HIV (human immunodeficiency virus) gradually destroys cells of the immune system and may eventually lead to AIDS (acquired immunodeficiency syndrome), a life-threatening condition. HIV is passed on by contact with infected body fluids, including blood, semen, vaginal fluids, and breast milk.
It can also be passed from an infected woman to her fetus or to the baby at birth. Initially, there may be a short flulike illness, mouth ulcers, or rash, or no symptoms at all. The virus then multiplies over several years, damaging the immune system. The damage can be assessed by counting the number of immune system cells called CD4 lymphocytes. As the infection progresses, fever, night sweats, diarrhea, weight loss, swollen lymph nodes, and recurrent infections may occur.
In the late stage, known as AIDS, the CD4 count drops very low and various diseases develop, including infections that are not normally serious in otherwise healthy people (such as candidiasis, Pneumocystis pneumonia, and cytomegalovirus infection) but may be so in a person with AIDS.
There is no vaccine or cure for HIV infection, but antiretroviral drugs can slow the damage to the immune system