Key Points

• A total of 176 confirmed cases of chikungunya were recorded between weeks 10 and 19 of 2025, including 101 locally acquired cases, 32 imported cases, and 43 cases of unknown status;

• A steady increase in the number of detected cases since week 10, with a sharp rise since week 15;

• Chikungunya cases have been detected in 15 of Mayotte’s 17 municipalities, with a higher concentration in the municipalities of Mamoudzou, Pamandzi, Dzaoudzi, and Koungou;

• Transition to Phase 2B of the ORSEC plan due to the intensification of the circulation of locally acquired chikungunya cases: several management and surveillance measures will be implemented to curb this trend and better prepare for a potential epidemic phase.

• Dengue transmission remains low on the island, with 10 confirmed cases since the beginning of the year, including 3 in week 17 and one in week 19.