Five people have died among the 161 locally acquired cases of West Nile virus infection recorded this year in mainland France, a number of cases almost three times higher than in 2025, the national health agency announced, still cautious about the cause of these deaths.
As of October 5, among these 161 infected individuals, 133 presented symptoms, including 60 who developed neurological forms, which can lead to severe complications: among them, five people died,« mainly elderly people, often with comorbidities«" , Public Health France (SpF) told AFP on Thursday.
“ However, caution is advised regarding attributing these deaths to the infection. » by the West Nile virus, because « This is based on an individual medical assessment, carried out by the clinicians who care for the patients.«", which takes time," she says.
Neuroinvasive forms
In 2025, the West Nile virus had caused five deaths in France, out of 62 reported cases of infection from the beginning of May to the end of November.
Last week, a regional report recorded three deaths in the Ile-de-France region, of patients aged 49, 73 and 88, who developed "« neuroinvasive forms »"of infection. Two more deaths have been added, in two separate regions, SpF indicates without further details.
The circulation of the West Nile virus, long concentrated around the Mediterranean arc, continues to spread across the territory.
This year, the regions of Provence-Alpes-Côte d'Azur, Occitanie, Île-de-France, Auvergne-Rhône-Alpes, Nouvelle-Aquitaine, Pays de la Loire and Centre-Val de Loire were affected - within which 13 departments were affected for the first time.
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No vaccine or preventative treatment
West Nile virus is transmitted to humans by Culex mosquitoes that have fed on the blood of an infected bird.
Although this infection is usually asymptomatic or causes flu-like symptoms, in rare cases (approximately 1%) it can lead to serious neurological complications, sometimes fatal, especially in elderly or immunocompromised individuals.
There is currently no commercially available vaccine for humans, nor any preventive treatment.
From the start of the mosquito season until the end of September, nearly 1,800 locally acquired human cases of West Nile virus have been detected in 16 European countries, according to the European Centre for Disease Prevention and Control (ECDC).
Italy is the most affected country (721), ahead of Greece (420), Spain (131) and France (128) in a 2026 that is already a record year.
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