West Nile virus in Europe in 2020 - infections among humans and outbreaks among equids and/or birds, updated 17 September 2020

Between 11 and 17 September 2020, EU Member States reported 36 human cases of WNV infection: Greece (18), Spain (12), Italy (3) and Hungary (3). All cases were reported from areas that have been affected during previous transmission seasons. This week, six deaths were reported, by Greece (4) and Spain (2). No human cases of WNV infection or deaths were reported from EU neighbouring countries.

On 16 September 2020, Dutch public health authorities reported the first animal, a warbler that tested positive for WNV in the Netherlands, in the Utrecht region. Warblers are migratory birds, but because this warbler was tested positive in late summer, it is very likely that it contracted WNV in the Netherlands. The same bird was also caught in the spring and had tested negative. In recent years, antibodies have been found in several birds in the Netherlands. As these were not migratory birds, they probably contracted the infection in the vicinity of the Netherlands.

Since the start of the 2020 transmission season and as of 17 September 2020, EU Member States have reported 209 human cases of WNV infection and 21 deaths through TESSy: Greece (109, including 16 deaths), Spain (61, including five deaths), Italy (32), Romania (4) and Hungary (3). All cases were reported from areas that have been affected during previous transmission seasons. No cases have been reported from EU-neighbouring countries.

On 3 September 2020, German public health authorities reported the first human autochthonous WNV infections in Germany during this transmission season. On 10 September, further human WNV infections were reported. A total of nine were reported, from Leipzig (7), Meissen (1) and Berlin (1). Further suspected cases are being investigated. Virus circulation in birds has been documented since July 2020 in Germany, in a similar area as in 2019. The human WNV infections and outbreaks among birds in 2020 have not been reported through TESSy and the Animal Disease Notification System (ADNS) yet. As a result, they are not currently represented on the maps and in the Surveillance Atlas.

Since the beginning of the 2020 transmission season, 69 outbreaks among equids have been reported. These outbreaks have been reported by Spain (51), Italy (8), Germany (8), France (1) and Portugal (1) through ADNS. No outbreaks among birds have been reported through ADNS.