Introduction and Nomenclature
Varicella virus causes two distinct clinical conditions, chickenpox and herpes zoster. Chickenpox, as varicella is commonly known, is a highly infectious disease which, when introduced by either chickenpox or herpes zoster cases, spreads rapidly in a susceptible population. On the other hand, epidemiological studies have failed to show that herpes zoster is acquired by contact with other cases of herpes zoster or cases of chickenpox. The sporadic occurrence of zoster has led to the hypothesis that this disease represents a reactivation of a latent infection following chickenpox.