoxic T lymphocytes.

Cell-mediated immunity (CMI)

Part of the immune system that deals with viruses and other infectious agents as well as cancer cells.

Centers for Disease Control and Prevention (CDC)

The U.S. Department of Health and Human Services agency with the mission to promote health and quality of life by preventing and controlling disease, injury, and disability.

Central nervous system (CNS)

The central nervous system is composed of the brain, spinal cord, and meninges (protective membranes surrounding them). The central nervous system is often affected, especially in advanced AIDS, and dementia can occur.

See HIV-associated dementia (HAD).

Cerebrospinal fluid (CSF)

Fluid that surrounds the brain and the spinal cord.

Cervical cancer

A cancer of the uterine cervix.

See Cervical dysplasia; Pap smear.

Cervical dysplasia

Abnormality in the size, shape, and organization of adult cells of the cervix. It is often found before cancer cells appear. A precursor lesion for cervical cancer. Studies indicate an increase of cervical dysplasia among women living with HIV.

Cervical intraepithelial neoplasia (CIN)

An abnormality of the epithelium (lining) of the cervix, often precancerous. Considerable evidence implicates a virus called human papilloma virus (HPV) in the development of CIN.


A highly contagious sexually transmitted disease caused by the Haemophilus ducreyi bacterium with symptoms appearing 3 to 5 days after exposure.

Chemokine receptor

A coreceptor used by HIV to infect cells.


Chemokines are messenger molecules secreted by CD8 cells whose major function is to attract immune cells to sites of infection. Several chemokines — called RANTES, MIP-1A, and MIP-1B — interfere with HIV multiplication by occupying these receptors.


In general, chemotherapy refers to the use of medicines to treat any disease. It is more commonly used to describe medicines to treat cancer.


A sexually transmitted disease (STD) caused by Chlamydia trachomatis that infects the genital tract. The infection is frequently asymptomatic (ie, shows no symptoms), but if left untreated, it can cause sterility in women.


Pertaining to observations, tests, or treatment of patients.

Clinical endpoint

See Endpoint.

Clinical latency

The period of time during which a virus or bacteria or other organism is living or developing in the body without causing symptoms. The period of time in which a person with HIV infection does not exhibit any evidence of disease or sickness.

Clinical trial

A scientifically designed study of the effects of a drug, vaccine, biologic, or behavior in humans. The goal is to define the safety, the benefit, and side effects of the treatment or intervention. Most countries require strict testing of all new drugs and vaccines prior to their approval for use.


An infectious fungal disease caused by the breathing in of Coccidioides immitis, which are carried on windblown dust particles.

Cognitive impairment

Loss of the ability to process, learn, and remember information.


A group of individuals with some characteristics in common.


Inflammation of the colon, the lower part of the intestine.


The first thick yellow milk secreted by a woman beginning lactation. Colostrum contains high levels of proteins and antibodies.

Combination therapy

Two or more drugs or treatments used together to obtain the best results against HIV or another infection. Combination drug therapy (treatment) is recommended for all persons with HIV.

Commercial sex worker (CSW)

A woman or man who offers sexual intercourse for a fee. The terms prostitute or prostitution are used more frequently outside the HIV/AIDS field.

Community planning

Community planning groups are responsible for developing HIV prevention, treatment, and care plans that are used in their communities. The goal of HIV community planning is to improve the effectiveness of HIV programs and to be certain that the needs of the community are being met.

Community-based organization (CBO)

A service organization that provides social, support, education, and care services at the local level.

Complementary and alternative therapy

Broad range of healing approaches and treatments that are not commonly practiced in conventional (Western) medicine. Examples include acupuncture, herbs, and homeopathy.

See Alternative medicine.

Complete blood count (CBC)

A frequently ordered blood test that provides the white and red blood cell count, hematocrit, and hemoglobulin in a microliter of whole blood.

Computed tomography scan

See C-T scan (computed tomography scan).

Concomitant drugs

Drugs that are taken together. Taking certain concomitant medications may cause adverse interactions.


A wartlike skin growth usually on the external genitalia or perianal area.

Condyloma acuminatum

A wart in the genital and perianal area. Although the lesions are usually few in number, they may aggregate to form large cauliflower-like masses. Caused by the human papillomavirus (HPV), it is infectious and capable of being transmitted from one part of the body to another). Also called genital warts, venereal warts, or verruca acuminata.

Confidential HIV test

Performing an HIV test and being certain that the result remains confidential.

See Confidentiality.


Relating to a piece of information about a person that should not be given to another person without that person's permission. An example would be the result, whether positive or negative, of an HIV test.

