Human immunodeficiency virus (HIV) is a virus that attacks the white blood cells called helper T cells (CD4). These cells are part of the immune system. They fight off infections and disease. As a result, an HIV infection can leave you vulnerable to severe illnesses.
AIDS is a late stage of HIV infection. It reflects severe damage to the immune system. One or more opportunistic infections will also likely exist. Opportunistic infections are a type of infection that only occur in people with compromised immune systems.
HIV is spread through contact with HIV-infected blood or other body fluids. This includes semen, vaginal fluid, and breast milk. The infection may be the result of HIV-1 or HIV-2 virus.
AIDS is caused by the destruction of T cells. The destruction is caused by the HIV virus.
HIV destroys white blood cells vital to the immune system.
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HIV is most commonly spread through:
Rarely, HIV can be spread through:
Factors that may increase your chance of HIV infection include:
HIV infection increases the chances of getting AIDS.
HIV may not cause symptoms for a number of years.
After these initial symptoms pass, there may be no symptoms for months to years. The following symptoms may occur over the years:
If left untreated, HIV infection progresses to AIDS. This may happen when the number of T helper cells fall below certain levels and opportunistic infections arise. People with AIDS are susceptible to many health complications. These may include:
Your doctor will ask about your symptoms and medical history. A physical exam will be done. To confirm a diagnosis of HIV infection, your doctor will run tests. These may include:
Medications can prevent, delay, or control the development of AIDS in many people infected with HIV.
Antiviral drugs are often given in combination. Categories of these drugs include:
People who have developed AIDS may be given other medications to help fight infections that are more likely to occur with a weak immune system. These may include antibiotics or antifungal medications.
To help reduce your chance of HIV infection:
If you are a healthcare worker or work in a correctional facility, take these steps:
If you live in a household with an HIV-infected person:
If you are infected with HIV, take these steps to prevent spreading HIV to others:
American Foundation for AIDS Research
Centers for Disease Control and Prevention
AIDS Committee of Toronto
Canadian AIDS Society
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Last reviewed May 2016 by David Horn, MD