HIV infection is a condition caused by the human immunodeficiency virus (HIV). The condition gradually destroys the immune system, which makes it harder for the body to fight infections.
This article provides a general overview. For more detailed information, see:
AIDS Acute HIV infection Asymptomatic HIV infection Early symptomatic HIV infection
Human immunodeficiency virus infection
Causes, incidence, and risk factors
The human immunodeficiency virus (HIV) can be spread by the following:
- Through sexual contact -- including oral, vaginal, and anal sex
- Through blood -- via blood transfusions (now very rare in the U.S.) or needle sharing
- From mother to child -- a pregnant woman can transmit the virus to her fetus through their shared blood circulation, or a nursing mother can pass it to her baby in her breast milk
People who become infected with HIV may have no symptoms for up to 10 years, but they can still pass the infection to others. After being exposed to the virus, it usually takes about 3 months for the HIV ELISA blood test to change from HIV negative to HIV positive.
HIV has spread throughout the U.S. The disease is more common in urban areas, especially in inner cities.
Review Date: 05/25/2010
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and Jatin M. Vyas, MD, PhD, Assistant Professor in Medicine, Harvard Medical School, Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.