Deadly West Nile virus sweeps Europe as southern Mediterranean expects heat dome

A deadly surge of the West Nile virus is sweeping across Europe, with southern Mediterranean nations bracing for a potential heat dome. Recent data from the European Centre for Disease Prevention and Control shows a nearly 50% increase in West Nile virus cases compared to last year. Italy and Greece account for three-quarters of these cases.

The virus is also spreading northwards, with a fatal case reported in the Netherlands. The virus, primarily transmitted through mosquito bites, can lead to severe illness in around one in 150 infected individuals, according to the World Health Organisation. Warmer temperatures are enabling mosquitoes to expand their range and transmission areas, according to the WHO.

Currently, 99 areas in 12 European countries are affected by the virus, with 67 areas in eight countries impacted in August 2025. Infection rates are high, with 46 cases reported in Italy, 17 in Greece, 14 in Romania, and 8 in France. The Culex mosquito is the primary carrier, while the Asian tiger mosquito, also capable of spreading dengue fever, has made inroads in Europe since the early 2000s.

German authorities reported two fatal cases among airport workers who contracted the virus from the Anopheles mosquito, despite no travel history to malaria-risk regions. Experts attribute the outbreak's size to heat, which is prevalent in Europe, the world's fastest-warming region. The continent has experienced a scorching summer resulting in over 35,000 excess deaths, with France, Spain, and Germany alone reporting 25,000 excess fatalities.

In Italy, temperatures are forecasted to soar to 37°C in Rome and 46°C in Sicily, while Greece is bracing for a heatwave with temperatures reaching 40°C in the north.