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

Since the beginning of the 2023 transmission season and as of 31 May 2023, EU/EEA countries have reported no human cases of WNV infection. EU-neighbouring countries also have reported no human cases of WNV infection.

Since the beginning of the 2023 transmission season, one outbreak among birds has been reported by Italy (on 12 May, in Varese).


Data on human cases are collected via The European Surveillance System (TESSy) managed by ECDC. Only locally acquired cases with known place of infection are included in this report. The following EU-neighbouring countries report human cases of WNV infection to ECDC: Albania, Kosovo*, Montenegro, North Macedonia, Serbia and Türkiye.

Animal data (i.e. outbreaks among equids and birds) are collected through the Animal Disease Information System (ADIS) of the European Commission. Reporting of WNV in equids and birds is mandatory at the EU/EEA level.

The distribution of human infections covers EU/EEA and EU-neighbouring countries, whereas outbreaks among equids and birds covers only EU/EEA countries.

* This designation is without prejudice to positions on status, and is in line with UNSCR 1244/1999 and the ICJ Opinion on the Kosovo declaration of independence

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 2 Jun 2023