HIV: Acronym for the Human Immunodeficiency Virus, the cause of AIDS (acquired immunodeficiency syndrome). HIV has also been called the human lymphotropic virus type III, the lymphadenopathy-associated virus and the lymphadenopathy virus. No matter what name is applied, it is a retrovirus. (A retrovirus has an RNA genome and a reverse transcriptase enzyme. Using the reverse transcriptase, the virus uses its RNA as a template for making complementary DNA which can integrate into the DNA of the host organism).

Although the American research Robert Gallo at the National Institutes of Health (NIH) believed he was the first to find HIV, it is now generally accepted that the French physician Luc Montagnier (1932-) and his team at the Pasteur Institute discovered HIV in 1983-84.