Loading ...

The European Centre for Disease Prevention and Control (ECDC), headquartered in Stockholm, Sweden, warned that the record number of West Nile virus (WNV) and chikungunya outbreaks reported in a year signals a “new normal” for Europe.

The agency stated that the situation demanded a coordinated response across the continent to prevent further spread and protect vulnerable populations.

“Europe is entering a new phase — where longer, more widespread, and more intense transmission of mosquito-borne diseases is becoming the new normal. The ECDC is working closely with all Member States to provide tailored support and timely public health guidance to strengthen Europe’s response,” said Pamela Rendi-Wagner, MD, director at the ECDC, in a press release.

Experts have linked this shift to climatic and environmental factors such as rising temperatures, longer summer seasons, milder winters, and changes in rainfall patterns, which combine to create a favourable environment for mosquitoes to thrive and transmit viruses.

WNV Cases

According to the ECDC epidemiologic update of 13 August, eight European countries reported 335 locally acquired human WNV infections, including 19 deaths, all in Italy. Italy remains the most affected country, with 274 confirmed cases, followed by Greece (35), Serbia (9), France (7), Romania (6), Hungary (2), and Bulgaria and Spain (1 each).

The Istituto Zooprofilattico Sperimentale dell’Abruzzo e del Molise, reporting for Italy’s Istituto Superiore di Sanità, confirmed 102 new WNV cases in the country between 7 and 13 August. Overall, 126 patients progressed to neuroinvasive disease, which carries a higher risk for death and long-term complications. Most cases have been reported in Campania (50) and Lazio (47), with fewer cases in Lombardy, Piedmont, Veneto, Emilia-Romagna, Calabria, Sardinia, Basilicata, and Friuli Venezia Giulia.

Nineteen deaths were recorded: eight in Lazio and Campania and one each in Piedmont, Lombardy, and Calabria. The case fatality rate among confirmed neuroinvasive cases was approximately 15%, which is consistent with previous outbreaks.

Animal surveillance has also confirmed the circulation of the WNV across multiple regions, with positive findings in horses, mosquitoes, and resident and migratory birds. The active hot spots in Italy include Molise, Sicily, Veneto, Piedmont, Sardinia, Emilia-Romagna, Puglia, Abruzzo, Lazio, Campania, and Lombardy.

Chikungunya Surge

France reported more chikungunya cases than Italy, with 111 vs 7 cases. Most of these cases have been linked to outbreaks in southern and southeastern France.

The mosquito vector Aedes albopictus is now firmly established in 16 European countries and 369 regions compared with 114 regions a decade ago.

Europe has already recorded 27 chikungunya outbreaks in 2025, the highest number recorded to date. For the first time, a locally acquired case was confirmed in Alsace, Strasbourg, France, at a latitude previously considered too cold for transmission.

In Italy, locally acquired chikungunya cases were reported for the first time in Latina and Frosinone, which are south of Rome.

Romania also reported its first case in Sălaj County in the northwest. The ECDC projected that infections would continue to increase, with seasonal peaks expected in August and September.

ECDC Guidance

In response, the ECDC issued detailed recommendations for the surveillance, prevention, and control of chikungunya, dengue, and Zika.

These guidelines are particularly important for countries with limited or no prior experience in managing mosquito-borne diseases, which until recently were seen as tropical threats.

“As the mosquito-borne disease landscape evolves, more people in Europe will be at risk in the future. This makes prevention more important than ever, both through coordinated public health actions and personal protection measures. There is an urgent need to strengthen and scale up efficient, environmentally friendly mosquito control interventions,” said Céline Gossner, PhD, head of Section Food-, Water-, Vector-borne and Zoonotic Diseases at ECDC.

The ECDC encourages individuals living in affected areas and visitors, especially older adults, children, and people with weakened immune systems, to protect themselves against mosquito bites by using mosquito repellents; wearing long sleeves and trousers, especially at dawn and dusk; and using window screens, bed nets, and air conditioning or fans.

Healthcare professionals should be aware of the circulation of these viruses to ensure early diagnosis.

This story was translated from Univadis Italy.