Touch

The Touch was an extremely contagious disease on P3X-797. By being touched by people having the disease, he or she is also a victim of the sickness.

The Untouched were the people not affected by the disease. The lived on the light side of the planet. When there was but any indication that somebody was Touched, he or she was immediately brought to the dark side to preserve the Untouched.

The Touch was stopped by SG-1 in 1997 and henceforth, everybody was Untouched again.