Definition

Human immunodeficiency virus (HIV) is a virus that attacks a part of the immune system. It targets white blood cells called CD4 (T cells). They are needed to fight off infections and other diseases. Low levels of CD4 cells make it harder for the body to stop or control infections and diseases.

AIDS is a late stage of HIV infection. It is a sign of severe damage to the immune system. This level of damage can lead to infections that do not usually occur in healthy people. It also allows the growth of some cancers.

Immune System

HIV destroys white blood cells vital to the immune system.

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Causes

HIV is spread through contact with HIV-infected body fluids. This includes blood, semen, vaginal fluid, and breast milk.

HIV is most commonly spread through:

• Sexual contact (especially vaginal or anal sex) with an HIV-infected person who is not taking medicine or has not reached maximal suppression of the virus
• Transfer of HIV from a mother to child during pregnancy, childbirth, or breastfeeding
• 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 that have been contaminated with blood or other body fluids of an HIV-infected person

Risk Factors

Factors that may increase your chance of HIV infection include:

• Sex with a high-risk individual or individual already infected with HIV
• Multiple sexual partners
• Sex without using a condom including vaginal and anal sex
• Having other sexually transmitted diseases
• Injecting drugs with used or dirty needles
• Regular exposure to HIV-contaminated blood or other body fluids
• Being born to an HIV-infected mother
• 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

Symptoms

HIV may not cause problems for a number of years.

Early symptoms may appear 1 to 2 months after an infection. They may last a couple of weeks. Early symptoms may include:

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

There may be no additional symptoms for months to years. Symptoms that do occur over the years may include:

• 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 may progress to AIDS. This may happen when the number of CD4 cells fall below certain levels. The body is more vulnerable to infections such as:

• Thrush
• Some types of pneumonia
• Fungal infections in the brain and/or lungs
• Toxoplasmosis
• Tuberculosis
• Viral brain infection
• Kaposi's sarcoma
• Lymphoma
• Cervical cancer
• Eye disease due to cytomegalovirus infection
• Severe intestinal infections
• Muscle wasting syndrome
• Severe skin rashes
• Reactions to medications
• Psychiatric problems, including depression and dementia

Diagnosis

Your doctor will ask about your symptoms and medical history. A physical exam will be done. Tests to confirm a diagnosis of HIV infection include:

• HIV antibody test—to detect specific proteins in blood or saliva
• Plasma RNA, or viral load test—to detect the amount of HIV in the blood
• Your doctor may also test for other infections. You may be tested for one or more of the following:
  • Tuberculosis
  • Hepatitis A, B, and C
  • Other sexually transmitted diseases (STDs)

Treatment

There is no cure for HIV at this time. The goal of treatment is to control HIV. Treatment, called antiretroviral treatment (ART), can:

• Keep immune system at normal or near-normal levels
• Prevent progression to AIDS
• Decrease the risk of passing the virus to someone else
• Play an important role in treatment for some HIV related infections and cancers