I.

Introduction

Herpes (Greek herpein, “to creep”), name applied to several types of skin eruptions characterized by formation of blisters. The term embraces primarily two distinct disorders, herpes simplex and herpes zoster, both caused by types of herpes viruses. Other herpes viruses include Epstein-Barr virus, the cause of infectious mononucleosis (see Mononucleosis, Infectious) and cytomegalovirus, which can lead to birth defects when the virus invades pregnant women. Together, these viruses are estimated to cause more human illnesses than any other group of viruses.