Key Points

• Mayotte has remained in the epidemic phase of chikungunya since May 27, 2025;

• a total of 969 confirmed cases of chikungunya were recorded between weeks 10 and 24 of 2025;

• chikungunya transmission remains active throughout the territory, with high intensity particularly in several municipalities outside the main epidemic hotspots of Mamoudzou, Pamandzi, and Dzaoudzi, which had previously been less affected;

• the epidemiological situation may be underestimated due to the lack of systematic use of confirmatory biological tests in private practice and emergency departments, as well as limited access to care for part of the population;

• One case of dengue was confirmed in week 24, bringing the total number of cases reported in 2025 to 27. At this stage, there is no evidence to suggest a significant resurgence in viral circulation;

• The current situation warrants the strengthening of vector control measures, particularly in municipalities outside of historical hotspots, as well as targeted actions to reduce larval breeding sites and raise public awareness to limit mosquito proliferation;

• The next epidemiological bulletin on arboviruses will be published in two weeks.