What is AIDS?
AIDS - acquired immunodeficiency syndrome - was first reported in the United States in 1981 and has since become a major worldwide epidemic. AIDS is caused by the human immunodeficiency virus (HIV). By killing or damaging cells of the body's immune system, HIV progressively destroys the body's ability to fight infections and certain cancers. People diagnosed with AIDS may get life-threatening diseases called opportunistic infections, which are caused by microbes such as viruses or bacteria that usually do not make healthy people sick.

More than 830,000 cases of AIDS have been reported in the United States since 1981. As many as 950,000 Americans may be infected with HIV, one-quarter of whom are unaware of their infection. The epidemic is growing most rapidly among minority populations and is a leading killer of African-American males ages 25 to 44. According to the U.S. Centers for Disease Control and Prevention (CDC), AIDS affects nearly seven times more African Americans and three times more Hispanics than whites.

The term AIDS applies to the most advanced stages of HIV infection. CDC developed official criteria for the definition of AIDS and is responsible for tracking the spread of AIDS in the United States.

CDC's definition of AIDS includes all HIV-infected people who have fewer than 200 CD4 positive T cells (abbreviated CD4+ T cells) per cubic millimeter of blood (Healthy adults usually have CD4 positive T-cell counts of 1,000 or more.). In addition, the definition includes 26 clinical conditions that affect people with advanced HIV disease. Most of these conditions are opportunistic infections that generally do not affect healthy people. In people with AIDS, these infections are often severe and sometimes fatal because the immune system is so ravaged by HIV that the body cannot fight off certain bacteria, viruses, fungi, parasites, and other microbes.

Symptoms of opportunistic infections common in people with AIDS include:

  • Coughing and shortness of breath
  • Seizures and lack of coordination
  • Difficult or painful swallowing
  • Mental symptoms such as confusion and forgetfulness
  • Severe and persistent diarrhea
  • Fever
  • Vision loss
  • Nausea, abdominal cramps, and vomiting
  • Weight loss and extreme fatigue
  • Severe headaches
  • Coma

    Children with AIDS may get the same opportunistic infections as do adults with the disease. In addition, they also have severe forms of the bacterial infections all children may get, such as conjunctivitis (pink eye), ear infections, and tonsillitis.

    People with AIDS are particularly prone to developing various cancers, especially those caused by viruses such as Kaposi's sarcoma and cervical cancer, or cancers of the immune system known as lymphomas. These cancers are usually more aggressive and difficult to treat in people with AIDS. Signs of Kaposi's sarcoma in light-skinned people are round brown, reddish, or purple spots that develop in the skin or in the mouth. In dark-skinned people, the spots are more pigmented.

    During the course of HIV infection, most people experience a gradual decline in the number of CD4 positive T cells; although some may have abrupt and dramatic drops in their CD4 positive T-cell counts. A person with CD4 positive T cells above 200 may experience some of the early symptoms of HIV disease. Others may have no symptoms even though their CD4 positive T-cell count is below 200.

    Many people are so debilitated by the symptoms of AIDS that they cannot hold steady employment or do household chores. Other people with AIDS may experience phases of intense life-threatening illness followed by phases in which they function normally.

    A small number of people first infected with HIV 10 or more years ago have not developed symptoms of AIDS. Scientists are trying to determine what factors may account for their lack of progression to AIDS, such as particular characteristics of their immune systems or whether they were infected with a less aggressive strain of the virus, or if their genes may protect them from the effects of HIV. Scientists hope that understanding the body's natural method of control may lead to ideas for protective HIV vaccines and use of vaccines to prevent the disease from progressing.


    Source: U.S. National Institutes of Health


    This document is provided solely for educational and informational purposes.
    Be sure to consult your doctor before making any major medical decision.
                                                                                                                                
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  • This fact sheet provides an overview of AIDS, a life-threatening disease of the immune system caused by the HIV virus. If you are currently experiencing symptoms of AIDS, be sure to consult your physician or other health care provider as soon as possible.

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