Human Immunodeficiency Virus or HIV is a type of lentivirus, this virus was found similar to Simian Immunodeficiency Virus or SIV, which was detected in chimpanzees. The chimpanzees in West Africa were considered as the source of HIV infection in humans. The very first case of HIV-1 in a blood sample of human was detected in 1959, from a man in Democratic republic of Congo.