Aids is a serious condition adversely affecting the body's ability to combat infection. A person is diagnosed with AIDS when that person develops a life-threatening illness not normally found in those with healthy immune systems. The two primary diseases affecting those with AIDS are Pneumosistis Carinii Pneumonia (PCP) and Kaposi's Sarcoma (KS), a rare cancer-type illness. It is these opportunistic infections—and several less common ones—which are the causes of deaths attributed to AIDS.