Viral infections of the central nervous system in elderly patients: a retrospective study

Objectives: Very few data exist on viral meningitis and encephalitis in elderly patients (>65 years old). Methods: This study investigated the detection of herpes simplex virus (HSV), varicella zoster virus (VZV), human herpes virus 6 (HHV-6), HHV-7, HHV-8, cytomegalovirus (CMV), Epstein–Barr virus (EBV), enterovirus (EV), human adenovirus (HAdV), human parechoviruses (HPeVs), and tick-borne encephalitis virus (TBEV) through real-time PCR (RT-PCR) in patients >65 years old who had cerebrospinal fluid (CSF) tested for a suspected central nervous system infection. Results: A total of 2868 RT-PCRs were performed on 502 CSF samples. Overall, 65 positive RT-PCRs were found: 23 for HSV (35.4% of positives), 15 for EV (23.1% of positives), 14 for EBV (21.5% of positives), 12 for VZV (18.5% of positives), and one for CMV (1.5% of positives). A positive RT-PCR in CSF was detected in 24 (17.4%) patients aged ≥80 years and in 35 (9.6%) patients aged 65–79 years (p = 0.02). VZV was more frequently detected in the oldest subjects (5.9% vs. 1.6%, p = 0.03). Conclusions: HSV was the most common viral aetiology identified in the study, with VZV infection being recognized more frequently in those patients aged ≥80 years.