Southwest France steps up mosquito control following 20 chikungunya cases

The chikungunya cases are described as “autochthonous”, meaning the virus was contracted in France rather than brought back by someone from abroad.

The largest-known outbreak of 16 cases is in Prignac-et-Marcamps, north of Bordeaux, where authorities have carried out insecticide treatments in parks and gardens.

They are also removing stagnant water where the invasive tiger mosquito lays its eggs.

France ramps up fight against tiger mosquitoes after record outbreaks

Ideal conditions

Thetiger mosquito, known scientifically as Aedes albopictus, is originally from Southeast Asia and can transmit chikungunya as well as dengue and Zika.

First detected in mainland France in 2004, it is now present across most of the country. The first locally acquired chikungunya case in Gironde was detected in summer 2025, in a five-year-old child. 

The mosquito's advance has been fuelled by warmer summers, urbanisation and increased international travel, which together create ideal conditions for both the insect and the viruses it can transmit.

Health authorities have been urging residents to remove stagnant water from gardens, balconies and around their homes, as even small amounts of water can become breeding sites.

Similar prevention measures have been introduced in the east of the Tarn department after two chikungunya cases were detected, following a case reported at the start of August.

What if we killed all mosquitoes?

Door-to-door visits

In Haute-Garonne, the towns of Cugnaux, Seysses and Brax, near Toulouse, were treated overnight on 10 August following several reports of cases.

The Regional Health Agency of Nouvelle-Aquitaine has stressed the importance of investigating confirmed infections.

“As soon as a confirmed case of dengue or chikungunya is reported, an epidemiological investigation is launched,” it said in a statement.

It added that health teams are carrying out field investigations, including door-to-door visits, in affected neighbourhoods in order to identify other cases and raise awareness on preventing mosquito bites to limit the spread of the diseases.

Residents have been advised to seek medical attention promptly if they develop symptoms, which include a high fever, joint or muscle pain, fatigue, headaches or a skin rash.