Full genome analysis of circulating DENV-2 in Senegal reveals a regional diversification into separate clades

To assess the genetic diversity of circulating dengue virus 2 (DENV-2) in Senegal, we analyzed nine newly generated complete genomes of strains isolated during the 2018 outbreaks and 06 sequences obtained in 2018 and 2019 from Thies and Rosso, respectively. Phylogenetic analyses revealed that Senegalese strains belonged to the cosmopolitan genotype of DENV-2, but we observed intragenotype variability leading to a divergence in two clades associated with specific geographic distribution. We report two DENV-2 variants belonging to two distinct clades. Isolates from the Northern Glade (n = 8) harbored three nonsynonymous mutations (V1183M, R1405K, P2266T) located respectively on NS2A, NS2B, and NS4A, while isolates from the Western Glade (n = 7) had two nonsynonymous mutations (V1185E, V3214E) located respectively in the NS2A and NS5 genes. These findings call for phylogeographic analysis to investigate routes of introductions, dispersal patterns, and in-depth in vitro and functional study to elucidate the impact of observed mutations on viral fitness, spread, epidemiology, and pathology.

Automated summary

This study assessed the genetic diversity of circulating dengue virus 2 (DENV-2) in Senegal and identified two distinct clades with nonsynonymous mutations in different genes. These findings are important for further understanding the transmission and impact of the virus.