The first recognition of what became known as HIV and AIDS appeared in June 1981. The U.S. Centers for Disease Control (CDC) reported that several otherwise healthy young men were dying of diseases usually seen only in elderly or immune-depressed patients. The men lived in Los Angeles and New York and all were gay. Within weeks, many more cases surfaced. 

HIV (human immunodeficiency virus) is the virus that produces AIDS by impairing the human immune system and allowing diseases such as pneumonia and various cancers to take hold.  AIDS (acquired immune deficiency syndrome) is the term for the combination of infection with HIV, a reduced number of specific immune system cells (ones with CD4 surface proteins), and the illnesses associated with HIV.