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What Is AIDS, HIV and HIV Disease?

August 25, 2008

What Is HIV?

Each letter stands for the following terms:

H -- Human -- because this virus can only infect human beings.

I -- Immuno-deficiency -- because the effect of the virus is to create a deficiency, a failure to work properly, within the body's immune system.

V -- Virus -- because this organism is a virus, which means one of its characteristics is that it is incapable of reproducing by itself. It reproduces by taking over the machinery of the human cell.

HIV is the virus medical researchers believe causes AIDS. Since the vast majority of researchers believe that HIV is the sole cause of AIDS, we often refer to HIV as "the AIDS virus."

Like other viruses, HIV attacks cells in the body. But what makes HIV different is that the immune system can never fully get rid of HIV because the virus attacks the immune system itself -- the very mechanism that would normally get rid of a virus.

Today there are medical treatments that can slow down the rate at which HIV weakens the immune system and that can prevent or cure some of the illnesses associated with advanced HIV disease. As with other diseases, early detection offers more options for treatment and preventive care.

What Is AIDS?

The term AIDS applies to the most advanced stages of HIV infection.

Each letter stands for the following terms:

A -- Acquired -- because it's a condition one must acquire or get infected with, not something transmitted through the genes.

I -- Immune -- because it affects the body's immune system, the part of the body which usually works to fight off germs such as bacteria and viruses.

D - Deficiency -- because it makes the immune system deficient (that is, the immune system may not function properly).

S -- Syndrome -- because someone with AIDS may experience a wide range of different diseases and opportunistic infections.

AIDS severely weakens the body's ability to fight infections and certain cancers. That is, people diagnosed with AIDS may have opportunistic infections, which are caused by microbes such as viruses or bacteria that usually do not make healthy people sick. The immune system of a person with AIDS is threatened to the point that medical intervention may be necessary to prevent or treat serious illness.

The Centers for Disease Control and Prevention (CDC) Definition of AIDS

The Centers for Disease Control and Prevention (CDC), a part of the United States federal government, is responsible for determining who is classified as having AIDS. The CDC is also responsible for tracking the spread of HIV and AIDS in the United States.

The AIDS definition developed by the CDC includes the following conditions:

  • a person must be HIV positive, AND
  • have a CD4 (T-cell) count below 200 OR one or more opportunistic infections.

A positive HIV test result does not mean that a person has AIDS. A diagnosis of AIDS is made by a physician using the above clinical criteria.

What Is HIV Disease?

HIV disease is used to broadly describe the disease or illness caused by infection with the human immunodeficiency virus; if untreated, the disease typically progress slowly from asymptomatic infection to worsening immunocompromise to AIDS. In general, this process takes about ten years, though this can vary widely from person to person.

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This article was provided by San Francisco AIDS Foundation. It is a part of the publication AIDS 101. Visit San Francisco AIDS Foundation's Web site to find out more about their activities, publications and services.
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