Background Information of Unit Five 1. AIDS: AIDS, acquired immune deficiency syndrome, is a disease which destroys the natural method the body uses to protect against other diseases. It is a disease caused by the HIv(human immunodeficiency virus), but AIDs is different from HIV in that the former usually causes death while Hiv may lead to AIDS HIV is spread in three ways: (1)contact with infected blood; (2)sex; ( 3) mother-to-child. AIDS usually develops in four stages: (1)In the first stage, there is only infection by HiV and antibody (A)production (2) In the second stage, the lymph nodes(淋巴结) enlarge(肿大).(3) In the third stage, an infected person may begin to have such signs (hE B )as tiredness, fever, and night sweats. (4)In the last stage, AIDS is diagnosed when a person develops certain uncommon, life-threatening illnesses, for example Pneumocystis carinii pneumonia(卡氏肺囊虫肺 K). In-depth coverage on AIDS and HIV can be found from http://dailynews.yahoocom/fc/health/aidsHiv• Background Information of Unit Five • 1. AIDS: AIDS, acquired immune deficiency syndrome, is a disease which destroys the natural method the body uses to protect against other diseases. It is a disease caused by the HIV (human immunodeficiency virus), but AIDS is different from HIV in that the former usually causes death while HIV may lead to AIDS. HIV is spread in three ways: (1) contact with infected blood; (2) sex; (3) mother-to-child. AIDS usually develops in four stages: (1) In the first stage, there is only infection by HIV and antibody (抗体) production. (2) In the second stage, the lymph nodes (淋巴结) enlarge (肿大). (3) In the third stage, an infected person may begin to have such signs (症 状) as tiredness, fever, and night sweats. (4) In the last stage, AIDS is diagnosed when a person develops certain uncommon, life-threatening illnesses, for example Pneumocystis carinii pneumonia(卡氏肺囊虫肺 炎 ). In-depth coverage on AIDS and HIV can be found from http://dailynews.yahoo.com/fc/Health/AIDS__HIV