Emerging West Nile virus infections in Türkiye.

PURPOSE: Türkiye experienced its largest West Nile virus (WNV) infection outbreak in 2024. We described the clinical and laboratory features of human cases with WNV infection collected from eleven tertiary hospitals in Türkiye in 2024.

METHODS

The clinical characteristics of the patients were gathered using a structured form in the retrospective study. According to the ECDC case definition of WNV infections, the patients were classified as 'confirmed' or 'probable' cases. The odds ratio (OR) and 95% confidence interval (CI) for possible mortality predictors in WNV infections were calculated using multivariate logistic regression analysis. p < 0.05 was considered statistically significant.

RESULTS

The mean age of the 51 patients was 63.3 ± 13.6 years, and 37 (72.5%) were male. Twenty-six cases (51%) were confirmed, and 49% were probable WNV infection. Forty-eight patients (94.1%) had WNV neuroinvasive disease: 24 (47%) were diagnosed with meningoencephalitis, 20 (39.2%) with encephalitis, one (2%) with meningitis, and seven (13.7%) with acute flaccid paralysis. Twenty patients (39.2%) had movement disorders (tremor, myoclonus, bradykinesia, or rigidity). The case fatality rate was 17.6%. In multivariate analysis, older age (OR: 1.09, CI: 1.03-1.19, p = 0.042) and secondary bacterial infection during hospitalization (OR: 10, CI: 1.55-64.95, p = 0.015) were associated with fatality.

CONCLUSION

We highlighted the increasing number of cases and diagnostic challenges by describing the highest number of the patients with WNV infections in Türkiye. Raising awareness among healthcare professionals, facilitating access to diagnostic tests, and developing rapid, reliable, and easily applicable tests would enable early diagnosis and help improve outcomes.