Confirmatory test

A second test, to show that the result of a previous test was correct. Because the diagnosis of HIV infection is so important, a second (confirmatory) test, is done. The confirmatory test should be of a different type than the first test.

Confirmed positive

For HIV, a blood sample that is positive on an initial ELISA test, repeatedly positive on a second ELISA run on the same specimen, or confirmed positive on Western blot or other supplemental test that indicates the client is infected.


Any infectious disease capable of being transmitted by direct or indirect contact from one person to another.


Any condition that renders a particular line of treatment improper or undesirable. Some drugs may be contraindicated when given together (eg, zidovudine and lamivudine).

Controlled clinical trials

A study performed in humans in which a control is used. A control is a standard against which study observations may be evaluated. For example, in clinical trials, one group of patients is given an experimental drug, while another group (ie, the control group) is given either the normal treatment for the disease or a placebo.


Also known as trimethoprim/sulfamethoxazole, Bactrim, Septra, or TMP/SMX. A combination antibiotic drug effective at preventing and treating Pneumocystis jiroveci pneumonia (PCP or PJP); also serves as a prophylaxis against toxoplasmosis. The drug is also active against certain bacterial infections.

See Trimethoprim/sulfamethoxazole.


Confidential dialogue between individuals and their health care providers. The term can refer to discussions between health care workers and clients/patients specific to HIV testing to help clients examine their risk of acquiring or transmitting HIV infection.


A protein found in muscles and blood, and excreted by the kidneys in urine. The level of creatinine in the blood or urine provides an indication of kidney function.


The process in which an infectious agent that acquires resistance to one drug through direct exposure also turns out to have resistance to one or more other drugs to which it has not been exposed.

Cryptococcal meningitis

A life-threatening infection of the membranes surrounding the brain and the spinal cord caused by the fungus Cryptococcus neoformans. Symptoms include headache, dizziness, stiff neck, and, if untreated, coma and death.

See Cryptococcus neoformans.


An infectious disease caused by the fungus Cryptococcus neoformans that is acquired via the respiratory tract. It can spread from the lungs to the central nervous system (especially the membranes surrounding the brain), the skin, the skeletal system, and the urinary tract. It is considered an AIDS-defining opportunistic infection in persons infected with HIV.

See Cryptococcal meningitis.

Cryptococcus neoformans

A fungus found in soil contaminated by bird droppings. Most people have been exposed to this organism, which does not usually cause disease in healthy people. In persons with AIDS, this organism can cause illness and death.


A diarrheal disease caused by the protozoa Cryptosporidium that grows in the intestines. Symptoms include abdominal cramps and severe chronic diarrhea. It is considered an AIDS-defining opportunistic infection in persons with HIV infection as immunological deterioration progresses.


The protozoan (parasite Cryptosporidium parvum), which causes cryptosporidiosis. The parasite is found in the intestines of animals and may be transmitted to humans by direct contact with an infected animal, by eating contaminated food, or by drinking contaminated water. The parasite grows in the intestines and, in people with HIV disease, causes cryptosporidiosis.

See Cryptosporidiosis.

C-T scan (computed tomography scan)

An x-ray in which a three-dimensional image of a body structure is constructed by computer from a series of images.

See Magnetic resonance imaging (MRI).


Of, pertaining to, or affecting the skin.

Cytomegalovirus (CMV)

A common herpes virus that is a common cause of opportunistic diseases in persons with AIDS and other persons with immune suppression. CMV has infected most adults; however the virus does not cause disease in healthy people. Because the virus remains in the body for life, it can cause disease if the immune system becomes severely damaged by drugs. While CMV can infect most organs of the body, persons with AIDS are most susceptible to CMV retinitis (disease of the eye) and colitis (disease of the colon).

See Cytomegalovirus (CMV) retinitis.

Cytomegalovirus (CMV) retinitis

An eye disease caused by the CMV virus, common among persons who are living with HIV. Without treatment, persons with CMV retinitis can lose their vision. CMV infection can affect both eyes and is the most common cause of blindness among persons with AIDS.

See Cytomegalovirus (CMV).


Deficiency in the cellular elements of the blood.


An agent or process that is toxic or destructive to cells.

Cytotoxic T lymphocyte (CTL)

A lymphocyte (white blood cell) that is able to kill foreign cells marked for destruction by the cellular immune system. CTLs can destroy cancer cells and cells infected with viruses, fungi, or certain bacteria. CTLs are also known as killer T cells; they carry the CD8 marker.

See CD8 (T8) cells.