Epidemiology of Herpes Simplex and Varicella Zoster Virus-Associated Central Nervous System Infections in Western Greece: A Five-Year Retrospective Analysis

The epidemiology of central nervous system (CNS) infections caused by herpesviruses varies with host factors and geographic distribution. Timely diagnosis and therapeutic intervention are life-saving. This study investigated the epidemiology of herpesvirus CNS infections in Western Greece, compared clinical and laboratory findings with international data and evaluated an internal laboratory algorithm for cerebrospinal fluid (CSF) molecular testing criteria. During the study period, 940 of 4300 CSF samples met eligibility criteria for RT-PCR detection of <i>herpes simplex virus</i> (HSV-1, HSV-2) and varicella zoster virus (VZV). Of these, 53 (5.63%) were positive: 37 VZV, 9 HSV-1, and 7 HSV-2. HSV-2 cases occurred in younger patients (median age 41) and had the highest CSF white blood cells (WBC) counts (231/mm³), followed by VZV (125/mm³) and HSV-1 (26/mm³). CSF protein was higher in HSV-2 infections. Magnetic resonance imaging (MRI) was the most sensitive imaging modality for detecting CNS inflammation. These results indicate VZV as the predominant herpesvirus in this region, underscoring the need for high clinical suspicion in older patients and timely molecular diagnosis.