Seasonal surveillance of West Nile Virus infections – 2026 (Monthly report)

In 2026, and as at 3 September, countries in Europe have reported 1 086 locally acquired1 human cases of West Nile Virus (WNV) infection. The earliest and latest dates of symptom onset among human cases were 12 May in North Macedonia and 1 September in Austria, respectively. Locally acquired cases have been reported by Italy (516 cases), Greece (284 cases, of which 11 had an unknown place of infection), Spain (88 cases), Romania (56 cases), North Macedonia (55 cases), France (36 cases), Serbia (18 cases), the Netherlands (9 cases), Croatia (7 cases), Cyprus (6 cases), Austria (4 cases), Hungary (3 cases), Germany (2 cases), Albania (1 case) and Kosovo* (1 case). A total of 61 deaths have been reported by Italy (25 deaths), Greece (24 deaths), North Macedonia (7 deaths), Romania (2 deaths), Spain (2 deaths) and the Netherlands (1 death).

The number of human cases reported to date (1 086 cases) exceeds the average number reported during the same period over the past decade (736 cases), indicating intense WNV circulation this year. Moreover, reporting delays may result in an under-estimation of the current burden.

As at 3 September 2026, locally acquired human cases have been reported in 143 NUTS 3 regions across 15 countries, similar to the same point in 2025. However, 2024 remains the most geographically widespread WNV season on record, with 218 affected regions by the end of the season.

As in previous years, most cases were reported among males aged 65 years and above. Overall, 78% of cases were hospitalised and 60% presented with neurological symptoms, compared with 10-year averages of 87% and 65%, respectively. The case fatality rate was approximately 6%, below the 10-year average of 10%. These preliminary findings are within expected levels and do not indicate increased disease severity, although clinical outcomes are not yet available for all cases and additional deaths may be reported as the season progresses. Country-specific case fatality rates are affected by the sensitivity of the surveillance system, including screening practices of blood donors, therefore direct comparisons between countries should be made with caution.

From the veterinary perspective, 10 countries in Europe have reported 121 WNV outbreaks among equids and 280 outbreaks among birds in 2026. The earliest reported WNV outbreak among equids had a suspected start date of 30 March 2026 in France, while the most recent had a suspected start date of 29 August 2026 in Belgium. Outbreaks among equids have been reported by France (43 outbreaks), Italy (34 outbreaks), Belgium (14 outbreaks), Spain (9 outbreaks), Greece (8 outbreaks), the Netherlands (5 outbreaks), Austria (3 outbreaks), Croatia (3 outbreaks) and Germany (2 outbreaks). Among birds, the earliest reported WNV outbreak had a suspected start date of 31 March 2026 in Italy, while the most recent had a suspected start date of 31 August 2026 in Austria and Croatia. Outbreaks among birds have been reported by Italy (218 outbreaks), Belgium (26 outbreaks), Croatia (9 outbreaks), Spain (8 outbreaks), Austria (7 outbreaks), France (5 outbreaks), Germany (3 outbreaks), North Macedonia (3 outbreaks) and the Netherlands (1 outbreak). In addition, Switzerland submitted outbreak data to Animal Disease Information System (ADIS) for the first time in 2026, reporting one bird outbreak in Aargau (CH033).

Most affected European countries reported both human WNV infections and outbreaks in equids and/or birds. Albania, Cyprus, Hungary, Kosovo*, Romania and Serbia only reported human WNV infections, while Belgium only reported outbreaks among equids and birds. EU candidate countries are not required to report animal outbreaks through ADIS.

Differences in WNV patterns across European countries may reflect a combination of ecological, climatic and surveillance-related factors. Climatic conditions, habitat characteristics and the local abundance and distribution of competent mosquito vectors and bird hosts can influence WNV circulation. Differences in surveillance design, intensity, diagnostic practices and reporting may also affect the number of human infections and animal outbreaks detected.

A selection of country-specific findings is presented below to further illustrate the heterogeneity of WNV activity across Europe.

Italy

Italy remains the most affected country in 2026, reporting the highest number of WNV human cases (516, 48% of all reported human cases), including 25 deaths (case fatality rate: 4.8%). It also reported 34 outbreaks in equids (28% of all reported equid outbreaks) and 218 outbreaks in birds (78% of all reported avian outbreaks). Nevertheless, the number of human cases reported was lower than that reported during the same period in 2018, 2022 and 2025, based on consolidated data. The number of outbreaks in birds and equids reported to ADIS in 2026 was comparable to that reported during the same period in 2025, slightly lower than in 2024, and higher than in 2018 and 2022. Overall, 67 of Italy’s 107 NUTS 3 regions are currently affected, with WNV human cases and/or animal outbreaks reported.

Greece

Greece has reported its highest number of human WNV cases for this time of year, with 284 cases, including 24 deaths (case fatality rate: 8.5%). WNV transmission is currently most intense in the Attica NUTS 2 region, which accounts for 162 cases, with the highest numbers reported in Anatoliki Attiki (East Attica, 86 cases) and Voreios Tomeas Athinon (North Athens, 48 cases). Despite accounting for 26% of all reported human cases in Europe, Greece has reported only eight outbreaks in equids, representing 5.5 % of all reported equid outbreaks, and no outbreaks in birds.

The Netherlands

Nine human WNV infections have been reported in the Netherlands, including one death. These are the first human cases reported in the Netherlands since 2020, when the country documented its first-ever locally acquired human WNV infections, with seven cases reported in Utrecht (previously NL310) and one in the Arnhem/Nijmegen region (NL226). In addition, five outbreaks in equids and one in birds were reported in 2026. WNV was first reported in equids in the Netherlands in 2025. Overall, WNV infections in humans and/or animals were detected across eight NUTS 3 regions this year.

Belgium

WNV was first detected in Belgium in 2025 through avian surveillance, having no previous detections reported in humans or animals. That year, seven bird outbreaks were reported in Arr. Mechelen (BE212), Arr. Dendermonde (BE232), and Arr. Halle-Vilvoorde (BE241). In 2026, WNV was again detected in birds in these three regions and in five previously unaffected regions. To date, Belgium has not reported any human WNV infections. However, the ongoing circulation of the virus in animals, with 14 outbreaks among equids and 26 outbreaks among birds reported across eight NUTS 3 regions, is indicative that there is a risk for human infections to occur.

North Macedonia

North Macedonia is reporting an unprecedented number of human WNV infections, with 55 cases and seven deaths (case fatality rate: 13%) reported from three NUTS3 region. Two of these regions have also reported outbreaks among birds. The Skopski region, which includes the capital city of Skopje, is by far the most affected, accounting for 53 human WNV infections and three bird outbreaks. In 2026, North Macedonia reported WNV outbreak data to ADIS for the first time, with three bird outbreaks across two regions. In the past decade, the country had reported a maximum of five human WNV infections per year.

More information

The full monthly epidemiological report on human and animal surveillance data including maps and graphs is available at: Monthly updates: 2026 West Nile virus transmission season (europa.eu).

Updated figures on human WNV infections are published weekly at: (Weekly updates: 2026 West Nile virus transmission season (europa.eu).

More background information on the Commission Directives on blood safety and EU/EEA notifications of WNV infections can be found here.

ECDC is monitoring WNV infections through indicator- and event-based surveillance activities.