Human Immunodeficiency Virus (HIV)
Mary D. Nettleman, MD, MS, MACP
Mary D. Nettleman, MD, MS, MACP is the Chair of the Department of Medicine at Michigan State University. She is a graduate of Vanderbilt Medical School, and completed her residency in Internal Medicine and a fellowship in Infectious Diseases at Indiana University.
Charles Patrick Davis, MD, PhD
Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.
- Human immunodeficiency virus (HIV) facts
- What is the human immunodeficiency virus?
- What is the history of HIV?
- What causes an HIV infection?
- What are the different stages of an HIV infection?
- What are risk factors for an HIV infection?
- What are HIV infection symptoms and signs?
- How do health-care professionals diagnose an HIV infection? What are the different types of HIV tests?
- What is the treatment for an HIV infection?
- What are complications of an HIV infection?
- What is the prognosis of an HIV infection?
- Is it possible to prevent the transmission of HIV?
- What research is being done on HIV?
- Are support groups available for people who are HIV positive?
- Where can people find more information on HIV?
- HIV-AIDS Rxlist FAQs
- Patient Comments: Human Immunodeficiency Virus (HIV, AIDS) - Symptoms
- Patient Comments: HIV - Risk Factors and How it's Spread
- Find a local Infectious Disease Specialist in your town
Human immunodeficiency virus (HIV) facts
- HIV is the virus that causes HIV infection and the acquired immunodeficiency syndrome (AIDS).
- Anal or vaginal sexual intercourse and illicit injectable drug use commonly transmit HIV. Infected mothers may also transmit HIV to their child during pregnancy or breastfeeding. Less common routes of transmission include needle-stick injuries or exposure to contaminated blood.
- The blood supply in the United States is tested for HIV before use, and statistics show the risk of acquiring HIV infection from a transfusion is less than one in 1.5 million.
- HIV attacks the immune system, especially cells known as CD-4 lymphocytes. Serious impairment of the CD-4 lymphocytes makes people susceptible to specific infections and cancers.
- Untreated HIV infected progresses through three stages, with stage three being AIDS.
- Health-care professionals diagnose HIV with tests that measure antibodies against the virus or measure the virus directly.
- Treatment with highly active antiretroviral therapy (HAART or ART) dramatically increases life expectancy although it does not cure HIV infection.
What is the human immunodeficiency virus?
The human immunodeficiency virus is the cause of HIV infection and the acquired immunodeficiency syndrome (AIDS). HIV belongs to a family of organisms known as retroviruses. Once someone acquires the virus, it attaches to and enters human cells, especially cells known as CD4 T-cells, macrophages, and dendritic cells. The virus contains RNA, which it transcribes into DNA using an enzyme called reverse transcriptase. The resulting DNA integrates into the human genome in the cell. In this way, the virus fools the human genome into making more copies of the virus.
HIV may remain quiescent (latent) in the genome or may be actively transcribed, causing the virus to replicate. HIV is a prolific virus and is able to create trillions of copies of itself in a short period of time. During times of peak viral reproduction, even 1 milliliter of blood can contain more than 1 million copies of the virus. Many of these copies differ in small ways from the original virus and may be resistant to different medications. There are two types of HIV: HIV-1 and HIV-2. HIV-1 is the primary cause of HIV infection and AIDS in the world. HIV-2 is less common and less easily transmitted.
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