Aseptic meningitis and encephalitis because of herpesviruses and enteroviruses in an immunocompetent adult population

Human herpesviruses (HHVs) and enteroviruses (EVs) are the major causative agents of CNS viral infections. The aim of the study was to identify the etiology and determine the frequency of aseptic meningitis and encephalitis due to HHVs and EVs in an immunocompetent adult population. Eighty-one patients (ages >= 15) with aseptic meningitis or encephalitis treated in the Infectious Diseases Hospital of Thessaloniki, Greece, during 2003-2006, were included in the study. Polymerase chain reaction for detection of herpes- and enterovirus genome direct in cerebrospinal fluid samples was performed. Based on clinical and laboratory data, 36/81 patients had meningitis and 45/81 had encephalitis. Etiology was defined in 11 patients (31%) with aseptic meningitis. EVs were the major causative agents (8/36, 22%), followed by varicella zoster virus (2/36, 5%) and herpes simplex virus-2 (HSV-2) (1/36, 3%). Etiology was identified in 8 of 45 (18%) patients with encephalitis, EV (4/45, 9%) and HSV-1 (4/45, 9%) being the most common pathogens. Enteroviruses are the most common cause of adult aseptic meningitis and together with HSV-1 the main causes of encephalitis.