Clinical Significance

Varicella (chicken pox) is an acute, highly contagious viral disease with worldwide distribution, seasonal prevalence in winter and spring, characterized by generalized vesicular exanthema often accompanied by fever. While mostly a mild disorder in childhood, varicella tends to be more severe in adults and it may be fatal, especially in neonates and in immunocompromised subjects. Varicella-zoster virus (VZV), a Herpesviridae, is the causative agent of the disease that shows little genetic variation (only one serotype is known). Following primary infection, the virus remains latent in neural ganglia, and upon subsequent reactivation VZV may cause zoster (shingles), a disease mainly affecting the elderly and immunocompromised persons, that consists in painful, circumscribed eruption of vesicular lesions with
inflammation of associated dorsal root or cranial nerve sensory ganglia. IgM antibodies to varicellazoster virus may be detected during primary and reactivated infection.
Evaluation of specific immune status for VZV may guide management of immunosuppressed patients and administration of antiviral agents. Varicella infection occurring in susceptible pregnant women can lead to severe, and even fatal, disease of the newborns. Infection occurring in the first four months of pregnancy can lead to child deformity, while infection at the time of delivery may cause life-threatening infection in newborns. Although individual cases may be prevented or modified by VZV immunoglobulin administration or treated with antiviral drugs, varicella can be controlled only by vaccination.