Tracing the Dispersal Pathway of HIV-1 Subtype C to Bahia: Phylogenetic Connections to Southern Brazil

The HIV-1 epidemic in Brazil is predominantly characterized by subtype B, except in the southern states, where subtype C (HIV-1C) is more prevalent. Continuous monitoring of this profile is essential to maintain an accurate understanding of the molecular landscape of the HIV epidemic in Brazil. In this study, we isolated and sequenced seven new HIV-1C strains from the state of Bahia, located in the Northeast region of Brazil. To reconstruct the phylogenetic history of HIV-1C in the Northeast and investigate its connections with other regions of the country and globally, we first compiled a dataset of 3631 HIV-1C sequences from Brazil, Africa, and Europe. As expected, most of the new HIV-1C sequences from Bahia (n = 6) clustered within the well-known Brazilian clade. However, one sequence from Bahia clustered within the African clade, suggesting a possible new introduction of HIV-1C into Brazil. Furthermore, our findings indicate that the HIV-1C cases in Bahia likely originated from southern states, particularly Santa Catarina. This study provides valuable insights into the molecular profile of the HIV epidemic in Brazil, expanding our understanding of HIV-1C beyond the Southern region.