Chikungunya in French Guiana: Sustained Increase in Cases and Expansion of the Outbreak in 2026. French Guiana continues to experience active circulation of the chikungunya virus throughout 2026. From January to May 7, 249 locally acquired cases have been confirmed, with a clear acceleration of transmission in recent weeks. In epidemiological week 18 alone, 40 new cases were reported, following 61 in week 17, 33 in week 16, and 15 in week 15. The majority of cases (198; 80%) are concentrated in the Littoral Ouest sector, in western French Guiana near the border with Suriname.
Health authorities declared this area to be in an epidemic phase on April 23, the highest level of alert within the local surveillance system. Furthermore, level 3 of the ORSEC plan for arbovirus control has been activated, corresponding to a low-intensity epidemic. Other areas are also showing progressive expansion of transmission. The Île de Cayenne sector is currently in the “epidemic cluster” phase, while Maroni and Savanes remain in a situation of sporadic transmission. At the moment, the Intérieur, Intérieur Est, and Oyapock regions remain in the surveillance phase with no cases detected. All cases were confirmed by RT-PCR. Genetic analysis identified a strain belonging to the ECSA (East/Central/South African) genotype, although without the E1-A226V mutation, classically associated with greater adaptation to the Aedes albopictus mosquito. The detected sequences also show a close genetic relationship with recent strains circulating in Cuba and Brazil.
The regional context is also a cause for concern. Suriname, a country bordering western French Guiana, reported 2,579 cases between January and mid-March 2016, reflecting intense regional circulation of the virus in northern South America. The ECDC notes that the rainy season in French Guiana—from January to July—significantly favors the proliferation of Aedes mosquitoes and the transmission of chikungunya. Although the risk to European travelers is currently considered low, environmental conditions in Europe are becoming progressively more favorable for vector activity and potential local transmission during the upcoming warmer months. Health authorities urge travelers to reinforce preventive measures, especially the use of insect repellent, long-sleeved clothing, accommodation with air conditioning or mosquito nets, and considering chikungunya vaccination when available and recommended based on the traveler’s country of origin. The last major chikungunya outbreak in French Guiana occurred between 2014 and 2015, when more than 16,000 suspected cases and around 500 hospitalizations were reported. Subsequent studies estimated a seroprevalence of approximately 20% of the population in 2017.
