Chikungunya Epidemic on La Reunion Island

Reunion Island, a French department located in the Indian Ocean, has just experienced, during the year 2025, a major chikungunya epidemic, with more than 54,500 cases recorded, requiring 554 hospitalizations, including 153 serious cases resulting in the 45 deaths. Severe cases were more frequent in young children and the elderly with longer hospital stays in patients over 65 years of age. The cause of death was primarily cardiac and respiratory failure. Chikungunya is a tropical arboviral disease caused by an RNA virus transmitted by Aedes mosquitoes. The reservoirs are monkeys and certain mammals, in humans, the disease manifests itself after a few days of incubation with a flu-like syndrome: high fever, intense arthralgia, myalgia, headache, and maculopapular rash. The progression can be rapid and favorable within a week or become chronic with persistent arthralgia lasting several months or years. Neurological and cardiac complications are possible. The mortality rate is low (1/1000). Diagnosis is confirmed by virus testing in the first week and then by serology. Prevention is based on mosquito control and vaccination.