In 2025, and as of 6 August 2025, 6 countries in Europe reported 202 locally acquired1 human cases of WNV infection with known place of infection. The earliest and latest date of onset were respectively on 2 June 2025 and 2 August 2025. Locally acquired cases were reported by Italy (168), Greece (26), France (3, of which 1 with unknown place of infection), Romania (3), Bulgaria (1) and Hungary (1). In Europe, 10 deaths were reported. Case numbers reported so far this year are slightly above the average for the past decade in the same period (163). However, these figures remain lower than those seen in 2024 and 2018—years when virus circulation was particularly intense, with 382 and 385 cases reported by this point in the year, respectively. As of 6 August, locally acquired human cases of West Nile virus (WNV) infection have been reported in 40 regions across six countries. This compares with 108 regions (11 countries) during the same period in 2024 and 68 regions in 2018 (seven countries). All six countries have previously reported human cases of WNV. Italy is currently experiencing a significant outbreak, with 168 confirmed human infections, including 10 fatalities. For the first time in Italy, the provinces of Latina (ITI44) and Frosinone (ITI45) have reported human cases. Similarly, Romania has reported its first cases in Sălaj County (RO116). As observed in previous years, most cases were among males aged 65 years and older. The hospitalisation rate was high compared with previous years, with 100% of cases hospitalised this year compared to 93% in the past decade. That most cases are hospitalised is most likely due to the nature of WNV surveillance, which tends to predominantly capture the most severe cases. The case fatality rate so far this year is 7%, which is comparable to the 11% observed in the previous decade. Neurological manifestations were reported in 56% of cases this year compared to 66% in the previous decade. In general, a dominance of neurological cases is expected, as cases with more severe symptoms are more likely to be diagnosed.
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