Molecular Investigation of 2013 Dengue Fever Outbreak from Delhi, India

Dengue fever is a self-limiting, acute febrile disease which may aggravate to haemorrhage, plasma leakage and organ impairment in small number of cases. An outbreak of dengue fever occurred in Delhi, India after rainy season in the year 2013. Dengue virus specific RT-PCR was carried out on 378 suspected blood samples that were collected during the outbreak. Dengue virus was detected in 71% samples with highest number of patients infected by DENV-2 (86%) followed by DENV-1 (19 %) and DENV-3 (8%). Co-infection with more than one DENV serotype was detected in 14% samples. Twenty nine DENV strains (10 DENV-1, 12 DENV-2 and 7 DENV-3) were sequenced for partial envelope protein gene. Phylogenetic analysis grouped DENV-1 strains in the American African genotype, DENV-2 strains in the Cosmopolitan genotype and DENV-3 in Genotype III. We report the serotype distribution, circulating genotypes and partial envelope protein gene sequence of 29 DENV strains detected during 2013 outbreak in Delhi, India.