AIDS stands for acquired immunodeficiency syndrome. It is a disease caused by infection with the human immunodeficiency virus, or HIV. HIV is a sexually transmitted virus that infects and destroys hel...AIDS stands for acquired immunodeficiency syndrome. It is a disease caused by infection with the human immunodeficiency virus, or HIV. HIV is a sexually transmitted virus that infects and destroys helper T cells of the human immune system (see the concept Disorders of the Immune System to learn more about how HIV infects immune system cells). AIDS eventually develops in most people with untreated HIV infections, usually several years after the initial infection with the virus.