Alternative Names Human immunodeficiency virus, AIDS, Acquired immune deficiency syndrome
Definition Human immunodeficiency virus (HIV) is an infection that damages the body's immune system. Over time, it leads to acquired immune deficiency syndrome (AIDS).
What is going on in the body? HIV affects the immune system in broad and devastating ways. Its main target is a special immune system cell called the CD4+ T lymphocyte. These cells are key to the body's ability to fight infections of all kinds. When HIV infects these cells, it decreases their numbers and affects how remaining cells function.
After an adult is infected with HIV, he or she typically has no obvious symptoms for 5 to 10 years. During this time, however, the virus is slowly attacking the immune system. When the immune system is sufficiently weakened, other organisms that the body can usually fight off or keep under control are able to cause infections. These other organisms include bacteria, other viruses, fungi, and parasites.
Many serious health problems occur as a result of the immune system damage caused by HIV. The most serious constellation of problems is AIDS.
What are the signs and symptoms of the disease? The signs and symptoms of HIV infection include:
What are the causes and risks of the disease? HIV is spread:
by sexual contact with a person who has HIV
by skin punctures from needles or other sharp devices contaminated with HIV-infected blood or other body secretions
by contact with HIV-infected blood or other secretions at the site of a cut or wound
from mother-to-infant around the time of birth
What can be done to prevent the disease? Although practicing safer sex cannot completely prevent a person from getting or spreading HIV, it can lower the risk. It is safest to avoid sexual intercourse with people who have HIV infection or unknown HIV status and those who use IV drugs.
A person should not share needles, syringes, or other drug paraphernalia that could carry tainted blood or body fluids with anyone.
A woman who is pregnant or thinking about getting pregnant, should ask her doctor to test her for HIV. If a woman has HIV, measures can be taken during pregnancy and birth to avoid passing it to her baby.
When caring for people in emergency situations, it is important to use gloves.
How is the disease diagnosed? The body produces antibodies to fight off HIV infection. HIV is usually diagnosed by blood tests called serum antibody tests. The enzyme immunoassay (EIA) is used as a screening test. If this test is positive, a Western blot test is done to confirm the diagnosis.
The virus can also be detected by testing for viral proteins, or viral DNA and RNA, and by performing blood cultures.
Negative tests do not always mean that a person is free of infection. Weeks or months might pass after exposure to the virus before antibodies can be detected in the body.
What are the long-term effects of the disease? HIV causes many long-term effects, including:
damage to the immune system, which can make the body vulnerable to infections
problems with autoimmune disorders, which cause the body to destroy its own tissues
What are the risks to others? Having unprotected sexual intercourse or sharing needles or syringes puts a person and his or her partners at risk for HIV. People with known or suspected HIV infection should not donate:
What are the treatments for the disease? There are a number of medications that effectively treat HIV. Over the past few years, combinations of certain drugs have been very promising in controlling HIV. These combinations may include:
HAART, which is highly active anti-retroviral therapy
Antibiotics are also used to treat or prevent the infections from other organisms. Support services are available to help with psychological and emotional difficulties.
What are the side effects of the treatments? Unfortunately most HIV medications have many side effects, which depend on the drug being taken. Some more common side effects include:
Some less common side effects include:
inflammation of the pancreas
changes in the brain and behaviour
What happens after treatment for the disease? There is no cure for HIV infection at this time. The goal of treatment is to keep the virus under control with the hope of preventing further immune damage. Currently, a person must be treated for life.
How is the disease monitored? A doctor specialising in HIV typically monitors a person who has this disease. Most doctors monitor HIV by following:
how the person feels.
the results of many blood tests. Tests include the quantity of HIV in the blood, called HIV viral load, and the number of CD4+ T lymphocytes in the blood.
Author: Danielle Zerr, MD Reviewer: HealthAnswers Australia Medical Review Panel Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia Last Updated: 1/10/2001 Contributors Potential conflict of interest information for reviewers available on request
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