herpes (n.)

late 14c., "any inflammatory, spreading skin condition" (used of shingles, gangrene, etc.), from Latin herpes "a spreading skin eruption," from Greek herpes, the name for the disease shingles, literally "creeping," from herpein "to creep, move slowly" (cognate with Latin serpere "to creep;" see serpent). The condition was not distinguished into specific diseases until early 19c.