HIV Infection and AIDS

(Human Immunodeficiency Virus and Acquired Immunodeficiency Syndrome)



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.

Immune System

HIV destroys white blood cells vital to the immune system.
Copyright © Nucleus Medical Media, Inc.

HIV is most commonly spread through:

  • Sexual contact with an HIV-infected person, especially vaginal or anal sex
  • Transfer of HIV from a mother to child during pregnancy, childbirth, or breastfeeding
  • Using an HIV-contaminated needle

Rarely, HIV can be spread through:

  • A blood transfusion with HIV-infected blood
  • Blood from an HIV-infected person getting into an open wound of another person
  • Being bitten by someone infected with HIV
  • Sharing personal hygiene items with an HIV-infected person

Risk Factors

Risk Factors

Factors that may increase your chance of HIV infection include:

  • Sexual relationship with a high-risk individual or a partner already infected with HIV
  • Multiple sexual partners
  • Sex without using a condom including vaginal and anal sex
  • Having other sexually transmitted diseases
  • Injecting illegal drugs, especially with used or dirty needles
  • Regular exposure to HIV-contaminated blood or other body fluids
  • Being born to an HIV-infected mother
  • Living in or being from a geographic locations with high numbers of people with AIDS
  • Receiving donor blood products, tissue, organs, or artificial insemination before 1985 (infections from donated tissue after 1985 is unlikely due to strict screening processes)
  • Uncircumcised penis—circumcised men are less likely to develop HIV infection than uncircumcised men

HIV infection increases the chances of getting AIDS.



HIV may not cause symptoms for a number of years.

Early symptoms may appear 1-2 months after becoming infected. They may last a couple of weeks and be similar to the flu or mononucleosis. These include:

  • Fever
  • Joint and muscle aches
  • Night sweats
  • Fatigue
  • Swollen lymph nodes in armpits, neck, or groin
  • Headache
  • Sore throat
  • Rash
  • Diarrhea

After these initial symptoms pass, there may be no symptoms for months to years. The following symptoms may occur over the years:

  • Lack of appetite
  • Fatigue
  • Muscle wasting
  • Swollen lymph glands all over the body
  • Memory loss
  • Development of lots of warts
  • Fungal infections of the mouth, fingernails, toes
  • Repeated vaginal infections
  • Flare-ups of prior conditions, such as eczema, psoriasis, or herpes
  • Chronic diarrhea

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:

  • HIV antibody test to detect specific proteins in the blood, urine, or saliva
  • Plasma RNA, or viral load test, to detect the amount of HIV in the blood
  • Your doctor may also test you for other infections, such as tuberculosis, hepatitis, or STDs



Medications can prevent, delay, or control the development of AIDS in many people infected with HIV.

Drugs That Fight HIV

Antiviral drugs are often given in combination. Categories of these drugs include:

  • Nucleoside reverse transcriptase inhibitors
  • Nonucleoside reverse transcriptase inhibitors
  • Protease inhibitors
  • HIV-1 integrase inhibitors
  • HIV-1 fusion inhibitors
  • CC chemokine receptor 5 antagonists

Drugs That Fight AIDS-Related Infections and Cancers

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:

  • Abstain from sex or limit your number of sexual partners.
  • Use a latex condom every time you have sex.
  • Avoid sexual partners who are HIV-infected or injection drug users.
  • Do not share needles for drug injection.
  • Talk to your partner about any sexually transmitted infections you or your partner have.
  • Let your doctor know if you share needles or have sex with someone who has HIV. Your doctor may want to start medication to help prevent an HIV infection from developing.
  • Go to regular check ups and get tested for HIV and other sexually transmitted diseases (STDs) as advised.

If you are a health care worker or work in a correctional facility, take these steps:

  • Wear appropriate gloves and facial masks during all procedures.
  • Carefully handle and properly dispose of needles.
  • Carefully follow universal precautions.

If you live in a household with an HIV-infected person:

  • Wear appropriate gloves if handling HIV-infected bodily fluids.
  • Cover all cuts and sores, yours and the HIV-infected person’s, with bandages.
  • Do not share any personal hygiene items such as razors, toothbrushes, etc.
  • Carefully handle and properly dispose of needles used for medication.

If you are infected with HIV, take these steps to prevent spreading HIV to others:

  • Abstain from sex.
  • If you do have sex, use a latex condom every time. This includes any sexual act that results in the exchange of bodily fluids. Options to consider:

    • A female condom may be used. Male condoms are better studied for HIV prevention but a female condom is better than no protection.
    • Use a dental dam (small square of latex) or similar barrier during oral sex.
  • If you are prescribed medications, be sure that you are taking them. Work with your doctor to monitor your viral load. Medications and low viral loads may decrease the chance of passing the infection.
  • Inform former or potential sexual partners about the infection. Encourage them to get tested.
  • Do not donate blood or organs.
  • If you are not planning a pregnancy, ask your doctor about contraception.
  • If you do wish to become pregnant, talk to your doctor. There are ways to lower your baby’s risk of being born infected with HIV.
  • If you have a baby, do not breastfeed.


American Foundation for AIDS Research

Centers for Disease Control and Prevention


AIDS Committee of Toronto

Canadian AIDS Society


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Last reviewed June 2015 by David L. Horn, MD, FACP
Last Updated: 10/8/2014

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