Phylogenetic studies reveal existence of multiple lineages of a single genotype of DENV-1 (genotype III) in India during 1956–2007

Background Dengue virus type 1 (DENV-1) have been mostly circulating silently with dominant serotypes DENV-2 and DENV-3 in India. However recent times have marked an increase in DENV-1 circulation in yearly outbreaks. Many studies have not been carried out on this virus type, leaving a lacunae pertaining to the circulating genotypes, since its earliest report in India. In the present study, we sequenced CprM gene junction of 13 DENV-1 isolated from Delhi and Gwalior (North India) between 2001–2007 and one 1956 Vellore isolate as reference. For comparison, we retrieved 11 other Indian and 70 global reference sequences from NCBI database, making sure that Indian and global isolates from all decades are available for comparative analysis.