Genomic insights into the re-emergence of chikungunya virus on Réunion Island, France, 2024 to 2025

Published on 5 June 2025 Updated on 2 July 2025

Chikungunya virus re-emerged on Réunion Island in August 2024, 18 years after a first major outbreak. Analysis of 173 genomes from the current epidemic reveals a monophyletic clade with mutations linked to adaptation to Aedes albopictus mosquitoes, including E1-A226V. Bayesian inference suggests only brief cryptic circulation before detection. The same lineage was also detected on Mayotte Island in March 2025. Continued spread and confirmed travel-related cases in mainland France and globally highlight the risk of wider regional and international dissemination.

Author(s): Frumence Etienne, Piorkowski Géraldine, Traversier Nicolas, Amaral Rayane, Vincent Muriel, Mercier Ambroise, Ayhan Nazli, Souply Laurent, Pezzi Laura, Lier Clément, Grard Gilda, Durand Guillaume André, Deparis Xavier, Thouillot Fabian, de Lamballerie Xavier, Klitting Raphaelle, Jaffar-Bandjee Marie-Christine

Publishing year: 2025

Pages: 2-7