West Nile virus neuroinvasive disease and cardiac involvement in critically ill patients in central Italy: a case series.

Introduction: West Nile virus (WNV) infection represents an emerging health concern in Southern Europe. Although most infections are asymptomatic, a small proportion progress to WNV neuroinvasive disease (WNND), occasionally complicated by cardiac involvement. Data describing critically ill patients with WNND and cardiac involvement requiring intensive care (ICU) are limited. Methods: We conducted a two-month observational case-series of consecutive adult patients with confirmed WNND admitted to the ICUs of two tertiary hospitals in Lazio region, Italy from July 1 to September 1, 2025. Clinical, laboratory, imaging, and outcome data were collected, with particular focus on neurological and cardiac manifestations. Results: Among 197 patients with confirmed WNV infection, 64 (32%) had WNND, of whom 12 (6.1%) required ICU admission. These 12 patients were subsequently enrolled in the study. The median age was 76.5 years (IQR 70-83), and 75% were male. The most common symptoms were fever, myalgia, and gastrointestinal complaints, followed by confusion, limb weakness, and psychomotor slowing. Cerebrospinal fluid analysis showed lymphocytic pleocytosis (median 135 cells/mm Conclusion: WNND remains a life-threatening condition requiring multi-disciplinary critical care. Cardiac involvement, including suspected myocarditis, was observed in a substantial proportion of critically ill WNND patients and occurred more frequently among non-survivors in this cohort. Although descriptive, these findings highlight the importance of early neuro-cardiac assessment and comprehensive supportive management to optimize outcomes in severe WNND.