Overview

• Europe has recorded 27 chikungunya outbreaks in 2025, with Aedes albopictus now established in 16 countries and 369 regions and a first locally acquired case confirmed in France’s Alsace.
• West Nile virus infections have been reported in eight countries and are at their highest level in three years, with first-time detections in Italy’s Latina and Frosinone provinces and Romania’s Sălaj County.
• ECDC expects West Nile activity to continue rising toward an August–September peak and urges intensified monitoring during the late-summer high-risk period.
• Updated ECDC guidance provides practical toolkits for surveillance, prevention and control of chikungunya, dengue and Zika, with a separate document for West Nile virus tailored to varying national readiness.
• ECDC calls for strengthened vector control, heightened clinical vigilance and personal protection, noting new chikungunya vaccines exist while no licensed human vaccine is available for West Nile virus.