• History and spread of AIDS
• Words to Know
• How HIV damages the immune system
• Methods of transmission
• Stopping the spread of AIDS
• AIDS therapies, vaccines, and a new treatment approach

Acquired immunodeficiency syndrome (AIDS) is a disease caused by the human immunodeficiency virus (HIV). HIV damages the immune system by attacking certain white blood cells called lymphocytes (specifically those called helper T cells). Lymphocytes normally help to protect the body against invading microorganisms. When these cells are destroyed, the body loses its ability to fight infection and becomes vulnerable to a variety of infections and rare cancers that are...