Phylogenetic characteristics of dengue virus revealed the high relatedness

25 Background: An outbreak of dengue occurred in Yunnan province with more than 26 2,000 infected cases from August to November of the past 2013. To characterize this 27 DENV prevalence in Dehong prefecture of Yunnan and explore its origin, 28 phylogenetic and evolutionary analysis on the DENV strains collected from local 29 patients and imported travelers were performed comparatively. 30 Methods: A total of 41 dengue positive serum samples were randomly collected from 31 these dengue positive travelers who entered China at Ruili port and local dengue fever 32 patients in Dehong prefecture of Yunnan Province, China. Envelope (E) Gene of 33 DENV was amplified and sequenced. Their genotypes distribution and evolutionary 34 characteristics were elucidated clearly by phylogenetic and bayesian analysis. 35 Results: Phylogenetically, all the collected 41 dengue positive samples could be 36 classified into Genotype I (43.9%) of serotype DENV-1 and Asian I genotype (56.1%) 37 of DENV-2 serotype. The DENV strains derived from local patients and cross border 38 travelers were scattered in this two clusters equally. Furthermore, high relatedness 39 *Corresponding author: [email protected] 1 Faculty of Life Science and Technology, Center for Molecular medicine in Yunnan province, Kunming University of Science and Technology, Kunming, China; [email protected] 3 Yunnan Research Institute of parasitic disease control, Kunming, China. # Equal contributor between DENV strains from these two populations was revealed by evolutionary 40 characteristics. 41 Conclusions: These results revealed the high relatedness between imported and local 42 DENV strains during the dengue outbreak in 2013. And these may imply this local 43 dengue outbreak was caused by newly imported infection from neighboring country 44 Myanmar. 45 46 Key worlds: dengue, outbreak, Phylogenetic analysis, Bayesian analysis, imported 47 infection. 48