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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Acquired immune deficiency syndrome (AIDS) is a collection of symptoms and infections resulting from the specific damage to the immune system caused by the human immunodeficiency virus (HIV) in humans,[1] and similar viruses in other species (SIV, FIV, etc.)
Causes
AIDS is the most severe acceleration of infection with HIV. HIV is a retrovirus that primarily infects vital organs of the human immune system such as CD4+ T cells (a subset of T cells), macrophages and dendritic cells. It directly and indirectly destroys CD4+ T cells.[2] CD4+ T cells are required for the proper functioning of the immune system. When HIV kills CD4+ T cells so that there are fewer than 200 CD4+ T cells per microliter (µL) of blood, cellular immunity is lost. In some countries, such as the United States, this leads to a diagnosis of AIDS. In other jurisdictions, such as in Canada, AIDS is only diagnosed when a person infected with HIV is diagnosed with one or more of several AIDS-related opportunistic infections or cancers.[3][4][5] Acute HIV infection progresses over time to clinical latent HIV infection and then to early symptomatic HIV infection and later to AIDS, which is identified either on the basis of the amount of CD4+ T cells in the blood, and/or the presence of certain infections, as noted above.
In the absence of antiretroviral therapy, the median time of progression from HIV infection to AIDS is nine to ten years, and the median survival time after developing AIDS is only 9.2 months.[6] However, the rate of clinical disease progression varies widely between individuals, from two weeks up to 20 years. Many factors affect the rate of progression. These include factors that influence the body's ability to defend against HIV such as the infected person's general immune function.[7][8] Older people have weaker immune systems, and therefore have a greater risk of rapid disease progression than younger people. Poor access to health care and the existence of coexisting infections such as tuberculosis also may predispose people to faster disease progression.[6][9][10] The infected person's genetic inheritance plays an important role and some people are resistant to certain strains of HIV. An example of this is people with the homozygous CCR5-Δ32 variation are resistant to infection with certain strains of HIV.[11] HIV is genetically variable and exists as different strains, which cause different rates of clinical disease progression.[12][13][14] The use of highly active antiretroviral therapy prolongs both the median time of progression to AIDS and the median survival time.
Alternative Hypotheses
A small minority of scientists and activists question the connection between HIV and AIDS,[15] the existence of HIV itself,[16] or the validity of current testing and treatment methods. Though these claims have been examined and widely rejected by the scientific community,[17] they continue to be promulgated through the Internet[18] and have had a significant political impact, particularly in South Africa, where until late 2006 the Thabo Mbeki government did not accept that AIDS was caused by HIV, lead to an ineffective response to that country's AIDS epidemic.[19][20][21][22]
Misconceptions
A number of misconceptions have arisen surrounding HIV/AIDS. Three of the most common are that AIDS can spread through casual contact, that sexual intercourse with a virgin will cure AIDS, and that HIV can infect only homosexual men and drug users. Other misconceptions are that any act of anal intercourse between gay men can lead to AIDS infection, and that open discussion of homosexuality and HIV in schools will lead to increased rates of homosexuality and AIDS.[23]
Related Chapters
References
- ↑ "The Relationship Between the Human Immunodeficiency Virus and the Acquired Immunodeficiency Syndrome". NIAID. Retrieved 2008-03-10.
- ↑ Alimonti JB, Ball TB, Fowke KR (2003). "Mechanisms of CD4+ T lymphocyte cell death in human immunodeficiency virus infection and AIDS". J. Gen. Virol. 84 (7): 1649&ndash, 1661. doi:10.1099/vir.0.19110-0. PMID 12810858.
- ↑ Public Health Agency of Canada (Note that this source is mistaken in its assertion that the U.S. definition of AIDS requires a CD4 count of <200.)
- ↑ McGovern, Theresa and Smith, Raymond (1998). AIDS, Case Definition of. TheBody.com. Retrieved on 2008-03-10.
- ↑ AEGIS
- ↑ 6.0 6.1 Morgan D, Mahe C, Mayanja B, Okongo JM, Lubega R, Whitworth JA (2002). "HIV-1 infection in rural Africa: is there a difference in median time to AIDS and survival compared with that in industrialized countries?". AIDS. 16 (4): 597&ndash, 632. PMID 11873003.
- ↑ Clerici M, Balotta C, Meroni L; et al. (1996). "Type 1 cytokine production and low prevalence of viral isolation correlate with long-term non progression in HIV infection". AIDS Res. Hum. Retroviruses. 12 (11): 1053&ndash, 1061. PMID 8827221.
