Key Points

• Chikungunya has entered the epidemic phase in Mayotte (Phase 3 of the ORSEC arbovirus plan) since May 27, reflecting intense and widespread transmission of the chikungunya virus throughout the territory;

• A total of 746 confirmed cases of chikungunya were recorded between S10 and S22-2025. The epidemic continues to spread;

• Chikungunya continues to circulate throughout the territory, particularly in the municipalities of Mamoudzou, Pamandzi, and Dzaoudzi;

• A possible underestimation due to the lack of systematic use of biological confirmation tests for chikungunya in emergency departments and private practice, as well as limited access to care among part of the population;

• Four new cases of dengue confirmed in S22, bringing the total number of cases in 2025 to 25, with no clear upward trend.