HIV Disease and AIDS

AIDS: the abbreviation for Acquired Immune Deficiency Syndrome, the disease caused by HIV which destroys the body's immune system defenses, making it unable to resist infection.

CD4 count: infection-fighting cells. The higher your CD4 cell count, the more effectively your body is fighting the disease and the stronger it is in fighting off other illnesses and infections.

Coinfection: when a person with HIV disease becomes infected a second time -- usually through unprotected sex or the sharing of syringes or needles. The new virus may be more powerful than the first, causing the disease to progress more quickly. Often referred to as reinfection.

High-risk behavior: actions which put people at greatest risk of developing a particular disease -- such as HIV. This would include people who have unprotected sexual intercourse or share needles and syringes.

HIV: the abbreviation for Human Immunodeficiency Virus. This is the virus that causes AIDS.

Immune system: although the immune system is highly complex, the role it plays in our health is clear: to protect the body from diseases such as HIV. The immune system enlists an army of different cells, each with a specialized function. Together, they create a powerful fighting force against viruses, bacteria, fungi and parasites that cause illnesses and infections.

Immunosuppression: when the immune system is weakened.

Lymphocytes: white blood cells. A specialized part of the immune system that defends against infection. Lymphocytes are divided into two major groups: B and T. CD4 cells are T-lymphocytes with the important role of organizing and coordinating the activities of other cells in the immune system. They are a prime target of HIV.

Reinfection: see Coinfection

Resistance: HIV's ability to resist the effects of certain antiviral drugs.

Replication: the process in which HIV produces copies of itself inside infected cells.

Reverse transcriptase: a substance that enables HIV to establish itself inside infected cells.

Serological test: the blood test that detects whether or not HIV is present in the body.

Seropositive: a person who has come into contact with HIV and is likely to be contagious through blood or sexual contact.

Std: the abbreviation for Sexually Transmitted Diseases -- diseases that are spread through sexual relations.

Viral load: a measurement of the amount of HIV in one's blood. A lower viral load is better than a higher viral load.

Virus: infectious agents or microbes that are responsible for a great many human diseases. Visible only under a high-power microscope, they depend on living cells to multiply and spread within a person's body.

White blood cells: blood cells that defend the body against illness and infectious diseases.