- ↑ Morgan D, Mahe C, Mayanja B, Whitworth JA (2002). "Progression to symptomatic disease in people infected with HIV-1 in rural Uganda: prospective cohort study". BMJ. 324 (7331): 193&ndash, 196. doi:10.1136/bmj.324.7331.193. PMID 11809639.
- ↑ Gendelman HE, Phelps W, Feigenbaum L; et al. (1986). "Transactivation of the human immunodeficiency virus long terminal repeat sequences by DNA viruses". Proc. Natl. Acad. Sci. U. S. A. 83 (24): 9759&ndash, 9763. PMID 2432602.
- ↑ Bentwich Z, Kalinkovich, A, Weisman Z (1995). "Immune activation is a dominant factor in the pathogenesis of African AIDS". Immunol. Today. 16 (4): 187&ndash, 191. PMID 7734046.
- ↑ Tang J, Kaslow RA (2003). "The impact of host genetics on HIV infection and disease progression in the era of highly active antiretroviral therapy". AIDS. 17 (Suppl 4): S51&ndash, S60. PMID 15080180.
- ↑ Quiñones-Mateu ME, Mas A, Lain de Lera T, Soriano V, Alcami J, Lederman MM, Domingo E (1998). "LTR and tat variability of HIV-1 isolates from patients with divergent rates of disease progression". Virus Research. 57 (1): 11&ndash, 20. PMID 9833881.
- ↑ Campbell GR, Pasquier E, Watkins J; et al. (2004). "The glutamine-rich region of the HIV-1 Tat protein is involved in T-cell apoptosis". J. Biol. Chem. 279 (46): 48197&ndash, 48204. doi:10.1074/jbc.M406195200. PMID 15331610.
- ↑ Kaleebu P, French N, Mahe C; et al. (2002). "Effect of human immunodeficiency virus (HIV) type 1 envelope subtypes A and D on disease progression in a large cohort of HIV-1-positive persons in Uganda". J. Infect. Dis. 185 (9): 1244&ndash, 1250. PMID 12001041.
- ↑ Duesberg PH (1988). "HIV is not the cause of AIDS". Science. 241 (4865): 514, 517. doi:10.1126/science.3399880. PMID 3399880.
- ↑ Papadopulos-Eleopulos E, Turner VF, Papadimitriou J; et al. (2004). "A critique of the Montagnier evidence for the HIV/AIDS hypothesis". Med Hypotheses. 63 (4): 597&ndash, 601. doi:10.1016/j.mehy.2004.03.025. PMID 15325002.
- ↑ For evidence of the scientific consensus that HIV is the cause of AIDS, see (for example):
- "The Durban Declaration". Nature. 406 (6791): 15&ndash, 6. 2000. doi:10.1038/35017662. PMID 10894520. – full text here.
- Cohen J (1994). "The Controversy over HIV and AIDS" (PDF). Science. 266 (5191): 1642&ndash, 1649.
- "Focus on the HIV-AIDS Connection: Resource links". National Institute of Allergy and Infectious Diseases. Retrieved 2006-09-07.
- O'Brien SJ, Goedert JJ (1996). "HIV causes AIDS: Koch's postulates fulfilled". Curr. Opin. Immunol. 8 (5): 613–8. PMID 8902385.
- Galéa P, Chermann JC (1998). "HIV as the cause of AIDS and associated diseases". Genetica. 104 (2): 133&ndash, 42. PMID 10220906.
- ↑ Smith TC, Novella SP (2007). "HIV denial in the Internet era". PLoS Med. 4 (8): e256. doi:10.1371/journal.pmed.0040256. PMID 17713982.
- ↑ Watson J (2006). "Scientists, activists sue South Africa's AIDS 'denialists'". Nat. Med. 12 (1): 6. doi:10.1038/nm0106-6a. PMID 16397537.
- ↑ Baleta A (2003). "S Africa's AIDS activists accuse government of murder". Lancet. 361 (9363): 1105. doi:10.1016/S0140-6736(03)12909-1. PMID 12672319.
- ↑ Cohen J (2000). "South Africa's new enemy". Science. 288 (5474): 2168–70. doi:10.1126/science.288.5474.2168. PMID 10896606.
- ↑ Andrew Meldrum. South African government ends Aids denial, guardian.co.uk, 27 October 2006
- ↑ Blechner MJ (1997). Hope and mortality: psychodynamic approaches to AIDS and HIV. Hillsdale, NJ: Analytic Press. ISBN 0-88163-223-6.