Key Points

Dengue, Chikungunya, and Zika

• While the chikungunya outbreaks in Réunion and the dengue outbreaks in the French West Indies continue to impact surveillance in mainland France, the decline in viral circulation in these territories—particularly in Réunion—is reflected in the number of imported cases reported in recent days.

• In Corsica, since May 1, 2 imported cases of dengue (+2 cases compared to last week) and 3 imported cases of chikungunya (+2 cases compared to last week) have been confirmed.

West Nile

• No indigenous cases have been detected in the region, or more broadly in mainland France, since the start of the enhanced surveillance period (May 1).

• A look back at 2024:

  • significant circulation in mainland France, with a number of human cases similar to that of 2023 but with a different geographical distribution (Nouvelle-Aquitaine in 2023 and Provence-Alpes-Côte d’Azur in 2024);

  • significant circulation in Europe as well, with lower intensity than in 2018, but with a record number of affected regions.

Pollen exposure, which may pose an allergy risk

• In Corsica, the pollen index, established by Atmo France and accredited air quality monitoring associations, is at a very high level, primarily due to grass pollen. Allergy-related activity at SOS Médecins clinics is high.