WNV transmission season in Europe, 2021

On 24 March 2022, the European Centre for Disease Control and Prevention (ECDC) published an annual update on West Nile virus (WNV) cases reported during the 2021 transmission season. The update found that, as of 10 February 2022, there were 164 reported human cases of WMV infection, which included 13 deaths, across the EU, EEA and EU-neighbouring countries in 2021, of which 159 were locally acquired and five were travel related. 

During the 2021 transmission season, EU and EEA countries reported 139 locally acquired human cases of WNV infection with known place of infection, including 10 deaths, through the European Surveillance System (TESSy), with the vast majority of the cases being reported by Greece and Italy. Greece further reported two additional locally acquired human cases with unknown place of infection, and also recorded eight of the ten deaths reported. 

Human WNV infections were reported in seven EU member states and in one EU-neighbouring country (which included three deaths), where seasonal circulation of the virus had been previously reported. Burgenlandkreis and Spree-Neisse in Germany and La Spezia in Italy reported locally acquired human cases of WNV infection for the first time, with all other cases reported through TESSy being from areas that had been affected during previous transmission seasons. 

The first locally acquired case of the season in the EU was notified by Italy in week 26 (26 June to 4 July), with disease two weeks earlier, while the last case was reported by Greece in week 45 (8 to 14 November), with disease onset again two weeks earlier. 

Animal data are collected through the Animal Disease Information System (ADIS) of the European Commission. The distribution reports for WNV outbreaks among equids and birds cover only EU and EEA countries, with seven countries reporting 43 outbreaks among equids during the 2021 transmission season. In addition, eight outbreaks among birds were reported in two countries. 

Source: ECDC, 24 March 2022