West Nile virus cases rise sharply in France

Public Health France (SPF) reported a significant increase in West Nile virus infections, with 17 new cases recorded on October 19, raising the total to 195 as of that date. This number is more than three times the total number of cases reported for the entire year of 2025, which had already been a record with 62 cases.

Surveillance continues through November

Enhanced monitoring of arboviruses, including West Nile, continues in France until the end of November. While the infection is usually mild, about 1% of cases can lead to serious neurological complications, especially in the elderly or those with weakened immune systems.

Symptoms and fatalities reported

Among the 195 infected individuals, 160 showed symptoms, with 76 of those cases involving neurological complications. Six deaths were reported, though SPF noted that the data available do not confirm that the virus was the direct cause of these fatalities.

Climate change linked to virus spread

The spread of West Nile virus is associated with climate change, which has allowed the virus to move northward across Europe. Previously concentrated around the Mediterranean, the virus is now transmitted by Culex mosquitoes that have bitten infected birds and then bite humans.

New records in Europe

The European Centre for Disease Prevention and Control (ECDC) reported that 2026 is a record year for West Nile virus in Europe, with over 1,900 cases across 19 countries. Italy and Greece have been the most affected, while in mainland France, chikungunya and dengue, spread by tiger mosquitoes, have led to 190 locally acquired cases since May.

Call for improved awareness and monitoring

Étienne Pot, director general of SPF, stressed the importance of closely monitoring these diseases and re-educating healthcare professionals about new mosquito-borne illnesses. He noted that he was not taught about West Nile virus during his medical training, highlighting a growing need for updated knowledge in the medical field.