Evolutionary and phylodynamic analyses of Dengue virus serotype I in Guangdong Province, China, between 1985 and 2015.

To determine the evolutionary and phylodynamic history of DENV-1 in Guangdong, the strains detected between 1985 and 2015 were determined with phylogenetic and Bayesian analyses of the E gene. Three DENV-1 genotypes (I, V, and VI) were circulating in Guangdong, and genotype I was detected most frequently. The evolutionary rate of DENV-1 was estimated to be 1.03 × 10-3 nucleotide substitutions/site/year. The most recent ancestor of the viruses existed approximately 141 years ago. The observed epidemiological dynamics correlated with similar fluctuations in diversity, and the epidemiological dynamics of DENV-1 transmission reflect dramatic changes in the viral population sizes. Two recombination events were identified in those strains. The selection pressures were estimated and revealed an abundance of negatively selected sites but few positively selected sites. These data improve our understanding of the evolution and molecular epidemiology of DENV-1 and provide insights that will facilitate the surveillance and control of DENV-1.