West Nile Virus Neuroinvasive Disease: A Retrospective Analysis of Hospitalized Cases in a Tertiary Care Center in Southern Europe.

BACKGROUND

West Nile virus (WNV) is a flavivirus primarily transmitted by mosquitoes of the Culex genus and is endemic to Southern Europe. Although infection is usually asymptomatic, it can lead to neuroinvasive syndromes with high morbidity and mortality. Due to the increasing incidence driven by climatic factors, we present a single-center series examining short- and long-term functional outcomes after infection.

METHODS

Patients with neurological symptoms and confirmed WNV infection through serology and/or detection in urine and/or cerebrospinal fluid (CSF) between 2017 and 2023 were included. Data on demographics, medical history, symptoms, diagnostic workup, treatment, and prognosis at discharge, 12 months, and 24 months were analyzed. Patients were categorized based on whether they required intensive care unit (ICU) admission, CSF biochemistry, and treatment employed, among other factors.

RESULTS

Forty patients with a median age of 65 years (45% female) were included; 8% were immunosuppressed. Fever was present in 95%, and 85% experienced prodromal symptoms. Altered consciousness (73%) was the most common neurological symptom. ICU admission was required in 33% of cases, and mechanical ventilation in 25%. In-hospital mortality was 15%. At 24 months, 48% maintained good functional status, with a median follow-up of 35 months. Diagnostic and therapeutic interventions did not influence prognosis.

CONCLUSIONS

Although neuroinvasive WNV disease is rare, it carries significant morbidity and mortality, with no specific therapeutic measures impacting outcomes. Prioritizing efforts to control infection spread is critical.