AIDS is the final, life-threatening stage of the infection with human immunodeficiency virus, or HIV. AIDS stands for acquired immunodeficiecy syndrome. The name refers to the fact that HIV severely damages the patient s disease-fighting immune system.

Cases of AIDS were first identified in 1981 in the United States, but scientists have traced cases to as early as 1959. Millions of AIDS cases have been diagnosed worldwide.

HIV can be present in the body for 2 to 12 years without producing any outward signs of illness, yet there are definite symptoms. Infection with HIV appears to be lifelong in all that become infected. People infected with HIV eventually develop symptoms that also may be caused by other, less serious conditions. However, with HIV, these symptoms are prolonged and much more severe. They include enlarged lymph glands, tiredness, fever, loss of appetite and weight, diarrhea, yeast infections, and night sweats.

HIV is commonly connected with a "wasting syndrome," which results in substantial weight loss, a general decline in health, and, in some cases, death. The virus also infects the nervous system. There, HIV may cause dementia, which is a condition characterized by sensory, thinking, and/or memory disorders. HIV infection of the brain may cause movement or coordination problems.

HIV s disruption of the immune system makes infected people susceptible to illnesses that are not normally serious. These diseases are called opportunistic illnesses because they take advantage of the damaged immune system. With the onset of several of these illnesses, an infected person is considered to have AIDS

Researchers have identified three ways in which HIV is transmitted: sexual intercourse, direct contact with infected blood, and transmission from and infected mother to her fetus. The most common way of becoming infected in through sexual contact. In the United States, sexual transmission has occurred mainly among

homosexual and bisexual men, but it is becoming more frequent among heterosexual men and women. HIV is transmitted through all forms of sexual intercourse, including genital, anal, and oral sex.

Treatments have been developed, but cures for HIV and AIDS have not yet been found. Many drugs help to slow the rapid growth, but produce dangerous side effects. Scientists continue to seek more effective and safer anti-viral drugs. They believe any eventual cure for AIDS must stop the growth of the virus, prevent opportunistic

illnesses, and restore the immune system.

To prevent transmission of the AIDS virus, intimate sexual contact with anyone infected must be avoided. Medical and public health authorities have recommended that a condom be used every time sexual intercourse occurs with an infected person or with someone whose status is unknown.