Human Immunodeficiency virus also knows as HIV, is a pathogen that leads to AIDS. It causes the immune system to fail, which allows life threatening infectious diseases and cancers to thrive (Wikepedia). The body's immune system normally finds and kills viruses fairly quickly. HIV attacks the immune system itself which is the thing that would normally get rid of a virus that has infected the body. HIV is a virus that cannot grow or reproduce on its own, it needs to infect the cells of a living organism in order to replicate. There are two types of human immunodeficiency viruses. They are known as HIV-1 and HIV-2. HIV-1 is more virulent and infectious. Globally it is the majority of HIV infections. HIV-2 is largely confined to West Africa. It implies fewer infectious causes than HIV-1. When a person develops AIDS, from being infected by HIV, his or her immune system is too weak to fight off infections. (Gordon et al., 2013) .
II. Magnitude of the Problem .
Since AIDS was first identified in the early 1980s, an unprecedented number of people have been affected by the global AIDS epidemic. Around 2.7 million people became affected with HIV in 2007. There are now an estimated 33 million people around the world living with HIV, including millions who have developed AIDS as well. It is a threating disease. In 2011, an estimated 1,201,100 people ages 13 and older were living with HIV infection in the United States, including 160,300 people who have not been diagnosed. The CDC estimates approximately 50,000 people in the United States are newly infected with HIV each year. In 2010, there was an estimated 47,500 new HIV infections. Nearly two thirds of these new infections occurred in gay and bisexual men. African American men and women were also highly affected and were estimated to have a HIV incidence rate that was almost eight times as high as the incidence rate among white men and women (CDC, 2015).