A EVOLUÇÃO DO VÍRUS CHIKUNGUNYA: DIVERSIDADE GENÔMICA E ESTRUTURA FILOGENÉTICA REVELAM ASSINATURAS ESPECÍFICAS ENTRE GENÓTIPOS

Abstract

Chikungunya virus (family Togaviridae) is an emerging arbovirus whose global expansion has been driven by genetic adaptations and the wide distribution of its vectors, mainly Aedes aegypti and Aedes albopictus. Its high dispersal capacity, coupled with environmental changes and increased human mobility, has favored the introduction and establishment of different virus genotypes in various regions of the world, including Brazil. In this study, 1,082 complete CHIKV genomes obtained from NCBI were analyzed to characterize the global genetic diversity of the virus and understand the evolutionary relationships between the main genotypes. The sequences were aligned using a phylogenetic tree constructed using the Maximum Likelihood method, followed by visualization. Additionally, geographic dispersion maps, haplotype networks using the Median-Joining method, and homology matrices were created to assess lineage similarity. The results revealed the presence of the West African, Asian, Asian-American, ECSA1, ECSA2, and IOL genotypes, evidencing different levels of internal diversity and distinct dispersal patterns. The ECSA2 genotype, predominant in Brazil since 2014, demonstrated low variability and strong adaptation to the A. aegypti vector, explaining its epidemiological success in the country. On the other hand, the IOL genotype showed greater diversity and signs of rapid expansion associated with adaptive mutations to A. albopictus. The integrated analysis of phylogenetic, phylogeographic, and homology data reinforces the African origin of CHIKV and highlights the influence of environmental and vectorial pressures on viral evolution. These findings underscore the importance of continuous genomic surveillance to understand the dynamics of CHIKV dispersal and to support strategies for monitoring and preventing outbreaks.