France: 6 additional locally transmitted chikungunya cases reported, Brings total to 8
In a follow-up on the indigenous chikungunya cases on mainland France, health authorities report six episodes of indigenous chikungunya transmission were identified in four regions- Provence-Alpes-Côte d'Azur, Corsica, Occitanie, and Auvergne-Rhône-Alpes, already affected by episodes of indigenous transmission in previous years.
These indigenous cases, whose first symptoms appeared between May 27 and June 19, are the earliest ever identified in mainland France.
In 2024, a record year for dengue fever episodes, only one case was identified in June (onset of symptoms on June 17, in the Occitanie region). In 2023, the first episode occurred in July (onset of symptoms on July 18), in the Provence-Alpes-Côte d'Azur region.
Such an early start to the mosquito's active season and such a high number of outbreaks have never been observed before.
Although declining, the number of chikungunya cases with travel to Réunion Island and the Indian Ocean remains high and contributes to the early onset of indigenous transmission, especially since the strain of chikungunya virus circulating in Réunion Island is well adapted to the Aedes albopictus mosquito.
Investigations are ongoing, with, to date, the identification of viremic cases from Réunion Island, likely the source of local transmission, for at least two indigenous cases. These data are likely to change as investigations continue.