HIV is another name for the human immunodeficiency virus. A virus is a very small germ that can cause disease, and HIV is a virus that causes a weakening of the person's immune system.
AIDS is another name for the acquired immunodeficiency syndrome. AIDS is caused by HIV, and it is a disease in which the body's immune system breaks down.
Infection occurs in two main ways: sexual activity, or sharing needles and syringes with an infected person. It is not spread by coughs and sneezes or from items. When people are infected with HIV, they may begin to develop illnesses that signal the onset of AIDS. These complications may include extreme weight loss, severe pneumonia, cancer, and damage to the nervous system.