Global Transmission and Evolution of Chikungunya Virus: Origins, Adaptive Mutations, and Intercontinental Spread of...

Chikungunya virus (CHIKV) is an arthropod-borne virus that has caused several major outbreaks around the world and is becoming increasingly harmful. Although significant progress has been made in understanding the global epidemiology and transmission of CHIKV, a systematic description of the transmission history of its three genotypes is still lacking. To address this gap, this study integrates multiple bioinformatics approaches to explore their origin, evolution, and transmission dynamics. We analyzed publicly available CHIKV genomes from NCBI to elucidate the genetic evolution and transmission potential of these genotypes. Phylogeographic and molecular evolutionary analyses showed that the West African (WA) genotype originated in Nigeria and spread exclusively within Africa; the Eastern/Central/South African (ECSA) genotype originated in Tanzania and spread globally; and the Asian genotype originated in Thailand, spread throughout Asia, Oceania, and the Americas, exhibiting the highest evolutionary rate among the three genotypes. We also identified 15 positively selected sites and 10 nonconservative mutation sites with altered hydrophobicity across CHIKV proteins, all of which need further investigation into their effects on viral protein function. The data from this study are important for understanding the transmission history of the three genotypes of CHIKV, providing new targets for CHIKV antiviral therapy and ideas for developing effective prevention and control measures in the future.