New Dengue Virus Type 1 Genotype in Colombo, Sri Lanka
Figure. Phylogenetic tree of dengue virus 1 (DENV-1) serotype viruses from Sri Lanka (SL), 2009–2010, and other DENV-1 viruses. The tree is based on a 498-bp (nt 2056–2554) fragment that encodes portions of the envelope protein and nonstructural protein 1. Phylogenetic analysis was conducted by using MEGA5 (10). Percentages of replicate trees in which the associated taxa clustered in the bootstrap test (1,000 replicates) are shown next to the branches. Genotype I (Asia) includes SL isolates from 2009–2010; genotype III (South Pacific) includes SL isolates from the early 1980s; genotype IV (Africa/Americas) includes SL isolates from the 1990s and early 2000s. Classification and naming of DENV-1 genotypes are based on the report by Rico-Hesse (11). DV, dengue virus. Scale bar indicates nucleotide substitutions per site.