Genotypic characterization of dengue virus strains circulating during 2007-2009 in New Delhi.

Dengue is an important arboviral disease of tropical and subtropical regions, with significant morbidity and mortality. Dengue virus is antigenically classified into four serotypes, which are further classified into 4-5 genotypes based on their genetic diversity. Since genotypes vary in their virulence, their detection and analysis of spatial and temporal transition are essential. We utilized sequence information from the E-NS1 gene region for molecular and phylogenetic characterization of dengue viruses isolated from dengue patients between 2007 and 2009. All four serotypes and multiple genotypes were detected, with predominance and emergence of DENV-1 genotype V. Phylogenetic analysis revealed the emergence of DENV-1 genotype V from India for the first time, which has replaced the earlier circulating genotype III and genotype I. The circulation of multiple genotypes and genotype replacement is critical, since genotypes vary in their virulence, and this should be a point of concern for healthcare agencies.