Acquired Immune Deficiency Syndrome (AIDS) is a deadly disease caused by Human Immuno-deficiency virus (HIV). AIDS is a sexually-transmitted disease that currently has no cure. As of December of 2000, approximately 36.1 million people have been infected with HIV. It is approximated that 21.8 million people have died since outbreak of the disease.

It has been proposed that HIV has been transferred to human race from a certain species of chimpanzee. Such "cross-over" could have occured during blood-to-blood interactions from hunting. As it is one of the most dangerous epidemics, researchers are eager to find its cure.