Key Points

Chikungunya, dengue, and Zika

• As of August 5, 2025, 21 outbreaks of local transmission have been identified in mainland France (+2 compared to S30): 16 of chikungunya (63 cases in total) and 5 of dengue (9 cases). These outbreaks are located in the following regions: PACA, Corsica, Occitanie, ARA, Grand Est, and Nouvelle-Aquitaine (in the latter two regions, this marks the first identified indigenous transmission of an arbovirus).

• No local transmission in Île-de-France in 2025, at this stage.

West Nile virus infections

• One confirmed case of indigenous West Nile virus infection has been detected. Based on the epidemiological (human and animal components) and entomological data available to date, it is impossible to determine the location where the infection occurred among the three departments visited during the exposure period: Jura (Burgundy-Franche-Comté), Seine-Saint-Denis (Île-de-France), and Val-d’Oise (Île-de-France). For both regions, this would be the first detection of a locally transmitted case of West Nile virus.

COVID-19

• Decrease in SOS Médecins calls for suspected COVID-19 and increase in emergency room visits.

• Cases remained low.

Asthma

• The summer vacation period corresponds to the time when the risk of asthma exacerbation is lowest. Long-term treatment for asthma patients is sometimes discontinued during the summer at the initiative of the doctor or the family, with instructions given to parents to resume it before school starts. It is important to resume long-term treatment at least 8 days before school starts, to ensure a back-to-school period free of asthma.