Santé publique France reported on October 5 that there have been 161 cases of infection with the West Nile virus in metropolitan France this year, including 133 individuals who showed symptoms, of whom 60 developed neurological complications. Five deaths have been reported, although it has not yet been confirmed that the virus directly caused them. The West Nile virus is transmitted by the Culex mosquito, which typically bites infected birds and then transmits the virus to humans. This year, the number of cases is nearly triple that of 2025, according to Santé publique France (SPF). Among the 161 infected individuals, five people have died, with the majority being elderly individuals who often had other health conditions. SPF cautioned that linking these deaths directly to the virus requires careful medical evaluation, which can take time. In 2025, the West Nile virus caused five deaths in France among the 62 cases reported from early May to the end of November. Last week, a regional report noted three deaths in the Île-de-France region, involving individuals aged 49, 73, and 88, who developed "neuroinvasive forms" of the infection. Two additional deaths were recorded in two different regions, though no further details were provided. The virus, once primarily found around the Mediterranean, has been spreading across Europe. This year, several regions, including Provence-Alpes-Côte d'Azur, Occitanie, Île-de-France, and others, have been affected, with 13 departments experiencing their first cases. The West Nile virus is typically transmitted when a Culex mosquito bites an infected bird and then bites a human. Most infections are asymptomatic or cause mild flu-like symptoms, but in rare cases—about 1 percent—the virus can lead to serious neurological complications, which can be fatal, especially among the elderly or those with weakened immune systems. There is currently no commercial vaccine or preventive treatment available for humans. Since the start of the mosquito season up to the end of September, nearly 1,800 cases of West Nile virus have been detected in 16 European countries, according to the European Centre for Disease Prevention and Control (ECDC). Italy has been the most affected, with 721 cases, followed by Greece, Spain, and France. In metropolitan France, the virus has been one of several mosquito-borne illnesses, including Chikungunya, dengue, and Zika, that have been monitored closely this year. The West Nile virus has been classified as a notifiable disease in France since June 2021.