A new human case of infection by a virus transmitted by mosquitoes has just been confirmed in the middle of summer 2026 in Occitania, while France is already monitoring dengue, chikungunya and Zika. In its bulletin of July 16, Public Health France reported a first case contracted locally in a tourist department in the south.
This is the
West Nile virusalso called West Nile virus, transmitted by mosquitoes Culex. Public Health France specifies: “As of July 16, 2026, one indigenous case of West Nile virus infection has been identified in the
Pyrenees-Orientales (Occitanie). This is the first detection of the circulation of the virus in humans in France, in 2026“. The first signs in this person date from June 30.
First indigenous case of West Nile virus 2026 in the Pyrénées-Orientales
In its bulletin on arboviruses, Public Health France indicates: “As of July 15, 2026, an indigenous case of West Nile virus infection, transmitted by mosquitoes of the Culex genus, was identified in mainland France.“. Indigenous means that the person from the Pyrénées-Orientales did not travel to an area where the virus circulated in the days preceding the illness: the contamination occurred locally.
This department had already experienced episodes linked to West Nile, with equine cases in 2006 then a human case in 2018, recall the authorities. For the moment, no other patient is associated with the 2026 episode. Dr. Vincent Ronin emphasizes that a human infection in West Nile does not cause a chain of contamination between people, with humans remaining an accidental host.
West Nile virus: Culex mosquitoes and symptoms to watch out for
The transmission cycle of West Nile virus relies on birds. The Pasteur Institute reminds that “The main reservoir of West Nile virus is migratory birds.“. Public Health France summarizes the role of the Culex mosquito: “The mosquito becomes infected by feeding on infected birds, then transmits the virus to its other prey“. Humans and horses are bitten by an already infected mosquito, without then transmitting the virus.
According to Public Health France, “80% of infected people remain asymptomatic or minimally symptomatic“. The others mainly present with a flu-like syndrome: sudden fever, headaches, aches, sometimes a rash. Dr. Vincent Ronin estimates that around 1% of infections progress to neurological damage and recalls that, among the 62 cases recorded in France in 2025, 20 were neurological and 5 resulted in death. He insists on protection against mosquitoes and rapid consultation of the doctor in the event of symptoms.
West Nile in France: increase in cases and organized surveillance
Dr Vincent Ronin observes that France has gone from very episodic cases to an increasing number of human infections, with around forty cases in 2023-2024 then 62 cases in 2025, the year when indigenous cases were detected in Ile-de-France. To avoid serious forms and secure products of human origin, West Nile virus infections are subject to mandatory reporting and reinforced surveillance between May 1 and November 30, in a “One Health” approach bringing together doctors, veterinarians and entomologists.