What Are AIDS and HIV?

What Are AIDS and HIV?

AIDS is the disease caused by human immunodeficiency virus type 1, or HIV-1 (usually referred to as HIV). HIV belongs to the retrovirus family, a group of viruses that have the ability to use cells' machinery to replicate (make more copies of the infecting virus).

HIV attacks the immune system by damaging or killing a specific type of white blood cell in the body called a T-lymphocyte (LIM-fo-site), also called a CD4+ or T-helper cell. T-lymphocytes help the immune system perform its important task of fighting disease in the body caused by invading germs. As a result of HIV infection, the immune system becomes weakened and the body has trouble battling certain infections caused by bacteria, viruses, parasites, and fungi. Many of these infections are highly unusual in people with healthy immune systems. They are called opportunistic infections because they take advantage of a weakened immune system. People with HIV disease not only are more likely to contract these infections, they are more likely to have them repeatedly and to become much more sick from them.