Genomic variants and molecular epidemiological characteristics of dengue virus in China revealed by genome-wide analysis.

Since its first academic record in 1978, dengue epidemics have occurred in all provinces of China, except Xizang. The epidemiological and molecular features of the whole genome of dengue virus (DENV) have not yet been completely elucidated, interfering with prevention and control strategies for dengue fever in China. Here, we obtained 553 complete genomes of the four serotypes of DENV (DENV1-4) isolated in China from the GenBank database to analyze the phylogeny, recombination, genomic variants, and selection pressure and to estimate the substitution rates of DENV genomes. Phylogenetic analyses indicated that DENV sequences from China did not cluster together and were genetically closer to those from Southeast Asian countries in the maximum likelihood trees, indicating that DENV was not endemic in China. Thirty intra-serotype recombinant sequences were identified for DENV1-4, with the highest frequency in DENV4. Selection pressure analyses revealed that 13 codons under positive selection were located in the C, NS1, NS2A, NS3, and NS5 proteins. For DENV1 to DENV3, the substitution rates evaluated in this study were 9.23 × 10^-4, 7.59 × 10^-4, and 7.06 × 10^-4 substitutions per site per year, respectively. These findings improve our understanding of the evolution of DENV in China.