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Genetic signatures coupled with lineage shift characterise endemic evolution of Dengue virus serotype 2 during 2015 outbreak in Delhi, India
Author(s) -
Choudhary Manish Chandra,
Gupta Ekta,
Sharma Shvetank,
Hasnain Nadeem,
Agarwala Pragya
Publication year - 2017
Publication title -
tropical medicine and international health
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.056
H-Index - 114
eISSN - 1365-3156
pISSN - 1360-2276
DOI - 10.1111/tmi.12898
Subject(s) - biology , lineage (genetic) , phylogenetic tree , dengue virus , virology , monophyly , serotype , molecular epidemiology , phylogenetics , genotype , dengue fever , outbreak , genetics , gene , clade
Objective In 2015, New Delhi witnessed a massive outbreak of Dengue virus ( DENV ) resulting in high morbidity and mortality. We report the molecular characterisation of the dominant circulating DENV strain to understand its evolution and dispersal. Materials and methods DENV infections were diagnosed by detection of IgM/ NS 1 antigen, and serotyping was performed by C‐PrM PCR . Envelope gene was amplified, and variation(s) in envelope gene were analysed. Phylogenetic tree construction, time‐based phylogeny and origin of DENV were analysed. Site‐specific selection pressure of envelope gene variants was analysed. Results Confirmed DENV infection was observed in 11.34% (32 of 282) cases, while PCR positivity for C‐PrM region was observed in 54.16% (13 of 24) of NS 1 antigen‐positive cases. All samples belonged to serotype 2 and cosmopolitan genotype. Phylogenetic analysis using envelope gene revealed segregation of cosmopolitan genotype strains into specific lineages. The Indian strains clustered separately forming a distinct monophyletic lineage (lineage III ) with a signature amino acid substitution viz., I162V and R288K. Selection pressure analysis revealed that 215D, 288R and 304K were positively selected sites. The rate of nucleotide substitution was 6.93 × 10 −4 substitutions site‐1 year‐1 with time to most common ancestor was around 10 years with JX 475906 (Hyderabad strain) and JN 030345 (Singapore strain) as its most probable ancestor. Conclusion We observed evolution of a distinct lineage of DENV ‐2 strains on the Indian subcontinent with possible changes in endemic circulating dengue strains that might give rise to more pathogenic strains.