What Causes AIDS?

Reviewed on 10/21/2020

What Is Acquired Immune Deficiency Syndrome (AIDS)?

AIDS (acquired immunodeficiency syndrome) is caused by the HIV virus.
AIDS (acquired immunodeficiency syndrome) is caused by the HIV virus.

Human immunodeficiency virus (HIV) is a virus that attacks the body's immune system, which is responsible for fighting infections. Acquired immune deficiency syndrome (AIDS) is the late stage of HIV infection. 

In the U.S., most people infected with HIV do not go on to develop AIDS because HIV medications are available to stop disease progression.

What Are Symptoms of Acquired Immune Deficiency Syndrome (AIDS)?

Early symptoms of human immunodeficiency virus (HIV) are referred to as primary or acute HIV infection. These symptoms usually occur two to four weeks after a person is infected with the virus and include: 

Painful open sores or ulcers that can develop in the mouth, the esophagus, the anus, or the penis (only occurs in a small proportion of those exposed to the virus)

After several years, if HIV is not treated, symptoms of AIDS may occur and include:

  • Swelling of lymph nodes, usually in the neck, armpits, or groin
  • Recurrent fever
  • Night sweats
  • Stomach pain
  • Nausea
  • Vomiting
  • Diarrhea that persists more than a week
  • Rapid weight loss
  • Sores on the mouth, anus, or genitals
  • Red, brown, pink, or purplish blotches on or under the skin or inside the mouth, nose, or eyelids
  • Memory loss, depression, and other neurologic disorders
  • Other infections (opportunistic infections)
    • Lung infections such as pneumonia that can cause shortness of breath
    • Brain infections
    • Eye infections that cause trouble seeing and blurred vision
    • Candidiasis of the mouth (oral thrush) that can cause soreness and raised, white patches

What Causes Acquired Immune Deficiency Syndrome (AIDS)?

Human immunodeficiency virus (HIV) infection is caused by exposure to the human immunodeficiency virus. The virus is transmitted via blood or through sexual intercourse and exposure to other bodily fluids (such as semen or vaginal fluids) from a person with HIV. It is NOT spread by casual contact.

Untreated HIV infection can progress to become acquired immune deficiency syndrome (AIDS).

HIV infection can occur if a person:

  • Has unprotected vaginal, anal, or oral sex with someone infected with HIV
  • Shares needles or syringes with a person who has HIV
  • A pregnant woman can transmit HIV to her baby during pregnancy, birth, or breastfeeding
    • This is uncommon with the use of HIV medications during and after pregnancy

People who may have an increased risk of contracting human immunodeficiency virus (HIV) include:

  • Men who have sex with other men
  • Drug users who share needles or “works”
  • Sexual partners of people who are infected with HIV
  • People with a history of a sexually transmitted disease (STD)
  • Victims of sexual assault 
  • People who have unprotected sex with multiple partners
  • People who exchange sex for money or drugs or have sex partners who do
  • Anyone accidentally stuck with a needle or sharp in a health care facility
  • People who received a blood transfusion or other blood products before 1984 
    • Blood products were not routinely screened for HIV prior to 1984


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How Is Acquired Immune Deficiency Syndrome (AIDS) Diagnosed?

Human immunodeficiency virus (HIV) is diagnosed with either a blood test or a saliva (spit) test. 

Rapid HIV test results are available in minutes, though some test results can take days.

Patients are diagnosed with acquired immune deficiency syndrome (AIDS) when their CD4 cell count drops below 200 cells/mm, or if they develop certain opportunistic infections.

What Is the Treatment for Acquired Immune Deficiency Syndrome (AIDS)?

Human immunodeficiency virus (HIV) is usually treated with different combinations of antiretroviral medicines to help control HIV infection.

Early HIV infection is often treated with one of the following antiretroviral therapy (ART) regimens: 

There is no cure for acquired immune deficiency syndrome (AIDS) but medications are used to reduce the amount of HIV virus in the body, keep the immune system healthy, and decrease the complications of the disease that can occur.

Types of medication used to treat AIDS include: 

  • Nucleoside reverse transcriptase inhibitors (NRTI)
  • Protease inhibitors (PI)
  • Fusion inhibitors
  • Highly active antiretroviral therapy (HAART)
  • Non-nucleoside reverse transcriptase inhibitors (NNRTI)

What Is the Life Expectancy for Acquired Immune Deficiency Syndrome (AIDS)?

Without treatment, HIV can progress to acquired immunodeficiency syndrome (AIDS). The life expectancy for AIDS patients is about three years.

How Do You Prevent Acquired Immune Deficiency Syndrome (AIDS)?

To prevent AIDS, you must prevent infection with human immunodeficiency virus (HIV). To reduce the chance of spreading HIV to other people:

  • Get tested for HIV 
    • If you test positive, begin treatment as soon as possible
  • Tell all potential sexual partners you have HIV
  • Use a latex condom every time you have vaginal, anal, or oral sex
  • Do not share razors or toothbrushes with others
  • Do not share drug needles or syringes with others

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Reviewed on 10/21/2020