Acquired immune deficiency syndrome or acquired immunodeficiency syndrome (AIDS) is a disease of the human immune system caused by the human immunodeficiency virus (HIV).
This condition progressively reduces the effectiveness of the immune system and leaves individuals susceptible to opportunistic infections and tumors. HIV is transmitted through direct contact of a mucous membrane or the bloodstream with a bodily fluid containing HIV, such as blood, semen, vaginal fluid, preseminal fluid, and breast milk.
This transmission can involve anal, vaginal or oral sex, blood transfusion, contaminated hypodermic needles, exchange between mother and baby during pregnancy, childbirth, breastfeeding or other exposure to one of the above bodily fluids.
AIDS is now a pandemic. AIDS was first recognized by the U.S. Centers for Disease Control and Prevention in 1981 and its cause, HIV, identified in the early 1980s.
Although treatments for AIDS and HIV can slow the course of the disease, there is currently no vaccine or cure. Antiretroviral treatment reduces both the mortality and the morbidity of HIV infection, but these drugs are expensive and routine access to antiretroviral medication is not available in all countries. Due to the difficulty in treating HIV infection, preventing infection is a key aim in controlling the AIDS pandemic, with health organizations promoting safe sex and needle-exchange programmes in attempts to slow the spread of the virus.
A retrovirus, the Human Immunodeficiency Virus (HIV) was identified in 1983 as the pathogen responsible for the Acquired Immunodeficiency Syndrome (AIDS). AIDS is characterized by changes in the population of T-cell lymphocytes that play a key role in the immune defense system. In the infected individual, the virus causes a depletion of T-cells, called “T-helper cells”, which leaves these patients susceptible to opportunistic infections, and certain malignancies. Credit: CDC/ C. Goldsmith, P. Feorino, E. L. Palmer, W. R. McManus
The AIDS pandemic can also be seen as several epidemics of separate subtypes; the major factors in its spread are sexual transmission and vertical transmission from mother to child at birth and through breast milk.
Globally, an estimated 33.2 million people lived with HIV in 2007, including 2.5 million children. An estimated 2.5 million (range 1.8–4.1 million) people were newly infected in 2007, including 420,000 children. South & South East Asia are second worst affected; in 2007 this region contained an estimated 18% of all people living with AIDS, and an estimated 300,000 deaths from AIDS.
In the United States, young African-American women are also at unusually high risk for HIV infection. This is due in part to a lack of information about AIDS and a perception that they are not vulnerable, as well as to limited access to health-care resources and a higher likelihood of sexual contact with at-risk male sexual partners. There are also geographic disparities in AIDS prevalence in the United States, where it is most common in rural areas and in the southern states, particularly in the Appalachian and Mississippi Delta regions and along the border with Mexico.
List of abbreviations
AIDS: Acquired immune deficiency syndrome
HIV: Human immunodeficiency virus CD4+: CD4+ T helper cells CCR5: Chemokine (C-C motif) receptor 5 CDC: Centers for Disease Control and Prevention WHO: World Health Organization PCP: Pneumocystis pneumonia TB: Tuberculosis MTCT: Mother-to-child transmission HAART: Highly active antiretroviral therapy STI/STD: Sexually transmitted infection/disease |
Further Reading
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