Weekly updates: 2023 West Nile virus transmission season


This weekly report provides an overview of West Nile virus (WNV) epidemiology in the EU/EEA and EU-neighbouring countries during the WNV transmission season (expected to be June-November). Following a One Health approach, WNV infections in humans and outbreaks in equids and birds are included in the report. For more information, visit the dedicated webpages on WNV infections and ECDC’s seasonal WNV surveillance.

Epidemiological summary

Updated on 15/12/2023 

This is the final update for the season, concluding the publication of the weekly seasonal WNV updates.

Since last week’s update, and as of 13th December 2023, European Union (EU) and European Economic Area (EEA) countries reported no human cases of West Nile virus (WNV) infection. EU-neighbouring countries also reported no human cases of WNV infection.

Since the beginning of the 2023 transmission season and as of 13th December 2023, EU/EEA countries have reported 707 human cases of WNV infection in Italy (336), Greece (162, of which 1 with unknown place of infection), Romania (103), France (43), Hungary (29), Spain (17), Germany (6), Croatia (6) and Cyprus (5). EU/EEA countries have reported 67 deaths in Italy (29), Greece (23), Romania (12) and Spain (3). EU-neighbouring countries have reported 93 human cases of WNV infection in Serbia (91) and North Macedonia (2) and 2 deaths in Serbia (2).

During the current transmission season, within the reporting countries, autochthonous human cases of WNV infection were reported from 141 different NUTS 3 or GAUL 1 regions, of which the following regions reported autochthonous human cases of WNV infection for the first time ever: Gironde, Charente-Maritime, Alpes-Maritimes, Charente and Haute-Corse in France, Sömmerda in Germany, Kastoria and Ioannina in Greece, Imperia, Taranto, Lecce, Cosenza, Bari, Salerno and Verbano-Cusio-Ossola in Italy, Gorj and Timiş in Romania, Cáceres, Huelva, Valencia/València, Barcelona and Toledo in Spain.

Since the beginning of the 2023 transmission season, and as of 13th December 2023, 152 outbreaks among equids and 247 outbreaks among birds have been reported by EU/EEA countries. Outbreaks among equids have been reported by France (44), Spain (37), Hungary (26), Italy (25), Germany (14), Portugal (5) and Austria (1). Outbreaks among birds have been reported by Italy (196), Germany (19), Spain (19), Bulgaria (6), Hungary (3), France (2), Austria (1) and Greece (1).

The latest date of onset reported as of 13th December 2023 was on 5th November 2023. As the weather conditions in most of the affected regions has become unfavourable and considering the current epidemiological situation, we have decided to conclude the publication of the weekly West Nile virus epidemiological updates for this season. Please be aware that the cases reported in this update are as of December 13, 2023.  This page will not be providing any more updates on this regard for the 2023 season.

Interactive dashboard

The interactive dashboard is available following the “View in full screen” link further below.

Download the data

Download the weekly data set for West Nile virus epidemiology.

Download weekly WNV data


Case definition

EU case definition for diagnosing and reporting West Nile virus infection, under Decision No 2119/98/EC of the European Parliament and of the Council.

See West Nile virus infection

ECDC publishes weekly WNV epidemiological updates during the WNV transmission season, including the geographical distribution of human cases in the EU/EEA and EU neighbouring countries. In addition, ECDC includes maps in its epidemiological updates highlighting areas where WNV outbreaks among equids have been reported. Read more

Page last updated 8 Dec 2023