West Nile virus cases in France, Digi Mart USA News: The West Nile virus is becoming established in France. As autumn arrives in mainland France, the number of cases continues to climb, according to a new bulletin from Santé publique France (SpF).
As of November 2, 212 locally acquired infections had been identified in mainland France, 11 more than the previous week, according to the weekly bulletin on enhanced surveillance of arboviruses. Cases were detected in the regions of Provence-Alpes-Côte d’Azur (3 departments), Occitanie (7), Île-de-France (7), Auvergne-Rhône-Alpes (5), Nouvelle-Aquitaine (2), Pays de la Loire (4), Centre-Val de Loire (Loiret department) and Corsica (2).
For 20 cases, no precise place of contamination could be identified, SpF said.
The total number of people infected this year is more than triple the full-year 2025 total, which was already a record with 62 locally acquired cases. The infection is transmitted by the common mosquito Culex, with cases counted from early May to late November.
After a peak in circulation during the last two weeks of August and the first week of September, the outbreak has been in a declining phase.
Of the 212 patients infected so far, 177 showed symptoms. Among them, 82 had neuro-invasive forms, and six died, SpF said, while noting that the data available at this stage do not allow those deaths to be attributed with certainty to the virus.
Generally asymptomatic or causing flu-like illness, the infection can lead in about 1% of cases to serious neurological complications, sometimes fatal, especially in older or immunocompromised people. There is currently no commercially available vaccine for humans and no preventive treatment.
Circulation of the West Nile virus, long concentrated around the Mediterranean arc, continues to spread across the country, driven by climate change and other environmental changes that favor the proliferation of mosquito vectors. This year, locally acquired human cases were detected for the first time in 16 mainland departments: Aude, Tarn, Hauts-de-Seine, Seine-et-Marne, Yvelines, Drôme, Rhône, Isère, Ain, Allier, Loire-Atlantique, Maine-et-Loire, Vendée, Mayenne, Loiret and Deux-Sèvres.
“2026 has been an exceptional year for West Nile,” said Florian Franke, an epidemiologist at Santé publique France, at a press conference organized by ANRS-MIE, noting that the “explosion of cases” is affecting many European countries. Since the start of the mosquito season, more than 2,000 cases have been detected in twenty European countries, led by Italy (780 cases) and Greece (463 cases), according to the latest figures from the European Centre for Disease Prevention and Control (ECDC).
“The epidemiology of this virus is very unpredictable and constantly evolving,” Franke said. “It is difficult to say what will happen in 2027, but the trend over recent years is toward increasing circulation,” and “it will certainly not get better.”
