primary infection with varicella- zoster virus (vzt) results in chickenpox, characterized by viremia with a diffuse rash and seeding of multiple sensory ganglia, where the virus establishes lifelong latency. hepes zoster is caused by reactivation of latent vzt in cranial-nerve or dorsal-root ganglia,with spread of the virus along the sensory nerve to the dermatome. There are more than 1 million cases of herpes zoster in the United states each year, with an annual rate of 3 to 4 cases per 1000 persons.