As Europe warms, Italy sees West Nile virus spread

Francesco Severino, a senior researcher in medical entomology, places a net over a cage containing mosquitoes inside a laboratory at the Italian National Institute of Health in Rome, Friday, Sept. 18, 2026. Gregorio Borgia/AP hide caption toggle caption Gregorio Borgia/AP Italian health authorities see evidence that rising temperatures and longer warm seasons are helping mosquitoes spread West Nile virus across a wider area, during more months of the year. More than 650 infections have been reported in Italy so far this year, accounting for roughly half of all cases recorded in Europe, according to local health authorities. "Higher temperatures linked to climate change help mosquitoes reproduce and extend the transmission season, increasing the chances that infected mosquitoes will spread the virus to people," said Antonino Bella, researcher at Italy's National Institute of Health, or ISS. West Nile has been considered endemic in Italy since 2020, when cases started to surge, and is now reported every summer and early fall. About 80% of infected people develop no symptoms, while most others experience a mild flu-like illness. Severe neurological complications occur in a small minor...