Epidemiological update: West Nile fever in Europe - Number of infections so far exceeds the total number in the previous five years

In 2018, as of 20 September 2018, 1 505 confirmed and probable locally acquired human WNV infections were reported by European countries. EU/EEA Member States reported 1 135 human cases in Italy (453), Greece (225), Romania (216), Hungary (167), Croatia (36), France (16), Austria (15), Bulgaria (4) and Slovenia (3). EU neighbouring countries reported 370 human cases in Serbia (286), Israel (81) and Kosovo** (3). To date, 115 deaths due to West Nile virus infection have been reported by Italy (35), Serbia (29), Romania (25), Greece (24), Hungary (1) and Kosovo** (1).

The case fatality ratio (CFR) in 2018 has not exceeded the CFR in the previous two years (7.6% in 2018 compared with 11.1% in both 2016 and 2017). The proportion of cases with West Nile neuroinvasive disease (WNND) among symptomatic cases is lower than the previous two years (70% in 2018 compared with 82% in 2017 and 86% in 2016).

All human cases reported during the current transmission season were in previously affected countries. The assessment of the transmission risk in the EU/EEA as stated in ECDC’s rapid risk assessment published on 13 August 2018 remains valid. Personal protection from mosquito bites is advisable for any person residing in or visiting affected areas, especially the elderly and immunocompromised who are at higher risk of developing severe symptoms.

Figure 1. Number of West Nile fever cases in EU/EEA and EU enlargement countries by epidemiological week of notification, 2014 to 2018, as of 20 September 2018