HIV, human immunodeficiency virus, either of two closely related retroviruses that invade T-helper lymphocytes and are responsible for AIDS. There are two types of HIV: HIV-1 and HIV-2. HIV-1 is responsible for the vast majority of AIDS in the United States. HIV-2, seen more often in western Africa, has a slower course than HIV-1. There are many strains of both types and the virus mutates rapidly, a trait that has made it especially difficult for researchers to find an effective treatment or vaccine. In many cases, a person's immune system will fight off the invasion of HIV for many years, producing billions of CD4 cells daily, always trying to keep up with the HIV's mutations, before it succumbs and permits the well-known signs of AIDS to develop.

HIV is especially lethal because it attacks the very immune system cells (variously called T4, CD4, or T-helper lymphocytes) that would ordinarily fight off such a viral infection. Receptors on these cells appear to enable the viral RNA to enter the cell. As with all retroviruses, once the RNA is inside the cell, an enzyme called reverse transcriptase allows it to act as the template for its own RNA to DNA transcription. The resultant viral DNA inserts itself into a cell's DNA and is reproduced along with the cell and its daughters. In 2012 the Food and Drug Administration approved a pill that combines two antiretroviral drugs, tenofovir and emtricitabine, for use in preventing infection with HIV.

The exact origin of the virus in humans is unclear. Scientists surmise that it jumped from African chimpanzees, who harbor a similar strain called SIV (simian immunodeficiency virus), to humans via the butchering of meat or an animal bite. The first case documented in humans dates from 1959, but genetic analysis published in 2008 estimated that it originated some time between 1884 and 1924. The virus was isolated by Luc Montagnier of France's Pasteur Institute in 1983. It went through several name changes before the official name, human immunodeficiency virus, was agreed upon.

The Columbia Encyclopedia, 6th ed. Copyright© 2013, The Columbia University Press.

Selected full-text books and articles on this topic

The HIV/AIDS Epidemic at 30
Melby, Todd.
Contemporary Sexuality, Vol. 45, No. 12, December 2011
New HIV Recommendations to Improve Health, Reduce Infections and Save Lives
Central European Journal of Public Health, Vol. 18, No. 2, June 2010
Impact of HIV/AIDS on Education and Poverty
Ijumba, Nelson.
UN Chronicle, Vol. 48, No. 1, March 2011
Getting to Zero New HIV Infections: The Prevention Revolution
Becker, Sumner; Taykhman, Nicole.
The Brown Journal of World Affairs, Vol. 17, No. 2, Spring 2011
National Fight against HIV/AIDS Targets Improved Care, Education
Currie, Donya.
The Nation's Health, Vol. 42, No. 1, February 2012
Career Issues and Concerns for Persons Living with HIV/AIDS
Dahlbeck, David T.; Lease, Suzanne H.
Career Development Quarterly, Vol. 58, No. 4, June 2010
Alcohol's Role in HIV Transmission and Disease Progression
Pandrea, Ivona; Happel, Kyle I.; Amedee, Angela M.; Bagby, Gregory J.; Nelson, Steve.
Alcohol Research, Vol. 33, No. 3, Fall 2010
HIV/AIDS and Older Adults: Challenges for Individuals, Families, and Communities
Charles A. Emlet.
Springer, 2004
Social Work and Disadvantage: Addressing the Roots of Stigma through Association
Peter Burke; Jonathan Parker.
Jessica Kingsley, 2007
Librarian’s tip: Chap. 5 "AIDS/HIV: Challenging Stigma by Association"
Biomedical Approaches to HIV Prevention
Mayer, Kenneth H.; Skeer, Margie; Mimiaga, Matthew J.
Alcohol Research, Vol. 33, No. 3, July 1, 2010
Microbicides New Hope for HIV Prevention
karim, Salim S. Abdool.
UN Chronicle, Vol. 48, No. 1, March 2011
Applied Ethics in Nursing
Vicki D. Lachman.
Springer, 2006
Librarian’s tip: "HIV-AIDS Patients and Ethical Issues" begins on p. 45
Health Psychology: A Textbook
Jane Ogden.
Open University Press, 2007 (4th edition)
Librarian’s tip: Chap. 14 "HIV and Cancer: Psychology throughout the Course of Illness"
HIV Knowledge, Attitudes and Practices among College Students in the United States
Inungu, Joseph; Mumford, Vincent; Younis, Mustafa; Langford, Sara.
Journal of Health and Human Services Administration, Vol. 32, No. 3, Winter 2009
HIV Stigma Is Linked to Lack of HIV-Related Knowledge
Rosenberg, Jared.
International Perspectives on Sexual and Reproductive Health, Vol. 35, No. 3, September 2009
The Endangered Self: Managing the Social Risk of HIV
Gill Green; Elisa J. Sobo.
Routledge, 2000
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