Characteristics and clinical outcomes of the West Nile virus outbreak in Israel 2024: A retrospective cohort study

Abstract

Background: In 2024, Israel experienced its largest West Nile virus (WNV) outbreak in two decades, with over 930 cases and 72 deaths, revealing unique epidemiological patterns.

Aim: To describe the clinical features, outcomes, and risk factors for poor hospitalization outcomes in patients with WNV infection during this outbreak.

Methods: A retrospective cohort study of WNV-infected patients admitted to Rabin Medical Center (RMC) during the year 2024. Data from electronic medical records were analyzed. A regression model was employed to identify risk factors associated with poor outcomes.

Results: We included 177 patients. Their median age was 77 years, and 72 (41 %) were female. Fever (82 %), altered mentation (62 %), malaise (62 %), thrombocytopenia (44 %), acute renal failure (38 %), and lymphopenia (36 %) were common. West Nile neuroinvasive disease (WNND), primarily encephalitis (41 %), was diagnosed in 89 (50 %) patients. The median hospital stay was 7 days, with 22 (12 %) in-hospital deaths. Risk factors for mortality included a history of stroke, WNND, acute renal failure, and lymphopenia. Among survivors, 45 (29 %) were discharged for rehabilitation or long-term care facilities.

Conclusions: These findings highlight the clinical severity of WNV infections during the outbreak and underscore the importance of identifying high-risk patients to guide management and public health strategies.

Keywords: Israel; Neuroinvasive disease; West Nile fever; West Nile virus.