 
Tables and Charts:
AGENT Human immunodeficiency virus (HIV), a retrovirus. Two major types of HIV have been recognized, HIV-1 and HIV-2. HIV-1 is the dominant type worldwide. HIV-2 is found principally in West Africa but cases have been reported from East Africa, Europe, Asia and Latin America. There are at least 10 different genetic subtypes of HIV-1, but their biological and epidemiological significance is unclear at present. DESCRIPTION AIDS is late-stage HIV infection, characterized by a severely weakened immune system that can no longer ward off life-threatening opportunistic infections and cancers. It is thought that everyone infected with HIV will eventually develop AIDS, because the body's immune system is steadily weakened by HIV. Unable to fight off infections, most people die within three years of the first signs of AIDS appearing. TRANSMISSION The main route is through unprotected sexual contact between man and woman (heterosexual) or between men (homosexual). There are no documented cases of sexual transmission between women. HIV is also transmitted through blood, blood products and donated organs or semen. Bloodborne transmission occurs primarily through the use of inadequately sterilized needles, syringes or other skin-piercing instruments, and the transfusion of infected blood. Finally, the virus may be transmitted from an infected mother to her fetus or infant during pregnancy or delivery, or when breast-feeding. This is known as mother-to-child, or vertical, transmission. It is not transmitted by casual contact such as interactions at school or at work or while eating at the same table. SYMPTOMS While some individuals experience mild HIV-related disease soon after initial infection, nearly all then remain well for years. Then, as the virus gradually damages their immune system, they begin to develop illnesses of increasing severity, characterized by various combinations of symptoms and diseases, such as diarrhoea, fever, wasting, fungal infections, tuberculosis, pneumonia, lymphoma, failure to thrive and Kaposi's sarcoma. INCIDENCE AND DISTRIBUTION Pandemic UNAIDS estimates that there are 8,500 new HIV infections every day. In 1996, 2,7 million adults and 400,000 children were newly infected with HIV. Since the start of the global epidemic, close to 30 million people are thought to have been infected with HIV - 26.8 million adults and 2.6 million children. Of these, an estimated 5 million adults and 1.4 million children have died. Today, 22.6 million people are estimated to be living with HIV infection or AIDS. Of these, 21.8 million are adults and 830,000 are children. Numbers of people living with HIV/AIDS across the globe: Sub-Saharan Africa: 14 million South and South-East Asia: 5.2 million North America, western Europe, Australia and New Zealand: 1.3 million Latin America 1.3 million. TREATMENT Several drugs are used to lengthen the life expectancy of AIDS patients. PREVENTION Safe sexual practices and safe IV usage, avoidance of body fluids of HIV infected, monitoring the blood supply. VACCINATION Under development. [Printing Hints] Copyright © 2000 United Nations Publications You can e-mail us at cyberschoolbus@un.org |
