France: 6 indigenous Chikungunya cases in 2024

In a recent follow-up analysis, French health authorities reported six cases of autochthonous chikungunya transmission in four mainland regions in 2024: Provence-Alpes-Côte d’Azur, Corsica, Occitanie and Auvergne-Rhône-Alpes. These regions have experienced similar outbreaks in previous years. Of these new cases, which presented symptoms between May 27 and June 19, the first case of locally transmitted chikungunya in mainland France was recorded. In 2023, the first such case occurred in mid-July. So far in 2024, only one locally transmitted dengue case has been reported in Occitanie. The health authorities have noted that the early start to the mosquito season and the large number of chikungunya outbreaks are both unprecedented. Although travel-related chikungunya cases overall are declining, the number of infections linked to Réunion Island and the Indian Ocean region remains significant. This ongoing importation is thought to have contributed to early local transmission in France. Of particular concern is the Réunion Island strain of the chikungunya virus, which is well adapted to the Aedes albopictus mosquito — the primary vector in France. Ongoing investigations have linked at least two indigenous cases to travellers from Réunion who were infected with the virus, and further updates are expected as the investigations continue.