Association of age and gender with alphaherpesvirus infections of the central nervous system in the immunocompetent host

Background: The alphaherpesviruses Varicella-zoster virus (VZV) and human herpes simplex virus types 1 (HSV-1) and 2 (HSV-2) can cause severe infections of the central nervous system (CNS). Objectives: To analyze whether age and gender of immunocompetent individuals are associated with the incidence of herpesvirus CNS diseases. Study design: A total of 241 patients with virologically confirmed HSV-1, HSV-2 or VZV-infection of the CNS (excluding neonatal infection and varicella), diagnosed at the Department of Virology, Medical University Vienna, from 2001 to 2009 were analyzed retrospectively. The relative incidence of disease was evaluated statistically with respect to gender and age. Results: The relative incidence of VZV CNS disease increased with age (p < 0.0001), and nonlinear age dependences were observed for HSV-1 (p = 0.005) and HSV-2 disease (p = 0.002). These effects were influenced significantly by the patient's gender in VZV (p = 0.0003) and HSV-1 disease (p = 0.008). Overall, 50.7% of VZV infections in males, but only 23.5% of those in females, occurred before age 45, and 28.9% of HSV-1 infections in males and 8.8% of those in females occurred before age 30. Women represented 71.9% of HSV-2 CNS infections (p = 0.02). Conclusions: The patient's gender is clearly associated with the incidence of CNS disease caused by VZV, HSV-1 and HSV-2, and its influence varies over one's lifetime. (C) 2012 Published by Elsevier B. V.