An unprecedented case in France. French public health announced in its bulletin this Thursday the detection this year of the first local case of West Nile virus (also known as West Nile virus) in mainland France. The patient was infected in the Eastern Pyrenees, in Occitania.
West Nile virus is not carried by the tiger mosquito (Aedes albopictus), which transmits chikungunya, dengue and Zika virus, but by Culex mosquitoes, known as “common mosquitoes.” The latter bites after infecting infected birds before transmitting the virus to humans. The common mosquito bites mainly in the evening and at night, while the tiger mosquito is active during the day.
Apparently expanding circulation of West Nile virus.
This case of West Nile virus is part of a major trend. In 2025, 62 local human cases were identified in six regions of mainland France, including three historically affected cases (PACA, New Aquitaine, Occitanie) and three new cases: Ile-de-France, Auvergne-Rhône-Alpes and Normandy, confirming the continued spread of the virus to the west and north of the country. On a European scale, the trend is similar, with more than 1,400 human cases reported in 19 countries in 2024, with Italy and Greece hit hardest.
The same French public health bulletin provides information on other arboviruses transmitted by tiger mosquitoes. Between 1 May and Sunday 12 July, 69 imported cases of chikungunya, 215 cases of dengue and 9 cases of Zika were reported, with no locally acquired cases at this stage. However, last year France experienced an unprecedented outbreak, with 809 local cases of chikungunya reported during the season. In most cases, the infection remains asymptomatic or results in a flu-like illness. Santé Publique France reminds you of preventive measures: clothing coverings, repellents, mosquito nets, diffusers, etc. with, depending on the local situation, targeted measures against larvae and adult mosquitoes.