Evolutionary Analysis of Dengue Serotype 2 Viruses Using Phylogenetic and Bayesian Methods from New Delhi,India

Dengue fever is the most important arboviral disease in the tropical and sub-tropical countries of the world. delhi,the metropolitan capital state of india,has reported many dengue outbreaks,with the last outbreak occurring in 2013. we have recently reported predominance of dengue virus serotype 2 during 2011–2014 in delhi. in the present study,we report molecular characterization and evolutionary analysis of dengue serotype 2 viruses which were detected in 2011–2014 in delhi. envelope genes of 42 denv-2 strains were sequenced in the study. all denv-2 strains grouped within the cosmopolitan genotype and further clustered into three lineages; lineage i,ii and iii. lineage iii replaced lineage i during dengue fever outbreak of 2013. further,a novel mutation thr404ile was detected in the stem region of the envelope protein of a single denv-2 strain in 2014. nucleotide substitution rate and time to the most recent common ancestor were determined by molecular clock analysis using bayesian methods. a change in effective population size of indian denv-2 viruses was investigated through bayesian skyline plot. the study will be a vital road map for investigation of epidemiology and evolutionary pattern of dengue viruses in india. © 2016 afreen et al.