Molecular characterization and recent spread of dengue virus type 3 lineage III_B.3.2 in Brazil: in silico analysis of protein motifs and epidemiology
摘要
The dengue virus (DENV) belongs to the Flaviviridae family and is responsible for a febrile arbovirus disease of global relevance. In Brazil, there has been endemic circulation of the four viral serotypes since the last century, with DENV-3 being frequently associated with more severe clinical conditions and major epidemics. This study aimed to perform the motif characterization of DENV-3 strains circulating in Brazil and its epidemiology. We obtained cases information by serotype from DATASUS/TABNET from 2013 to 2025. Furthermore, 184 complete genomes of Brazilian samples available in the GenBank and GISAID databases were analyzed with the genome reference sequence of DENV-3 (NC_001475.2). The sequences were edited and analyzed with the MAFFT, BioEdit, Nextclade, and GeneDoc software to identify lineages and amino acid motifs and were subsequently submitted to phylogenetic analyses in the IQ-Tree and FigTree programs. The results indicated a historical predominance of serotype one, but with a considerable increase in DENV-2 and DENV-3 cases in 2024 compared to the previous year. By December 2025, DENV-3 cases had already surpassed those of DENV-1 for that year. Nine amino acid motifs were identified throughout the genome, especially sites of N-myristoylation, casein kinase II phosphorylation, protein kinase C phosphorylation, and N-glycosylation. The predominant lineages were 3III_C.2 and 3III_C.2.2 until 2022, when lineage 3III_B.3.2 was introduced in Brazil, being associated with the increase in cases. This genotype presented substitutions and the absence of protein motifs compared to previous lineages, suggesting that such alterations contributed to its replicative success.