HIV is an acronym that stands for Human Immunodeficiency Virus. These are viruses that cause the disease known as HIV, as well as (in the untreated state, if patients have this disease) eventually they may end up with a syndrome known as AIDS (Acquired Immunodeficiency Syndrome.) In the absence of any therapy, if patients or individuals acquire HIV, perhaps 10 years later and no medications or no diagnosis, they may end up with a syndrome known as Acquired Immunodeficiency Syndrome. In this circumstance, these are individuals who are known to have infection with HIV, but their immunity has been destroyed over the intervening years to the point where they're subject to infections with very uncommon and weak diseases, bacteria, parasites and other viruses.