AIDS, or acquired immunodeficiency syndrome, is a disease caused by the human immunodeficiency virus (HIV). Not everyone with the HIV virus has AIDS. Rather, AIDS is an end-stage disease that results over time from having HIV, but treatments can delay the onset of AIDS in people with HIV. Currently, however, there is no cure for ridding the body of the HIV virus once you contract it.
The most common way that the HIV virus is spread from person to person is through unprotected sex, or sex without using a condom. Anal sex is the highest-risk behavior for transmitting HIV, and vaginal sex is second. Having a number of different sexual partners can also increase the chance of spreading HIV.
Another high-risk behavior that can spread HIV is sharing drug needles. In rare instances, HIV can also be passed from a mother to a baby during pregnancy or birth. HIV transmission from other sources, such as blood transfusions, oral sex, bites or other activities, has occurred but is very rare.
About two to four weeks after being infected with HIV, people typically get sick with what feels like the flu. This is known as acute retroviral syndrome (ARS), and it occurs as large amounts of HIV are being produced in the body. Eventually, the level falls and the initial symptoms subside. But the body is still infected with HIV.
The next phase of HIV infection is often called asymptomatic or chronic HIV infection. During this period, the body is still infected with HIV, but the person may not show any symptoms. People who begin treatment at this time may be able to live without developing AIDS for many decades. However, if treatment is not started, the progression to AIDS will occur more quickly.
AIDS is typically the end stage of an HIV infection. The disease is diagnosed when the number of immune system cells in the body, called CD4 cells, fall below a certain level. At this point, the body is too weak to fight off many infections, and AIDS often ends in death within a few years without treatment.
Though there is currently no cure for HIV infection, people with the virus can live a long, productive life with treatment. The treatment for HIV is known as antiretroviral therapy, and it can be effective at keeping virus levels low in the body and preventing AIDS. Getting tested for HIV is the only way to know if you need this treatment, so testing is important, especially for those who engage in high-risk behaviors.
SOURCE: U.S. Centers for Disease Control and Prevention