The global epidemic of Human Immunodeficiency Virus (HIV) and subsequently Acquired
Immunodeficiency Syndrome (AIDS) has become the most pressing public health emergency of the century. HIV, first reported by the New England Journal of Medicine in 1981, cited four homosexual men with pneumonia, fungal infections in the mouth, and numerous other viral infections, characteristic of a nonfunctioning immune system. Currently HIV infects 33.4 million people worldwide and approximately 17 million people have died as a result of this infection (Stine, 1999).

Human Immunodeficiency Virus(HIV) is a disease identified by the decline of a functional immune response. HIV primarily infects CD4 T cells, which are crucial to the immune response by signaling and activating effector cells to carry out specific functions (Janeway et al., 1999). After a period of latency the number of CD4 T cells, also known as T-helper cells, will decline significantly leading to opportunistic infections which characterize the end stage of HIV know as Acquired immunodeficiency Syndrome (AIDS). HIV occurs in two strains: HIV-1 and HIV-2, however HIV-1 is generally accepted to be the cause of AIDS throughout the majority of the world (Stine, 1999).

HIV is approximately 1,000Å in diameter and is the basic surface structure consists of envelope proteins (shown in brown) that allow the virion to bind to target cells. This image is used with permission from the Aids Education and Research Trust (AVERT).