varicella zoster virus (VZV) [L, varius, diverse; Gk, zoster, girdle; L, virus, poison] , a member of the herpesvirus family, which causes the diseases varicella (chickenpox) with primary infection and herpes zoster (shingles) of the virus reactivator. The virus has been isolated from vesicle fluid in chickenpox, is highly contagious, and may be spread by direct contact or droplets. Dried crusts of skin lesions do not contain active virus particles. Herpes zoster is produced by reactivation of latent varicella virus, usually several years after the initial infection. There is no simple test for measuring antibodies to this virus. However, zoster immune globulin (ZIG) obtained from convalescing zoster patients will prevent varicella in susceptible children if injected within 3 days of their exposure. The temporary nature of this protection and the relative scarcity of ZIG warrant reservation of its use to children receiving immunosuppressive therapy or suffering from immune deficiency diseases. Herpes zoster should be treated promptly with acyclovir, desciclovir, valaciclovir, or penciclovir to speed healing. (Famciclovir is used for postherpetic neuralgia.) A licensed vaccine is available and highly effective. See also chickenpox, herpes zoster.
