Part 1 of Essay
AIDS is the final, life-threatening stage of infection with human immunodeficiency virus (HIV). AIDS stands for acquired immunodeficiency syndrome. The name refers to the fact that HIV severely damages the patient's disease-fighting immune system. Cases of AIDS were first identified in 1981 in the United States, but res ....

Part 2 of Essay
.... specific molecules found only on the surface of the cells. These molecules are called CD4 receptor molecules, and the cells themselves are often referred to as CD4 cells. When an AIDS virus enters one of these cells, the virus inserts its genes into the cell's reproductive system and uses it to produce more HIV. This infection kills the CD4 cell and spreads AIDS viruses to other CD4 cells, where the process is repeated. HIV can be present in the body for 2 to 12 or more years without producing any outwar ....