Acquired immune deficiency syndrome or acquired immunodeficiency syndrome (AIDS)

is a disease of the human immune system caused by the human immunodeficiency virus (HIV).[1][2][3]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.[4][5
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.[6] In 2007, it was estimated that 33.2 million people lived with the disease worldwide, and that AIDS killed an estimated 2.1 million people, including 330,000 children.[7] Over three-quarters of these deaths occurred in sub-Saharan Africa,[7] retarding economic growth and destroying human capital.[8]
Genetic research indicates that HIV originated in west-central Africa during the late nineteenth or early twentieth century.[9][10] 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.[11]
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.[12] 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.
The symptoms of AIDS are primarily the result of conditions that do not normally develop in individuals with healthy immune systems. Most of these conditions are infections caused by bacteria, viruses, fungi and parasites that are normally controlled by the elements of the immune system that HIV damages.
Opportunistic infections are common in people with AIDS.[13] These infections affect nearly every organ system.People with AIDS also have an increased risk of developing various cancers such as Kaposi's sarcoma, cervical cancer and cancers of the immune system known as lymphomas. Additionally, people with AIDS often have systemic symptoms of infection like fevers, sweats (particularly at night), swollen glands, chills, weakness, and weight loss.[14][15] The specific opportunistic infections that AIDS patients develop depend in part on the prevalence of these infections in the geographic area in which the patient lives.
The term HIV has been used since 1986 (Coffin et al., 1986) as the name for the retrovirus that was first proposed as the cause of AIDS by Luc Montagnier of France, who originally called it LAV (lymphadenopathy-associated virus) (Barre-Sinoussi et al., 1983 ) and by Robert Gallo of the United States, which initially called HTLV-III (human T lymphotropic virus type III) (Popovic et al., 1984).
HIV is a member of the genus Lentivirus [1], part of the Retroviridae family [2] is characterized by a long latency period and a lipid envelope from the initial host cell surrounding a central protein / RNA. Two species of HIV infect humans: HIV-1 and HIV-2. HIV-1 is a more "virulent" and more easily transmitted, and is the source of most HIV infections throughout the world, most HIV-2 is still locked in west Africa (Reeves and Doms, 2002). Both species originated in west and central Africa, jumping from primates to humans in a process known as zoonoses.
HIV-1 has evolved from a simian immunodeficiency virus (SIVcpz) found in the chimpanzee subspecies, Pan Troglodyte Troglodyte (Gao et al., 1999). HIV-2 jumped species from a different strain of SIV, found in Sooty mangabeys, monkey world old Guinea-Bissau (Reeves and Doms, 2002).
HIV-1 has 3 groups or groups that have been identified based on the difference in his envelope is M, N, and O (Thomson et al, 2002). Group F The greatest prevalence and divided into 8 subtypes based on the entire genome, each of which are geographically distinct (Carr et al, 1998). The largest subtype is the prevalence of subtype B (commonly found in Africa and Asia), subtype A and D (usually found in Africa), and C (commonly found in Africa and Asia); subtype-subtype is part of the group M of HIV -1. Co-infection with a subtype that berrbeda increasing the circulation of recombinant forms (CRFs)
[edit] Transmission
HIV is transmitted through sexual intercourse and oral sex, or through the anus, blood transfusions, sharing contaminated needles through drug injection and in health care, and between mothers and their babies during pregnancy, birth and lactation. UNAIDS transmission. The use of physical protection such as latex condoms are recommended to reduce transmission of HIV through sex. In recent years, suggested that circumcision can reduce the risk of spreading the HIV virus [3], but many experts believe that it is still too early to recommend male circumcision in order to prevent HIV [4].
At the end of the year 2004 is estimated between 36 to 44 million people living with HIV, 25 million of whom are residents of sub-Saharan Africa. Estimated number of people infected with HIV worldwide in 2004 was between 4.3 million and 6.4 million people. (AIDS epidemic update December 2004).
This outbreak is not evenly distributed in the region-specific because there wilayan countries suffer more than others. Even at the state level was no difference in levels of infection in areas different. The number of people living with HIV continue to increase in all parts of the world, although it has conducted a variety of strict preventive measures.
Sub-Saharan Africa remains the region most heavily affected by HIV among pregnant women at age 15-24 years in some countries there. This is thought to be caused by a number of venereal disease, practice nock body, blood transfusions, and poor health and nutrition levels there (Bentwich et al., 1995). In 2000, WHO estimates that 25% of blood units transfused in Africa is not tested for HIV, and that 10% of HIV infections occur in the continent through the blood. [5].
In Asia, HIV epidemics caused primarily by drug users through needle, either sex between men as well as with commercial sex workers, and customers, as well as their sexual partners. Prevention is still inadequate.